The somatotopic organization of the ventroposterior thalamus of the squirrel monkey, <i>Saimiri sciureus</i>

Kaas, Jon H.; Nelson, Randall J.; Sur, Mriganka; Dykes, Robert W.; Merzenich, Michael M.

doi:10.1002/cne.902260109

Cited by 172 publications

(135 citation statements)

References 61 publications

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“…The overall somatotopic organization of VP agrees with earlier studies (Kaas et al, 1984;Chung et al, 1986). However, the receptive field sizes of LT and nociresponsive neurons in VP Cel l s that were found at a distance greater than 100 pm from spinothalamic terminals (-) are assumed to be unable to receive spinothalamic inputs.…”

Section: Comparison With Other Thalamic Physiologic Studiessupporting

confidence: 87%

Squirrel monkey lateral thalamus. I. Somatic nociresponsive neurons and their relation to spinothalamic terminals

1994

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The incidence and response properties of nociresponsive neurons, their locations relative to spinothalamic terminals, and their relations to cytoarchitectonic borders were studied in the lateral thalamus of the squirrel monkey. Nociceptive neurons were found in ventral posterior inferior nucleus (VPI), in the lateral and medial nuclei (VPL and VPM) of the ventral posterior complex (VP = VPL + VPM), as well as the posterior complex (PO). The overall incidence of nociresponsive cells was 19% (50 of 270 cells). The proportion of nociresponsive neurons within VPI was 50% (23 of 46), 38% in PO (8 of 21), and 10% in VP (19 of 203). Most nociresponsive cells (90%) in VP were of wide-dynamic- range type, while within VPI 43% of nociresponsive cells were nociceptive-specific type. Most of these nociresponsive cells had thermal and mechanical responses, and a small number also responded to cooling. The receptive fields of nociresponsive cells in VPL were in continuity, in both size and body location, with surrounding low- threshold units. The receptive fields of VPI and PO nociresponsive cells were larger than those in VPL. The probability of encountering nociresponsive cells located within 100 microns of spinothalamic terminations was high in VPI (73%) and low in VPL (33%). On the other hand, the probability of encountering non-nociceptive cells located within 100 microns of spinothalamic terminals was low in both VPI (20%) and VPL (26%). The results indicate segregation of nociresponsive cell types across VP, VPI, and PO and suggest that VPI, and perhaps PO, is an important region for discriminative processing and perception of painful stimuli.

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Section: Comparison With Other Thalamic Physiologic Studiessupporting

confidence: 87%

Squirrel monkey lateral thalamus. I. Somatic nociresponsive neurons and their relation to spinothalamic terminals

1994

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“…First, injections of tracers that were largely or completely confined to the O1 oval representing teeth labeled neurons in a very medial part of the medial division of the ventral posterior nucleus, VPM. This location corresponds closely with the location in VPM of the teeth representation determined in microelectrode recording experiments in squirrel monkeys (Kaas et al, 1984). Part of this teeth representation responds to the ipsilateral teeth (Bombardieri et al, 1975), indicating that there is a thalamic source for the representation of ipsilateral teeth in O1 and again in O3.…”

Section: Thalamic and Cortical Connections Of Teeth And Tongue 01 Andsupporting

confidence: 79%

Cortical network for representing the teeth and tongue in primates

Kaas

Iyengar

2006

Anat. Rec.

