Somatosensory system

About: Somatosensory system is a research topic. Over the lifetime, 6371 publications have been published within this topic receiving 316900 citations.

Neuronal correlates of decision-making in secondary somatosensory cortex

Abstract: The ability to discriminate between two sequential stimuli requires evaluation of current sensory information in reference to stored information Where and how does this evaluation occur? We trained monkeys to compare two mechanical vibrations applied sequentially to the fingertips and to report which of the two had the higher frequency We recorded single neurons in secondary somatosensory cortex (S2) while the monkeys performed the task During the first stimulus period, the firing rate of S2 neurons encoded the stimulus frequency During the second stimulus period, however, some S2 neurons did not merely encode the stimulus frequency The responses of these neurons were a function of both the remembered (first) and current (second) stimulus Moreover, a few hundred milliseconds after the presentation of the second stimulus, these responses were correlated with the monkey's decision This suggests that some S2 neurons may combine past and present sensory information for decision-making

Abnormal somatosensory homunculus in dystonia of the hand

Abstract: Abnormalities of the sensory system have been proposed as causative factors for dystonia. By mapping the human cortical hand somatosensory area of 6 patients with focal dystonia of the hand, we found an abnormality of the normal homuncular organization of the finger representations in the primary somatosensory cortex (S1). Although a remote antecedent event or even a developmental anomaly cannot entirely be ruled out, our findings may support the concept that abnormal plasticity is involved in the development of dystonia.

Single cell studies of the primate putamen. I. Functional organization.

Abstract: In order to clarify the functional organization of the putamen and the nature of sensory inputs to this structure we studied the relation of single cell activity to active movements and somatosensory stimulation in the awake primate. Neurons (N = 707) were categorized on the basis of their relation to active movements or responses to sensory stimulation of individual body parts. 38% of neurons studied were related to the arm, 9% to the leg, 11% to the mouth or face, and 3% to axial portions of the body. The remaining neurons exhibited non-specific activation which could not be confidently localized to an individual body part (12%) or did not respond during the examination (26%). The high proportion of arm neurons was due to the focus of this study on cells related to arm movements. A large proportion (41%; N = 270) of the “arm” neurons was responsive to somatosensory stimulation. For these neurons the most effective stimulus (82%) was passive joint rotation. Six (5%) of the arm neurons responded to cutaneous stimulation. The putamen was found to be somatotopically organized. Neurons related to different body parts (leg, arm, and face) were segregated, and each body part was represented over a long anteroposterior extent of the nucleus. Clusters of 2–5 neurons with similar relations to active movements or responsive to passive movements of a single joint were often encountered over a 100–500 μ distance. Clusters of neurons with sensory driving were organized by joints. Rather than a single elbow or shoulder area, multiple clusters of neurons related to each joint were widely distributed over a long anteroposterior extent of the nucleus and were adjacent to clusters of neurons related to other joints of the arm. These clusters of neurons with similar functional properties may correspond to the subunits of the striatum which have been revealed by anatomic and morphologic studies. We propose that these clusters of neurons with similar functional properties represent the basic functional units of the striatum in a manner analogous to the functional columns of the neocortex.

The Vestibular Cortex: Its Locations, Functions, and Disorders

Abstract: The two major cortical functions of the vestibular system are spatial orientation and self-motion perception. These functions, however, are not exclusively vestibular; they also rely on visual and somatosensory input. All three systems (vestibular, visual and somatosensory) provide us with redundant information about the position and motion of our body relative to the external space. Although the vestibular cortex function is distributed among several multisensory areas in the parietal and temporal cortices, it is also integrated in a larger network for spatial attention and sensorimotor control of eye and body motion in space.