Academic literature on the topic 'Primate cortical movement area'

Upper motoneurons (UMNs) in motor areas of the cerebral cortex influence spinal and cranial motor mechanisms through the corticospinal tract (CST) and through projections to brainstem motor pathways. The primate corticospinal system has a diverse cortical origin and a wide spectrum of fibre diameters, including large diameter fibres which are unique to humans and other large primates. Direct cortico-motoneuronal (CM) projections from the motor cortex to arm and hand motoneurons are a late evolutionary feature only present in dexterous primates and best developed in humans. CM projections are derived from a more restricted cortical territory (‘new’ M1, area 3a) and arise not only from corticospinal neurons with large, fast axons but also from those with relatively slow-conducting axons. During movement, corticospinal neurons are organised and recruited quite differently from ‘lower’ motoneurons. Accumulating evidence strongly implicates the corticospinal system in the early stages of ALS, with particular involvement of CM projections to distal limb muscles, but also to other muscle groups influenced by the CM system. There are important species differences in the organisation and function of the corticospinal system, and appropriate animal models are needed to understand disorders involving the human corticospinal system.

1. Cells were recorded in areas 3b and 1 of the primary somatosensory cortex (SI) of three monkeys during active arm movements. Successful reconstructions were made of 46 microelectrode penetrations, and 298 cells with tactile receptive fields (RFs) were located as to cytoarchitectonic area, lamina, or both. 2. Area 3b contained a greater proportion of cells with slowly adapting responses to tactile stimuli and fewer cells with deep modality inputs than did area 1. Area 3b also showed a greater level of movement-related modulation in tactile activity than area 1. Other cell properties were equally distributed in the two areas. 3. The distribution of cells with low-threshold tactile RFs that also responded to lateral stretch of the skin or to passive arm movements was skewed toward deeper laminae than for tactile cells that did not respond to those manipulations. 4. The variation of activity of tactile neurons during arm movements in different directions was weaker in the superficial laminae than in deeper cortical laminae. 5. Cells with only increases in activity during arm movements were preferentially but not exclusively located in middle and superficial layers. Cells with reciprocal responses were found mainly in laminae III and V, whereas cells with only decreases in activity were concentrated in lamina V. 6. Overall, active arm movements evoke directionally tuned tactile and “deep” activity in areas 3b and 1, in particular in the deeper cortical laminae that are the source of the descending output pathways from SI.

Although the cerebral cortex has been implicated in the control of swallowing, the output organization of the cortical swallowing representation, and features of cortically evoked swallowing, remain unclear. The present study defined the output features of the primate “cortical swallowing representation” with intracortical microstimulation (ICMS) applied within the lateral sensorimotor cortex. In four hemispheres of two awake monkeys, microelectrode penetrations were made at ≤1-mm intervals, initially within the face primary motor cortex (face-MI), and subsequently within the cortical regions immediately rostral, lateral, and caudal to MI. Two ICMS pulse trains [35-ms train, 0.2-ms pulses at 333 Hz, ≤30 μA (short train stimulus, T/S); 3- to 4-s train, 0.2-ms pulses at 50 Hz, ≤60 μA (continuous stimulus, C/S)] were applied at ≤500-μm intervals along each microelectrode penetration to a depth of 8–10 mm, and electromyographic (EMG) activity was recorded simultaneously from various orofacial and laryngeal muscles. Evoked orofacial movements, including swallowing, were verified by EMG analysis, and T/S and C/S movement thresholds were determined. Effects of varying ICMS intensity on swallow-related EMG properties were examined by applying suprathreshold C/S at selected intracortical sites. EMG patterns of swallows evoked from various cortical regions were compared with those of natural swallows recorded as the monkeys swallowed liquid and solid material. Results indicated that swallowing was evoked by C/S at ∼20% of 1,569 intracortical sites where ICMS elicited an orofacial motor response in both hemispheres of the two monkeys, typically at C/S intensities ≤30 μA. In contrast, swallowing was not evoked by T/S in either monkey. Swallowing was evoked from four cortical regions: the ICMS-defined face-MI, the face primary somatosensory cortex (face-SI), the region lateral and anterior to face-MI corresponding to the cortical masticatory area (CMA), and an area >5 mm deep to the cortical surface corresponding to both the white matter underlying the CMA and the frontal operculum; EMG patterns of swallows elicited from these four cortical regions showed some statistically significant differences. Whereas swallowing only was evoked at some sites, particularly within the deep cortical area, swallowing was more frequently evoked together with other orofacial responses including rhythmic jaw movements. Increasing ICMS intensity increased the magnitude, and decreased the latency, of the swallow-related EMG burst in the genioglossus muscle at some sites. These findings suggest that a number of distinct cortical foci may participate in the initiation and modulation of the swallowing synergy as well as in integrating the swallow within the masticatory sequence.

