Evidence accumulation during a sensorimotor decision task revealed by whole-brain imaging

Area of Science:

• Neuroscience
• Sensory processing
• Behavioral biology

Background:

• Animals integrate sensory information over time for adaptive behavior.
• The neural mechanisms underlying this sensory evidence accumulation in vertebrates are not fully understood.

Purpose of the Study:

• To investigate the neural basis of sensorimotor decision-making in larval zebrafish.
• To identify brain regions involved in accumulating sensory evidence and guiding behavioral choices.

Main Methods:

• Developed a novel sensorimotor decision-making assay using whole-field visual motion in larval zebrafish.
• Employed whole-brain functional imaging to monitor neural activity during the decision-making task.
• Analyzed neural activity patterns and their correlation with behavioral responses (latency, accuracy).

Main Results:

• Behavioral responses (swimming latency, turn accuracy) were modulated by visual motion strength.
• Identified distributed neural activity across brain regions associated with sensory evidence evaluation and accumulation.
• Observed a range of time constants in neural activity, reflecting diverse temporal processing.
• The caudal interpeduncular nucleus (IPN) was found to reliably encode turning rates.

Conclusions:

• Larval zebrafish exhibit sophisticated sensorimotor decision-making based on accumulated visual evidence.
• Neural activity supporting decision-making is distributed across multiple brain regions with varying temporal dynamics.
• The IPN plays a crucial role in encoding motor output (turning rates) related to the decision.