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Perez-Vidal, Carlos, Alejandro Garcia, Nicolas Garcia-Aracil, Jose M. Sabater, and Eduardo Fernandez. "SYSTEM FOR MEASURING RODENTS' VISUAL FUNCTION: DESIGN AND IMPLEMENTATION." Biomedical Engineering: Applications, Basis and Communications 26, no. 02 (March 12, 2014): 1450018. http://dx.doi.org/10.4015/s1016237214500185.
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The aim of the work presented in this paper is the design, manufacturing and assembling of a system able to measure rodents' (mice and rats) visual function and to study the evolution of degenerative retina diseases. Measurement of contrast sensitivity and visual acuity is essential to design new drugs and understand mechanisms of visual development to evaluate treatments' effectiveness. Classical methods to study visual perception of animals such as electroretinogram (ERG) or histological analysis are not supplying enough information because connection between eyes and brain is not considered. The system proposed in this work consists of four screens forming a cube with black methacrylate plastic floor and roof. Screens display visual stimulus and the rodent's behaviour (placed over a platform in the middle of the cube) is analized to determine its visual acuity and contrast sensitivity. These visual stimuli are generated from a FPGA board designed in this project. This board has a USB link with a computer and it controls screens via VGA signals. Rodents' behaviour is analized using computer vision algorithms under OpenCV libraries. To test the system, more than 30 mice (C57 and RD10 type) have been used to validate the hardware, the software, the procedure and protocol.
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VAN HOOSER, STEPHEN D., and SACHA B. NELSON. "The squirrel as a rodent model of the human visual system." Visual Neuroscience 23, no. 5 (September 2006): 765–78. http://dx.doi.org/10.1017/s0952523806230098.
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Over the last 50 years, studies of receptive fields in the early mammalian visual system have identified many classes of response properties in brain areas such as retina, lateral geniculate nucleus (LGN), and primary visual cortex (V1). Recently, there has been significant interest in understanding the cellular and network mechanisms that underlie these visual responses and their functional architecture. Small mammals like rodents offer many advantages for such studies, because they are appropriate for a wide variety of experimental techniques. However, the traditional rodent models, mice and rats, do not rely heavily on vision and have small visual brain areas. Squirrels are highly visual rodents that may be excellent model preparations for understanding mechanisms of function and disease in the human visual system. They use vision for navigating in their environment, predator avoidance, and foraging for food. Visual brain areas such as LGN, V1, superior colliculus, and pulvinar are particularly large and well elaborated in the squirrel, and the squirrel has several extrastriate cortical areas lateral to V1. Unlike many mammals, most squirrel species are diurnal with cone-dominated retinas, similar to the primate fovea, and have excellent dichromatic color vision that is mediated by green and blue cones. Owing to their larger size, squirrels are physiologically more robust than mice and rats under anesthesia, and some hibernating species are particularly tolerant of hypoxia that occurs during procedures such as brain slicing. Finally, many basic anatomical and physiological properties in the early visual system of squirrel have now been described, permitting investigations of cellular mechanisms. In this article, we review four decades of anatomical, behavioral, and physiological studies in squirrel and make comparisons with other species.
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Gesnik, Marc, Kevin Blaize, Thomas Deffieux, Jean-Luc Gennisson, José-Alain Sahel, Mathias Fink, Serge Picaud, and Mickaël Tanter. "3D functional ultrasound imaging of the cerebral visual system in rodents." NeuroImage 149 (April 2017): 267–74. http://dx.doi.org/10.1016/j.neuroimage.2017.01.071.
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Francescoli, Gabriel, and Carlos A. Altuna. "Vibrational Communication in Subterranean Rodents." Evolution of Communication 2, no. 2 (December 31, 1998): 217–31. http://dx.doi.org/10.1075/eoc.2.2.04fra.
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Here we discuss different factors that could influence the development of vocal and/or seismic communicative channels in subterranean rodents. We suggest that: 1) Highly social subterranean rodents that do not leave their burrows use essentially vocal signals in the vibrational channel; 2) Solitary and almost permanently fossorial species use vocal signals in short range and seismic signals in long range communication; 3) Other solitary species that leave the burrow system more frequently and that retain good visual capabilities are constrained to use vocal communication only. Also we suggest that seismic communication probably derives from digging activities and, consequently, developed after the acquisition of the subterranean way of life. The first three statements are based on a previously proposed relationship between visual capabilities, hearing capabilities, time spent outside the burrows, social organization and type of vibrational signals used by the species. The fourth statement is based in the correlation found between digging and transporting tools and thumping tools, that are the same across the literature on pertinent genera. Some thumping techniques unique to subterranean animals lead us to propose an evolutionary sequence leading from digging to thumping.
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Scholl, Benjamin, Jagruti J. Pattadkal, Ashlee Rowe, and Nicholas J. Priebe. "Functional characterization and spatial clustering of visual cortical neurons in the predatory grasshopper mouse Onychomys arenicola." Journal of Neurophysiology 117, no. 3 (March 1, 2017): 910–18. http://dx.doi.org/10.1152/jn.00779.2016.
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Mammalian neocortical circuits are functionally organized such that the selectivity of individual neurons systematically shifts across the cortical surface, forming a continuous map. Maps of the sensory space exist in cortex, such as retinotopic maps in the visual system or tonotopic maps in the auditory system, but other functional response properties also may be similarly organized. For example, many carnivores and primates possess a map for orientation selectivity in primary visual cortex (V1), whereas mice, rabbits, and the gray squirrel lack orientation maps. In this report we show that a carnivorous rodent with predatory behaviors, the grasshopper mouse ( Onychomys arenicola), lacks a canonical columnar organization of orientation preference in V1; however, neighboring neurons within 50 μm exhibit related tuning preference. Using a combination of two-photon microscopy and extracellular electrophysiology, we demonstrate that the functional organization of visual cortical neurons in the grasshopper mouse is largely the same as in the C57/BL6 laboratory mouse. We also find similarity in the selectivity for stimulus orientation, direction, and spatial frequency. Our results suggest that the properties of V1 neurons across rodent species are largely conserved. NEW & NOTEWORTHY Carnivores and primates possess a map for orientation selectivity in primary visual cortex (V1), whereas rodents and lagomorphs lack this organization. We examine, for the first time, V1 of a wild carnivorous rodent with predatory behaviors, the grasshopper mouse ( Onychomys arenicola). We demonstrate the cellular organization of V1 in the grasshopper mouse is largely the same as the C57/BL6 laboratory mouse, suggesting that V1 neuron properties across rodent species are largely conserved.
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Nadasdy, Zoltan, T. Peter Nguyen, Ágoston Török, Jason Y. Shen, Deborah E. Briggs, Pradeep N. Modur, and Robert J. Buchanan. "Context-dependent spatially periodic activity in the human entorhinal cortex." Proceedings of the National Academy of Sciences 114, no. 17 (April 10, 2017): E3516—E3525. http://dx.doi.org/10.1073/pnas.1701352114.
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The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60° rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency.
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Salzwedel, A., M. Mauck, J. Kuchenbecker, K. Mancuso, M. Wagner, C. Pawela, A. Hudetz, J. Hyde, M. Neitz, and J. Neitz. "Two S-cone pathways in the visual system that are evolutionarily conserved between rodents and primates." Journal of Vision 9, no. 14 (December 1, 2009): 75. http://dx.doi.org/10.1167/9.14.75.
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Micaelo-Fernandes, Catarina, Joseph Bouskila, Jean-François Bouchard, and Maurice Ptito. "Presence of the Endocannabinoid System in the Inferior Pulvinar of the Vervet Monkey." Brain Sciences 11, no. 6 (June 10, 2021): 770. http://dx.doi.org/10.3390/brainsci11060770.