Two rhesus monkeys were trained to intercept a moving target at a fixed location with a feedback cursor controlled bya 2-D manipulandum. The direction from which the target appeared, the time from the target onset to its arrival at the interception point, and the target acceleration were randomized for each trial, thus requiring the animal to adjust its movement according to the visual input on a trail-by-trail basis. The two animals adopted different strategies, similar to those identified previously in human subjects. Single-cell activity was recorded from the arm area of the primary motor cortex in these two animals, and the neurons were classified based on the temporal patterns in their activity, using a nonhierarchical cluster analysis. Results of this analysis revealed differences in the complexity and diversity of motor cortical activity between the two animals that paralleled those of behavioral strategies. Most clusters displayed activity closedly related to the kinematics of hand movements. In addition, some clusters displayed patterns of activation that conveyed additional information necessary for successful performance of the task, such as the initial target velocity and the interval between successive submovements, suggesting that such information is represented in selective subpopulations of neurons in the primary motor cortex. These results also suggest that conversion of information about target motion into movement-related signals takes place in a broad network of cortical areas including the primary motor cortex.

Recent evidence has suggested that theta-frequency (4–7 Hz) oscillations around the human anterior cingulate cortex (ACC) and frontal cortex—that is, frontal midline theta (Fm theta) oscillations—may be involved in attentional processes in the brain. However, little is known about the physiological basis of Fm theta oscillations because invasive study in the human is allowed in only limited cases. In the present study, we developed a monkey model for Fm theta oscillations and located the generators of theta waves using electrodes implanted in various cortical areas. Monkeys were engaged in a self-initiated hand-movement task with a waiting period. The theta power in area 9 (the medial prefrontal cortex) and area 32 (the rostral ACC) was gradually increased from a few seconds before the movement and reached a peak immediately after the movement. When the movement was rewarded, the theta power attained a second peak, whereas it swiftly decreased in the unrewarded trials. Theta oscillations in areas 9 and 32 were coherent and phase locked together. This theta activity may be associated with “executive attention” including self-control, internal timing, and assessment of reward. It is probably a homologue of human Fm theta oscillations, as judged from the similar localization, corresponding frequency, and dependency on attentional processes. The monkey model would be useful for studying executive functions in the frontal cortex.

Primate visual cortex consists of dozens of distinct brain areas, each providing a highly specialized component to the sophisticated task of encoding the incoming sensory information and creating a representation of our visual environment that underlies our perception and action. One such area is the medial superior temporal cortex (MST), a motion-sensitive, direction-selective part of the primate visual cortex. It receives most of its input from the middle temporal (MT) area, but MST cells have larger receptive fields and respond to more complex motion patterns. The finding that MST cells are tuned for optic flow patterns has led to the suggestion that the area plays an important role in the perception of self-motion. This hypothesis has received further support from studies showing that some MST cells also respond selectively to vestibular cues. Furthermore, the area is part of a network that controls the planning and execution of smooth pursuit eye movements and its activity is modulated by cognitive factors, such as attention and working memory. This review of more than 90 studies focuses on providing clarity of the heterogeneous findings on MST in the macaque cortex and its putative homolog in the human cortex. From this analysis of the unique anatomical and functional position in the hierarchy of areas and processing steps in primate visual cortex, MST emerges as a gateway between perception, cognition, and action planning. Given this pivotal role, this area represents an ideal model system for the transition from sensation to cognition.

The middle temporal (MT) area is a cortical area integral to the “where” pathway of primate visual processing, signaling the movement and position of objects in the visual world. The receptive field of a single MT neuron is sensitive to the direction of object motion but is too large to signal precise spatial position. Here, we asked if the activity of MT neurons could be combined to support the high spatial precision required in the where pathway. With the use of multielectrode arrays, we recorded simultaneously neural activity at 24–65 sites in area MT of anesthetized marmoset monkeys. We found that although individual receptive fields span more than 5° of the visual field, the combined population response can support fine spatial discriminations (<0.2°). This is because receptive fields at neighboring sites overlapped substantially, and changes in spatial position are therefore projected onto neural activity in a large ensemble of neurons. This fine spatial discrimination is supported primarily by neurons with receptive fields flanking the target locations. Population performance is degraded (by 13–22%) when correlations in neural activity are ignored, further reflecting the contribution of population neural interactions. Our results show that population signals can provide high spatial precision despite large receptive fields, allowing area MT to represent both the motion and the position of objects in the visual world.

1. The basal ganglia of primates receive somatosensory input carried largely by corticostriatal fibers. To determine whether map-transformations occur in this corticostriatal system, we investigated how electrophysiologically defined regions of the primary somatosensory cortex (SI) project to the striatum in the squirrel monkey (Saimiri sciureus). Receptive fields in the hand, mouth, and foot representations of cortical areas 3a, 3b, and 1 were mapped by multiunit recording; and small volumes of distinguishable anterograde tracers were injected into different body-part representations in single SI areas. 2. Analysis of labeled projections established that at least four types of systematic remapping occur in the primate corticostriatal system. 1) An area of cortex representing a single body part sends fibers that diverge to innervate multiple regions in the putamen, forming branching, patchy fields that are densest in the lateral putamen. The fields do not form elongated cylindrical forms; rather, they are nearly as extended mediolaterally as they are rostrocaudally. 2) Cortical regions representing hand, mouth, and foot send globally somatotopic, nonoverlapping projections to the putamen, but regions with closely related representations (such as those of the thumb and 5th finger in area 3b) send convergent, overlapping corticostriatal projections. The overlap is fairly precise in the caudal putamen, but in the rostral putamen the densest zones of the projections do not overlap. 3) Regions representing homologous body parts in different SI cortical areas send projections that converge in the putamen. This was true of paired projections from areas 3a and 3b, and from areas 3b and 1. Thus corticostriatal inputs representing distinct somatosensory submodalities can project to the same local regions within the striatum. Convergence is not always complete, however: in the rostral putamen of two cases comparing projections from areas 3a and 1, the densest zones of the projections did not overlap. 4) All projections from SI avoid striosomes and innervate discrete zones within the matrix. 3. These experiments demonstrate that the somatosensory representations of the body are reorganized as they are projected from SI to the somatosensory sector of the primate putamen. This remapping suggests that the striatal representation of the body may be functionally distinct from that of each area of SI. The patchy projections may provide a basis for redistribution of somatosensory information to discrete output systems in the basal ganglia. Transformations in the corticostriatal system could thus be designed for modulating different movement-related programs.

