Thalamic Ventrobasal Complex

The morphology of Golgi-impregnated thalamic neurons was investigated quantitatively. In particular, it was sought to test whether the dendritic bifurcations can be described by the scaling law (d0)n=(d1)n+(d2)nwith a single value of the diameter exponent n. Here d0 is the diameter of the parent branch, d1 and d2 are the diameters of the two daughter branches. Neurons from two functionally distinct regions were compared: the somatosensory ventrobasal complex (VB) and its nociceptive ventral periphery (VBvp). It is shown that for the neuronal trees studied in both regions, the scaling law was fulfilled. The diameter exponent n, however, was not a constant. It increased from n=1.76 for the 1st order branches to n=3.92 for the 7th order branches of neurons from both regions. These findings suggest that more than one simple intrinsic rule is involved in the neuronal growth process, and it is assumed that the branching ratio d0/d1 is not required to be encoded genetically. Furthermore, the results support the concept of the dendritic trees having a statistically identical topology in neurons of VB and VBvp and thus may be regarded as integrative modules.

Download Full-text

Differential depressive action of two μ and δ opioid ligands on neuronal responses to noxious stimuli in the thalamic ventrobasal complex of rat

Brain Research ◽

10.1016/0006-8993(86)91248-5 ◽

1986 ◽

Vol 398 (1) ◽

pp. 49-56 ◽

Cited By ~ 10

Author(s):

J.M. Benoist ◽

V. Kayser ◽

G. Gacel ◽

J.M. Zajac ◽

M. Gautron ◽

...

Keyword(s):

Neuronal Responses ◽

Opioid Ligands ◽

Ventrobasal Complex ◽

Noxious Stimuli

Download Full-text

Distribution of nociceptive neurons in the ventrobasal complex of monkey thalamus

Neuroscience Research Supplements ◽

10.1016/0921-8696(86)90318-x ◽

1986 ◽

Vol 3 ◽

pp. S157

Author(s):

Natsu Koyama ◽

Takuya Masuda ◽

Toshikatsu Yokota

Keyword(s):

Nociceptive Neurons ◽

Ventrobasal Complex

Download Full-text

Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat

Journal of Neurophysiology ◽

10.1152/jn.1983.50.4.896 ◽

1983 ◽

Vol 50 (4) ◽

pp. 896-909 ◽

Cited By ~ 76

Author(s):

B. E. Stein ◽

R. F. Spencer ◽

S. B. Edwards

Keyword(s):

Superior Colliculus ◽

Somatosensory Cortex ◽

Species Difference ◽

Pyramidal Cells ◽

Thalamic Nuclei ◽

Anterior Ectosylvian Sulcus ◽

Ventrobasal Complex ◽

Posterior Group ◽

Corticothalamic Projection ◽

Efferent Projections

Substantial corticotectal (and corticothalamic) projections from the cortex of the anterior ectosylvian sulcus (AES) were demonstrated in the cat using the axonal transport methods of autoradiography and horseradish peroxidase. The corticotectal projection arises nearly exclusively from medium-large pyramidal cells in lamina V. One of the densest projecting areas of the AES is the rostral aspect of its superior bank, where a fourth somatotopic representation (SIV) has recently been demonstrated. It terminates in the intermediate and deep laminae of the superior colliculus, where somatic cells are located. The pathway is bilateral but much heavier ipsilaterally than contralaterally. In contrast to the substantial corticotectal projection from SIV and adjacent tissue, there was no unequivocal evidence for a corticotectal projection from traditional somatosensory cortex SI-SIII. This finding, that somatosensory projections to the cat superior colliculus arise from an area outside of SI-SIII, was unexpected on the basis of what is known about visual corticotectal projections. However, it is consistent with the patterns of other cortical projections that terminate in the intermediate and deep laminae of this structure and with the absence of demonstrable corticotectal influences from SI to SIII in this animal. These data are in contrast to demonstrations by other investigators that there is a corticotectal projection from SI cortex in rodents. Apparently there is a fundamental species difference in the organization of descending somatosensory pathways. A corticothalamic projection of the AES was also observed. This descending projection appeared to form a shell of labeled cells and fibers around the ventrobasal complex, but unequivocal terminal labeling within the ventrobasal complex could not be demonstrated. Dense terminal labeling was apparent in the posterior group of thalamic nuclei (PO) where thalamocortical afferents to the AES originate.

