Spatial and temporal features of afferent inhibition of thalamocortical relay cells.

1. The temporal and spatial features of the afferent inhibition of thalamocortical relay (TCR) cells in the ventrobasal complex of the thalamus have been examined using paired conditioning and test air jets. 2. The response of TCR units to air jets may be divided into three parts: a) an early response of 1--6 impulses, which begins after a latency of 8--10 ms and lasts for 10--25 ms; b) a period of 70--80 ms following the early response, during which the spontaneous activity is inhibited; and c) a period of late activity, which follows the inhibitory period. 3. The inhibition of TCR units generated by an air jet lasts about 80 ms. The time course of inhibition is the same in hair units and in units activated by Pacinian corpuscles. Evidence is presented that suggests that inhibition decays at the same rate throughout the inhibitory receptive field. 4. The spatial features of inhibition demonstrated in this study are: a) that the excitatory and inhibitory receptive-field centers coincide; b) that these fields have different shape; and c) that there is a significant area in which the inhibitory receptive field surrounds the excitatory receptive field.

[1]  D. Tapper,et al.  Terminal properties of a vibro-tactile sensor. , 1967, Experimental neurology.

[2]  R. Schmidt.  Presynaptic inhibition in the vertebrate central nervous system. , 1971, Ergebnisse der Physiologie, biologischen Chemie und experimentellen Pharmakologie.

[3]  M. Rowe,et al.  Somatic afferent input to posterior thalamic neurones and their axon projection to the cerebral cortex in the cat , 1968, The Journal of physiology.

[4]  Mountcastle Vb,et al.  Activity of single neurons in the tactile thalamic region of the cat in response to a transient peripheral stimulus. , 1954 .

[5]  J. Eccles.  Inhibition in Thalamic and Cortical Neurones and its Role in Phasing Neuronal Discharges , 1965, Epilepsia.

[6]  K. Horch,et al.  Response of cutaneous hair and field mechanoreceptors in cat to threshold stimuli. , 1978, Journal of neurophysiology.

[7]  W. Spencer,et al.  Temporal and spatial parameters of excitation and afferent inhibition in cuneothalamic relay neurons. , 1977, Journal of neurophysiology.

[8]  E Jankowska,et al.  post‐synaptic excitation and inhibition from primary afferents in neurones of the spinocervical tract , 1968, The Journal of physiology.

[9]  H. Nakahama,et al.  Excitation and inhibition in ventrobasal thalamic neurons before and after cutaneous input deprivation. , 1966, Progress in brain research.

[10]  M. A. Baker.  Spontaneous and evoked activity of neurones in the somatosensory thalamus of the waking cat , 1971, The Journal of physiology.

[11]  P R Burgess,et al.  Receptor types in cat hairy skin supplied by myelinated fibers. , 1968, Journal of neurophysiology.

[12]  V. Mountcastle,et al.  THE FUNCTIONAL PROPERTIES OF VENTROBASAL THALAMIC NEURONSSTUDIED IN UNANESTHETIZED MONKEYS. , 1963, Journal of neurophysiology.

[13]  J. Eccles,et al.  The ventro‐basal nucleus of the thalamus: potential fields, synaptic transmission and excitability of both presnyaptic and post‐synaptic components , 1964, The Journal of physiology.

[14]  J. Eccles,et al.  The ventro‐basal complex of the thalamus: types of cells, their responses and their functional organization , 1964, The Journal of physiology.

[15]  J. Eccles,et al.  IDENTIFICATION OF RELAY CELLS AND INTERNEURONS IN THE CUNEATE NUCLEUS. , 1964, Journal of neurophysiology.

[16]  R. Tuckett.  Response of cutaneous hair and field mechanoreceptors in cat to paired mechanical stimuli. , 1978, Journal of neurophysiology.

[17]  P R Burgess,et al.  Dynamic properties of mechanoreceptors with unmyelinated (C) fibers. , 1971, Journal of neurophysiology.

[18]  H H Kornhuber,et al.  A quantitative study of C‐mechanoreceptors in hairy skin of the cat. , 1977, The Journal of physiology.

[19]  K. Maekawa,et al.  Properties of spontaneous and evoked synaptic activities of thalamic ventrobasal neurons. , 1967, Journal of neurophysiology.

[20]  L. Kruger,et al.  Two classes of slowly adapting mechanoreceptor fibres in reptile cutaneous nerve , 1971, The Journal of physiology.

[21]  J. Eccles,et al.  MECHANISMS OF SYNAPTIC TRANSMISSION IN THE CUNEATE NUCLEUS. , 1964, Journal of neurophysiology.