'form GABAergic (i.e., inhibitory) synapses onto Purkinje cell dendrites'—Elsewhere, it's 'forms with'; please check that 'onto' is OK here.

'originate within' > 'in'; please check my rewording to accommodate the repetition of origin...

'Obstruction of the AICA can cause paresis, paralysis, and loss of sensation in the face, and hearing impairment.' I've reworded to try to clarify the application of 'facial'.

In the section 'Lesions to the cerebellum', the second para about alchohol abuse doesn't explicitly relate to lesions. PS I've taken the liberty of messing with this para.

Double spaces between sentences are creeping back in. (These are undesirable because they can result in 'rivers of white' in the text.)