Adaptation improves neural coding efficiency despite increasing correlations in variability.

Area of Science:

• Neuroscience
• Sensory Systems
• Computational Neuroscience

Background:

• Neuronal response functions change with sustained sensory stimuli, a process known as adaptation.
• Adaptation is a widespread phenomenon across different sensory modalities.
• Understanding adaptation's effect on neural ensembles is crucial for comprehending sensory processing.

Purpose of the Study:

• To quantify the functional impact of adaptation on cortical neuron ensemble activity.
• To investigate how adaptation affects neuronal response functions and information coding in the rat whisker-barrel system.

Main Methods:

• Utilized a multishank electrode array for simultaneous neuronal activity sampling.
• Characterized neuronal responses to sinusoidal whisker vibrations across varying amplitudes and adaptation states.
• Analyzed neuronal response functions, mutual information, Fano factor, and noise correlations.

Main Results:

• Adaptation caused a rightward shift in neuronal response functions.
• Peak discrimination performance shifted to higher stimulus amplitudes post-adaptation.
• Stimulus presentation reduced single-neuron and population response variability.
• Adaptation led to lower firing rates, higher Fano factors, and increased noise correlations.
• Noise correlations were positive and detrimental to coding efficiency.
• Adaptation increased total information coding despite elevated noise correlations.

Conclusions:

• Adaptation systematically alters neuronal coding by shifting response functions and modifying response variability.
• While adaptation increases noise correlations, its net effect is an enhancement of total information transmission.
• The findings provide insights into the adaptive mechanisms governing sensory information processing in the cortex.