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The expression of the endocannabinoid (eCB) system, including cannabinoid receptor type 1 (CB1R) and the cannabinoid synthesizing (NAPE-PLD) and degrading (FAAH) enzymes, has been well-characterized in the retina of rodents and monkeys. More recently, the presence of CB1R was localized throughout the dorsal lateral geniculate nucleus of the thalamus of vervet monkeys. Given that the retina projects also to the pulvinar either via a direct projection or via the superior colliculus, it was reasonable to assume that this system would be present therein. The visual pulvinar, namely the inferior pulvinar (PI) region, was delineated with calbindin immunohistochemical staining. Using Western blots and immunofluorescence, we demonstrated that CB1R, NAPE-PLD and FAAH are expressed in the PI of the vervet monkey. Throughout the PI, CB1R was mainly colocalized with VGLUT2-positive axon terminals in the vicinity of calbindin and parvalbumin-positive neurons. NAPE-PLD and FAAH rather colocalized with calbindin over the somatodendritic compartment of PI neurons. Our results suggest that visual information coming from the retina and entering the PI is modulated by the eCB system on its way to the dorsal visual stream. These results provide insights for understanding the role of eCBs in the modulation of visual thalamic inputs and, hence, visual perception.
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Ross, Robert, Lyle Parsons, Ba Son Thai, Richard Hall, and Meha Kaushik. "An IoT Smart Rodent Bait Station System Utilizing Computer Vision." Sensors 20, no. 17 (August 19, 2020): 4670. http://dx.doi.org/10.3390/s20174670.
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Across the world billions of dollars of damage are attributed to rodents, resulting in them being classified collectively as the biggest animal pest in the world. At a commercial scale most pest control companies employ the labour intensive approach of deploying and manually monitoring rodenticide bait stations. In this paper was present, RatSpy, a visual, low-power bait station monitoring system which wirelessly reports both on bait station levels and intruders entering the bait station. The smart bait stations report data back to a custom designed cloud platform. The system performance was evaluated under realistic field conditions (on an active cattle farm) with initial results showing significant potential in terms of reducing manual labour, improving scalability and data.
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de Tejada, Pilar Herreros, and Carmen Muñoz Tedó. "Contrast Sensitivity Function of the Albino Rat Determined Electrophysiologically." Spanish Journal of Psychology 1 (May 1998): 11–17. http://dx.doi.org/10.1017/s1138741600005369.
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Albinism alters the neural projections of the visual system. The authors wondered how this would affect visual function in rodents. They had previously shown that it doesn't alter the luminance threshold. They now explore visual acuity in the albino rat. In this work, they describe its contrast sensitivity function (CSF), as determined electro-physiologically. They recorded cortical visual evoked potentials (VEP) on six albino rats, stimulated by sinusoidal contrast reversal gratings. The curve showed the same characteristics that this function has in other mammals. Compared with the pigmented rat, the albino reached lower sensitivity values and showed a loss of sensitivity at high spatial frequencies. The estimated cut-off was 0.48 c/°, that is, 0.72 log units below the estimated cut-off for the pigmented rat under similar experimental conditions. VEP and behavioral cut-off were very close, the VEP estimation being slightly higher than the behavioral one.
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ARTAL, PABLO, PILAR HERREROS de TEJADA, CARMEN MUÑOZ TEDÓ, and DANIEL G. GREEN. "Retinal image quality in the rodent eye." Visual Neuroscience 15, no. 4 (April 1998): 597–605. http://dx.doi.org/10.1017/s0952523898154020.
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Many rodents do not see well. For a target to be resolved by a rat or a mouse, it must subtend a visual angle of a degree or more. It is commonly assumed that this poor spatial resolving capacity is due to neural rather than optical limitations, but the quality of the retinal image has not been well characterized in these animals. We have modified a double-pass apparatus, initially designed for the human eye, so it could be used with rodents to measure the modulation transfer function (MTF) of the eye's optics. That is, the double-pass retinal image of a monochromatic (λ = 632.8 nm) point source was digitized with a CCD camera. From these double-pass measurements, the single-pass MTF was computed under a variety of conditions of focus and with different pupil sizes. Even with the eye in best focus, the image quality in both rats and mice is exceedingly poor. With a 1-mm pupil, for example, the MTF in the rat had an upper limit of about 2.5 cycles/deg, rather than the 28 cycles/deg one would obtain if the eye were a diffraction-limited system. These images are about 10 times worse than the comparable retinal images in the human eye. Using our measurements of the optics and the published behavioral and electrophysiological contrast sensitivity functions (CSFs) of rats, we have calculated the CSF that the rat would have if it had perfect rather than poor optics. We find, interestingly, that diffraction-limited optics would produce only slight improvement overall. That is, in spite of retinal images which are of very low quality, the upper limit of visual resolution in rodents is neurally determined. Rats and mice seem to have eyes in which the optics and retina/brain are well matched.
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Hunt, David M., Livia S. Carvalho, Jill A. Cowing, and Wayne L. Davies. "Evolution and spectral tuning of visual pigments in birds and mammals." Philosophical Transactions of the Royal Society B: Biological Sciences 364, no. 1531 (October 12, 2009): 2941–55. http://dx.doi.org/10.1098/rstb.2009.0044.
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Variation in the types and spectral characteristics of visual pigments is a common mechanism for the adaptation of the vertebrate visual system to prevailing light conditions. The extent of this diversity in mammals and birds is discussed in detail in this review, alongside an in-depth consideration of the molecular changes involved. In mammals, a nocturnal stage in early evolution is thought to underlie the reduction in the number of classes of cone visual pigment genes from four to only two, with the secondary loss of one of these genes in many monochromatic nocturnal and marine species. The trichromacy seen in many primates arises from either a polymorphism or duplication of one of these genes. In contrast, birds have retained the four ancestral cone visual pigment genes, with a generally conserved expression in either single or double cone classes. The loss of sensitivity to ultraviolet (UV) irradiation is a feature of both mammalian and avian visual evolution, with UV sensitivity retained among mammals by only a subset of rodents and marsupials. Where it is found in birds, it is not ancestral but newly acquired.
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Notz, E., C. Imholt, D. Reil, and J. Jacob. "Testing automated sensor traps for mammal field studies." Wildlife Research 44, no. 1 (2017): 72. http://dx.doi.org/10.1071/wr16192.
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Context Live traps are regularly used in field and enclosure studies with mammals. In some scenarios, such as, for example, when the focus is on temporal patterns or to minimise the time animals are contained inside the trap for animal-ethics reasons, it can be highly useful to be alerted immediately when an individual is trapped. Aims In the present study, an automated system was trialed that is designed to automatically send a signal to a receiving device (pager, computer, mobile phone) when the body heat or movement of a trapped small mammal is registered by an infrared sensor (ERMINEA permanent monitoring system for rodent detection). Methods Sensors were attached to Ugglan multiple-capture traps and used in laboratory conditions and in semi-natural outdoor enclosures with common voles (Microtus arvalis) and bank voles (Myodes glareolus), as well as in the field with bank voles, Apodemus species and common voles. Sensor readings were compared to visual observation and trapping results. Key results In enclosure and field conditions, 100% and 98.7% of traps recorded captured animals correctly. There were no sensor signals when rodents moved along the outside or in the entrance compartment of the traps. Rodents sitting on the trap door triggered the sensor in 50% of cases when there was no bedding in the trap; however, there were no sensor signals if bedding was present. In laboratory trials, 20–70% of traps were falsely triggered by large insects (crickets), depending on ambient temperature and whether bedding was in the trap. Conclusions Generally, the system was a reliable, flexible and easy-to-handle tool to monitor live captures. To minimise false negatives (animals trapped without signal), testing sensor function in the pre-baiting phase and software adjustments are recommended. Implications The sensors are compatible with various trapping and other monitoring devices, providing the potential to be used in a wide range of applications. Their use is likely to optimise study designs, especially when temporal patterns are recorded or animals or samples need to be obtained soon after capture, and to minimise stress of trapped animals because they can be removed shortly after capture.
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Löwel, Siegrid, Evgenia Kalogeraki, Susanne Dehmel, and Kalina Makowiecki. "Environmental conditions strongly affect brain plasticity." e-Neuroforum 24, no. 1 (February 23, 2018): A19—A29. http://dx.doi.org/10.1515/nf-2017-a050.
