Sensory coding and the causal impact of mouse cortex in a visual decision

Area of Science:

• Neuroscience
• Systems Neuroscience
• Cognitive Neuroscience

Background:

• Sensory-motor correlations are observed across cortical areas, but their causal role in task performance remains unclear.
• Understanding the neural basis of decision-making requires distinguishing causal areas from mere correlates.

Purpose of the Study:

• To determine the causal relevance of specific cortical areas in a visual-motor decision task.
• To investigate the role of visual (VIS) and medial orbital (MOs) cortex in stimulus discrimination and action execution.

Main Methods:

• Mice were trained on a visual contrast discrimination task, reporting choices via wheel steering.
• Widefield calcium imaging and Neuropixels recordings were used to monitor neural activity.
• Optogenetic inactivation was employed to assess causal roles of cortical areas.

Main Results:

• Stimulus-related activity was found in VIS and MOs; movement-related activity was widespread across the dorsal cortex.
• Optogenetic inactivation in VIS and MOs biased choices, correlating with stimulus encoding and decoding times.
• A neurometric model based on VIS and MOs activity accurately predicted behavior and inactivation effects.

Conclusions:

• Sensory signals in VIS and MOs cortex are causally involved in visual decision-making.
• Widespread dorsal cortical activity correlating with movement does not play a causal role in this task.
• This study differentiates critical neural substrates from mere neural correlates in cortical function.