Parallel Processing of Cutaneous Information in the Somatosensory System of the Cat

Dykes, Robert W.

doi:10.1017/s0317167100043560

Cited by 11 publications

(6 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, it would be useful to know whether local circuit neurons are the special targets of descending projections from cortical layer VI neurons (Jones and Wise, 1977;Wise and Jones, 1977) and whether they receive fibers from brain stem centers that are not identified with one single sensory system and, thus, may convey signals about the general state of the organism. Finally, since the ventral posterior nucleus represents the body surface as well as different receptors or "submodalities" (Dykes, 1982), it is natural to wonder whether inhibitory local circuit cells play any role in adjusting the threshold for somatotopic discrimination or in relating information conveyed by the various submodalities.…”

Section: Discussionmentioning

confidence: 99%

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Penny¹,

Fitzpatrick²,

Schmechel³

et al. 1983

J. Neurosci.

116

View full text Add to dashboard Cite

Immunocytochemical methods were used to identify neurons in the ventral posterior nucleus of the cat and Galago senegalensis that contain glutamic acid decarboxylase (GAD), the synthetic enzyme for the inhibitory neurotransmitter, GABA. In both species GAD-immunoreactive neurons make up about 30% of the total neurons in the ventral posterior nucleus and form a distinct class of small cells. After cortical injections of horseradish peroxidase (HRP), GAD-immunoreactive cells are not labeled with HRP and may, therefore, be GABAergic local circuit neurons. Comparison of the dendritic morphology of GAD-immunoreactive neurons with that of HRP-filled projection neurons reveals that the morphology of the GAD-containing neurons is distinct and, in particular, that the GAD-immunoreactive neurons display fewer primary dendrites. The relay neurons, in turn, can be divided into classes based on dendritic morphology and cell body size.The idea that thalamic neurons could be divided into classes based on morphological criteria has a long history. According to Rambn y Cajal (1909, the most fundamental distinction was between the neurons with long axons that project to the cerebral cortex and neurons with short axons that were thought to be local circuit neurons. Cajal found the neurons with short axons or "cellules 6 cylindre-axe court" to be distributed widely in the nervous system and to be especially numerous in the thalamus and neocortex of higher mammals. The neurons with long axons (or projection neurons) could be further subdivided into classes based on their appearance in Golgi material. T6mb61 recently (1967) identified at least two classes in the case of the somatosensory ventral posterior nucleus of the cat.

show abstract

Section: Discussionmentioning

confidence: 99%

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Penny¹,

Fitzpatrick²,

Schmechel³

et al. 1983

J. Neurosci.

116

View full text Add to dashboard Cite

show abstract

“…The dorsal column-medial lemnlscal system and parietal cortex medlate sensations of proprioception, two-point discrimination, point localization, stereognosis, position sense, klnesthesia and directionality (Carlson, 1981;Dykes. 1982;Roland.…”

Section: Sommairementioning

confidence: 99%

“…Thus, the majority of the neurons in 3a are activated by subcutaneous muscle spindle afferents, area 3b by cutaneous inputs, area 1 by a mixture of cutaneous and deep afferents, and area 2 neurons are excited by deep receptors. Area 1 can be differentiated from area 3b as it has been shown ta receive Pacinian corpuscle inputs (Dykes, 1982;Paul et al, 1972). Recent studies have shown the existence of many homunculi in the 8 1 of higher primates.…”

Section: Somatosensorv Systemmentioning

confidence: 99%

“…Sensory inputs to 8 1 originate from the contralateral body surface, whereas S Il receives inputs from both the ipsilateral and the contralateral side of the body (Dykes, 1982;Kandel and Jessel, 1991). Afferent inputs are also relayed to the posterior panetal lobule consisting of Broadmann area 5 and portions of area 7.…”

Section: Somatosensorv Systemmentioning

confidence: 99%

“…Unilateral lesions of the thalamus InvolvinQ the VPL complex may cause defects on the contralateral slde of the body involv:ng the modalities of pressure, temperalure and kmesthesla (Norsell, 1980). Removal of the S 1 in primates may result ln sensory deficits such as decreased 2pd, point locallzatlon, stereognosls, position sense, kinesthesia and tactual discrimination on the contralateral side (Carlson, 1981;Corkm et al, 1970;Darlan-Smith et al, 1982;Roland, 1987;Semmes and Turner, 1977) Severe impairments in tactile learning and memory may result from bilateral excision of S 1/ with relative sparmg of tactile sensitivity, or welgtlt discrimination (Dykes, 1982;Rldley and Ettlinger, 1976;Sem mes and Porter, 1972). Thus S Il probably has a greater bearing on sensory-motor integration than on dlscrim!natory uses (Roland, 1987).…”

