Mild Traumatic Brain Injury Impairs Coupling of CA1 Neuronal Activity to Theta Oscillations
Mild traumatic brain injury (mTBI) is the most prevalent form of brain injury, and persons sustaining an mTBI can experience a number of neurological and behavioral impairments that in some cases can linger for weeks to months. The hippocampus plays a prominent role in learning and memory and in nov...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Mary Ann Liebert
2024-11-01
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| Series: | Neurotrauma Reports |
| Subjects: | |
| Online Access: | https://www.liebertpub.com/doi/10.1089/neur.2024.0119 |
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| Summary: | Mild traumatic brain injury (mTBI) is the most prevalent form of brain injury, and persons sustaining an mTBI can experience a number of neurological and behavioral impairments that in some cases can linger for weeks to months. The hippocampus plays a prominent role in learning and memory and in novelty detection. The activity of hippocampal neurons is modulated by oscillations of the local field potential, especially theta oscillations. Theta oscillations are thought to coordinate and organize hippocampal neuronal activities to encode information essential for memory formation. Both clinical and experimental studies have indicated that hippocampal function is often impaired in persons with mTBI. However, the neural mechanisms underlying these impairments are not well understood. In the present study, we examined the activity of hippocampal neurons and their coupling to local theta oscillations in awake, freely moving animals with mTBI. Electrodes were implanted into the CA1 subfield of the hippocampus in sham and mTBI rats in order to simultaneously record local field potentials and the activity of CA1 neurons. Consistent with previous studies, we found that theta power is reduced after mTBI. This reduction was not associated with any significant loss of either cholinergic or parvalbumin-positive interneurons in the medial septum nucleus/diagonal band. Furthermore, an analysis of waveform properties of unit activity indicated that the coupling of both excitatory and inhibitory (wide and narrow) neurons to theta in rats with mild fluid percussion injury (mFPI) is severely compromised. The lack of hippocampal neuronal coupling to theta may contribute to the poor memory of animals with mFPI. |
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| ISSN: | 2689-288X |