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Responses of neurones of interpositus nucleus to stimulation of the sensorimotor cortex
SHORTCOMMUNICATIONS
585
Responses of neurones of interpositus nucleus to stimulation of the sensorimotor cortex Individual Purkyn~ cells of the pars intermedia in the cat receive early mossy fibre and later climbing fibre inputs from the sensorimotor cortex (discharge range, 4-10 msec and 13-25 msec after stimulation, respectively) 2. Those Purkyn6 cells that receive peripheral inputs primarily from the forelimb receive their cortically evoked mossy and climbing fibre inputs from forelimb areas of the sensorimotor cortex a. A similar arrangement holds for the hindlimb inputs. Although there are inputs coming from other limbs and cortical areas, there is a strong tendency for information from nerves and cortical areas representing the same limb to converge onto a Purkyn~ cella. The Purkyn~ cells of the pars intermedia project to the interpositus nucleus12, providing an inhibitory input 1°, while collaterals of mossy and climbing fibres provide excitatory inputs xl,la. The goal of this study was to determine how the excitatory and inhibitory inputs converge onto single interpositus neurones following cortical stimulation, and to compare these patterns with those from peripheral nervess. The 10 cats used in this investigation were initially anaesthetized with halothane for the duration of the surgical preparation and maintained with thiopental (15 mg/ kg, initially; 3 mg/kg/h, continuous infusion) during the period of recording. The animals were paralyzed with gallamine triethiodide and artificially ventilated. Four monopolar stimulating electrodes were inserted into the white matter of the right pericruciate gyrus (lateral and medial, anterior and posterior sigmoid gyri) so as to stimulate cortico-spinal and cortico-bulbar fibres with specific forelimb (MsFL, SmFL) or hindlimb (MsHL, SmHL) action 14. Each cortical area was stimulated by a pair of pulses (duration, 0.1 msec; interval, 2 msec) at an intensity of 0.4-0.8 mA. Four forelimb nerves (superficial radial (SR), deep radial (DR), median (MED) and ulnar (UL)) and 4 hindlimb nerves (quadriceps (QUAD), peroneal (PER), tibial (TIB) and sural (SUP,)) were stimulated on the left side with a pair of pulses at 3-5 times threshold. The unitary discharges of interpositus neurones were recorded by glass micropipettes (2 M NaCI, 2-4 Mf~) and fed to a Fabri-Tek 1062 computer for post-stimulus time histograms (PSTHs) and cumulative frequency distributions (CFDs) 7. The neurones were located in the anterior nucleus of the left interpositus and were identified by antidromic activation from the red nucleus (Fig. 2H) as well as subsequent histological checks. Fig. 1 shows the types of responses that characterize the input to interpositus neurones from the contralateral sensorimotor (SM) cortex. The neurone of Fig. IA illustrates all of the components commonly seen, beginning with a mild increase in the discharge rate at 4.5 msec and then a depression at 8.0 msec. Another increase in firing started at 11.5 msec which was stronger and longer lasting than the first. This facilitation was terminated at 21.5 msec by a silent period lasting until 36 msec. Although this sequence of early excitation, inhibition, late excitation, and inhibition may be observed in response to cortical stimulation, most neurones do not respond with all of these components. For example, the neurone of Fig. 1B lacked the early excitation, responding with inhibition at 10.0 msec, late excitation at 15.0 msec, and Brain Research, 45 (1972) 585-589
586
SHORT COMMUNICATIONS
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Fig. 1. Response patterns of interpositus neurones to stimulation of sensorimotor cortex. A-E, responses of 5 interpositus neurones from intact cats. The top pair of traces are specimen records. The third row is the PSTH constructed from 128 responses. The bottom row is the CFD obtained by integrating the PSTH. A, stimulation of lateral anterior sigmoid gyrus. B, stimulation of the medial posterior sigmoid gyrus. C, stimulation of the lateral posterior sigmoid gyrus. D, stimulation of medial anterior sigmoid gyrus. E, stimulation of medial posterior sigmoid gyrus. F shows response of a neurone to stimulation of medial posterior sigmoid gyrus after bilateral transection of brachium pontis; from top to bottom, specimen record, PSTH and CFD. This neurone was recorded in a cat anaesthetized with nitrous oxide (80 ~ ) . Transection of each cerebellar peduncle was performed by electrolytic lesion with a stereotaxically placed electrode as previously described 1. G, diagram of composite response of interpositus neurone to cortical stimulation. The time scale of 10 msec (below E) applies to A-F. The calibratioia of 1 mV applies to the specimen records, that of 20 counts to the PSTH and 2 counts added per stimulus to the CFD.
