Mild Traumatic Brain Injury Decreases Broadband Power in Area CA1

Abstract

Cognitive impairment caused by traumatic brain injury (TBI) can lead to devastating consequences for both patients and their families. The underlying neurological basis for TBI-induced cognitive dysfunction remains unknown. However, many lines of research have implicated the hippocampus in the pathophysiology of TBI. In particular, past research has found that theta oscillations, long thought to be the electrophysiological basis of learning and memory, are decreased in the hippocampus post-TBI. Here, we recorded in vivo electrophysiological activity in the hippocampi of 16 mice, 8 of which had previously undergone a TBI. Consistent with previous data, we found that theta power in the hippocampus was decreased in TBI animals compared to sham controls; however, this effect was driven by changes in broadband power and not theta oscillations. This result suggests that broadband fluctuations in the hippocampal local field potential can be used as an electrophysiological surrogate of abnormal neurological activity post-TBI.

Enhanced astrocytic d-serine underlies synaptic damage after traumatic brain injury

“…Within the hippocampus, θ oscillations are known to facilitate memory processes, although the exact mechanisms are not completely understood. TBI can result in a decrease in power in the θ frequency band (39,40). However, changes in θ frequency after TBI are dependent on the severity of the injury (41).…”

Modified device for fluid percussion injury in rodents

“…The LFP data were obtained by resampling the raw data with a sampling rate of 100 Hz and band filter of 1.3–50 Hz. Theta power in 6–12 Hz band (Paterno, Metheny, Xiong, Elkind, & Cohen, ) was averaged from every 10‐min epoch of the 1 hr LFP raw data with 0.39 Hz frequency resolution. Overall firing data were harvested by resampling the raw data with a sampling rate of 1 kHz and band filter of 50–250 Hz.…”

Pathophysiology and Treatment of Memory Dysfunction After Traumatic Brain Injury

“…Another study measuring single-neuron spiking activity found that FPI animals had decreased bursting activity in place cells, which was also associated with poor memory performance in the T-maze [116]. In contrast, in a mild FPI model, a study showed only a decrease in broadband activity (a measure of the overall multi-unit activity) and not theta oscillations [117] supporting the hypothesis that TBI severity leads to different pathologies.…”