[Wakefulness and central basal nuclei: experimental observations and possible implications in XXXX ].

@entity13299 @entity1246 @entity191 @entity2915 @entity35 @entity717 @entity2955 @entity25
@entity717 in @entity191 , notably dampened during sleep, are associated with @entity2915 of the subthalamic nucleus (STN), whose origin is controversial. We have studied, on non-anaesthetized head-restrained @entity35 , the STN spontaneous unit activity and the one of its principal GABAergic afferents, the globus pallidus (GP). In normal @entity35 , STN neurons shifted from a random discharge in wakefulness (W) to a bursting pattern in @entity25 ( @entity25 ), without any change in their mean firing rate. In contrast GP neurons, with a mean firing rate higher in W than in @entity25 , exhibited a relatively regular discharge rate whatever the vigilance state. During @entity25 , both STN and GP neurons increased markedly their firing rate. When applied during W, @entity1246 -A antagonists increased the STN firing rate but did not change the typical W random pattern. When applied during @entity25 , they strongly reinforced the spontaneous burst pattern into a particularly marked one with instantaneous frequencies reaching 500Hz. @entity25 -W transitions occurring during ongoing antagonist iontophoresis invariably disrupted this burst pattern into a random one. On @entity2955 unilaterally treated @entity35 , the ipsilateral STN was hyperactive whatever the vigilance state (with an abnormal burst pattern during W on some neurons), but this @entity2915 did not seem to be associated with a @entity13299 . These results show that STN activity is not inversely correlated with GP activity, that its discharge pattern is strongly dependent on vigilance states, that @entity1246 receptors do not play an exclusive role in regulating its firing pattern, and question the depolarization block hypothesis during STN high frequency stimulation.