Previous studies of the motor cortex in behaving animals were focused on the relations between the activity of single cells, usually pyramidal tract neurons, and parameters of isometric contraction (e.g., intensity of force) or parameters of movement along one axis (e.g., flexion–extension) of a single joint (e.g., elbow or wrist). However, the commonly meaningful behavioral parameter is the trajectory of the hand in extrapersonal space, which is realized by simultaneous motions about two or three joints (e.g., elbow, shoulder, wrist) and concurrent engagement of several muscles. The spatial parameters of a straight trajectory are its direction and extent. We hypothesized that a major function of the motor cortex, among other possible roles, is the specification and control of the direction of the movement trajectory in space. This reference of motor cortical function to the control of spatial aspects of the trajectory differentiated our approach from the other approaches outlined above. We investigated the directional selectivity cells in the arm area of the motor cortex by recording their activity while monkeys moved their hands in various directions in space towards visual targets. There were two salient findings of these studies. First, the intensity of the discharge of single cells varies in an orderly fashion with the direction of movement in space, so that the discharge rate is highest with movements in a preferred direction, and decreases progressively with movements made in directions more and more away from the preferred one. Thus single cells are broadly tuned around a preferred direction which differs among different cells. The second finding of our studies is a code by which this neuronal population can represent uniquely the direction of the trajectory in space. The outcome of this population code can be visualized as a vector in space that points in the direction of the movement well before the movement begins, and even in the absence of immediate movement. These results establish the motor cortex as a nodal point in the construction of motor signals controlling the direction of hand trajectory in space. Moreover, the population coding of direction may be of more general significance concerning the representation of information in neuronal ensembles and has been applied successfully to other areas of neurophysiological research.

An evolutionary hallmark of anthropoid primates, including humans, is the use of vision to guide precise manual movements. These behaviors are reliant on a specialized visual input to the posterior parietal cortex. Here, we show that normal primate reaching-and-grasping behavior depends critically on a visual pathway through the thalamic pulvinar, which is thought to relay information to the middle temporal (MT) area during early life and then swiftly withdraws. Small MRI-guided lesions to a subdivision of the inferior pulvinar subnucleus (PIm) in the infant marmoset monkey led to permanent deficits in reaching-and-grasping behavior in the adult. This functional loss coincided with the abnormal anatomical development of multiple cortical areas responsible for the guidance of actions. Our study reveals that the transient retino–pulvinar–MT pathway underpins the development of visually guided manual behaviors in primates that are crucial for interacting with complex features in the environment.

The neural correlates of bilateral upper limb movement are poorly understood. It has been proposed that interhemispheric pathways contribute to the modulation of motor cortical excitability during bimanual movements, possibly via direct connections between primary motor areas (M1), or via a central cortical structure, such as the supplementary motor area (SMA). The ability of one hemisphere to facilitate activation in the other presents a unique opportunity for motor rehabilitation programs using bilateral movements. The focus of this thesis was to investigate the mechanisms underlying bimanual movements in a group of healthy control participants using functional magnetic resonance imaging (fMRI), and subsequently to identify the types of movements that are most likely to maximize M1 activity. It was hypothesized first, that movements involving more proximal muscles, which are known to have a greater number of transcallosal connections, would produce a larger facilitation of M1 activity; and secondly, that the greatest facilitation would occur during those phases of movements where homologous muscles are active simultaneously (i.e. in-phase bilateral movements). The current results demonstrate that the M1 regions and the SMA work together to modulate motor cortical excitability, and that the greatest modulation of activity is seen during movements involving proximal muscles. The findings presented may have clinical relevance to motor rehabilitation programs involving bilateral movements.

