Blockade of GABA-A receptors in the primate deep superior colliculus: behavioral effects

摘要: The deep layers of the superior colliculus (DLSC) are a major output target of the basal ganglia, via the nigrotectal GABA pathway. In rats, blockade of this pathway induces contraversive head movements, turning, and stereotyped chewing. In the present study, we examined the effects of unilateral microinjections of the GABA-A receptor antagonist, bicuculline methiodide (BIC, 5-15nmol) into the DLSC of awake male and female pigtailed macaques. BIC or saline was infused stereotaxically via chronically implanted guides into various sites within the DLSC and behavior was monitored and videorecorded for one hour. In response to infusions of BIC, but not to saline, two categories of behavior were observed with a latency of onset within 10 min:(1) motor abnormalities, including postural instability, contraversive eye movements, head turning with occasional circling, and dyskinetic twitches of the contralateral leg;(2 …