# Detection and Amelioration of Gamma Oscillation Abnormalities in Blast-Related Brain Injury_523_Spencer

> **NIH VA I21** · VA BOSTON HEALTH CARE SYSTEM · 2020 · —

## Abstract

Veterans of recent conflicts have experienced serious cognitive and emotional problems resulting from
exposure to blasts. Recent work suggests that a critical factor in the sequelae of blast exposure is distance
from the blast, rather than the presence or absence of concussion symptoms. Exposure to blasts from a
distance of <10 m has been associated with significantly greater cognitive and neural disturbances than
exposure to blasts from >10 m. The neural correlates of blast-related brain injury are poorly understood, as to
date this type of brain injury has received little research focus.
 We propose to use oscillations in the gamma band (30-100 Hz) of the electroencephalogram (EEG) to
detect and remediate neural circuit dysfunction related to blast injury in veterans. Gamma band oscillations
have been shown to be involved in several brain functions, including visual perception, selective attention,
working memory, long term memory, and motor control. Recent studies in animal models have linked the
effects of traumatic brain injury to parvalbumin-expressing (PV+) inhibitory interneurons, which are a critical
element of the cortical circuitry that generates gamma oscillations. PV+ interneuron dysfunction is associated
with deficits in evoked gamma oscillations and increased power of broadband gamma “noise”, as well as
cognitive deficits. It has also recently been shown that stimulation of PV+ interneurons by patterned stimuli in
the gamma band can improve the function of these interneurons, as well as cognitive function, in animal
models of neuropsychiatric disorders. Hence, we believe that gamma oscillations and stimulation provide
promising targets for investigation in veterans who suffer from blast-related brain injury. We will investigate
gamma band activity and stimulation in 50 veterans who will be recruited from the participant pool of the VA
Translational Research Center for TBI and Stress Disorders (TRACTS) at the VA Boston Healthcare System.
 Aim 1: To assess whether evoked gamma deficits and increased gamma noise are present in
individuals exposed to Close (<10 m) vs. Far (>10 m) blasts. We predict that evoked gamma will be reduced in
power and phase synchrony, while gamma noise will be increased in power, in Close compared to Far blast
groups.
 Aim 2: To determine whether gamma oscillation abnormalities associated with close blast exposure
can be remediated by non-invasive patterned sensory stimulation in the gamma band. We will administer 6 min
of auditory steady-state stimulation at 40 Hz. We predict that gamma conditioning will increase evoked gamma
oscillations elicited by tones at the conditioned vs. unconditioned frequency, while gamma noise will be
decreased. These effects will be greater in the Close compared to the Far blast groups.
 This project also has 2 exploratory aims: 1) To investigate whether resting state delta-band (1-4 Hz)
EEG power is increased in Close relative to Far blast exposure groups, as delta power is incr...

## Key facts

- **NIH application ID:** 9990583
- **Project number:** 5I21RX003162-02
- **Recipient organization:** VA BOSTON HEALTH CARE SYSTEM
- **Principal Investigator:** KEVIN M SPENCER
- **Activity code:** I21 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2020
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9990583

## Citation

> US National Institutes of Health, RePORTER application 9990583, Detection and Amelioration of Gamma Oscillation Abnormalities in Blast-Related Brain Injury_523_Spencer (5I21RX003162-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9990583. Licensed CC0.

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