Section: Somatosensorv Systemmentioning

confidence: 99%

See 2 more Smart Citations

The Determination of Sensory Deficits in Children With Hemiplegic Cerebral Palsy

et al. 1995

View full text Add to dashboard Cite

Cerebral paisy is a non-progressive disorder associated with brain in jury, detect, or dlsease, of early onset. Emphasis IS placed on the more easily observable motor deficits, with any underlying sensory deficits often being overlooked. Existing sensory assessments have either been standardized on an adult population or for a paediatric population without significant neuromotor impalrment. Thus, there is a need to formulate a standardized sensory assessment battery that may be used to evaluate physically handicapped children. A review of the literature hlghlights the necessity to evaluate the presence and extent of sensory dysfunction in school-age hemipleglc children, us mg a standardlzed clinical sensory assessment battery, as weil as somatosensory evoked potentials.A relJable sensory battery, which asses ses 5 sensory modalltl8s, was formulated and normative data for school-age chlldren was derived. Sensory function was evaluated in 9 hemiplegic children (4-19 years) and 18 healthy age-matched controls. Significant bilateral sensory deficits were documented in hemiplegic childr9n. Thus a sensory assessment should be an integral part of the evaluation of a child with hemiplegia .

show abstract

The somatotopic organization of the ventroposterior thalamus of the squirrel monkey, Saimiri sciureus

Kaas

Nelson

Sur

et al. 1984

J of Comparative Neurology

172

113

View full text Add to dashboard Cite

Multiunit microelectrode mapping techniques were used to investigate the organization of the somatosensory thalamus in squirrel monkeys. Receptive fields and response characteristics were determined for closely spaced recording sites along arrays of electrode penetrations that passed through the ventral thalamus dorsoventrally, rostrocaudally, or lateromedially. The results were related to thalamic architecture and led to the following conclusions: (1) A large, single, systematic representation of the body surface occupied most or all of the ventroposterior nucleus, VP. The nucleus was further defined by a distinct cytoarchitectonic appearance, produced by densely packed, deeply stained neurons. (2) Recording sequences in VP were characterized by (a) abrupt shifts in receptive field locations over short recording distances indicating that the electrode had crossed discontinuities or folds in the representation, (b) long sequences of overlapping receptive fields indicating regions of continuous representation and the maintenance of adjacency in the map, and (c) similar receptive field locations for sites along the trajectory of a penetration indicating regions of isorepresentation. Major somatotopic discontinuities were associated with crossing narrow cell-poor laminae that partially divided VP into subnuclei related to the hand, foot, trunk, and tail in lateral VP and the face in medial VP. Somatotopic discontinuities occurred for electrode penetrations in all three planes, but discontinuities were greater and more frequent for lateromedial electrode penetrations. Lines of isorepresentation and gradual change were most extensive in the rostrocaudal and dorsoventral planes. We hypothesize that the disruptions, regions of isorepresentation, and regions of gradual change result from the thickening, splitting, and folding of a two-dimensional representation of the skin surface to occupy a three-dimensional volume. (3) The magnifications of various skin surfaces in VP were variable so that some skin surfaces, especially the tips of the digits, occupied relatively large portions of the nucleus, while other skin surfaces such as the trunk activated little tissue. It appeared that regions of isorepresentation varied in extent according to magnification factor and position in the map. (4) Within VP, neurons could be classified as slowly adapting or rapidly adapting to maintained skin indentation. Each type of neuron formed small groups or clusters in the nucleus so that several successive recording sites typically encountered one type before a sequence of the other type was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

show abstract

Parallel Processing of Cutaneous Information in the Somatosensory System of the Cat

Cited by 11 publications

References 30 publications

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

The Determination of Sensory Deficits in Children With Hemiplegic Cerebral Palsy

The somatotopic organization of the ventroposterior thalamus of the squirrel monkey, Saimiri sciureus

Contact Info

Product

Resources

About