Biased inter-columnar communication and short-term plasticity in mouse barrel cortex.

Area of Science:

• Neuroscience
• Sensory processing
• Computational neuroscience

Background:

• The barrel cortex (BC) is crucial for processing whisker-mediated sensory information.
• Whisker input has complex spatiotemporal structures influenced by whisking kinematics.
• Understanding BC microcircuit communication is vital for deciphering sensory feature extraction.

Purpose of the Study:

• Investigate communication within and between cortical barrels.
• Elucidate how BC microcircuits extract spatiotemporal features from multi-whisker input.
• Determine the role of synaptic transmission and inhibition in BC communication.

Main Methods:

• Utilized a hybrid voltage sensor (hVOS) targeted to Scnn1a excitatory neurons in BC layer 4 (L4).
• Imaged population responses to electrical stimulation in coronal and sagittal slices of mouse brain.
• Employed AMPA receptor blockade to assess the role of excitatory transmission and inhibition.

Main Results:

• Voltage imaging revealed an L4→L2/3→L4 relay crucial for inter-barrel communication.
• AMPA receptor blockade confirmed reliance on excitatory transmission and uncovered feedforward inhibition.
• Single-pulse responses showed direction-dependent latency and anisotropic short-term plasticity, particularly for protraction-related inputs.

Conclusions:

• Identified direction-dependent synaptic circuitry shaping inter-barrel communication in the BC.
• Short-term plasticity exhibits anisotropy aligned with whisker motion kinematics.
• BC microcircuits are tuned to preserve temporal fidelity and selectively filter inputs based on whisking phase and direction.