i n h i b i t i o n at 22.5 m s e c . T h i s s e q u e n c e w a s f o l l o w e d by a r e b o u n d at 44.5 msec. Fig. 1C s h o w s a n o t h e r c o m m o n r e s p o n s e pattern, late excitation at 11.5 m s e c a n d inhibition at 21.5 m s e c . In coatrast, the n e u r o n e o f Fig. 1 D s h o w e d o n l y the late excitation f r o m 12.0 to 21.5 m s e c , w h i l e that o f Fig. 1E w a s i n h i b i t e d f r o m 9.5 m s e c until a r e b o u n d b e g a n at 43 m s e c .
Brain Research, 45 (1972) 585-589
SHORT COMMUNICATIONS
587
The responses of interpositus neurones to stimulation of the contralateral cortex can then be generalized into several components as drawn in Fig. 1G: a relatively weak early excitation (El) at 6.1 msec (S.D., 1.2 msec; n = 27), inhibition 01) at 8.4 msec (S.D., 1.5 msec; n = 56), a strong, long lasting excitation (E2) at 14.1 msec (S.D., 2.5 msec; n = 142), inhibition (I2) at 22.7 msec (S.D., 4.0 msec; n = 57) and a rebound at 30-50 msec. The presence and size of each component depended upon the cortical area stimulated and varied from one neurone to another (see also Fig. 2). For example, the 3 cells of Fig. 1E, B and C were sequentially recorded in one dorso-ventral track, with inter-neuronal distances of 340/zm and 480 ~m, respectively. Considering the El-I1 sequence, I1 can be assumed to result from the short latency (4-10 msec) Purkyn~ cell firing mediated by the early pontine and lateral reticular nucleus (LRN) inputs 1,2, while E1 is due to the collateral action of these mossy fibres onto interpositus neurones. Although the relative contributions of pontine and L R N collaterals to E1 generation have not been assessed, the L R N mossy fibres can be shown to produce E1 when the pontine input is eliminated (Fig. 1F). For the Ez--I2 sequence, I2 should be due to the activation of Purkyn6 cells by climbing fibres (CF) and late mossy fibres (MF) presumably of L R N origin 2. The inhibition underlying I2 may include inhibition which started at I1 and was hidden by the late excitation, E2 (see Fig. 1E). Collaterals of CFs and late MFs of L R N origin both appear to contribute to E29. This inference is derived from experiments in which inferior olive or L R N conditioning stimuli were paired with cortical stimuli, and is consistent with the latencies of CF and late M F responses of Purkyn~ cells 2. These patterns observed with cortical stimulation agree with those evoked in Deiters', fastigial and interpositus nuclei by peripheral nerve stimulation4,~,s, 9. In the MsFL
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Fig. 2. Responses of an interpositus neurone to stimulation of fore- and hindlimb cortical areas and peripheral nerves. For each stimulus site of A-G, one specimen record and the PSTH and CFD are shown. H, antidromic activation of this neurone from red nucleus (RN) using threshold stimulus. Six traces are superimposed. The time scale of 10 msec applies to A-G and 1 msec to H. The calibration of 1 mV applies to all specimen records, that of 20 counts to the PSTH and 1 count added per stimulus to the CFD. Brain Research, 45 (1972) 585-589
588
SHORT COMMUNICATIONS
