Event-related neuronal responses in the human strio-pallido-thalamic system. I. Sensory and motor functions.
Multiunit activity was recorded from strio-pallido-thalamic sites in parkinsonian patients bearing gold electrodes for diagnosis and therapy. The patients voluntarily participated in tasks designed to study neuronal correlates of both physical and semantic characteristics of stimuli as well as motor responses. Six modifications of the stimulus-response paradigm were used: visual odd-ball, visual and acoustic odd-ball tasks; tasks in which either the stimulus intensity or the meaning of non-target stimuli varied; single-stage delayed response and dual-stage delayed response tasks, respectively. In each task the patients had to evaluate some of the stimulus characteristics and to respond in a particular way according to the preliminary instructions. Peristimulus time histograms for each multiunit separately as well as profiles of reactions and profiles of reaction differences for the whole set of multiunits were calculated and subjected to statistical analysis. Two functional groups of subcortical neuronal reactions, stimulus-related and response-related activities, were separated. The stimulus-related activities of most multiunits were modality-unspecific. Their most striking feature was dependence on stimulus relevance and also its probability, the strongest reactions observed in response to task relevant stimuli occurring with low probability. The response-related activities occurred prior to initiation of movements, dependent upon the particular action and its probability. The data suggest at least two different and spatially overlapping subcortical channels responsible for goal-directed behaviour: the one related to stimulus assessment and the other to preparation for motor action.
Kropotov
J D
JD
Human Brain Institute, Academy of Sciences U.S.S.R., St. Petersburg.
Etlinger
S C
SC
Ponomarev
V A
VA
Sevastyanov
A V
AV
D000328:Adult; D001921:Brain / Q000502:physiology*; D016009:Chi-Square Distribution; D003342:Corpus Striatum / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D005917:Globus Pallidus / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D011930:Reaction Time; D013647:Task Performance and Analysis; D013788:Thalamus / Q000502:physiology