Intrinsic dynamic shapes responses to external stimulation in the human brain.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Brain activity involves recurrent neural networks responding to sensory stimulation.
• Current computational models often fail to differentiate immediate sensory responses from intrinsic brain dynamics.
• Understanding the interplay between external stimuli and intrinsic neural activity is crucial.

Purpose of the Study:

• To develop a computational model that separates immediate sensory responses from intrinsic brain dynamics.
• To investigate how the brain's intrinsic recurrent activity influences neural responses to external stimuli.
• To analyze functional connectivity patterns in sensory and higher-order brain areas.

Main Methods:

• Application of a vector-autoregressive model with external input (VARX) to intracranial recordings in humans.
• Integration of concepts from functional connectivity and encoding models.
• Analysis of neural responses to audiovisual stimuli, including scene cuts, eye movements, and sounds.

Main Results:

• The intrinsic brain dynamic enhances and prolongs neural responses to sensory stimuli.
• Failure to account for external inputs can lead to misidentification of recurrent connections.
• Recurrent connectivity decreases during movie watching compared to rest.
• External stimuli can reduce intrinsic neural noise.
• Sensory areas exhibit predominantly outward connections, while higher-order areas show mostly incoming connections.

Conclusions:

• The brain's intrinsic dynamic plays a significant role in processing external audiovisual stimuli.
• The intrinsic neural activity observed during rest largely explains responses to external stimuli.
• Accurate modeling requires separating extrinsic stimulus effects from intrinsic neural dynamics.