Chez les primates, le raffinement des mouvements de la main est associé à l’apparition d’aires prémotrices corticales additionnelles. Chacune de ces aires prémotrices semble avoir une fonction spécialisée dans le contrôle moteur de la main, appuyant l’idée qu’elles sont apparues au cours de l’évolution afin de soutenir un répertoire comportemental accru. Afin de participer à l’exécution de ce vaste répertoire, il est suggéré que les aires prémotrices modulent les efférences du cortex moteur primaire (M1), une aire corticale jouant un rôle clé dans la production des mouvements volontaires. En effet, grâce à leurs nombreuses projections cortico-corticales vers M1 ainsi que leurs projections vers des structures sous-corticales qui sont également innervées par M1, les aires prémotrices se trouvent dans une position idéale pour moduler les efférences motrices de M1. Néanmoins, la contribution de ces projections anatomiques à la production des mouvements de la main demeure peu comprise. La fonction de ces projections est toutefois importante à investiguer afin de mieux comprendre les interactions corticales qui sous-tendent l’augmentation du répertoire des mouvements de la main chez les primates. S’intégrant dans ce contexte de recherche, les expériences présentées dans cette thèse visent à caractériser les interactions corticales entre les aires prémotrices et M1 qui sont impliquées dans les mouvements de la main chez le singe capucin. Dans une première étude, les effets modulateurs du cortex prémoteur ventral (PMv) sur les efférences de M1 ont été investigués (Chapitre I). Dans une seconde étude, les effets modulateurs du cortex prémoteur dorsal (PMd) ont été étudiés et comparés à ceux de PMv (Chapitre II). Finalement, dans une troisième étude, les effets modulateurs de l’aire supplémentaire motrice (SMA) ont été examinés et comparés à ceux de PMv et de PMd (Chapitre III). En résumé, les résultats présentés dans cette thèse offrent une nouvelle perspective quant aux interactions corticales liant les aires prémotrices à M1. Il est démontré que chaque aire prémotrice influence les efférences de M1 de manière unique. Ceci appuie l’idée que chaque aire prémotrice joue un rôle spécialisé dans le contrôle moteur de la main et est en mesure d’accomplir cette fonction, entre autres, à travers sa modulation des efférences motrices de M1. Ces résultats contribuent à une meilleure compréhension des interactions corticales qui sous-tendent le raffinement des mouvements de la main accompagnant l’évolution du système moteur.
In primates, the refinement of hand movements is associated with the appearance of additional cortical premotor areas. Each of these premotor areas appears to have a specialized function in the motor control of the hand, supporting the idea that they have appeared during evolution to support an increased behavioral repertoire. In order to participate in the execution of this vast repertoire, it is suggested that the premotor areas modulate the motor outputs of the primary motor cortex (M1), a cortical area that plays a key role in the production of voluntary movements. Indeed, thanks to their numerous cortico-cortical projections to M1 as well as their projections to sub-cortical structures also innervated by M1, premotor areas are in an ideal position to modulate the motor outputs of M1. Nevertheless, the contribution of these anatomical projections to the production of hand movements is still unclear. The function of these projections, however, is important to investigate in order to better understand the cortical interactions that underlie the increased motor repertoire of primates. As an integral part of this research context, the experiments presented in this thesis aim to characterize the cortical interactions between the premotor areas and M1 involved in hand movements in the capuchin monkey. In a first study, the modulatory effects of ventral premotor cortex (PMv) on M1 outputs were investigated (Chapter I). In a second study, the modulatory effects of the dorsal premotor cortex (PMd) were studied and compared to those of PMv (Chapter II). Lastly, in a third study, the modulatory effects of the supplementary motor area (SMA) were examined and compared to those of PMv and PMd (Chapter III). In summary, the results presented in this thesis offer a new perspective on the cortical interactions linking the premotor areas to M1. It is shown that each premotor area influences the outputs of M1 in a unique way. This supports the idea that each premotor area plays a specialized role in the motor control of the hand and is able to accomplish this function, in part, through its modulation of M1 outputs. These results contribute to a better understanding of the cortical interactions that underlie the refinement of hand movements accompanying the evolution of the motor system.

There is extensive machinery at cerebral and spinal levels to support voluntary movement, but spinal mechanisms are often ignored by clinicians and researchers. For movements of the upper and lower limbs, what the brain commands can be modified or even suppressed completely at spinal level. The corticospinal system is the executive pathway for movement arising largely from primary motor cortex, but movement is not initiated there, and other pathways normally contribute to movement. Greater use of these pathways can allow movement to be restored when the corticospinal system is damaged by, e.g. stroke, but there can be unwanted consequences of this ‘plasticity’. There is an extensive literature on cerebral mechanisms in the control of movement, and an equally large literature on spinal reflex function and the changes that occur during movement, and when pathology results in weakness and/or spasticity.

This article reviews studies on the brains of musicians. Making music not only engages primary auditory and motor regions and the connections between them, but also regions that integrate and connect areas involved in both auditory and motor operations, as well as in the integration of other multisensory information. Professional instrumentalists learn and repeatedly practice associating hand/finger movements with meaningful patterns in sound, and sounds and movements with specific visual patterns (notation) while receiving continuous multisensory feedback. Learning to associate actions with particular sounds leads to functional but also structural changes in frontal cortices.

This chapter briefly reviews recent empirical research on touch, including the role of touch in early development, emotions that can be conveyed by touch, the importance of touch for interpersonal relationships, and how friendly touch affects compliance in different situations. Physiological and biochemical effects of touch are also reviewed, including decreased heart rate, blood pressure and cortisol, and increased oxytocin. The beneficial effects of touch, including massage therapy, for socioemotional and physical well-being are explained in light of the importance of mother–infant contact in all primate species. To develop normally, primate infants and human babies need much physical contact with their mothers; touch deprivation is one of the most pathogenic condition for a young primate. The second part of the chapter analyzes how cultural evolution has elaborated the natural predisposition toward affiliative touch, creating complex rituals and specific taboos. Finally, the chapter briefly discusses “displacement activities” that consist mostly of movements focused on one’s own body, such as self-touching, scratching, and self-grooming.