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AbstractDuring development, experience continuously interacts with genetic information to shape and optimize neuronal circuits and behaviour. Therefore, environmental conditions have a powerful impact on the brain. To date, accumulating evidence shows that raising animals in a so-called “enriched environment” elicits remarkable effects on the brain across molecular, anatomical, and functional levels when compared to animals raised in a “standard cage” environment. In our article, we provide a brief review of the field and illustrate the different results of “enriched” versus standard cage-raised rodents with examples from visual system plasticity. We also briefly discuss parallel studies of enrichment effects in humans. Collectively, these data highlight that results should always be considered in the context of the animals’ environment.
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Hoel, Erik P., Larissa Albantakis, Chiara Cirelli, and Giulio Tononi. "Synaptic refinement during development and its effect on slow-wave activity: a computational study." Journal of Neurophysiology 115, no. 4 (April 1, 2016): 2199–213. http://dx.doi.org/10.1152/jn.00812.2015.
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Recent evidence suggests that synaptic refinement, the reorganization of synapses and connections without significant change in their number or strength, is important for the development of the visual system of juvenile rodents. Other evidence in rodents and humans shows that there is a marked drop in sleep slow-wave activity (SWA) during adolescence. Slow waves reflect synchronous transitions of neuronal populations between active and inactive states, and the amount of SWA is influenced by the connection strength and organization of cortical neurons. In this study, we investigated whether synaptic refinement could account for the observed developmental drop in SWA. To this end, we employed a large-scale neural model of primary visual cortex and sections of the thalamus, capable of producing realistic slow waves. In this model, we reorganized intralaminar connections according to experimental data on synaptic refinement: during prerefinement, local connections between neurons were homogenous, whereas in postrefinement, neurons connected preferentially to neurons with similar receptive fields and preferred orientations. Synaptic refinement led to a drop in SWA and to changes in slow-wave morphology, consistent with experimental data. To test whether learning can induce synaptic refinement, intralaminar connections were equipped with spike timing-dependent plasticity. Oriented stimuli were presented during a learning period, followed by homeostatic synaptic renormalization. This led to activity-dependent refinement accompanied again by a decline in SWA. Together, these modeling results show that synaptic refinement can account for developmental changes in SWA. Thus sleep SWA may be used to track noninvasively the reorganization of cortical connections during development.
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Koopman, K. E., A. Roefs, D. C. E. Elbers, E. Fliers, J. Booij, M. J. Serlie, and S. E. la Fleur. "Brain dopamine and serotonin transporter binding are associated with visual attention bias for food in lean men." Psychological Medicine 46, no. 8 (March 17, 2016): 1707–17. http://dx.doi.org/10.1017/s0033291716000222.
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BackgroundIn rodents, the striatal dopamine (DA) system and the (hypo)thalamic serotonin (5-HT) system are involved in the regulation of feedingbehavior. In lean humans, little is known about the relationship between these brain neurotransmitter systems and feeding. We studied the relationship between striatal DA transporters (DAT) and diencephalic 5-HT transporters (SERT), behavioral tasks and questionnaires, and food intake.MethodWe measured striatal DAT and diencephalic SERT binding with [123I]FP-CIT SPECT in 36 lean male subjects. Visual attention bias for food (detection speed and distraction time) and degree of impulsivity were measured using response-latency-based computer tasks. Craving and emotional eating were assessed with questionnaires and ratings of hunger by means of VAS scores. Food intake was assessed through a self-reported online diet journal.ResultsStriatal DAT and diencephalic SERT binding negatively correlated with food detection speed (p= 0.008,r= −0.50 andp= 0.002,r= −0.57, respectively), but not with food distraction time, ratings of hunger, craving or impulsivity. Striatal DAT and diencephalic SERT binding did not correlate with free choice food intake, whereas food detection speed positively correlated with total caloric intake (p= 0.001,r= 0.60), protein intake (p= 0.01,r= 0.44), carbohydrate intake (p= 0.03,r= 0.39) and fat intake (p= 0.06,r= 0.35).ConclusionsThese results indicate a role for the central 5-HT and DA system in the regulation of visual attention bias for food, which contributes to the motivation to eat, in non-obese, healthy humans. In addition, this study confirms that food detection speed, measured with the latency-based computer task, positively correlates with total food and macronutrient intake.
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Kaupert, Ursula, Kay Thurley, Katja Frei, Francesco Bagorda, Alexej Schatz, Gilad Tocker, Sophie Rapoport, Dori Derdikman, and York Winter. "Spatial cognition in a virtual reality home-cage extension for freely moving rodents." Journal of Neurophysiology 117, no. 4 (April 1, 2017): 1736–48. http://dx.doi.org/10.1152/jn.00630.2016.
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Virtual reality (VR) environments are a powerful tool to investigate brain mechanisms involved in the behavior of animals. With this technique, animals are usually head fixed or secured in a harness, and training for cognitively more complex VR paradigms is time consuming. A VR apparatus allowing free animal movement and the constant operator-independent training of tasks would enable many new applications. Key prospective usages include brain imaging of animal behavior when carrying a miniaturized mobile device such as a fluorescence microscope or an optetrode. Here, we introduce the Servoball, a spherical VR treadmill based on the closed-loop tracking of a freely moving animal and feedback counterrotation of the ball. Furthermore, we present the complete integration of this experimental system with the animals’ group home cage, from which single individuals can voluntarily enter through a tunnel with radio-frequency identification (RFID)-automated access control and commence experiments. This automated animal sorter functions as a mechanical replacement of the experimenter. We automatically trained rats using visual or acoustic cues to solve spatial cognitive tasks and recorded spatially modulated entorhinal cells. When electrophysiological extracellular recordings from awake behaving rats were performed, head fixation can dramatically alter results, so that any complex behavior that requires head movement is impossible to achieve. We circumvented this problem with the use of the Servoball in open-field scenarios, as it allows the combination of open-field behavior with the recording of nerve cells, along with all the flexibility that a virtual environment brings. This integrated home cage with a VR arena experimental system permits highly efficient experimentation for complex cognitive experiments. NEW & NOTEWORTHY Virtual reality (VR) environments are a powerful tool for the investigation of brain mechanisms. We introduce the Servoball, a VR treadmill for freely moving rodents. The Servoball is integrated with the animals’ group home cage. Single individuals voluntarily enter using automated access control. Training is highly time-efficient, even for cognitively complex VR paradigms.
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McNaughton, B. L., L. L. Chen, and E. J. Markus. "“Dead Reckoning,” Landmark Learning, and the Sense of Direction: A Neurophysiological and Computational Hypothesis." Journal of Cognitive Neuroscience 3, no. 2 (April 1991): 190–202. http://dx.doi.org/10.1162/jocn.1991.3.2.190.
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Behavioral and neurophysiological evidence strongly suggests that, within certain limits, rodents and humans can keep track of their directional heading relative to an inertial, and hence allocentric coordinate system. This “sense of direction” appears to involve the integration of angular velocity signals that arise primarily in the vestibular system. A hypothesis is proposed in which the integration process, an operation that may be difficult for neurons to implement, is replaced by a linear associative mapping, an operation that is at least theoretically easy to implement with neurons. The proposed system makes use of a set of linearly independent vectors representing the combination of the current head direction, and head angular velocity representations to “recall” the resulting head direction. It is then proposed that visual landmarks become incorporated into the directional system, enabling both the correction of cumulative error and, ultimately, the computation of novel, optimal trajectories between locations. According to the hypothesis, this occurs through the association of hippo-campal “local-view” cells (i.e., direction selective “place cells”) with “head-direction” cells located downstream in the dorsal presubiculum. The possible neurophysiological and neuroan-atomical bases for the proposed system are discussed.
