Reduced avoidance coping in male, but not in female rats, after mild traumatic brain injury: Implications for depression.

Although there is evidence that traumatic brain injury (mTBI) induces emotional sequelae in rats, it is unclear whether the phenotype is reminiscent of major depressive disorder (MDD) or posttraumatic stress disorder (PTSD). Three behavioral protocols with oppositional indicators for MDD or PTSD were assessed: acoustic startle responses (ASRs), eyeblink conditioning, and instrumental escape/avoidance (E/A) learning. Female and male rats were exposed to lateral fluid percussion injury (LFPi) consistent with mild TBI (mTBI) or sham (SHAM) surgery.

Startle suppression after mild traumatic brain injury is associated with an increase in pro-inflammatory cytokines, reactive gliosis and neuronal loss in the caudal pontine reticular nucleus.

Mild traumatic brain injury (mTBI) can produce somatic symptoms such as headache, dizziness, fatigue, sleep disturbances and sensorimotor dysfunction. Sensorimotor function can be measured by tests such as the acoustic startle reflex (ASR), an evolutionarily conserved defensive response to a brief yet sharp acoustic stimulus. mTBI produces a long-lasting suppression of ASR in rodents and humans; however, the mechanism of this suppression is unknown.

Brain and Serum Androsterone Is Elevated in Response to Stress in Rats with Mild Traumatic Brain Injury.

Exposure to lateral fluid percussion (LFP) injury consistent with mild traumatic brain injury (mTBI) persistently attenuates acoustic startle responses (ASRs) in rats. Here, we examined whether the experience of head trauma affects stress reactivity. Male Sprague-Dawley rats were matched for ASRs and randomly assigned to receive mTBI through LFP or experience a sham surgery (SHAM).

Long-lasting suppression of acoustic startle response after mild traumatic brain injury.

Acoustic startle response (ASR) is a defensive reflex that is largely ignored unless greatly exaggerated. ASR is suppressed after moderate and severe traumatic brain injury (TBI), but the effect of mild TBI (mTBI) on ASR has not been investigated. Because the neural circuitry for ASR resides in the pons in all mammals, ASR may be a good measure of brainstem function after mTBI.

Damage of GABAergic neurons in the medial septum impairs spatial working memory and extinction of active avoidance: effects on proactive interference.

The medial septum and diagonal band (MSDB) are important in spatial learning and memory. On the basis of the excitotoxic damage of GABAergic MSDB neurons, we have recently suggested a role for these neurons in controlling proactive interference. Our study sought to test this hypothesis in different behavioral procedures using a new GABAergic immunotoxin.