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Property and distribution of masticatory-related neuron (M-R neuron) in the primary somatosensory cortex (SI) of awake cats
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POSSIBLE GAP JUNCTIONS IN RAT SOMATOSENSORY NEOCORTEX. MUNEYUKI ITO I Department of Physiology, Institute for Developmental Research, Aichi Prefectural Colony, Kamiya-cho 71~-81 Kasugai 4800)I Japan. During the course of a study aimed at examining structural correlates of neuronal response types in the rat somatossnsory cortex, I came across quite a few instances where more than one neuron was stained by a single intracellular injection of horseradish peroxidase (HRP). Rats were anesthetized with urethane and the whisker representation of the somatosensory cortex was exposed to allow penetration of glass microelectrodes filled with a solution consisting of 4~ HRP and 0.2 M KCI (in 0.05 M tris-buffer at pH 8.6) for cellular recording and staining. All the neurons that were held stable gave a transient discharge in response to a steady deflection of s whisker. Successful staining was obtained in a total of 56 injections. Seventeen of these resulted in simultaneous staining of more than one neuron. Multiple staining involved two neurons in 13 instances and three neurons in 4 instances. Most of the HRP-coupled cells were pyramidal neurons situated in the deeper aspect of the cortex (layers 4 and 5). The coupled neurons were often found side by side and appeared to share a common dendritic field.
DOUBLE REPRESENTATION OF OROFACIAL STRUCTURES IN THE ANTERIOR CORONAL GYRUS OF THE CAT. KOSEI TAIRA, KEI KAWARADA~w AND KAZUHISA, OKUDA~ Department of Oral Physiolop_7. School of Dentistry, Iwate Medical University! Morioka 020 r Japan. To define the SII oral area, multi-unit recordings and histological examinations were employed in the anterior coronal gyrus of the cat. Tracheotomy and craniotomy were performed using ketamine (i.m.) and local anesthetic. The animal was immobilized by tubocurarine and artificially ventilated. Receptive fields of the units were determined by applying light mechanical stimulations to orofacial structures. After the e^periment was finished, serial sections ( 2 5 ~ ) of the cerebral cortex were stained with cresyl violet. Two representations of the gingivae and periodontal membranes were found in the anterior coronal gyrus. One was observed in the medial region of the Eyrus and identified with the SI oral area because it had the same ~omatotopic arrangement as previously reported in the cytoarchitectural area 3b (Taira, 1987). The other, new one, was located in the region (2 x 3 mm a) lateral to the SI oral a r e a and rostral to the SII forelimb area. There, when electrode penetrations were shifted in a caudo-rostral direction, the location of the receptive fields of units was altered in the order of contralateral hairy lips, non-hairy lips, gingivae, and periodontal membranes. At the rostral site of this area, the receptive fields of units were on the middle and ipsilateral parts of the gingivae and periodontal membranes. The lower jaw was represented on the lateral side near the diagonal sulcus, while the upper jaw was represented on the middle convexity of the Syrus contiguous with the upper jaw representation of the SI oral area. The cytoarchitecture of the lateral oral region, in the anterior coronal gyrus was area 2, It is discussed that this region is a subdivision of somatic sensory cortex SI or SII in reference to cytoarchitectural characteristics of these cortices.
PROPERTY AND DISTRIBUTION OF MASTICATORY-RELATED NEURON (M-R NEURON~ IN THE PRIMARY SOMATOSENSORY CORTEX ( S I ) OF AWAKE CATS. HISAO HIRABA-, TAMIKO YOSHIDA*. CHIHIRO TSUJIMOTO* AND RHYUJI SUMIN0, D e p a r t m e n t o__ff P h y s l o l o g T . Nlhon University School of Dentistry, 1-8-13 Kanda-slurugadal. C h l y o d a - k u , Tokyo I01, Japan. Prevlously, we h a v e revealed that some S I neurons in cats showed a rhythmlcal burst firing In relation to movements of the Jaw (opening and closing), the tongue (protrusion and retraction), and teeth (touching) during mastication. I n t h e p r e s e n t s t u d y , 437 S I n e u r o n s w e r e r e c o r d e d I n l n t r a o r a l and facial projection a r e a s ( a r e a s 3a a n d 3b) o f S I I n 7 a w a k e cats. Fifty-nine percent o f t h e r e c o r d e d SI n e u r o n s ( 2 5 8 / 4 3 7 ) were f o u n d t o be t h e M-R n e u r o n s . A p p r o x i m a t e l y 80~ o f t h e M-R n e u r o n s h a d r e c e p t i v e fields In the perioral region, tongue, vermilion border, palate, and teeth which were easy to stimulate during mastication. M-R n e u r o n s w i t h r e c e p t i v e fields in these regions Intermingled with n o n M-R n e u r o n s i n e a c h p r o j e c t i o n area of SI. Distinction between the M-R and n o n M-R n e u r o n s w i t h t h e same r e c e p t i v e f i e l d d e p e n d e d on d i f f e r e n c e s in the direction-sensitivity and threshold value to stimulation.