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Sergeeva, Elena G., Anton B. Fedorov, Petra Henrich-Noack, and Bernhard A. Sabel. "Transcorneal alternating current stimulation induces EEG “aftereffects” only in rats with an intact visual system but not after severe optic nerve damage." Journal of Neurophysiology 108, no. 9 (November 1, 2012): 2494–500. http://dx.doi.org/10.1152/jn.00341.2012.
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Noninvasive alternating current stimulation can induce vision restoration in patients with chronic optic nerve damage and results in electroencephalogram (EEG) aftereffects. To better understand the mechanisms of action, we studied such EEG “aftereffects” of transcorneal alternating current stimulation (tACS) at the chronic posttraumatic state in rats. EEG baseline was recorded from visual cortex under ketamine/xylazine narcosis of healthy rats and rats with chronic severe optic nerve crush. One week later, both groups were again anesthetized and stimulated transcorneally twice for 12 min each time. tACS-induced changes were compared with baseline EEG. Over the course of 65 min narcosis baseline EEG revealed a shift from a dominant delta power to theta. This shift was significantly delayed in lesioned animals compared with healthy controls. tACS applied during the late narcosis stage in normal rats led to significantly increased theta power with a parallel shift of the dominating peak to higher frequency which outlasted the stimulation period by 15 min (aftereffects). EEG in lesioned rats was not significantly changed. In rodents, tACS can induce neuroplasticity as shown by EEG aftereffects that outlast the stimulation period. But this requires a minimal level of brain activation because aftereffects are not seen when tACS is applied during deep anesthesia and not when applied to animals after severe optic nerve damage. We conclude that tACS is only effective to induce cortical plasticity when the the retina can be excited.
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Byrne, Patrick A., and J. Douglas Crawford. "Cue Reliability and a Landmark Stability Heuristic Determine Relative Weighting Between Egocentric and Allocentric Visual Information in Memory-Guided Reach." Journal of Neurophysiology 103, no. 6 (June 2010): 3054–69. http://dx.doi.org/10.1152/jn.01008.2009.
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It is not known how egocentric visual information (location of a target relative to the self) and allocentric visual information (location of a target relative to external landmarks) are integrated to form reach plans. Based on behavioral data from rodents and humans we hypothesized that the degree of stability in visual landmarks would influence the relative weighting. Furthermore, based on numerous cue-combination studies we hypothesized that the reach system would act like a maximum-likelihood estimator (MLE), where the reliability of both cues determines their relative weighting. To predict how these factors might interact we developed an MLE model that weighs egocentric and allocentric information based on their respective reliabilities, and also on an additional stability heuristic. We tested the predictions of this model in 10 human subjects by manipulating landmark stability and reliability (via variable amplitude vibration of the landmarks and variable amplitude gaze shifts) in three reach-to-touch tasks: an egocentric control (reaching without landmarks), an allocentric control (reaching relative to landmarks), and a cue-conflict task (involving a subtle landmark “shift” during the memory interval). Variability from all three experiments was used to derive parameters for the MLE model, which was then used to simulate egocentric–allocentric weighting in the cue-conflict experiment. As predicted by the model, landmark vibration—despite its lack of influence on pointing variability (and thus allocentric reliability) in the control experiment—had a strong influence on egocentric–allocentric weighting. A reduced model without the stability heuristic was unable to reproduce this effect. These results suggest heuristics for extrinsic cue stability are at least as important as reliability for determining cue weighting in memory-guided reaching.
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Kuang, R. Z., M. Merline, and K. Kalil. "Topographic specificity of corticospinal connections formed in explant coculture." Development 120, no. 7 (July 1, 1994): 1937–47. http://dx.doi.org/10.1242/dev.120.7.1937.
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The corticospinal pathway connects layer V pyramidal neurons in discrete regions of the sensorimotor cortex to topographically matching targets in the spinal cord. In rodents initial pathway errors occur transiently during early postnatal development, such that visual cortical axons project inappropriately into the corticospinal tract. Nevertheless, only sensorimotor axons form corticospinal connections, which are topographically ordered in hamsters from the earliest stages of innervation. Previous work in vivo suggests that pathfinding is carried out by primary cortical axons whereas target innervation occurs by extension of axon collaterals at appropriate locations. In vitro studies have provided evidence that chemotropic factors may selectively attract extension of neurites into specific targets. To investigate the basis for corticospinal target selection during development, we have used an in vitro explant coculture system. Sensorimotor and visual cortical explants from newborn hamsters were presented with inappropriate targets from olfactory bulb and cerebellum and targets from the cervical (forelimb) and lumbar (hindlimb) enlargements of the early postnatal spinal cord. Under in vitro conditions, corticospinal target selection was highly specific and remarkably similar to corticospinal connectivity in vivo. Visual and sensorimotor cortical neurites extended nonselectively into the white matter of the spinal cord. However, only neurites from the sensorimotor cortex were able to extend into and arborize within the spinal gray. In the majority of cases, these connections were topographically appropriate, matching forelimb cortex to cervical cord and hindlimb cortex to lumbar cord. However, we found no evidence that chemotropic attraction was responsible for selection of appropriate targets by cortical neurites or that spinal target tissue promoted extension of cortical axon collaterals within the collagen matrix. These results suggest that the ability of cortical neurites to recognize correct spinal targets and form terminal arbors may require direct axon target interaction.
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Lingley, Alexander J., Donald E. Mitchell, Nathan A. Crowder, and Kevin R. Duffy. "Modification of Peak Plasticity Induced by Brief Dark Exposure." Neural Plasticity 2019 (September 3, 2019): 1–10. http://dx.doi.org/10.1155/2019/3198285.
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The capacity for neural plasticity in the mammalian central visual system adheres to a temporal profile in which plasticity peaks early in postnatal development and then declines to reach enduring negligible levels. Early studies to delineate the critical period in cats employed a fixed duration of monocular deprivation to measure the extent of ocular dominance changes induced at different ages. The largest deprivation effects were observed at about 4 weeks postnatal, with a steady decline in plasticity thereafter so that by about 16 weeks only small changes were measured. The capacity for plasticity is regulated by a changing landscape of molecules in the visual system across the lifespan. Studies in rodents and cats have demonstrated that the critical period can be altered by environmental or pharmacological manipulations that enhance plasticity at ages when it would normally be low. Immersion in complete darkness for long durations (dark rearing) has long been known to alter plasticity capacity by modifying plasticity-related molecules and slowing progress of the critical period. In this study, we investigated the possibility that brief darkness (dark exposure) imposed just prior to the critical period peak can enhance the level of plasticity beyond that observed naturally. We examined the level of plasticity by measuring two sensitive markers of monocular deprivation, namely, soma size of neurons and neurofilament labeling within the dorsal lateral geniculate nucleus. Significantly larger modification of soma size, but not neurofilament labeling, was observed at the critical period peak when dark exposure preceded monocular deprivation. This indicated that the natural plasticity ceiling is modifiable and also that brief darkness does not simply slow progress of the critical period. As an antecedent to traditional amblyopia treatment, darkness may increase treatment efficacy even at ages when plasticity is at its highest.
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Trevelyan, A. J., and I. D. Thompson. "Neonatal monocular enucleation and the geniculo-cortical system in the golden hamster: Shrinkage in dorsal lateral geniculate nucleus and area 17 and the effects on relay cell size and number." Visual Neuroscience 12, no. 5 (September 1995): 971–83. http://dx.doi.org/10.1017/s0952523800009512.
