Rapid Adaptation Induces Persistent Biases in Population Codes for Visual Motion.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Visual Perception

Background:

• Visual experience dynamically alters neural responses.
• Failure to incorporate these neural encoding changes leads to perceptual biases.
• Adaptation's effects are typically studied in isolation, not under naturalistic conditions.

Purpose of the Study:

• To investigate how adaptation-induced biases arise and persist during continuous, naturalistic visual stimulation.
• To understand the temporal dynamics of adaptation's effects on neural encoding and population decoding.

Main Methods:

• Simultaneous recording of up to 61 neurons in the marmoset middle temporal area.
• Presentation of rapidly changing visual stimuli (direction changes every 500 ms).
• Analysis of neural encoding changes (gain, spike count correlations, bandwidth, preferred direction) and population decoding performance.

Main Results:

• Short-term (0.5 s) direction-specific adaptation significantly altered neural encoding for up to 2 s.
• Adaptation reduced neural gain and spike count correlations, predicting repulsive perceptual biases (direction aftereffect).
• Population decoding errors correlated with adaptation strength, and removing spike count correlations did not affect decoding performance or bias.

Conclusions:

• Neural and perceptual repulsion are likely consequences of optimizing neural encoding for diverse stimuli and contexts, rather than mechanisms to enhance performance.
• Adaptation's effects on neural code and its temporal persistence are crucial for understanding visual perception.
• This study provides novel insights into the cascade of adaptation effects during continuous naturalistic vision.