Dysregulation of visual motion inhibition in major depression.
Individuals with depression show depleted concentrations of the inhibitory neurotransmitter GABA in occipital (visual) cortex, predicting weakened inhibition within their visual systems. Yet, visual inhibition in depression remains largely unexplored. To fill this gap, we examined the inhibitory process of center-surround suppression (CSS) of visual motion in depressed individuals. Perceptual performance in discriminating the direction of motion was measured as a function of stimulus presentation time and contrast in depressed individuals (n=27) and controls (n=22). CSS was operationalized as the accuracy difference between conditions using large (7.5°) and small (1.5°) grating stimuli. Both depressed and control participants displayed the expected advantage in accuracy for small stimuli at high contrast. A significant interaction emerged between subject group, contrast level and presentation time, indicating that alterations of CSS in depression were modulated by stimulus conditions. At high contrast, depressed individuals showed significantly greater CSS than controls at the 66ms presentation time (where the effect peaked in both groups). The results' specificity and dependence on stimulus features such as contrast, size and presentation time suggest that they arise from changes in early visual processing, and are not the results of a generalized deficit or cognitive bias.
Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA; McLean Hospital, and Department of Psychiatry, Harvard Medical School, Belmont, MA, USA; Massachusetts General Hospital, Boston MA, USA. Electronic address: danieljnorton@gmail.com.
Daniel J
DJ
Norton
Department of Global Health and Population, Harvard School of Public Health, Boston, MA, USA.
Ryan K
RK
McBain
McLean Hospital, and Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
Diego A
DA
Pizzagalli
Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA.
Alice
A
Cronin-Golomb
McLean Hospital, and Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
Yue
Y
Chen
D000328:Adult; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology*; D014793:Visual Cortex / Q000503:physiopathology
Center surround; Cognitive; Depression; Mood; Motion; Neuroscience; Psychophysics; Vision