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AbstractWe have examined the effects of neonatal monocular enucleation on the volume of the dorsal lateral geniculate nucleus (dLGN), the area of area 17, and the size and numbers of geniculate relay neurons identified by retrograde transport of HRP from cortex. Compared to values for normal animals, the only significant change contralateral to the remaining eye was an increase in relay cell radius. The effects ipsilateral to the remaining eye were more widespread: we found significant reductions in the volume of the dLGN (27% reduction), the area of striate cortex (22%), and the number (16%) and average soma radius (6%) of geniculate relay neurons. The relay neurons were also more densely packed, suggesting that other geniculate cell types were affected similarly, although this was not explicitly examined. These changes were not uniform throughout the nucleus, and as such, reflected the changes in retinal input. The greatest reduction in cell size occurred in the region of the ipsilateral dLGN receiving the most sparse retinal input subsequent to enucleation. Nor was the shrinkage of the dLGN uniform, being most apparent in the coronal plane especially along the axis orthogonal to the pia; there appeared to be little change in the anteroposterior extent. Shrinkage in area 17 ipsilateral to the remaining eye was the same (about 22%) whether it was defined by myelin staining or transneuronal transport of WGA-HRP. These results show that the transneuronal changes seen in the organization of visual cortex after early monocular enucleation in rodents are associated with only a moderate loss of geniculate relay cells.
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Friedmann, V. S. "Group adaptations do not need group selection." SOCIALNO-ECOLOGICHESKIE TECHNOLOGII, no. 3. 2018 (2018): 62–115. http://dx.doi.org/10.31862/2500-2965-2018-3-62-115.
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The article provides an overview of the works on different species of birds and mammals (and other vertebrates to a lesser extent), which show the origin of group adaptations that benefit society as a whole or the entire population developing a new landscape, but costly and / or risky for each of the individuals. Their formation and development are recorded in three cases: urbanization of “wild” birds and mammal species culminating in the emergence of specialized urban populations; animal communication, when individuals in communities interact not directly, but the action of one and the counter-action of the other is mediated by a specific set of demonstrations, visual and acoustic, with a characteristic shape and signal function; in the formation of a family-group lifestyle of rodents. The objective of the research was to investigate whether the formation of group adaptations (at least in these three cases) really requires “multiplication of entities” – the use of the concept of group selection or, like the others, these adaptations can be explained by the action of individual selection. In all three cases, it turns out that the formation of the corresponding group adaptations is an action of individual selection, but influencing individuals not independent, but connected by a certain structure – social or population (spatial-ethological) to the corresponding system of supra-individual level. In all cases it turns out that first of all the structure of the system is transformed, and only then there is the process of selection of individuals who are the most adapted to the changed relationships, i.e. the selection is stabilizing rather than moving. So we pass between Scylla of socio-biological explanations and Charybdis of group selection. This is necessary because both of them are useless as a general explanation of the origin of group adaptations.
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Silveira, L. C. L., C. W. Picanço-Diniz, and E. Oswaldo-Cruz. "Distribution and size of ganglion cells in the retinae of large Amazon rodents." Visual Neuroscience 2, no. 3 (March 1989): 221–35. http://dx.doi.org/10.1017/s0952523800001140.
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AbstractThe topographical distribution of density and soma size of the retinal ganglion cells were studied in three species of hystricomorph rodents. Flat-mounted retinae were stained by the Nissl method and the ganglion cells counted on a matrix covering the whole retinae. Soma size was determined for samples at different retinal regions. The agouti, a diurnal rodent, shows a well-developed visual streak, reaching a peak density of 6250 ganglion cells/mm2. The total number of ganglion cells ranged from 477, 427–548, 205 in eight retinae. The ganglion-cell-size histogram of the visual streak region exhibits a marked shift towards smaller values when compared to retinal periphery. Upper and lower regions differ in both cell density and cell size. The crepuscular capybara shows a less-developed visual streak with a peak ganglion cell density of 2250/mm2. The shift towards small-sized cells in the visual streak is less marked. Total ganglion cell population is 368,840. In the nocturnal paca, the upper half of the fundus oculi includes a tapetum lucidum. The retina of this species shows the least-developed visual streak of this group, with the lowest peak ganglion cell density reaching 925/mm2. The total ganglion cell number (230,804) is also smaller than in the two other species. Soma-size spectra of this species are characterized by the presence, in the lower hemi-retina, of very large perikarya comparable in size to the cat's alpha ganglion cells.
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Bastos, Elisa Ferreira, Joyce Lira de Souza Marcelino, Angélica Rocha Amaral, and Claudio Alberto Serfaty. "Fluoxetine-induced plasticity in the rodent visual system." Brain Research 824, no. 1 (April 1999): 28–35. http://dx.doi.org/10.1016/s0006-8993(99)01184-1.
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Johnston, Kevin D., Kevin Barker, Lauren Schaeffer, David Schaeffer, and Stefan Everling. "Methods for chair restraint and training of the common marmoset on oculomotor tasks." Journal of Neurophysiology 119, no. 5 (May 1, 2018): 1636–46. http://dx.doi.org/10.1152/jn.00866.2017.
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The oculomotor system is the most thoroughly understood sensorimotor system in the brain, due in large part to electrophysiological studies carried out in macaque monkeys trained to perform oculomotor tasks. A disadvantage of the macaque model is that many cortical oculomotor areas of interest lie within sulci, making high-density array and laminar recordings impractical. Many techniques of molecular biology developed in rodents, such as optogenetic manipulation of neuronal subtypes, are also limited in this species. The common marmoset ( Callithrix jacchus) possesses a smooth cortex, allowing easy access to frontoparietal oculomotor areas, and may bridge the gap between systems neuroscience in macaques and molecular techniques. Techniques for restraint, training, and neural recording in these animals have been well developed in auditory neuroscience. Those for oculomotor neuroscience, however, remain at a relatively early stage. In this article we provide details of a custom-designed restraint chair for marmosets, a combination head restraint/recording chamber allowing access to cortical oculomotor areas and providing stability suitable for eye movement and neural recordings, as well as a training protocol for oculomotor tasks. We additionally report the results of a psychophysical study in marmosets trained to perform a saccade task using these methods, showing that, as in rhesus and humans, marmosets exhibit a “gap effect,” a decrease in reaction time when the fixation stimulus is removed before the onset of a visual saccade target. These results are the first evidence of this effect in marmosets and support the common marmoset model for neurophysiological investigations of oculomotor control. NEW & NOTEWORTHY The ability to carry out neuronal recordings in behaving primates has provided a wealth of information regarding the neural circuits underlying the control of eye movements. Such studies require restraint of the animal within a primate chair, head fixation, methods of acclimating the animals to this restraint, and the use of operant conditioning methods for training on oculomotor tasks. In contrast to the macaque model, relatively few studies have reported in detail methods for use in the common marmoset. In this report we detail custom-designed equipment and methods by which we have used to successfully train head-restrained marmosets to perform basic oculomotor tasks.
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Knight, Rebecca, Caitlin E. Piette, Hector Page, Daniel Walters, Elizabeth Marozzi, Marko Nardini, Simon Stringer, and Kathryn J. Jeffery. "Weighted cue integration in the rodent head direction system." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1635 (February 5, 2014): 20120512. http://dx.doi.org/10.1098/rstb.2012.0512.
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How the brain combines information from different sensory modalities and of differing reliability is an important and still-unanswered question. Using the head direction (HD) system as a model, we explored the resolution of conflicts between landmarks and background cues. Sensory cue integration models predict averaging of the two cues, whereas attractor models predict capture of the signal by the dominant cue. We found that a visual landmark mostly captured the HD signal at low conflicts: however, there was an increasing propensity for the cells to integrate the cues thereafter. A large conflict presented to naive rats resulted in greater visual cue capture (less integration) than in experienced rats, revealing an effect of experience. We propose that weighted cue integration in HD cells arises from dynamic plasticity of the feed-forward inputs to the network, causing within-trial spatial redistribution of the visual inputs onto the ring. This suggests that an attractor network can implement decision processes about cue reliability using simple architecture and learning rules, thus providing a potential neural substrate for weighted cue integration.
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Bray, George A. "Afferent signals regulating food intake." Proceedings of the Nutrition Society 59, no. 3 (August 2000): 373–84. http://dx.doi.org/10.1017/s0029665100000422.
