TAPPING, TALKING AND THE THALAMUS - POSSIBLE INFLUENCE OF THE INTRALAMINAR NUCLEI ON BASAL GANGLIA FUNCTION

A patient with a discrete lesion of the left, intralaminar thalamic, n uclei exhibited a paradoxical finding with regard to finger-tapping. N ormal subjects typically reduce their tapping rate when performing sim ultaneous verbal activity. Tapping was impaired in our patient's contr alesional hand on baseline trials; however, performing the controlled oral word association (COWA) task, while finger-tapping, normalized he r deficit. Subsequent experiments showed that motoric tasks rather tha n cognitive aspects of the COWA task were critical in potentiating fin ger-tapping performance. A SPECT study performed at rest revealed foca l perfusion asymmetries in motor and premotor cortices. Because the ca udal intralaminar nuclei project heavily to the striatum, striatal dea fferentiation may account for these asymmetries. These observations pr ovide some insight into the influences of the caudal intralaminar thal amic nuclei on basal ganglia function and the basal ganglia's influenc e on motor gating. Copyright (C) 1996 Elsevier Science Ltd.