A Modality-Specific Feedforward Component of Choice-Related Activity in MT

Area of Science:

• Neuroscience
• Sensory processing
• Decision-making

Background:

• Individual sensory neuron activity predicts animal choices.
• Decision signals originate from network properties influenced by feedforward and feedback inputs.
• The precise roles of these input pathways remain unclear.

Purpose of the Study:

• To investigate the contribution of feedforward pathways to decision signals in the medial temporal area (MT).
• To determine the differential roles of V2 and V3 inputs in motion versus depth perception tasks.

Main Methods:

• Neuronal activity in MT was recorded in monkeys during motion and depth discrimination tasks.
• V2 and V3, key feedforward input regions to MT, were reversibly inactivated.
• Choice-related activity of MT neurons was monitored before and during V2/V3 inactivation.

Main Results:

• MT neuron activity became less predictive of choices during the depth task when V2/V3 were inactivated.
• Inactivation of V2/V3 did not significantly affect MT neuron predictiveness for the motion task.
• Data suggest V2/V3 input contributes to decision signals and may induce structured noise correlations in the MT population.

Conclusions:

• Feedforward pathways, specifically from V2/V3, play a crucial role in shaping decision signals in MT.
• These pathways are differentially important for processing different sensory modalities (depth vs. motion).
• The findings highlight the contribution of feedforward input to both sensory tuning and decision formation.