In 1982 he returned to Portland as a Senior Scientist at the Neurological Sciences Institute. In 1998 he joined the faculty at OHSU when the NSI became a department. How the brain is modified by experience is one of the most intriguing questions in neurobiology. The major premise underlying the research in the Barmack lab is that it is necessary to understand both the microcircuitry underlying plastic behaviors, as well as the molecular constituents in order to understand how changes in behavior are accomplished. One of the physiologically-defined pathways that the Barmack lab has studied conveys information about visual motion to the cerebellum.
Optokinetic stimulation activates directionally-selective ganglion cells.
These ganglion cells project to neurons in the nucleus of the optic tract which in turn project to neurons in the dorsal cap of the inferior olive. Dorsal cap neurons project to Purkinje cells in the contralateral flocculus and nodulus of the cerebellum. Activity of cerebellar Purkinje neurons directly modifies the activity of neurons in the vestibular nuclei. The output of the vestibular nuclei influences the brainstem circuitry that controls eye movements and posture. Prolonged optokinetic stimulation of this circuitry induces modification of posture and reflexive eye movements.