Transient cortical beta-frequency oscillations associated with contextual novelty in high density mouse EEG

Area of Science:

• Neuroscience
• Computational Neuroscience
• Cognitive Neuroscience

Background:

• Beta-frequency oscillations (20-30 Hz) are common in human and rodent electroencephalogram (EEG) recordings.
• Beta oscillations are observed in the hippocampus and other brain regions during exploration of novel environments.
• Limited knowledge exists on the spatial distribution and temporal dynamics of cortical beta oscillations in novel contexts.

Purpose of the Study:

• To investigate the spatial distribution and temporal relationships of beta oscillations across the cortex in response to novel environments.
• To understand the role of the retrosplenial cortex in processing environmental novelty.

Main Methods:

• Mice were fitted with 30-channel EEG-style multi-electrode arrays for high-density EEG recordings.
• Recordings were conducted during a single session in a novel environment to capture responses to novelty.
• Analysis focused on spectral properties, burst rates, and functional connectivity in the beta frequency range.

Main Results:

• A significant increase in the rate of beta bursts was observed across the cortex, especially during the initial phase of exposure to the novel environment.
• This increase was most pronounced over the retrosplenial cortex.
• Environmental novelty enhanced beta-frequency connectivity between retrosplenial areas and other cortical regions.

Conclusions:

• The retrosplenial cortex plays a crucial role as a hub for distinguishing environmental context.
• Cortical activity, particularly beta oscillations, is significantly modulated by environmental novelty.
• High-density EEG reveals the diverse functions of beta oscillations across the brain in response to novel stimuli.