Active Licking Shapes Cortical Taste Coding.

Area of Science:

• Neuroscience
• Sensory Processing
• Gustation

Background:

• Neurons in the gustatory cortex (GC) represent taste via time-varying spiking activity.
• The predominant view suggests neural firing rate is the sole unit of taste information.
• The role of spike timing relative to licking in taste encoding remains unclear.

Purpose of the Study:

• To investigate whether GC neurons use spike phase relative to lick timing for taste encoding.
• To quantify the contribution of spike rate versus spike timing to taste discrimination.

Main Methods:

• Recorded spiking activity from over 500 single GC neurons in mice during free licking.
• Utilized machine learning algorithms and functional data analysis to classify spike trains.
• Developed tools to quantify taste information in spike rate and spike timing relative to licks.

Main Results:

• GC neurons primarily encode taste information using a rate code, but spike timing is also crucial for discrimination.
• Taste discrimination accuracy improves when spike timing is analyzed relative to lick timing (interlick phase).
• Optimal taste discrimination is achieved when both spike rate and timing are interpreted relative to lick timing.

Conclusions:

• Spike timing, particularly the interlick phase, provides significant taste information beyond firing rate.
• The lick cycle is a key factor in gustatory processing within the mouse GC.
• Integrating spike rate and timing relative to licking offers the most comprehensive taste discrimination.