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Visual Cortex Controls the Gain, but Not the Selectivity, of Superior Collicular Responses to Looming Stimuli in Awake Mice (LB827)
Author(s) -
Liu Mingna,
Zhao Xinyu,
Cang Jianhua
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb827
Subject(s) - looming , superior colliculus , neuroscience , visual cortex , cortex (anatomy) , optogenetics , psychology , cognitive psychology
Neural circuits in the brain often receive inputs from multiple sources, such as the bottom‐up input from early processing stages and the top‐down input from higher‐order areas. Here, we study the function of top‐down input in the mouse Superior Colliculus (SC), which receives convergent inputs from the retina and visual cortex. Neurons in the superficial SC display robust speed tuning to looming stimuli that mimic approaching objects. The looming‐evoked responses are reduced by almost half when the visual cortex is optogenetically silenced in awake, but not in anesthetized mice. Silencing the cortex does not change the speed tuning of SC neurons, or the response time course except at the lowest tested speed. Consistent with these findings, we further show that cortical responses to the looming stimuli are speed‐insensitive and slow. The strong gain control we have revealed thus provides a neural substrate for the cortex to modulate SC‐mediated visual behaviors. Grant Funding Source : Supported by US National Institutes of Health (NIH) grant (EY020950) to J.C. and HHMI international student fellowship to X.Z.