Publications by authors named "Richard Servatius"

We assessed the cross-cultural role of Time Perspective (TP) tendencies [Past Positive (PP), Past Negative (PN), Present Hedonistic (PH), Present Fatalistic (PF), and Future (F)], the Deviation from a Balanced Time Perspective (DBTP) profile, the Deviation from a Negative Time Perspective (DNTP) profile, and mindfulness on life satisfaction (LS). The sample consisted of psychology undergraduate students (N= 867, M= 20.19, = 3.

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A recent study in active-duty military in the Coast Guard suggested that lifetime experience with mild traumatic brain injury (mTBI) was associated with subtle deficits in postural control when exposed to multi-sensory discordance (i.e., rotating visual stimulation).

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Enhanced acquisition of eyeblink conditioning is observed in active duty military and veterans expressing PTSD symptoms (PTSD) and those expressing temperamental vulnerabilities to develop PTSD after traumatic experiences, such as behaviorally inhibited temperament. There is a growing literature showing persistent cerebellar abnormalities in those experiencing mild traumatic brain injury (mTBI) as well as linkages between mTBI and PTSD. With the dependency of eyeblink conditioning on cerebellar processes, the impact of mTBI on eyeblink conditioning in veterans expressing PTSD is unknown.

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Behaviorally inhibited (BI) temperament is marked by heightened behavioral sensitivity to environmental threats. The degree to which threat sensitivity is reflected in cardiorespiratory responses has been relatively unexplored. Female college students were exposed to modest hypercapnia (7.

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Individual differences or vulnerabilities must exist which bias some individuals toward psychopathology while others remain resilient in the face of trauma. Recent work has studied the effects of uncertainty on individuals expressing behavioral inhibition (BI). The current study extended this work with uncertainty to Wistar Kyoto (WKY) rats which are a behaviorally inhibited inbred strain that models learning vulnerabilities for anxiety disorders and posttraumatic stress disorder (PTSD).

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Models of animal behavior suggest that anxiety and major depressive disorder (MDD) may be characterized by different profiles of escape and avoidance behavior. However, the literature on coping strategies fails to distinguish between avoidance and escape coping patterns, instead grouping escape behaviors into the larger category of avoidant coping. We argue that investigating both escape and avoidance coping behavior in those with anxiety and depression may reveal distinct behavioral profiles, whereas the current conceptual framework has failed to find significant differences coping style.

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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.

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Military service members are frequently subjected to subconcussive blast events during training and deployment. Emerging evidence suggests blast exposures of these magnitudes may have long-term consequences for dimensions of cognitive function. Less is known about cognitive sequelae acutely following deployment-related subconcussive blast events.

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Although many individuals who experience a trauma go on to develop post-traumatic stress disorder (PTSD), the rate of PTSD following trauma is only about 15-24%. There must be some pre-existing conditions that impart increased vulnerability to some individuals and not others. Diathesis models of PTSD theorize that pre-existing vulnerabilities interact with traumatic experiences to produce psychopathology.

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Postural control and stress reactivity were investigated in active duty coast guard personnel to determine whether they are sensitive to lifetime effects of mild traumatic brain injury (mTBI). A custom-designed and validated virtual reality-based computerized posturography device was used to assess postural stability, whereas emotional reactivity was assessed using the acoustic startle response (ASR), and neurocognitive performance was assessed using the defense-automated neurobehavioral assessment (DANA). It was hypothesized that residual and subtle postural control imbalance and deficits in cognitive and sensory reactivity would be evident in those reporting multiple lifetime mTBI.

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Adolescents are at high risk for sustaining concussions. There is considerable controversy regarding the sensitivity of neurocognitive tests to detect and track dysfunction in the aftermath of concussion. Two neurocognitive test batteries were compared during the subacute phase of recovery from concussion to determine sensitivity to concussion.

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Objective: Learning diathesis models underscore the role of hyper-conditioning in the development of PTSD following trauma exposure. Eyeblink classical conditioning is one method of examining associative learning biases independent of fear and threat produced by trauma. Facilitated learning is apparent in individuals self-expressing PTSD symptoms, as well as behaviorally inhibited (BI) temperament, a vulnerability factor for PTSD.

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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.

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Historically known for its key contribution to motor behavior, the cerebellum continues to break boundaries. Researchers have demonstrated the cerebellum also plays a role in learning, memory, and more recent evidence for contributions in language, attention, working memory, emotions, and social processes. Here, we present a study that adds to the list of nonmotor processes of the cerebellum.

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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).

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The Wistar-Kyoto (WKY) rat has been proposed as a model of anxiety vulnerability as it exhibits pronounced behavioral inhibition, passive avoidance, exaggerated startle response, enhanced HPA-axis activation, and active avoidance that is resistant to extinction. Accumulating evidence suggests that WKY rats respond differently to rewarding stimuli when compared to outbred strains of rat. Conditioned responding to drug-associated cues is linked with alterations in the activation of mu opioid receptors (MOR) and kappa opioid receptors (KOR) in the nucleus accumbens (NAc).

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Objective: The perseveration of avoidance behavior, even in the absence of once threatening stimuli, is a key feature of anxiety and related psychiatric conditions. This phenomenon can be observed in the Wistar-Kyoto (WKY) rat which, in comparison to outbred controls, demonstrates impaired extinction of avoidance behavior. Also characteristic of the WKY rat is abnormalities of the neurocircuitry and neuroplasticity of the medial prefrontal cortex (mPFC).

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Objective: Addiction is often conceptualized as a behavioral strategy for avoiding negative experiences. In rodents, opioid intake has been associated with abnormal acquisition and extinction of avoidance behavior. Here, we tested the hypothesis that these findings would generalize to human opioid-dependent subjects.

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Behavioral inhibition (BI), a tendency to withdraw from or avoid novel social and non-social situations, is a personality trait which can confer risk for anxiety disorders. Like many personality traits, BI is often assessed via self-report questionnaires where respondents rate themselves for frequency of certain behaviors or feelings. However, questionnaires have inherent limitations, particularly in psychiatric populations where there may be unawareness of deficit.

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Individuals exhibiting an anxiety disorder are believed to possess an innate vulnerability that makes them susceptible to the disorder. Anxiety disorders are also associated with abnormalities in the interconnected brain regions of the amygdala and prefrontal cortex (PFC). However, the link between anxiety vulnerability and amygdala-PFC dysfunction is currently unclear.

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Altered medial prefrontal cortex (mPFC) and amygdala function is associated with anxiety-related disorders. While the mPFC-amygdala pathway has a clear role in fear conditioning, these structures are also involved in active avoidance. Given that avoidance perseveration represents a core symptom of anxiety disorders, the neural substrate of avoidance, especially its extinction, requires better understanding.

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One interpretation of re-experiencing symptoms in post-traumatic stress disorder (PTSD) is that memories related to emotional information are stored strongly, but with insufficient specificity, so that stimuli which are minimally related to the traumatic event are sufficient to trigger recall. If so, re-experiencing symptoms may reflect a general bias against encoding background information during a learning experience, and this tendency might not be limited to learning about traumatic or even autobiographical events. To test this possibility, we administered a discrimination-and-transfer task to 60 Veterans (11.

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Dysregulation of brain-derived neurotrophic factor (BDNF), behavioral inhibition temperament (BI), and small hippocampal volume have been linked to anxiety disorders. Individuals with BI show facilitated acquisition of the classically conditioned eyeblink response (CCER) as compared to non-BI individuals, and a similar pattern is seen in an animal model of BI, the Wistar-Kyoto (WKY) rat. The present study examined the role of hippocampal BDNF in the facilitated delay CCER of WKY rats.

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