We don’t perceive the world and then react to it. We learn to know it from our interactions with it. All inputs that reach the cerebral cortex about events in the brain, the body, or the world bring two messages: one is about these events, the other, travelling along a branch of that input, is an instruction already on its way to execution. This second message, not a part of standard textbook teaching, allows us to anticipate our actions, distinguishing them from the actions of others, and thus providing a clear sense of self. The mammalian brain has a hierarchy of cortical areas, where higher areas monitor actions of lower areas, and each area can modify actions to be executed by the phylogenetically older brain parts. Brains of our premammalian ancestors lacked this hierarchy, but their descendants are still strikingly capable of movement control: frogs can catch flies. The cortical hierarchy itself appears to establish and increase, from lower to higher levels, our conscious access to events. This book explores the neural connections that provide us with a sense of self and generate our conscious experiences. It reveals how much yet needs to be learnt about the relevant neural pathways.

This chapter discusses the use of somatosensory evoked potentials (SEPs) and pain evoked potentials for diagnostic purposes. The generators of SEPs following upper limb stimulation have been identified through intracranial recordings, permitting the analysis of somatosensory disorders caused by neurological diseases. Laser activation of fibers involved in thermal and pain sensation has extended the applications of evoked potentials to neuropathic pain disorders. Knowledge of the effects of motor programming, paired stimulations, and simultaneous stimulation of adjacent somatic territories has broadened SEP use in movement disorders. The recording of high-frequency cortical oscillations evoked by peripheral nerve stimulation gives access to the functioning of SI area neuronal circuitry. SEPs complement electro-neuro-myography in patients with neuropathies and radiculopathies, spinal cord and hemispheric lesions, and coma. Neuroimaging has overtaken SEPs in detecting and localizing central nervous system lesions, but SEPs still permit assessment of somatosensory and pain disorders that remain unexplained by anatomical investigations.