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Food intake is a regulated system. Afferent signals provide information to the central nervous system, which is the centre for the control of satiety or food seeking. Such signals can begin even before food is ingested through visual, auditory and olfactory stimuli. One of the recent interesting findings is the demonstration that there are selective fatty acid taste receptors on the tongue of rodents. The suppression of food intake by essential fatty acids infused into the stomach and the suppression of electrical signals in taste buds reflect activation of a K rectifier channel (K 1.5). In animals that become fat eating a high-fat diet the suppression of this current by linoleic acid is less than that in animals that are resistant to obesity induced by dietary fat. Inhibition of fatty acid oxidation with either mercaptoacetate (which blocks acetyl-CoA dehydrogenase) or methylpalmoxirate will increase food intake. When animals have a choice of food, mercaptoacetate stimulates the intake of protein and carbohydrate, but not fat. Afferent gut signals also signal satiety. The first of these gut signals to be identified was cholecystokinin (CCK). When CCK acts on CCK-A receptors in the gastrointestinal tract, food intake is suppressed. These signals are transmitted by the vagus nerve to the nucleus tractus solitarius and thence to higher centres including the lateral parabrachial nucleus, amygdala, and other sites. Rats that lack the CCK-A receptor become obese, but transgenic mice lacking CCK-A receptors do not become obese. CCK inhibits food intake in human subjects. Enterostatin, the pentapeptide produced when pancreatic colipase is cleaved in the gut, has been shown to reduce food intake. This peptide differs in its action from CCK by selectively reducing fat intake. Enterostatin reduces hunger ratings in human subjects. Bombesin and its human analogue, gastrin inhibitory peptide (also gastrin-insulin peptide), reduce food intake in obese and lean subjects. Animals lacking bombesin-3 receptor become obese, suggesting that this peptide may also be important. Circulating glucose concentrations show a dip before the onset of most meals in human subjects and rodents. When the glucose dip is prevented, the next meal is delayed. The dip in glucose is preceded by a rise in insulin, and stimulating insulin release will decrease circulating glucose and lead to food intake. Pyruvate and lactate inhibit food intake differently in animals that become obese compared with lean animals. Leptin released from fat cells is an important peripheral signal from fat stores which modulates food intake. Leptin deficiency or leptin receptor defects produce massive obesity. This peptide signals a variety of central mechanisms by acting on receptors in the arcuate nucleus and hypothalamus. Pancreatic hormones including glucagon, amylin and pancreatic polypeptide reduce food intake. Four pituitary peptides also modify food intake. Vasopressin decreases feeding. In contrast, injections of desacetyl melanocyte-stimulating hormone, growth hormone and prolactin are associated with increased food intake. Finally, there are a group of miscellaneous peptides that modulate feeding. β-Casomorphin, a heptapeptide produced during the hydrolysis of casein, stimulates food intake in experimental animals. In contrast, the other peptides in this group, including calcitonin, apolipoprotein A-IV, the cyclized form of histidyl-proline, several cytokines and thyrotropin-releasing hormone, all decrease food intake. Many of these peptides act on gastrointestinal or hepatic receptors that relay messages to the brain via the afferent vagus nerve. As a group they provide a number of leads for potential drug development.
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Page, Hector J. I., Daniel M. Walters, Rebecca Knight, Caitlin E. Piette, Kathryn J. Jeffery, and Simon M. Stringer. "A theoretical account of cue averaging in the rodent head direction system." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1635 (February 5, 2014): 20130283. http://dx.doi.org/10.1098/rstb.2013.0283.
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Head direction (HD) cell responses are thought to be derived from a combination of internal (or idiothetic) and external (or allothetic) sources of information. Recent work from the Jeffery laboratory shows that the relative influence of visual versus vestibular inputs upon the HD cell response depends on the disparity between these sources. In this paper, we present simulation results from a model designed to explain these observations. The model accurately replicates the Knight et al. data. We suggest that cue conflict resolution is critically dependent on plastic remapping of visual information onto the HD cell layer. This remap results in a shift in preferred directions of a subset of HD cells, which is then inherited by the rest of the cells during path integration. Thus, we demonstrate how, over a period of several minutes, a visual landmark may gain cue control. Furthermore, simulation results show that weaker visual landmarks fail to gain cue control as readily. We therefore suggest a second longer term plasticity in visual projections onto HD cell areas, through which landmarks with an inconsistent relationship to idiothetic information are made less salient, significantly hindering their ability to gain cue control. Our results provide a mechanism for reliability-weighted cue averaging that may pertain to other neural systems in addition to the HD system.
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VAN HOOSER, STEPHEN D., and SACHA B. NELSON. "The squirrel as a rodent model of the human visual system." Visual Neuroscience 23, no. 6 (November 2006): 941. http://dx.doi.org/10.1017/s095252380623030x.
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CHAN, KEVIN C., MATTHEW M. CHEUNG, and ED X. WU. "IN VIVOMULTIPARAMETRIC MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY OF RODENT VISUAL SYSTEM." Journal of Integrative Neuroscience 09, no. 04 (December 2010): 477–508. http://dx.doi.org/10.1142/s0219635210002524.
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Balkema, Grant W., and Ursula C. Dräger. "Impaired visual thresholds in hypopigmented animals." Visual Neuroscience 6, no. 6 (June 1991): 577–85. http://dx.doi.org/10.1017/s095252380000256x.
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AbstractOcular hypopigmentation is associated with neurological defects in structure and function. This paper investigates the ab/Fute visual thresholds in dark-adapted hypopigmented animals compared to their normally pigmented controls. Here we asked (1) whether the threshold elevation found in hypopigmented animals is a general consequence of the reduction in melanin content; (2) if so, which melanin components in the eye are likely to influence visual thresholds; and (3) whether similar threshold defects can be detected in orders other than rodents. By single-unit recordings from the superior colliculus, we compared incremental thresholds of normal black mice of the C57BL/6J strain to hypopigmented mutants: beige (bg/bg), pale ear (ep/ep), and albino (c2J/c2J) mice, three mutants in which melanin pigment throughout the body is affected; and Steel (Sl/Sld) and dorninant-spotting/W-mice (W/Wν), two mutants with normal pigmentation in the retinal pigment epithelium (RPE) but without any melanin in the choroid or the rest of the body. We found that all mutants had elevated thresholds that varied with the reduction in melanin. The albinos were 25 times less sensitive than black mice, pale ear mice 20 times, beige mice 11 times, and Steel and W-mice 5 times. The mean thresholds of dark-adapted black mice were 0.008 cd/m2. Recordings from rabbits showed a similar impairment of visual sensitivity: incremental thresholds were elevated 40 times in New Zealand-White albino rabbits (0.0008 cd/m2) compared to Dutch-Belted pigmented controls (0.00002 cd/m2). Previously, it has been shown that hypopigmented rats have elevated dark-adapted thresholds compared to pigmented controls (Balkema, 1988); here we show that the difference between hypopigmented rats and pigmented controls is not caused by insufficient dark adaptation or excessive variability in the results from albino mutant compared to its control.Mutations that cause a reduction of ocular melanin pigmentation, regardless of the gene mutated or the mechanism underlying the hypopigmentation, are accompanied by an elevation in visual thresholds which is roughly proportional to the reduction in melanin. Melanin both in the RPE and choroid exert an effect on visual thresholds. Like the defects in optic nerve crossing and eye movements, the effect of melanin on visual thresholds is not restricted to rodents, but is seen in other orders. The threshold impairment in hypopigmented animals cannot be explained by impaired photoprotection, but it points to another physiological action of melanin.
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Innis, Sheila M. "Essential fatty acid requirements in human nutrition." Canadian Journal of Physiology and Pharmacology 71, no. 9 (September 1, 1993): 699–706. http://dx.doi.org/10.1139/y93-104.