present study, E2 was the most prominent component and every cell responding to cortical stimulation displayed an E2 from at least one of the 4 cortical areas tested. The 11 was stronger than that reported for the nerve-evoked responses in fastigial and interpositusS,L The early excitation was weak; only 4 of 70 cells studied under the light thiopental anaesthesia showed a significant El, although in 14 other cells there were weak responses. Since interpositus neurones have many patterns available in response to cortical stimulation, it is useful to know how the responses from the 4 SM cortical areas compare in a single neurone. Also, it is useful to compare the responses from the various fore- and hindlimb nerves and cortical areas for a given interpositus neurone. Fig. 2 shows the responses of a typical cell to stimulation of the 4 SM cortical areas, 2 forelimb nerves and one hindlimb nerve. The strongest cortically evoked response came from the forelimb region of the posterior sigmoid gyrus (SmFL) and consisted of 11, E2 and 12. On the other hand, stimulation of the corresponding region of the anterior sigmoid gyrus (MsFL) elicited an I1-E2 sequence. Stimulation of the hindlimb region of the posterior sigmoid gyrus (SmHL) produced an I1-E2-I2 response with a smaller Ez than SmFL. The corresponding region of the anterior sigmoid gyrus (MsHL) was ineffective for this cell. Characteristically, the responses of" interpositus neurones can be elicited over most of the SM cortex, including both the forelimb and the hindlimb regions, although the response patterns may differ from one cortical area to another. This same interpositus neurone responded most strongly from the forelimb nerve, UL, primarily displaying a late excitation at 17 msec (equivalent to E2) preceded by a brief inhibition (11). However, this neurone also responded with a fairly strong excitation from the hindlimb nerve, TIB, as well as from SR. Although this interpositus neurone received its strongest cortical input from a forelimb region and its strongest peripheral input from a forelimb nerve, it was activated widely from peripheral nerves and SM cortex, with significant inputs representing both limbs. In fact, there were relatively few interpositus neurones receiving cortical and peripheral inputs restricted to one limb as was seen in the Purkyn6 cells of the pars intermedia 3. This spread of afferent excitatory collaterals from forelimb and hindlimb inputs was anticipated from the previous studies of nerve-evoked responses in Deiters, fastigial and interpositus nuclei 4,5,s,9. However, it was expected that the inhibitory Purkyn~ cell focus would be sharper and restricted to cortical or nerve inputs representing one limb4,5,1L Even though interpositus neurones displayed less somatotopical sharpness than Purkyn~ cells, the strongest cortical and peripheral inputs still represented the same limb in 51 of 69 units. Furthermore, localized stimulation of the pars intermedia is known to have a specific effect on one limb 6. Therefore, it must be assumed that information specific to a certain limb can pass through the interpositus nucleus, even if a higher degree o f integration exists than is present for the Purkyn6 cell. The authors thank Prof. J. C. Eccles for his constant encouragement and advice, and Mrs. J. Lakatos for her technical assistance. This work was supported by the National Institute of Neurological Diseases and Brain Research, 45 (1972) 585-589
SHORT COMMUNICATIONS
589
Stroke, G r a n t No. R01 NS08221-03, 4 a n d by generous research s u p p o r t f r o m the Dr. H e n r y C. a n d Bertha H. Buswell F u n d to T. O h n o . G. B. Azzena was supported by a fellowship from C. N. R., Italy.
Laboratory of Neurobiology, Department of Physiology, School of Medicine, State University o f New York at Buffalo, Buffalo, N.Y. 14214 (U.S.A.)
