Effects of ethanol on non-invasively recorded cerebellar, cerebral, and postural responses to axial perturbation: A case study.

We report for the first time non-invasively recorded ethanol (EtOH) induced changes in the spontaneous and evoked activity of the human cerebellum. We recorded electroencephalography (EEG), electro-cerebellography (ECeG), lower limb electro-myography (EMG), and posturography in a 64 year old adult male before and after oral ingestion of EtOH while standing at rest and in response to axial perturbation of the trunk. The a xial perturbation is known to give rise to a well-defined postural reflex of likely brain-stem origin in lower-limb muscles accompanied by correlated short and long latency cerebral and cerebellar responses. The associated cerebellar response is of likely climbing fiber (CF) origin, characterized by post-CF inhibition of the spontaneous Purkinje cell (PC) activity, non-invasively manifest as pausing in the high-frequency ECeG. In our case, EtOH reversibly attenuated the postural reflex and associated cerebral responses, whilst also causing an increase in the spontaneous high-frequency ECeG and severely disrupting the post-CF pausing of the ECeG in response to axial perturbation. The initial component of the CF response was unaffected, however, likely reflecting the afferent volley to the perturbation. These effects demonstrate that non-invasive recordings of cerebellar electrophysiology are possible and can provide important pathophysiological insights.