Sensory Encoding Alternates With Hippocampal Ripples across Cycles of Forebrain Spiking Cascades.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Computational Neuroscience

Background:

• Brain's response to external stimuli is modulated by internal arousal states.
• Neuromodulatory systems govern arousal, influencing brain network activity.
• Coordinated spike timing cascades are linked to arousal fluctuations.

Purpose of the Study:

• To investigate if intrinsic brain processes persist during continuous visual stimulation.
• To determine how arousal fluctuations and spiking cascades affect neural function.
• To explore the impact of locomotion on these brain dynamics.

Main Methods:

• Analysis of large-scale neural recording data from the Allen Institute.
• Examination of brain activity in mice under stationary and locomotion conditions.
• Correlation of neural activity patterns with visual encoding and hippocampal ripples.

Main Results:

• Intrinsic arousal fluctuations and spiking cascades persist during visual stimulation.
• A quasi-periodic cascade cycle influences visual encoding efficacy and hippocampal ripples.
• Active locomotion abolishes this cycle, maintaining high visual coding efficiency and reducing ripples.

Conclusions:

• Infra-slow cascade dynamics may represent an adaptive cycle of sensory sampling and memory function.
• This cycle is suppressed during active environmental exploration.
• Brain dynamics shift to prioritize external processing during active locomotion.