ALTERATIONS IN PALLIDAL NEURONAL RESPONSES TO PERIPHERAL SENSORY AND STRIATAL STIMULATION IN SYMPTOMATIC AND RECOVERED PARKINSONIAN CATS

Citation
Ds. Rothblat et Js. Schneider, ALTERATIONS IN PALLIDAL NEURONAL RESPONSES TO PERIPHERAL SENSORY AND STRIATAL STIMULATION IN SYMPTOMATIC AND RECOVERED PARKINSONIAN CATS, Brain research, 705(1-2), 1995, pp. 1-14
Citations number
70
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
0006-8993
Volume
705
Issue
1-2
Year of publication
1995
Pages
1 - 14
Database
ISI
SICI code
0006-8993(1995)705:1-2<1:AIPNRT>2.0.ZU;2-C
Abstract
The spontaneous activity, responses to peripheral sensory and ipsilate ral caudate nucleus stimulation of globus pallidus (GP) and entopedunc ular nucleus (ENTO) neurons were studied in cats while normal, symptom atic for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced p arkinsonism, and when spontaneously recovered from gross parkinsonian motor deficits. Administration of MPTP resulted in parkinsonian motor symptoms that spontaneously recovered approximately 4-6 weeks after th e MPTP administration. Post-mortem dopamine levels in recovered animal s was approximately 95% below levels previously measured in normal ani mals. In symptomatic animals, the mean spontaneous firing rate for GP units was decreased by 50% and increased by 55% for ENTO units recorde d. Spontaneous firing rates for GP and ENTO units in recovered cats we re not significantly different from those observed in normal cats. In normal cats, 31.4% of GP and 29% of ENTO units tested responded to tac tile stimulation of the face. Only 12.2% of GP and 13% of ENTO units r esponded to such stimulation in parkinsonian animals while the respons es were generally less specific (larger receptive fields, more bilater al receptive fields, and more responses to multiple stimulation types) than normal. In recovered cats GP and ENTO responses resembled those observed in normal cats. There was no difference in the overall percen tage of pallidal units responding to striatal stimulation across the 3 experimental conditions. There was, however, an increase in the perce ntage of units responding with complex response sequences (i.e. decrea se in activity followed by an increase in activity) in symptomatic ani mals as compared to normal and recovered animals. The results suggest that loss of striatal dopamine in parkinsonian animals has profound ef fects on the sensory responsiveness of GP and ENTO neurons and that th ese effects coincide with the appearance of and recovery from parkinso nian motor deficits. These data further support the notion that sensor y information processing by the basal ganglia may play an important ro le in influencing motor output.