Bones are multifunctional passive organs of movement that supports soft tissue and directly attached muscles. They also protect internal organs and are a reserve of calcium, phosphorus and magnesium. Each bone is covered with periosteum, and the adjacent bone surfaces are covered by articular cartilage. Histologically, the bone is an organ composed of many different tissues. The main component is bone tissue (cortical and spongy) composed of a set of bone cells and intercellular substance (mineral and organic), it also contains fat, hematopoietic (bone marrow) and cartilaginous tissue. Bones are a tissue that even in adult life retains the ability to change shape and structure depending on changes in their mechanical and hormonal environment, as well as self-renewal and repair capabilities. This process is called bone turnover. The basic processes of bone turnover are: • bone modeling (incessantly changes in bone shape during individual growth) following resorption and tissue formation at various locations (e.g. bone marrow formation) to increase mass and skeletal morphology. This process occurs in the bones of growing individuals and stops after reaching puberty • bone remodeling (processes involve in maintaining bone tissue by resorbing and replacing old bone tissue with new tissue in the same place, e.g. repairing micro fractures). It is a process involving the removal and internal remodeling of existing bone and is responsible for maintaining tissue mass and architecture of mature bones. Bone turnover is regulated by two types of transformation: • osteoclastogenesis, i.e. formation of cells responsible for bone resorption • osteoblastogenesis, i.e. formation of cells responsible for bone formation (bone matrix synthesis and mineralization) Bone maturity can be defined as the completion of basic structural development and mineralization leading to maximum mass and optimal mechanical strength. The highest rate of increase in pig bone mass is observed in the first twelve weeks after birth. This period of growth is considered crucial for optimizing the growth of the skeleton of pigs, because the degree of bone mineralization in later life stages (adulthood) depends largely on the amount of bone minerals accumulated in the early stages of their growth. The development of the technique allows to determine the condition of the skeletal system (or individual bones) in living animals by methods used in human medicine, or after their slaughter. For in vivo determination of bone properties, Abstract 10 double energy X-ray absorptiometry or computed tomography scanning techniques are used. Both methods allow the quantification of mineral content and bone mineral density. The most important property from a practical point of view is the bone’s bending strength, which is directly determined by the maximum bending force. The most important factors affecting bone strength are: • age (growth period), • gender and the associated hormonal balance, • genotype and modification of genes responsible for bone growth • chemical composition of the body (protein and fat content, and the proportion between these components), • physical activity and related bone load, • nutritional factors: – protein intake influencing synthesis of organic matrix of bone, – content of minerals in the feed (CA, P, Zn, Ca/P, Mg, Mn, Na, Cl, K, Cu ratio) influencing synthesis of the inorganic matrix of bone, – mineral/protein ratio in the diet (Ca/protein, P/protein, Zn/protein) – feed energy concentration, – energy source (content of saturated fatty acids - SFA, content of polyun saturated fatty acids - PUFA, in particular ALA, EPA, DPA, DHA), – feed additives, in particular: enzymes (e.g. phytase releasing of minerals bounded in phytin complexes), probiotics and prebiotics (e.g. inulin improving the function of the digestive tract by increasing absorption of nutrients), – vitamin content that regulate metabolism and biochemical changes occurring in bone tissue (e.g. vitamin D3, B6, C and K). This study was based on the results of research experiments from available literature, and studies on growing pigs carried out at the Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences. The tests were performed in total on 300 pigs of Duroc, Pietrain, Puławska breeds, line 990 and hybrids (Great White × Duroc, Great White × Landrace), PIC pigs, slaughtered at different body weight during the growth period from 15 to 130 kg. Bones for biomechanical tests were collected after slaughter from each pig. Their length, mass and volume were determined. Based on these measurements, the specific weight (density, g/cm3) was calculated. Then each bone was cut in the middle of the shaft and the outer and inner diameters were measured both horizontally and vertically. Based on these measurements, the following indicators were calculated: • cortical thickness, • cortical surface, • cortical index. Abstract 11 Bone strength was tested by a three-point bending test. The obtained data enabled the determination of: • bending force (the magnitude of the maximum force at which disintegration and disruption of bone structure occurs), • strength (the amount of maximum force needed to break/crack of bone), • stiffness (quotient of the force acting on the bone and the amount of displacement occurring under the influence of this force). Investigation of changes in physical and biomechanical features of bones during growth was performed on pigs of the synthetic 990 line growing from 15 to 130 kg body weight. The animals were slaughtered successively at a body weight of 15, 30, 40, 50, 70, 90, 110 and 130 kg. After slaughter, the following bones were separated from the right half-carcass: humerus, 3rd and 4th metatarsal bone, femur, tibia and fibula as well as 3rd and 4th metatarsal bone. The features of bones were determined using methods described in the methodology. Describing bone growth with the Gompertz equation, it was found that the earliest slowdown of bone growth curve was observed for metacarpal and metatarsal bones. This means that these bones matured the most quickly. The established data also indicate that the rib is the slowest maturing bone. The femur, humerus, tibia and fibula were between the values of these features for the metatarsal, metacarpal and rib bones. The rate of increase in bone mass and length differed significantly between the examined bones, but in all cases it was lower (coefficient b <1) than the growth rate of the whole body of the animal. The fastest growth rate was estimated for the rib mass (coefficient b = 0.93). Among the long bones, the humerus (coefficient b = 0.81) was characterized by the fastest rate of weight gain, however femur the smallest (coefficient b = 0.71). The lowest rate of bone mass increase was observed in the foot bones, with the metacarpal bones having a slightly higher value of coefficient b than the metatarsal bones (0.67 vs 0.62). The third bone had a lower growth rate than the fourth bone, regardless of whether they were metatarsal or metacarpal. The value of the bending force increased as the animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. The rate of change in the value of this indicator increased at a similar rate as the body weight changes of the animals in the case of the fibula and the fourth metacarpal bone (b value = 0.98), and more slowly in the case of the metatarsal bone, the third metacarpal bone, and the tibia bone (values of the b ratio 0.81–0.85), and the slowest femur, humerus and rib (value of b = 0.60–0.66). Bone stiffness increased as animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. Abstract 12 The rate of change in the value of this indicator changed at a faster rate than the increase in weight of pigs in the case of metacarpal and metatarsal bones (coefficient b = 1.01–1.22), slightly slower in the case of fibula (coefficient b = 0.92), definitely slower in the case of the tibia (b = 0.73), ribs (b = 0.66), femur (b = 0.59) and humerus (b = 0.50). Bone strength increased as animals grew. Regardless of the growth point tested, bone strength was as follows femur > tibia > humerus > 4 metacarpal> 3 metacarpal> 3 metatarsal > 4 metatarsal > rib> fibula. The rate of increase in strength of all examined bones was greater than the rate of weight gain of pigs (value of the coefficient b = 2.04–3.26). As the animals grew, the bone density increased. However, the growth rate of this indicator for the majority of bones was slower than the rate of weight gain (the value of the coefficient b ranged from 0.37 – humerus to 0.84 – fibula). The exception was the rib, whose density increased at a similar pace increasing the body weight of animals (value of the coefficient b = 0.97). The study on the influence of the breed and the feeding intensity on bone characteristics (physical and biomechanical) was performed on pigs of the breeds Duroc, Pietrain, and synthetic 990 during a growth period of 15 to 70 kg body weight. Animals were fed ad libitum or dosed system. After slaughter at a body weight of 70 kg, three bones were taken from the right half-carcass: femur, three metatarsal, and three metacarpal and subjected to the determinations described in the methodology. The weight of bones of animals fed aa libitum was significantly lower than in pigs fed restrictively All bones of Duroc breed were significantly heavier and longer than Pietrain and 990 pig bones. The average values of bending force for the examined bones took the following order: III metatarsal bone (63.5 kg) <III metacarpal bone (77.9 kg) <femur (271.5 kg). The feeding system and breed of pigs had no significant effect on the value of this indicator. The average values of the bones strength took the following order: III metatarsal bone (92.6 kg) <III metacarpal (107.2 kg) <femur (353.1 kg). Feeding intensity and breed of animals had no significant effect on the value of this feature of the bones tested. The average bone density took the following order: femur (1.23 g/cm3) <III metatarsal bone (1.26 g/cm3) <III metacarpal bone (1.34 g / cm3). The density of bones of animals fed aa libitum was higher (P<0.01) than in animals fed with a dosing system. The density of examined bones within the breeds took the following order: Pietrain race> line 990> Duroc race. The differences between the “extreme” breeds were: 7.2% (III metatarsal bone), 8.3% (III metacarpal bone), 8.4% (femur). Abstract 13 The average bone stiffness took the following order: III metatarsal bone (35.1 kg/mm) <III metacarpus (41.5 kg/mm) <femur (60.5 kg/mm). This indicator did not differ between the groups of pigs fed at different intensity, except for the metacarpal bone, which was more stiffer in pigs fed aa libitum (P<0.05). The femur of animals fed ad libitum showed a tendency (P<0.09) to be more stiffer and a force of 4.5 kg required for its displacement by 1 mm. Breed differences in stiffness were found for the femur (P <0.05) and III metacarpal bone (P <0.05). For femur, the highest value of this indicator was found in Pietrain pigs (64.5 kg/mm), lower in pigs of 990 line (61.6 kg/mm) and the lowest in Duroc pigs (55.3 kg/mm). In turn, the 3rd metacarpal bone of Duroc and Pietrain pigs had similar stiffness (39.0 and 40.0 kg/mm respectively) and was smaller than that of line 990 pigs (45.4 kg/mm). The thickness of the cortical bone layer took the following order: III metatarsal bone (2.25 mm) <III metacarpal bone (2.41 mm) <femur (5.12 mm). The feeding system did not affect this indicator. Breed differences (P <0.05) for this trait were found only for the femur bone: Duroc (5.42 mm)> line 990 (5.13 mm)> Pietrain (4.81 mm). The cross sectional area of the examined bones was arranged in the following order: III metatarsal bone (84 mm2) <III metacarpal bone (90 mm2) <femur (286 mm2). The feeding system had no effect on the value of this bone trait, with the exception of the femur, which in animals fed the dosing system was 4.7% higher (P<0.05) than in pigs fed ad libitum. Breed differences (P<0.01) in the coross sectional area were found only in femur and III metatarsal bone. The value of this indicator was the highest in Duroc pigs, lower in 990 animals and the lowest in Pietrain pigs. The cortical index of individual bones was in the following order: III metatarsal bone (31.86) <III metacarpal bone (33.86) <femur (44.75). However, its value did not significantly depend on the intensity of feeding or the breed of pigs.