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Arachidonic acid (20:4ω−6) and docosahexaenoic acid (22:6ω−3) are major acyl components of cell membrane phospholipids, and are particularly enriched in the nonmyelin membranes of the central nervous system. Dietary deficiency of linoleic acid (18:2ω−6) and linolenic acid (18:3ω−3) during development has been shown to result in reduced levels of 20:4ω−6 and 22:6ω−3 in the developing central nervous system, and this has been associated with altered learning behaviour and visual function. Synthesis of 20:4ω−6 and 22:6ω−3 depends on the dietary intake of 18:2ω−6 and 18:3ω−3, respectively, and the activity of the fatty acid desaturase–elongase enzymes. Oxidation of 18:2ω−6 and 18:3ω−3 for energy, or direct acylation of 18:2ω−6 into triglycerides, cholesteryl esters, and phospholipids, could also influence the amount of 20:4ω−6 and 22:6ω−3 formed. The tissue levels of 20:4ω−6 and 22:6ω−3, or other (ω − 6) and (ω − 3) fatty acids, compatible with optimum growth and development or health are not known. The amount of preformed 22:6ω−3 in the diet of adults, infants fed various milks or formulae, or animals is reflected in the circulating lipid levels of 22:6ω−3. Human milk levels of (ω − 6) and (ω − 3) fatty acids vary, depending in part on the mother's diet. A valid, scientific approach to extrapolate dietary essential fatty acid requirements from the composition of human milk or the circulating lipids of infants fed different diets has not been agreed on. Current data suggest that fatty acid requirements for development of term-gestation piglet brain and retina are met with 5.0% dietary kcal (1 cal = 4.1868 J) 18:2ω−6 and > 1.0% kcal 18:3ω−3, As in rodents and non-human primates, a diet source of 20:4ω−6 and 22:6ω−3 does not seem essential for the developing piglet central nervous system. However, studies in very premature infants suggest these infants may benefit from a dietary source of 20:4ω−6 and 22:6ω−3. Whether the low 20:4ω−6 and 22:6ω−3 status is due to oxidation of 18:2ω−6 and 18:3ω−3 for energy, the effects of early intravenous feeding with lipid emulsions, rapid growth, or immaturity of physiological or metabolic pathways in very preterm infants is not yet known.Key words: linoleic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, brain, retina.
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Allen, Rachael S., Amber Douglass, Harrison Vo, and Andrew J. Feola. "Ovariectomy worsens visual function after mild optic nerve crush in rodents." Experimental Eye Research 202 (January 2021): 108333. http://dx.doi.org/10.1016/j.exer.2020.108333.
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VIDAL-SANZ, M., C. GALINDO-ROMERO, M. SALINAS-NAVARRO, FJ VALIENTE-SORIANO, B. GALLEGO, B. ROJAS, R. DE HOZ, et al. "Reactive gliosis along the visual system in rodent models of ocular hypertension." Acta Ophthalmologica 92 (August 20, 2014): 0. http://dx.doi.org/10.1111/j.1755-3768.2014.2424.x.
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Card, J. P., M. E. Whealy, A. K. Robbins, R. Y. Moore, and L. W. Enquist. "Two α-herpesvirus strains are transported differentially in the rodent visual system." Neuron 6, no. 6 (June 1991): 957–69. http://dx.doi.org/10.1016/0896-6273(91)90236-s.
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Dai, Xufeng, Siming Ye, Xiaoping Chen, Ting Jiang, Haixiao Huang, Wenjiong Li, Hongqiang Yu, Jinhua Bao, and Hao Chen. "Rodent retinal microcirculation and visual electrophysiology following simulated microgravity." Experimental Eye Research 194 (May 2020): 108023. http://dx.doi.org/10.1016/j.exer.2020.108023.
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Němec, Pavel, Pavla Cveková, Oldřich Benada, Ewa Wielkopolska, Seweryn Olkowicz, Kris Turlejski, Hynek Burda, Nigel C. Bennett, and Leo Peichl. "The visual system in subterranean African mole-rats (Rodentia, Bathyergidae): Retina, subcortical visual nuclei and primary visual cortex." Brain Research Bulletin 75, no. 2-4 (March 2008): 356–64. http://dx.doi.org/10.1016/j.brainresbull.2007.10.055.
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Conwell, Colin, and George Alvarez. "Is Rodent Visual Cortex Really Just a Randomly Initialized Neural Network?" Journal of Vision 20, no. 11 (October 20, 2020): 968. http://dx.doi.org/10.1167/jov.20.11.968.
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West, Greg L., Kyoko Konishi, and Veronique D. Bohbot. "Video Games and Hippocampus-Dependent Learning." Current Directions in Psychological Science 26, no. 2 (April 2017): 152–58. http://dx.doi.org/10.1177/0963721416687342.
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Research examining the impact of video games on neural systems has largely focused on visual attention and motor control. Recent evidence now shows that video games can also impact the hippocampal memory system. Further, action and 3D-platform video-game genres are thought to have differential impacts on this system. In this review, we examine the specific design elements unique to either action or 3D-platform video games and break down how they could either favor or discourage use of the hippocampal memory system during gameplay. Analysis is based on well-established principles of hippocampus-dependent and non-hippocampus-dependent forms of learning from the human and rodent literature.
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McCoy, Portia, Thomas T. Norton, and Lori L. McMahon. "Layer 2/3 Synapses in Monocular and Binocular Regions of Tree Shrew Visual Cortex Express mAChR-Dependent Long-Term Depression and Long-Term Potentiation." Journal of Neurophysiology 100, no. 1 (July 2008): 336–45. http://dx.doi.org/10.1152/jn.01134.2007.
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Acetylcholine is an important modulator of synaptic efficacy and is required for learning and memory tasks involving the visual cortex. In rodent visual cortex, activation of muscarinic acetylcholine receptors (mAChRs) induces a persistent long-term depression (LTD) of transmission at synapses recorded in layer 2/3 of acute slices. Although the rodent studies expand our knowledge of how the cholinergic system modulates synaptic function underlying learning and memory, they are not easily extrapolated to more complex visual systems. Here we used tree shrews for their similarities to primates, including a visual cortex with separate, defined regions of monocular and binocular innervation, to determine whether mAChR activation induces long-term plasticity. We find that the cholinergic agonist carbachol (CCh) not only induces long-term plasticity, but the direction of the plasticity depends on the subregion. In the monocular region, CCh application induces LTD of the postsynaptic potential recorded in layer 2/3 that requires activation of m3 mAChRs and a signaling cascade that includes activation of extracellular signal-regulated kinase (ERK) 1/2. In contrast, layer 2/3 postsynaptic potentials recorded in the binocular region express long-term potentiation (LTP) following CCh application that requires activation of m1 mAChRs and phospholipase C. Our results show that activation of mAChRs induces long-term plasticity at excitatory synapses in tree shrew visual cortex. However, depending on the ocular inputs to that region, variation exists as to the direction of plasticity, as well as to the specific mAChR and signaling mechanisms that are required.
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Choi, Veronica, and Nicholas J. Priebe. "Interocular velocity cues elicit vergence eye movements in mice." Journal of Neurophysiology 124, no. 2 (August 1, 2020): 623–33. http://dx.doi.org/10.1152/jn.00697.2019.
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The visual system integrates signals from the left and right eye to generate a representation of the world in depth. The binocular integration of signals may be observed from the coordinated vergence eye movements elicited by object motion in depth. We explored the circuits and signals responsible for these vergence eye movements in rodent and find these vergence eye movements are generated by a comparison of the motion and not spatial visual signals.
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PAKAN, JANELLE M. P., DAVID J. GRAHAM, CRISTIÁN GUTIÉRREZ-IBÁÑEZ, and DOUGLAS R. WYLIE. "Organization of the cerebellum: Correlating zebrin immunochemistry with optic flow zones in the pigeon flocculus." Visual Neuroscience 28, no. 2 (March 2011): 163–74. http://dx.doi.org/10.1017/s0952523810000532.