GARY I. ALLEN GIAN BATTISTA AZZENA TADAO OHNO
1 ALLEN, G.I., AZZENA, G.B., AND OHNO, T., Contribution of the cerebro-reticulo-cerebellar pathway to the early mossy fibre response in the cerebellar cortex, Brain Research, 44 (1972) 670-675. 2 ALLEN, G. I., AZZENA,G. B., AND OHNO, T., Cerebellar Purkyn6 cell responses to inputs from sensorimotor cortex, in preparation. 3 ALLEN,G. I., AZZENA,G. B., AND OHNO, T., Somatotopically organized inputs from fore- and hindlimb areas of sensorimotor cortex to cerebellar Purkyn6 cells, in preparation. 4 ALLEN;G. I., SABAH,N. H., ANDTOYAMA,K., Synaptic actions of peripheral nerve impulses upon Deiters neurones via the climbing fibre afferents, J. Physiol. (Lond.), 226 (1972). 5 ALLEN, G.I., SABAH,N. H., AND TOYAMA,K., Synaptic actions of peripheral nerve impulses upon Deiters neurones via the mossy fibre afferents, J. Physiol. (Lond.), 226 (1972). 6 Dow, R. S., AND MORUZZl,G., The Physiology and Pathology of the Cerebellum, Univ. of Minnesota Press, Minneapolis, 1958, pp. 103-157. 7 ECCLES,J. C., FABER,D. S., MURPHY,J. T., SABAH,N. H., ANDT~,eoi~fKOV~,H., Afferent volleys in limb nerves influencing impulse discharges in cerebellar cortex. I. In mossy fibers and granule ceils, Exp. Brain Res., 13 (1971) 15-35. 8 ECCLES,J. C., ROS~N,I., SCHEID,P., ANDT.~BOkfKOV.~,H., Cutaneous afferent responses in interpositus neurones of the cat, Brain Research, 42 (1972) 207-211. 9 ECCLES,J. C., SABAH,N. H., ANDTAaOkfKOVA,H., Responses evoked in neurones of the fastigial nucleus by cutaneous mechanoreceptors, Brain Research, 35 (1971) 523-527. 10 lTo, M., YOSHIDA,M., OBATA,K., KAWAI,N., ANDUDO, M., Inhibitory control of intracerebellar nuclei by the Purkinje cell axons, Exp. Brain Res., 10 (1970) 64-80. 11 MATSUSHITA,i . , AND IKEDA, M., Olivary projections to the cerebellar nuclei in the cat, Exp. Brain Res., 10 (1970) 488-500. 12 POMPEIANO,O., Functional organization of the cerebellar projections to the spinal cord. In C. A. Fox AND R. S. SNIOER (Eds.), The Cerebellum, Progress in Brain Research, Vol. 25, Elsevier, Amsterdam, 1967, pp. 282-321. 13 TSUKAHARA,N., KORN,H., AND STONE,J., Pontine relay from cerebral cortex to cerebellar cortex and nucleus interpositus, Brain Research, 10 (1968) 448-453. 14 WOOLSEY,C. N., Organization of somatic sensory and motor areas of the cerebral cortex. In H. F. HARLOWANt) C. N. WOOLSEY(Eds.), Biological and Biochemical Basis of Behavior, Univ. of Wisconsin Press, Madison, Wisc., 1958, pp. 63-81. (Accepted August 4th, 1972)
Brain Research, 45 (1972) 585-589
585
Responses of neurones of interpositus nucleus to stimulation of the sensorimotor cortex Individual Purkyn~ cells of the pars intermedia in the cat receive early mossy fibre and later climbing fibre inputs from the sensorimotor cortex (discharge range, 4-10 msec and 13-25 msec after stimulation, respectively) 2. Those Purkyn6 cells that receive peripheral inputs primarily from the forelimb receive their cortically evoked mossy and climbing fibre inputs from forelimb areas of the sensorimotor cortex a. A similar arrangement holds for the hindlimb inputs. Although there are inputs coming from other limbs and cortical areas, there is a strong tendency for information from nerves and cortical areas representing the same limb to converge onto a Purkyn~ cella. The Purkyn~ cells of the pars intermedia project to the interpositus nucleus12, providing an inhibitory input 1°, while collaterals of mossy and climbing fibres provide excitatory inputs xl,la. The goal of this study was to determine how the excitatory and inhibitory inputs converge onto single interpositus neurones following cortical stimulation, and to compare these patterns with those from peripheral nervess. The 10 cats used in this investigation were initially anaesthetized with halothane for the duration of the surgical preparation and maintained with thiopental (15 mg/ kg, initially; 3 mg/kg/h, continuous infusion) during the period of recording. The animals were paralyzed with gallamine triethiodide and artificially ventilated. Four monopolar stimulating electrodes were inserted into the white matter of the right pericruciate gyrus (lateral and medial, anterior and posterior sigmoid gyri) so as to stimulate cortico-spinal and cortico-bulbar fibres with specific forelimb (MsFL, SmFL) or hindlimb (MsHL, SmHL) action 14. Each cortical area was stimulated by a pair of pulses (duration, 0.1 msec; interval, 2 msec) at an intensity of 0.4-0.8 mA. Four forelimb nerves (superficial radial (SR), deep radial (DR), median (MED) and ulnar (UL)) and 4 hindlimb nerves (quadriceps (QUAD), peroneal (PER), tibial (TIB) and sural (SUP,)) were stimulated on the left side with a pair of pulses at 3-5 times threshold. The unitary discharges of interpositus neurones were recorded by glass micropipettes (2 M NaCI, 2-4 Mf~) and fed to a Fabri-Tek 1062 computer for post-stimulus time histograms (PSTHs) and cumulative frequency distributions (CFDs) 7. The neurones were located in the anterior nucleus of the left interpositus and were identified by antidromic activation from the red nucleus (Fig. 2H) as well as subsequent histological checks. Fig. 1 shows the types of responses that characterize the input to interpositus neurones from the contralateral sensorimotor (SM) cortex. The neurone of Fig. IA illustrates all of the components commonly seen, beginning with a mild increase in the discharge rate at 4.5 msec and then a depression at 8.0 msec. Another increase in firing started at 11.5 msec which was stronger and longer lasting than the first. This facilitation was terminated at 21.5 msec by a silent period lasting until 36 msec. Although this sequence of early excitation, inhibition, late excitation, and inhibition may be observed in response to cortical stimulation, most neurones do not respond with all of these components. For example, the neurone of Fig. 1B lacked the early excitation, responding with inhibition at 10.0 msec, late excitation at 15.0 msec, and Brain Research, 45 (1972) 585-589
586
SHORT COMMUNICATIONS
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.
