Spatial structure of multiwhisker receptive fields in the barrel cortex is stimulus dependent

Area of Science:

• Neuroscience
• Sensory Systems
• Somatosensation

Background:

• Rodents use the whisker-trigeminal system for object detection and discrimination.
• Whisker-trigeminal system capabilities depend on the temporal and spatial structure of whisker deflections.
• Barrel cortex receptive fields integrate input from multiple vibrissae, reflecting environmental interactions.

Purpose of the Study:

• To investigate how stimulus parameters influence the spatial structure of cortical receptive fields.
• To characterize receptive fields based on different directions of whisker deflection.

Main Methods:

• Utilized a novel 24-whisker stimulation matrix for precise whisker deflection.
• Applied forward correlation analysis to spiking activity in response to randomized whisker deflections (sparse noise).
• Characterized receptive fields for both caudal and rostral whisker deflection directions.

Main Results:

• The principal whisker (strongest, shortest latency response) varied with deflection direction.
• Maximal neuronal responses to opposite deflection directions were spatially separated.
• This spatial separation led to a displacement in the center of mass between rostral and caudal subfields, with differing response latencies.

Conclusions:

• Cortical receptive field organization in the barrel cortex is direction-dependent.
• The spatial structure of these receptive fields is not fixed but is shaped by sensory input properties.
• Direction-dependent organization was consistently observed across all cortical layers.