Task-Dependent Changes in the Large-Scale Dynamics and Necessity of Cortical Regions

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Neural activity across the cortex correlates with perceptual decisions.
• Inactivation studies indicate a limited number of cortical areas are critical for these behaviors.

Purpose of the Study:

• To investigate how the number and dynamics of required cortical areas vary across different cognitive tasks.
• To understand the neural basis of decision-making in tasks with varying computational demands.

Main Methods:

• Bilateral inactivation of cortical regions in rodents during visually guided T-maze, evidence accumulation, and post-stimulus memory tasks.
• Wide-field calcium (Ca2+) imaging to monitor neural activity.
• Analysis of neural activity dynamics and inter-area correlations.
• Utilizing a modular recurrent neural network model for computational analysis.

Main Results:

• A visually guided T-maze task required only a few dorsal cortical regions for performance.
• Tasks involving evidence accumulation or post-stimulus memory were impaired by inactivation of widespread cortical areas.
• Widespread Ca2+ activity ramps were observed during accumulation and visually guided tasks.
• Accumulation tasks showed more diverse regional activity profiles and reduced inter-area correlations.
• A neural network model suggested computational strategy differences could explain the observed variations.

Conclusions:

• The necessity and dynamics of cortical areas in decision-making are task-dependent.
• Complex cognitive computations, like evidence accumulation, engage broader cortical networks with distinct activity patterns.
• Computational strategies may underlie the observed differences in neural requirements across tasks.