.
.
.
.
.
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Fig. 1. Response patterns of interpositus neurones to stimulation of sensorimotor cortex. A-E, responses of 5 interpositus neurones from intact cats. The top pair of traces are specimen records. The third row is the PSTH constructed from 128 responses. The bottom row is the CFD obtained by integrating the PSTH. A, stimulation of lateral anterior sigmoid gyrus. B, stimulation of the medial posterior sigmoid gyrus. C, stimulation of the lateral posterior sigmoid gyrus. D, stimulation of medial anterior sigmoid gyrus. E, stimulation of medial posterior sigmoid gyrus. F shows response of a neurone to stimulation of medial posterior sigmoid gyrus after bilateral transection of brachium pontis; from top to bottom, specimen record, PSTH and CFD. This neurone was recorded in a cat anaesthetized with nitrous oxide (80 ~ ) . Transection of each cerebellar peduncle was performed by electrolytic lesion with a stereotaxically placed electrode as previously described 1. G, diagram of composite response of interpositus neurone to cortical stimulation. The time scale of 10 msec (below E) applies to A-F. The calibratioia of 1 mV applies to the specimen records, that of 20 counts to the PSTH and 2 counts added per stimulus to the CFD.
i n h i b i t i o n at 22.5 m s e c . T h i s s e q u e n c e w a s f o l l o w e d by a r e b o u n d at 44.5 msec. Fig. 1C s h o w s a n o t h e r c o m m o n r e s p o n s e pattern, late excitation at 11.5 m s e c a n d inhibition at 21.5 m s e c . In coatrast, the n e u r o n e o f Fig. 1 D s h o w e d o n l y the late excitation f r o m 12.0 to 21.5 m s e c , w h i l e that o f Fig. 1E w a s i n h i b i t e d f r o m 9.5 m s e c until a r e b o u n d b e g a n at 43 m s e c .