Inhibitory mechanisms are crucial for the integrated operation of the motor cortical circuit. Local inhibition is exerted by interneurons that are GABAergic, nonpyramidal cells with short, nonprojecting axons. Interneurons can be classified into at least two groups: fast-spiking (FS) neurons and instrinsic bursting (IB) neurons. In the primary motor cortex, FS cells may sculpe the tuning dispersion of directionally selective putative pyramidal cells during reaching in behaving monkeys. Analysis of putative interneuronal activity also allowed to discard the role of inhibition as a gating mechanism in motor control. The development of high-density, semichronic electrode systems for extracellular recordings in behaving primates will allow a closer investigation of the role of interneuronal inhibition in directional tuning and voluntary motor control. The results discussed in this chapter agree with the authors’ proposal that local inhibitory mechanisms may be intimately involved in controlling the directional accuracy and speed of the reaching movement.

In this chapter, a mummified monkey’s paw causes big trouble; a bushbaby eyes a wicked witch; and a monkey pigs out on fresh berries. But mainly we consider memories that evolved in early primates. As these ancestors adapted to a life in the trees, they became a lot like us. They developed forward-facing eyes and grasping hands; guided reaching movements with vision; moved themselves with their legs; and had a large brain. New cortical areas helped these ancestors survive by using new memories: of how to reach accurately while perched on swaying branches; of the precise amount of force needed to grasp valuable items; of the location and value of items hidden in a clutter of branches and leaves; and of objects and actions linked to a hidden food item’s desirability.

This chapter draws on a range of studies of macaque and humans to forge an anatomical scheme for the control of gaze. At each stage, this scheme is used to predict effects of focal lesions on the control of gaze, with video examples. Contributions include the abducens nucleus, medial longitudinal fasciculus (MLF), and paramedian pontine reticular formation (PPRF) to horizontal gaze; the rostral interstitial nucleus of the medial longitudinal fasciculus (RIMLF), interstitial nucleus of Cajal, and posterior commissure to vertical gaze; cerebellar flocculus, paraflocculus, dorsal vermis, fastigial nucleus, and inferior olive to adaptive optimization of gaze. Cortical control of gaze by structures including primary visual cortex (V1), middle temporal visual area (MT, V5), medial superior temporal visual area (MST), posterior parietal cortex, frontal eye fields, supplementary eye fields, dorsolateral prefrontal cortex, cingulate cortex, descending pathways, thalamus, pulvinar, caudate, substantia nigra pars reticulata, subthalamic nucleus, and superior colliculus are each discussed.

