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Authors & Affiliations
Katarína Studeničová, Xing Chen, Karolína Korvasová
Abstract
The brain continuously receives vast amounts of information from the rest of the body and the environment, only a fraction of which can be consciously processed and stored in memory. It is believed that hippocampal sharp-wave ripples tag memories that are relevant and should be remembered (Yang et al 2024). However, this selection of relevant information must occur already during sensory processing to avoid overloading the system with irrelevant information. The hypothesis of this project is that short bursts of high gamma activity, referred to as cortical ripples to distinguish them from hippocampal sharp wave ripples, are markers of relevance, as they originate from strong synchronous spiking of a local neural population that facilitates the transmission of information to other brain areas. To assess whether this hypothesis is consistent with experimental results, the temporal and spatial relationship between ripples and neural spiking activity were investigated in the visual cortex under various visual stimulation tasks, as well as during spontaneous activity recorded with 16 Utah electrode arrays from 2 macaque monkeys (publicly available data from Chen et al. 2020). On a coarse spatial scale, cortical ripples co-occur with increased neuronal spiking activity. However, the level of temporal agreement between spikes and ripples recorded on the same channel is task-dependent and area-dependent. Moreover, the activation of ripples is functionally specific both in visually evoked conditions and during spontaneous activity, when ripples are organized into large-scale spatio-temporal waves across the cortex.