Download Full-text

Correlation between function and morphology of neurons in the ventrobasal complex of cat thalamus

Neuroscience Research Supplements ◽

10.1016/0921-8696(90)90849-x ◽

1990 ◽

Vol 11 ◽

pp. S132

Author(s):

Tetsuya Nomura ◽

Nozomu Nishikawa ◽

Natsu Koyama

Keyword(s):

Ventrobasal Complex

Download Full-text

Striatal input from the ventrobasal complex of the rat thalamus

Histochemistry and Cell Biology ◽

10.1007/s004180100273 ◽

2001 ◽

Vol 115 (6) ◽

pp. 447-454 ◽

Cited By ~ 15

Author(s):

María Erro ◽

José Lanciego ◽

José Arribas ◽

José Giménez-Amaya

Keyword(s):

Ventrobasal Complex

Download Full-text

Responses of neurons in and near the thalamic ventrobasal complex of the rat to stimulation of uterus, cervix, vagina, colon, and skin

Journal of Neurophysiology ◽

10.1152/jn.1993.69.2.557 ◽

1993 ◽

Vol 69 (2) ◽

pp. 557-568 ◽

Cited By ~ 76

Author(s):

K. J. Berkley ◽

G. Guilbaud ◽

J. M. Benoist ◽

M. Gautron

Keyword(s):

Receptive Fields ◽

The Body ◽

Female Rats ◽

Caudal Part ◽

Response Characteristics ◽

The Core ◽

Ventrobasal Complex ◽

Gentle Pressure ◽

Somatic Receptive Fields ◽

Stimulation Of

1. Previous studies in the rat and other species have shown that neurons in and near the ventrobasal complex (VB) can be activated by various visceral as well as somatic stimuli. 2. This study examined the responses of 84 single neurons in and near the rostral 2/3 of VB in 19 adult female rats in estrus to mechanical stimulation of the skin (brush, pressure, noxious pinch) and 4 different visceral stimuli, as follows: distension of both uterine horns, mechanical probing of the vagina, gentle pressure against the cervix, and distension of the colon. The rats were studied while under moderate gaseous anesthesia (33% O2-67% N2O + 0.5% halothane) and paralyzed (pancuronium bromide). 3. Of 77 neurons tested with both somatic and visceral stimuli, 70 were responsive to one type and/or the other. Responses to somatic stimuli were immediate with brief afterdischarges to the pinch stimuli. In contrast, responses to visceral stimuli were delayed an average of 9 s with long afterdischarges averaging 2 min. Most viscerally responsive neurons (74%) had somatic receptive fields, often (44%) to noxious pinch. 4. Of the 70 responsive neurons, 43 (61%) responded to 1 or more of the 4 visceral stimuli, primarily with excitation. Most of these 43 neurons (71%) were responsive to uterine distension, whereas fewer responded to stimulation of the cervix (45%), vagina (29%), or colon (34%). 5. Viscerally responsive neurons were preferentially located in regions bordering or near VB. Only 6 of 22 neurons within the core of VB (27%) responded to visceral stimuli, in contrast with 37 of 48 neurons bordering or near VB (77%). 6. The six viscerally responsive neurons within VB all had somatic receptive fields located primarily on the caudal part of the body and were responsive to only one or two of the four visceral stimuli, usually the uterus. The 37 viscerally responsive neurons bordering or near VB were of 3 types. Neurons of the first type (n = 15) were scattered throughout the areas bordering VB and responded to both somatic and visceral stimuli much like VB neurons, except that they showed more visceral convergence. Neurons of the second type (n = 11) were concentrated at the rostral and dorsal borders of VB and responded only to visceral stimuli, mainly the uterus. Neurons of the third type (n = 11) were concentrated ventrally and had very complex, long-lasting and history-dependent response characteristics to both visceral and somatic stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

Download Full-text