Dynamics and sources of response variability and its coordination in visual cortex

Area of Science:

• Neuroscience
• Computational Neuroscience

Background:

• Trial-to-trial response variability in sensory cortices is crucial for signal processing.
• Understanding the sources and coordination of this variability is limited.

Purpose of the Study:

• To investigate the contributions and dynamics of distinct sources to cortical response variability.
• To analyze the correlations of variability across cortical units.

Main Methods:

• Multisite local field potential (LFP) recordings from turtle visual cortex.
• Decomposition of LFP variability into input, network, and local fluctuation sources.
• Simulations of various model networks.

Main Results:

• Input fluctuations dominate early cortical responses; network fluctuations dominate steady-state responses.
• Network fluctuations drive correlations in variability during ongoing and steady-state activity.
• Synaptic time constants, clustering, and depression are essential for observed variability dynamics.

Conclusions:

• Cortical response variability arises from a complex interplay of input, network, and local factors.
• Thalamocortical circuit features shape stimulus-modulated cortical activity and apparent response variability.