Oral cancer is first treated with surgery for the patients. In most cases, it becomes difficult for these patients to perform smooth jaw movements postoperatively, causing masticatory dysfunctions, due to the mandible excision including muscles and peripheral nerves. However, it is still unknown whether the surgery affects the brain function for jaw movement in the patients. In this study, therefore, we investigated a significance of the movement-related cortical potential (MRCP) for jaw movements in the patients after the cancer surgery, to clarify the motor preparation process in the brain, as compared with healthy subjects. Eight normal subjects and seven patients with oral cancers were enrolled in the study. Experiment 1: The normal subjects were instructed to perform jaw-biting movement and hand movement, respectively. The MRCPs appeared bilaterally over the scalp approximately 1 to 2 s before the onset of muscle discharge in both movements. Experiment 2: The MRCPs appeared preoperatively in the jaw biting movement in all patients. However, the amplitudes of the MRCP decreased significantly after than before the surgery (p < 0.05). Our data indicated the dysfunction of the motor preparation process for jaw movements in the patient after the surgery, suggesting impairment of feed-forward system in the maxillofacial area.

This chapter explains why visual motion perception is not just perception of the changing positions of moving objects. Computationally complementary processes process static objects with different orientations, and moving objects with different motion directions, via parallel cortical form and motion streams through V2 and MT. The motion stream pools multiple oriented object contours to estimate object motion direction. Such pooling coarsens estimates of object depth, which require precise matches of oriented stimuli from both eyes. Negative aftereffects of form and motion stimuli illustrate these complementary properties. Feature tracking signals begin to overcome directional ambiguities due to the aperture problem. Motion capture by short-range and long-range directional filters, together with competitive interactions, process feature tracking and ambiguous motion directional signals to generate a coherent representation of object motion direction and speed. Many properties of motion perception are explained, notably barberpole illusion and properties of long-range apparent motion, including how apparent motion speed varies with flash interstimulus interval, distance, and luminance; apparent motion of illusory contours; phi and beta motion; split motion; gamma motion; Ternus motion; Korte’s Laws; line motion illusion; induced motion; motion transparency; chopsticks illusion; Johannson motion; and Duncker motion. Gaussian waves of apparent motion clarify how tracking occurs, and explain spatial attention shifts through time. This motion processor helps to quantitatively simulate neurophysiological data about motion-based decision-making in monkeys when it inputs to a model of how the lateral intraparietal, or LIP, area chooses a movement direction from the motion direction estimate. Bayesian decision-making models cannot explain these data.

Traumatic brain injuries (TBIs) involve a significant portion of human injuries resulting from a wide range of civilian accidents as well as many military scenarios. Axonal damage is one of the most common and important pathologic features of traumatic brain injury. Axons become brittle when exposed to rapid deformations associated with brain trauma. Accordingly, rapid stretch of axons can damage the axonal cytoskeleton, resulting in a loss of elasticity and impairment of axoplasmic transport. Subsequent swelling of the axon occurs in discrete bulb formations or in elongated varicosities that accumulate organelles. Ultimately, swollen axons may become disconnected [1]. The shock waves generated by a blast, subject all the organs in the head to displacement, shearing and tearing forces. The brain is especially vulnerable to these forces — the fronts of compressed air waves cause rapid forward or backward movements of the head, so that the brain rattles against the inside of the skull. This can cause subdural hemorrhage and contusions. The forces exerted on the brain by shock waves are known to damage axons in the affected areas. This axonal damage begins within minutes of injury, and can continue for hours or days following the injury [2]. Shock waves are also known to damage the brain at the subcellular level, but exactly how remains unclear. Kato et al., [3] described the effects of a small controlled explosion on rats’ brain tissue. They found that high pressure shock waves led to contusions and hemorrhage in both cortical and subcortical brain regions. Based on their result, the threshold for shock wave-induced brain injury is speculated to be under 1 MPa. This is the first report to demonstrate the pressure-dependent effect of shock wave on the histological characteristics of brain tissue. An important step in understanding the primary blast injury mechanism due to explosion is to translate the global head loads to the loading conditions, and consequently damage, of the cells at the local level and to project cell level and tissue level injury criteria towards the level of the head. In order to reach this aim, we have developed a multi-scale non-linear finite element modeling to bridge the micro- and macroscopic scales and establish the connection between microstructure and effective behavior of brain tissue to develop acceptable injury threshold. Part of this effort has been focused on measuring the shock waves created from a blast, and studying the response of the brain model of a human head exposed to such an environment. The Arbitrary Lagrangian Eulerian (ALE) and Fluid/Solid Interactions (FSI) formulation have been used to model the brain-blast interactions. Another part has gone into developing a validated fiber-matrix based micro-scale model of a brain tissue to reproduce the effective response and to capturing local details of the tissue’s deformations causing axonal injury. The micro-model of the axon and matrix is characterized by a transversely isotropic viscoelastic material and the material model is formulated for numerical implementation. Model parameters are fit to experimental frequency response of the storage and loss modulus data obtained and determined using a genetic algorithm (GA) optimizing method. The results from macro-scale model are used in the micro-scale brain tissue to study the effective behavior of this tissue under injury-based loadings. The research involves the development of a tool providing a better understanding of the mechanical behavior of the brain tissue against blast loads and a rational multi-scale approach for driving injury criteria.