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Sensory information from the tongue and teeth is used to evaluate and distinguish food and nonfood items in the mouth, reject some and masticate and swallow others. While it is known that primates have a complex array of 10 or more somatosensory areas that contribute to the analysis of sensory information from the hand, less is known about what cortical areas are involved in processing information from receptors of the tongue and teeth. The tongue contains taste receptors, as well as mechanoreceptors. Afferents from taste receptors and mechanoreceptors of the tongue access different ascending systems in the brainstem. However, it is uncertain how these two sources of information are processed in cortex. Here the parts of somatosensory areas 3b, 3a, and presumptive 1 that represent the mechanoreceptors of the teeth and tongue are identified, and evidence is presented that the representations of the tongue also get information from the taste nucleus of the thalamus, VPMpc. As areas 3b, 3a, and 1 project to other areas of somatosensory cortex, and those areas to additional areas, some or all of the currently defined somatosensory areas of cortex may be involved in processing gustatory, as well as tactile, information from the tongue and thus have a role in the biologically important function of evaluating food in the mouth. © 2006 Wiley-Liss, Inc.Key words: somatosensory cortex; area 3b; ventroposterior nucleus; parietal cortex; taste; gustatory system Sensory inputs from the tongue and teeth are obviously very important to the health and survival of most mammals. Based on inputs from receptors in the tongue and periodontal receptors around the teeth, distinctions are made between food and nonfood objects in the mouth, how much pressure can be delivered via the teeth on such items in the mouth, and how to guide tongue and jaw movements in food processing (Jacobs et al., 1998). For judgments about the desirability of food objects, taste information is integrated with somatosensory information on texture, compliance, and item size. Thus, inputs from taste receptors and mechanoreceptors in the mouth, in part, must be evaluated together in order to facilitate the basic function of eating. But where and how is this done? As neocortex is obviously important in the processing of sensory information, how are sensory systems, which are related to sensory afferents from the tongue and teeth, organized at the cortical level? Given the obvious importance of this issue, it may come as a surprise that little is known about the anatomical framework in cortex for processing information, and most of this understanding is focused on the cortical processing of taste. Because the system for processing somatosensory information at the cortical level has been well studied in monkeys, and many of the recent studies of cortical structures related to taste have been in monkeys, this review is focused on these primates. We argue that it is likely that the rather extensive cortical network for processing tactile information from the...

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“…As shown in Figure 5, there were a number of penetration sites in omt592 that contained receptive fields with either multidigit receptive fields, or hairy and glabrous response properties. These combination receptive fields were not found in the VPL of om624, or in the normal primate VPL (Mountcastle and Henneman, 1952;Poggio and Mountcastle, 1963;Kaas et al, 1984).…”

Section: Thalamic Datamentioning

confidence: 74%

“…A 250 μm volumetric grid of penetrations was made to include all areas of ventral posterolateral nucleus (VPL), and the reticular thalamus, spanning from interaural 6.25 mm to interaural 4.25 mm. Only VPL responses were included for analysis based on location of the electrode and evoked response characeristics (Mountcastle and Henneman, 1952;Poggio and Mountcastle, 1963;Kaas et al, 1984). By these criteria, recording in the deepest 300 μm of these penetrations in which cutaneous response properties were noted that had extraordinarily large receptive fields were categorized as reticular thalamus recordings.…”

Section: Mapping Experimentsmentioning

confidence: 99%

Sensory representation abnormalities that parallel focal hand dystonia in a primate model

Blake

Byl

Cheung

et al. 2002

Somatosensory & Motor Research

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In our hypothesis of focal dystonia, attended repetitive behaviors generate aberrant sensory representations. Those aberrant representations interfere with motor control. Abnormal motor control strengthens sensory abnormalities. The positive feedback loop reinforces the dystonic condition. Previous studies of primates with focal hand dystonia have demonstrated multi-digit or hairyglabrous responses at single sites in area 3b, receptive fields that average ten times larger than normal, and high receptive field overlap as a function of horizontal distance. In this study, we strengthen and elaborate these findings. One animal was implanted with an array of micro-electrodes that spanned the border between the face and digits. After the animal developed hand dystonia, responses in the initial hand representation increasingly responded to low threshold stimulation of the face in a columnar substitution. The hand-face border that is normally sharp became patchy and smeared over one millimeter of cortex within six weeks. Two more trained animals developed a focal hand dystonia variable in severity across the hand. Receptive field size, presence of multi-digit or hairy-glabrous receptive fields, and columnar overlap covaried with the animal's ability to use specific digits. A fourth animal performed the same behaviors without developing dystonia. Many of its physiological measures were similar to the dystonic animals, but receptive field overlap functions were minimally abnormal, and no sites shared response properties that are normally segregated such as hairy-glabrous combined fields, or multi-digit fields. Thalamic mapping demonstrated proportionate levels of abnormality in thalamic representations as was found in cortical representations.

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

Cited by 172 publications

References 61 publications

Squirrel monkey lateral thalamus. I. Somatic nociresponsive neurons and their relation to spinothalamic terminals

Squirrel monkey lateral thalamus. I. Somatic nociresponsive neurons and their relation to spinothalamic terminals

Cortical network for representing the teeth and tongue in primates

Sensory representation abnormalities that parallel focal hand dystonia in a primate model

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