Brain Research, 45 (1972) 585-589
SHORT COMMUNICATIONS
587
The responses of interpositus neurones to stimulation of the contralateral cortex can then be generalized into several components as drawn in Fig. 1G: a relatively weak early excitation (El) at 6.1 msec (S.D., 1.2 msec; n = 27), inhibition 01) at 8.4 msec (S.D., 1.5 msec; n = 56), a strong, long lasting excitation (E2) at 14.1 msec (S.D., 2.5 msec; n = 142), inhibition (I2) at 22.7 msec (S.D., 4.0 msec; n = 57) and a rebound at 30-50 msec. The presence and size of each component depended upon the cortical area stimulated and varied from one neurone to another (see also Fig. 2). For example, the 3 cells of Fig. 1E, B and C were sequentially recorded in one dorso-ventral track, with inter-neuronal distances of 340/zm and 480 ~m, respectively. Considering the El-I1 sequence, I1 can be assumed to result from the short latency (4-10 msec) Purkyn~ cell firing mediated by the early pontine and lateral reticular nucleus (LRN) inputs 1,2, while E1 is due to the collateral action of these mossy fibres onto interpositus neurones. Although the relative contributions of pontine and L R N collaterals to E1 generation have not been assessed, the L R N mossy fibres can be shown to produce E1 when the pontine input is eliminated (Fig. 1F). For the Ez--I2 sequence, I2 should be due to the activation of Purkyn6 cells by climbing fibres (CF) and late mossy fibres (MF) presumably of L R N origin 2. The inhibition underlying I2 may include inhibition which started at I1 and was hidden by the late excitation, E2 (see Fig. 1E). Collaterals of CFs and late MFs of L R N origin both appear to contribute to E29. This inference is derived from experiments in which inferior olive or L R N conditioning stimuli were paired with cortical stimuli, and is consistent with the latencies of CF and late M F responses of Purkyn~ cells 2. These patterns observed with cortical stimulation agree with those evoked in Deiters', fastigial and interpositus nuclei by peripheral nerve stimulation4,~,s, 9. In the MsFL
A
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Fig. 2. Responses of an interpositus neurone to stimulation of fore- and hindlimb cortical areas and peripheral nerves. For each stimulus site of A-G, one specimen record and the PSTH and CFD are shown. H, antidromic activation of this neurone from red nucleus (RN) using threshold stimulus. Six traces are superimposed. The time scale of 10 msec applies to A-G and 1 msec to H. The calibration of 1 mV applies to all specimen records, that of 20 counts to the PSTH and 1 count added per stimulus to the CFD. Brain Research, 45 (1972) 585-589
588
SHORT COMMUNICATIONS
present study, E2 was the most prominent component and every cell responding to cortical stimulation displayed an E2 from at least one of the 4 cortical areas tested. The 11 was stronger than that reported for the nerve-evoked responses in fastigial and interpositusS,L The early excitation was weak; only 4 of 70 cells studied under the light thiopental anaesthesia showed a significant El, although in 14 other cells there were weak responses. Since interpositus neurones have many patterns available in response to cortical stimulation, it is useful to know how the responses from the 4 SM cortical areas compare in a single neurone. Also, it is useful to compare the responses from the various fore- and hindlimb nerves and cortical areas for a given interpositus neurone. Fig. 2 shows the responses of a typical cell to stimulation of the 4 SM cortical areas, 2 forelimb nerves and one hindlimb nerve. The strongest cortically evoked response came from the forelimb region of the posterior sigmoid gyrus (SmFL) and consisted of 11, E2 and 12. On the other hand, stimulation of the corresponding region of the anterior sigmoid gyrus (MsFL) elicited an I1-E2 sequence. Stimulation of the hindlimb region of the posterior sigmoid gyrus (SmHL) produced an I1-E2-I2 response with a smaller Ez than SmFL. The corresponding region of the anterior sigmoid gyrus (MsHL) was ineffective for this cell. Characteristically, the responses of" interpositus neurones can be elicited over most of the SM cortex, including both the forelimb and the hindlimb regions, although the response patterns may differ from one cortical area to another. This same interpositus neurone responded most strongly from the forelimb nerve, UL, primarily displaying a late excitation at 17 msec (equivalent to E2) preceded by a brief inhibition (11). However, this neurone also responded with a fairly strong excitation from the hindlimb nerve, TIB, as well as from SR. Although this interpositus neurone received its strongest cortical input from a forelimb region and its strongest peripheral input from a forelimb nerve, it was activated widely from peripheral nerves and SM cortex, with significant inputs representing both limbs. In fact, there were relatively few interpositus neurones receiving cortical and peripheral inputs restricted to one limb as was seen in the Purkyn6 cells of the pars intermedia 3. This spread of afferent excitatory collaterals from forelimb and hindlimb inputs was anticipated from the previous studies of nerve-evoked responses in Deiters, fastigial and interpositus nuclei 4,5,s,9. However, it was expected that the inhibitory Purkyn~ cell focus would be sharper and restricted to cortical or nerve inputs representing one limb4,5,1L Even though interpositus neurones displayed less somatotopical sharpness than Purkyn~ cells, the strongest cortical and peripheral inputs still represented the same limb in 51 of 69 units. Furthermore, localized stimulation of the pars intermedia is known to have a specific effect on one limb 6. Therefore, it must be assumed that information specific to a certain limb can pass through the interpositus nucleus, even if a higher degree o f integration exists than is present for the Purkyn6 cell. The authors thank Prof. J. C. Eccles for his constant encouragement and advice, and Mrs. J. Lakatos for her technical assistance. This work was supported by the National Institute of Neurological Diseases and Brain Research, 45 (1972) 585-589
SHORT COMMUNICATIONS
589
Stroke, G r a n t No. R01 NS08221-03, 4 a n d by generous research s u p p o r t f r o m the Dr. H e n r y C. a n d Bertha H. Buswell F u n d to T. O h n o . G. B. Azzena was supported by a fellowship from C. N. R., Italy.
