Title: Alterations in corticospinal neuron activity associated with thalamocortical recruiting responses
Abstract: 1. The relation between different varieties of repetitively evoked thalamocortical responses in motor cortex and corticospinal neuron activity has been studied in locally anesthetized-paralyzed cats. 2. Long-latency (> 20 msec) recruiting responses evoked by medial thalamic stimulation are associate dwith long-latency (> 20 msec) relayed corticospinal tract discharges which recruit pari passu with surface-negativity. Short-latency (8–15 msec) recruiting responses evoked by stimulation of antero-lateral components of the thalamic reticular system (TRS) are associated with recruiting tract discharges that are initiated during the prior surface-positivity that characterizes many of these responses. 3. Relayed tract discharges triggered during short or long-latency recruiting responses are distinguishable from those associated with augmenting and non-augmenting specific thalamocortical activities in terms of latency, magnitude and duration. 4. Direct and indirect corticospinal tract responses evoked by 7–10/sec weak motor cortex stimulation and short-latency (2–4 msec) relayed discharges evoked during specific thalamocortical responses are inhibited prior to and after relayed tract volleys associated with short and long-latency recruiting responses. 5. Relayed activity in corticobulbar and corticospinal pathways associated with recruiting responses in motor cortex is distributed to a wide variety of elements in brain stem reticular organizations and spinal cord. 6. Evidence is presented indicating that sub-surface synaptic events responsible for the alterations in corticospinal neuron activity during different varieties of recruiting responses are independent of those involved in the production of recruiting surface-negativity.
Publication Year: 1961
Publication Date: 1961-06-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 47
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