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AbstractThe cerebellar cortex has a fundamental parasagittal organization that is apparent in the physiological response properties of Purkinje cells (PCs) and the expression of several molecular markers such as zebrin II (ZII). ZII is heterogeneously expressed in PCs such that there are sagittal stripes of high expression [ZII immunopositive (ZII+)] interdigitated with stripes of little or no expression [ZII immunonegative (ZII−)]. Several studies in rodents have suggested that climbing fiber (CF) afferents from an individual subnucleus in the inferior olive project to either ZII+ or ZII− stripes but not both. In this report, we show that this is not the case in the pigeon flocculus. The flocculus (the lateral half of folia IXcd and X) receives visual-optokinetic information and is important for generating compensatory eye movements to facilitate gaze stabilization. Previous electrophysiological studies from our lab have shown that the pigeon flocculus consists of four parasagittal zones: 0, 1, 2, and 3. PC complex spike activity (CSA), which reflects CF input, in zones 0 and 2 responds best to rotational optokinetic stimuli about the vertical axis (VA zones), whereas CSA in zones 1 and 3 responds best to rotational optokinetic stimuli about the horizontal axis (HA zones). In addition, folium IXcd consists of seven pairs of ZII+/− stripes. Here, we recorded CSA of floccular PCs to optokinetic stimuli, marked recording locations, and subsequently visualized ZII expression in the flocculus. VA neurons were localized to the P4+/− and P6+/− stripes and HA neurons were localized to the P5+/− and P7− stripes. This is the first study showing that a series of adjacent ZII+/− stripes are tied to specific physiological functions as measured in the responses of PCs to natural stimulation. Moreover, this study shows that the functional zone in the pigeon flocculus spans a ZII+/− stripe pair, which is contrary to the scheme proposed from rodent research.
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Campbell, Malcolm G., and Lisa M. Giocomo. "Self-motion processing in visual and entorhinal cortices: inputs, integration, and implications for position coding." Journal of Neurophysiology 120, no. 4 (October 1, 2018): 2091–106. http://dx.doi.org/10.1152/jn.00686.2017.
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The sensory signals generated by self-motion are complex and multimodal, but the ability to integrate these signals into a unified self-motion percept to guide navigation is essential for animal survival. Here, we summarize classic and recent work on self-motion coding in the visual and entorhinal cortices of the rodent brain. We compare motion processing in rodent and primate visual cortices, highlighting the strengths of classic primate work in establishing causal links between neural activity and perception, and discuss the integration of motor and visual signals in rodent visual cortex. We then turn to the medial entorhinal cortex (MEC), where calculations using self-motion to update position estimates are thought to occur. We focus on several key sources of self-motion information to MEC: the medial septum, which provides locomotor speed information; visual cortex, whose input has been increasingly recognized as essential to both position and speed-tuned MEC cells; and the head direction system, which is a major source of directional information for self-motion estimates. These inputs create a large and diverse group of self-motion codes in MEC, and great interest remains in how these self-motion codes might be integrated by MEC grid cells to estimate position. However, which signals are used in these calculations and the mechanisms by which they are integrated remain controversial. We end by proposing future experiments that could further our understanding of the interactions between MEC cells that code for self-motion and position and clarify the relationship between the activity of these cells and spatial perception.
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Mass, Alla M., and Alexander Ya Supin. "Eye Optics in Semiaquatic Mammals for Aerial and Aquatic Vision." Brain, Behavior and Evolution 92, no. 3-4 (2018): 117–24. http://dx.doi.org/10.1159/000496326.
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Based on anatomical measurements of refractive structures in the eye, the positions of focused images were computed for several groups of semiaquatic mammals: rodents, a nonpinniped semiaquatic carnivore (the sea otter), and pinniped carnivores (seals, sea lions, and the walrus). In semiaquatic rodents, eye optics enable emmetropia in the air but cause substantial hypermetropia in the water. In semiaquatic carnivores, there are several mechanisms for amphibious vision that focus images on the retina in both air and water. These mechanisms include the potential for a substantial change in the lens shape of sea otters and the presence of the corneal emmetropic window in pinnipeds. The results suggest that several groups of mammals that independently adapted to aquatic environments vary in how their visual systems adapted to aquatic vision.
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DE LIMA, S. M. A., P. K. AHNELT, T. O. CARVALHO, J. S. SILVEIRA, F. A. F. ROCHA, C. A. SAITO, and L. C. L. SILVEIRA. "Horizontal cells in the retina of a diurnal rodent, the agouti (Dasyprocta aguti)." Visual Neuroscience 22, no. 6 (November 2005): 707–20. http://dx.doi.org/10.1017/s0952523805226032.
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The morphology and distribution of normally placed and displaced A horizontal cells were studied in the retina of a diurnal hystricomorph rodent, the agouti Dasyprocta aguti. Cells were labeled with anti-calbindin immunocytochemistry. Dendritic-field size reaches a minimum in the visual streak, of about 9000 μm2, and increases toward the retinal periphery both in the dorsal and ventral regions. There is a dorsoventral asymmetry, with dorsal cells being larger than ventral cells at equal distances from the streak. The peak value for cell density of 281 ± 28 cells/mm2 occurs in the center of the visual streak, decreasing toward the dorsal and ventral retinal periphery, paralleling the increase in dendritic-field size. Along the visual streak, the decline in cell density is less pronounced, remaining between 100–200 cells/mm2 in the temporal and nasal periphery. Displaced horizontal cells are rare and occur in the retinal periphery. They tend to be smaller than normally placed horizontal cells in the ventral region, whilst no systematic difference was observed between the two cell groups in the dorsal region. Mosaic regularity was studied using nearest-neighbor analysis and the Ripley function. When mosaic regularity was determined removing the displaced horizontal cells, there was a slight increase in the conformity ratio, but the bivariate Ripley function indicated some repulsive dependence between the two mosaics. Both results were near the level of significance. A similar analysis performed in the capybara retina, a closely related hystricomorph rodent bearing a higher density of displaced horizontal cells than found in the agouti, suggested spatial independence between the two mosaics, normally placed versus displaced horizontal cells.
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O’Brien, Shannon L., Mauro N. Tammone, Pablo A. Cuello, and Eileen A. Lacey. "Facultative sociality in a subterranean rodent, the highland tuco-tuco (Ctenomys opimus)." Biological Journal of the Linnean Society 129, no. 4 (February 17, 2020): 918–30. http://dx.doi.org/10.1093/biolinnean/blaa011.
Full textAbstract:
Abstract Understanding why social relationships vary among conspecifics is central to studies of animal behaviour. For many species, patterns of space use provide important insights into social behaviour. To characterize the social organization of the highland tuco-tuco (Ctenomys opimus), we used visual observations and radiotelemetry to quantify spatial relationships among adults in a population at Laguna de los Pozuelos, Jujuy Province, Argentina. Specifically, we sought to confirm anecdotal reports that these subterranean rodents are social, meaning that adults share burrow systems and nest sites. Our data indicate that the animals live in spatially distinct groups, although the number of individuals per group varies markedly. Although these relationships were robust with regard to location (above vs. below ground) and type of data (visual vs. telemetry), some groups identified during the daytime fissioned during the night. We suggest that the population of C. opimus at Pozuelos is facultatively social, meaning that individuals display predictable, adaptive differences in social relationships with conspecifics. More generally, our findings add to the growing number of subterranean species of rodents recognized as social, thereby generating new opportunities for comparative studies of these animals aimed at assessing the causes and consequences of variation in social organization.
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De Velasco, P. C., P. C. Sandre, M. G. Tavares Do Carmo, A. C. Faria-Melibeu, P. Campello-Costa, A. C. Ferraz, B. L. S. Andrade Da Costa, and C. A. Serfaty. "A critical period for omega-3 nutritional supplementation in the development of the rodent visual system." Brain Research 1615 (July 2015): 106–15. http://dx.doi.org/10.1016/j.brainres.2015.04.036.
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Rodrigues Junior, Wandilson dos Santos, Priscilla Oliveira-Silva, Adriana da Cunha Faria-Melibeu, Paula Campello-Costa, and Claudio Alberto Serfaty. "Serotonin transporter immunoreactivity is modulated during development and after fluoxetine treatment in the rodent visual system." Neuroscience Letters 657 (September 2017): 38–44. http://dx.doi.org/10.1016/j.neulet.2017.07.047.
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