Laboratory of Neurobiology, Department of Physiology, School of Medicine, State University o f New York at Buffalo, Buffalo, N.Y. 14214 (U.S.A.)
GARY I. ALLEN GIAN BATTISTA AZZENA TADAO OHNO
1 ALLEN, G.I., AZZENA, G.B., AND OHNO, T., Contribution of the cerebro-reticulo-cerebellar pathway to the early mossy fibre response in the cerebellar cortex, Brain Research, 44 (1972) 670-675. 2 ALLEN, G. I., AZZENA,G. B., AND OHNO, T., Cerebellar Purkyn6 cell responses to inputs from sensorimotor cortex, in preparation. 3 ALLEN,G. I., AZZENA,G. B., AND OHNO, T., Somatotopically organized inputs from fore- and hindlimb areas of sensorimotor cortex to cerebellar Purkyn6 cells, in preparation. 4 ALLEN;G. I., SABAH,N. H., ANDTOYAMA,K., Synaptic actions of peripheral nerve impulses upon Deiters neurones via the climbing fibre afferents, J. Physiol. (Lond.), 226 (1972). 5 ALLEN, G.I., SABAH,N. H., AND TOYAMA,K., Synaptic actions of peripheral nerve impulses upon Deiters neurones via the mossy fibre afferents, J. Physiol. (Lond.), 226 (1972). 6 Dow, R. S., AND MORUZZl,G., The Physiology and Pathology of the Cerebellum, Univ. of Minnesota Press, Minneapolis, 1958, pp. 103-157. 7 ECCLES,J. C., FABER,D. S., MURPHY,J. T., SABAH,N. H., ANDT~,eoi~fKOV~,H., Afferent volleys in limb nerves influencing impulse discharges in cerebellar cortex. I. In mossy fibers and granule ceils, Exp. Brain Res., 13 (1971) 15-35. 8 ECCLES,J. C., ROS~N,I., SCHEID,P., ANDT.~BOkfKOV.~,H., Cutaneous afferent responses in interpositus neurones of the cat, Brain Research, 42 (1972) 207-211. 9 ECCLES,J. C., SABAH,N. H., ANDTAaOkfKOVA,H., Responses evoked in neurones of the fastigial nucleus by cutaneous mechanoreceptors, Brain Research, 35 (1971) 523-527. 10 lTo, M., YOSHIDA,M., OBATA,K., KAWAI,N., ANDUDO, M., Inhibitory control of intracerebellar nuclei by the Purkinje cell axons, Exp. Brain Res., 10 (1970) 64-80. 11 MATSUSHITA,i . , AND IKEDA, M., Olivary projections to the cerebellar nuclei in the cat, Exp. Brain Res., 10 (1970) 488-500. 12 POMPEIANO,O., Functional organization of the cerebellar projections to the spinal cord. In C. A. Fox AND R. S. SNIOER (Eds.), The Cerebellum, Progress in Brain Research, Vol. 25, Elsevier, Amsterdam, 1967, pp. 282-321. 13 TSUKAHARA,N., KORN,H., AND STONE,J., Pontine relay from cerebral cortex to cerebellar cortex and nucleus interpositus, Brain Research, 10 (1968) 448-453. 14 WOOLSEY,C. N., Organization of somatic sensory and motor areas of the cerebral cortex. In H. F. HARLOWANt) C. N. WOOLSEY(Eds.), Biological and Biochemical Basis of Behavior, Univ. of Wisconsin Press, Madison, Wisc., 1958, pp. 63-81. (Accepted August 4th, 1972)
Brain Research, 45 (1972) 585-589