POSSIBLE GAP JUNCTIONS IN RAT SOMATOSENSORY NEOCORTEX. MUNEYUKI ITO I Department of Physiology, Institute for Developmental Research, Aichi Prefectural Colony, Kamiya-cho 71~-81 Kasugai 4800)I Japan. During the course of a study aimed at examining structural correlates of neuronal response types in the rat somatossnsory cortex, I came across quite a few instances where more than one neuron was stained by a single intracellular injection of horseradish peroxidase (HRP). Rats were anesthetized with urethane and the whisker representation of the somatosensory cortex was exposed to allow penetration of glass microelectrodes filled with a solution consisting of 4~ HRP and 0.2 M KCI (in 0.05 M tris-buffer at pH 8.6) for cellular recording and staining. All the neurons that were held stable gave a transient discharge in response to a steady deflection of s whisker. Successful staining was obtained in a total of 56 injections. Seventeen of these resulted in simultaneous staining of more than one neuron. Multiple staining involved two neurons in 13 instances and three neurons in 4 instances. Most of the HRP-coupled cells were pyramidal neurons situated in the deeper aspect of the cortex (layers 4 and 5). The coupled neurons were often found side by side and appeared to share a common dendritic field.
DOUBLE REPRESENTATION OF OROFACIAL STRUCTURES IN THE ANTERIOR CORONAL GYRUS OF THE CAT. KOSEI TAIRA, KEI KAWARADA~w AND KAZUHISA, OKUDA~ Department of Oral Physiolop_7. School of Dentistry, Iwate Medical University! Morioka 020 r Japan. To define the SII oral area, multi-unit recordings and histological examinations were employed in the anterior coronal gyrus of the cat. Tracheotomy and craniotomy were performed using ketamine (i.m.) and local anesthetic. The animal was immobilized by tubocurarine and artificially ventilated. Receptive fields of the units were determined by applying light mechanical stimulations to orofacial structures. After the e^periment was finished, serial sections ( 2 5 ~ ) of the cerebral cortex were stained with cresyl violet. Two representations of the gingivae and periodontal membranes were found in the anterior coronal gyrus. One was observed in the medial region of the Eyrus and identified with the SI oral area because it had the same ~omatotopic arrangement as previously reported in the cytoarchitectural area 3b (Taira, 1987). The other, new one, was located in the region (2 x 3 mm a) lateral to the SI oral a r e a and rostral to the SII forelimb area. There, when electrode penetrations were shifted in a caudo-rostral direction, the location of the receptive fields of units was altered in the order of contralateral hairy lips, non-hairy lips, gingivae, and periodontal membranes. At the rostral site of this area, the receptive fields of units were on the middle and ipsilateral parts of the gingivae and periodontal membranes. The lower jaw was represented on the lateral side near the diagonal sulcus, while the upper jaw was represented on the middle convexity of the Syrus contiguous with the upper jaw representation of the SI oral area. The cytoarchitecture of the lateral oral region, in the anterior coronal gyrus was area 2, It is discussed that this region is a subdivision of somatic sensory cortex SI or SII in reference to cytoarchitectural characteristics of these cortices.
PROPERTY AND DISTRIBUTION OF MASTICATORY-RELATED NEURON (M-R NEURON~ IN THE PRIMARY SOMATOSENSORY CORTEX ( S I ) OF AWAKE CATS. HISAO HIRABA-, TAMIKO YOSHIDA*. CHIHIRO TSUJIMOTO* AND RHYUJI SUMIN0, D e p a r t m e n t o__ff P h y s l o l o g T . Nlhon University School of Dentistry, 1-8-13 Kanda-slurugadal. C h l y o d a - k u , Tokyo I01, Japan. Prevlously, we h a v e revealed that some S I neurons in cats showed a rhythmlcal burst firing In relation to movements of the Jaw (opening and closing), the tongue (protrusion and retraction), and teeth (touching) during mastication. I n t h e p r e s e n t s t u d y , 437 S I n e u r o n s w e r e r e c o r d e d I n l n t r a o r a l and facial projection a r e a s ( a r e a s 3a a n d 3b) o f S I I n 7 a w a k e cats. Fifty-nine percent o f t h e r e c o r d e d SI n e u r o n s ( 2 5 8 / 4 3 7 ) were f o u n d t o be t h e M-R n e u r o n s . A p p r o x i m a t e l y 80~ o f t h e M-R n e u r o n s h a d r e c e p t i v e fields In the perioral region, tongue, vermilion border, palate, and teeth which were easy to stimulate during mastication. M-R n e u r o n s w i t h r e c e p t i v e fields in these regions Intermingled with n o n M-R n e u r o n s i n e a c h p r o j e c t i o n area of SI. Distinction between the M-R and n o n M-R n e u r o n s w i t h t h e same r e c e p t i v e f i e l d d e p e n d e d on d i f f e r e n c e s in the direction-sensitivity and threshold value to stimulation.