The effects of lorazepam on visual integration processes: How useful for neuroscientists?

Abstract

The effects of psychotropic drugs can be seen as a reversible lesion of the central nervous system. We studied the effect of lorazepam, a benzodiazepine facilitating the fixation of GABA on the GABA_A receptor. Evidence will be reviewed that lorazepam affects integration processes, using static fragmented pictures or compound stimuli. It will be shown how these effects can be dissociated from other peripheral or central effects of the drug. As a whole, the results suggest that lorazepam improves the detection of discontinuities between collinear elements, but impairs the detection of discontinuities between two parallel line-ends. Recent results will be presented that support the hypothesis that lorazepam does not affect integration processes themselves but modulates the mechanisms involved in the processing of discontinuities, i.e., the processing of line-ends and/or the production of virtual lines orthogonal to the line-ends. An understanding of the effects of the drug might give insights into the way these signals are used and modulated by the visual system.