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Create Alert. Share This Paper. Topics from this paper. Mammals Primates Science Pan troglodytes. Substance abuse problem Traumatic cerebral hemorrhage Social Sciences. Citations Publications citing this paper. Wright Amos , Leonie Segal. Chitra Raghavan , Ba Kendra Doychak. Hostage incident management : preparedness and response of international non-governmental organisations Lauvik.
Kjell Erik. References Publications referenced by this paper. Can depression, anxiety and somatization be understood as appeasement displays? The Stockholm syndrome: Toward an understanding. Irka Kuleshnyk. Beha v ioural depression and positron emission tomographydetermined serotonin 1 A receptor binding potential in cynomolgus monkeys. Powell was for decades a leading researcher in classical Pavlovian conditioning of autonomic and somatomotor function and the founder of our laboratory.
His major findings summarized below continue to guide the work in our laboratory at the present time. A fear conditioning paradigm was used to concomitantly condition autonomic cardiac adjustments and somatic eyeblink function [ 51 ]. This approach was applied to a classical conditioning model of PTSD in veterans and a parallel translational lesion model of conditioning in rabbits [ 52 , 53 ].
During millions of years human beings have been hunter-gatherers in the African savannas, and these environmental pressures shaped the species features Buss and Shackelford Published on Sep 10, This book is the first to examine PTSD from an evolutionary perspective. In animals that are organized in social ranks, status is signaled by appeasement displays, which indicate acceptance of a submissive status as to a dominant conspecific. Yet, in these extreme circumstances certain species, such as the guinea pig, display tonic immobility or death feigning Olsen et al. However, the way each species carries out the same defense strategy varies considerably.
Lesions of substantia nigra prevented acquisition of the eyeblink conditioned response and had no effect on conditioned bradycardia [ 54 , 55 ]. Moreover, while deep nuclei of the cerebellum are understood to be necessary for eyeblink conditioning [ 60 ], manipulation of this extrapyramidal substrate does not affect heart rate conditioning [ 61 ]. Interestingly, subiculum of the hippocampus was not found to be necessary for acquisition of conditioned bradycardia in this paradigm [ 67 ]. Furthermore, autonomic cardiac conditioning is rapid compared to somatomotor eyeblink conditioning.
giuliettasprint.konfer.eu: Evolution and Posttraumatic Stress: Disorders of Vigilance and Defence (): Chris Cantor: Books. Evolution and Posttraumatic Stress: Disorders of Vigilance and Defence - CRC Press Book.
In animals, conditioned slowing of heart rate was shown to occur within the first 3—5 conditioning trials, whereas eyeblink conditioning requires many more trials, in the range of 50—60 [ 68 ]. Similarly, heart rate conditioning in humans was more quickly acquired with shorter interstimulus interval than eyeblink [ 69 ]. Since the same set of stimulus contingencies will classically condition both autonomic function and somatomotor behavior, the existence of a process that integrates the two would be expected.
Intraseptal injection of the antimuscarinic anticholinergic scopolamine in the concomitant autonomic and somatomotor conditioning paradigm enhanced cardiac deceleration and impaired eyeblink conditioning [ 72 ]. More research is needed in this area to integrate these crucially important past and current constructs of arousal, attention, and behavior.
This is traumatization of the nervous system. When the nervous system is traumatized, current environmental stimuli, or associatively conditioned reminders of the original danger, repetitively trigger the behavioral response to past fearful events. A simple working definition of PTSD then, apart from the formal clinical diagnostic criteria, is that the ANS of the traumatized individual has become stuck in, or is easily shifted into, a state of ergotropic behavioral response to fear, dominated by sympathetic outflow and its accelerative effects on cardiac adjustment.
Furthermore, and importantly, in this study reduced HRV was also shown to be associated with poorer performance on the immediate verbal memory test [ 12 ]. Further analysis revealed the effects of eyeblink conditioning on heart rate responding in the same study [ 10 ]. This is strong evidence that PTSD disrupts bradycardia during vigilance. Healthy adaptation requires people to allocate attention to genuine threats in the environment while ignoring other similar stimuli.
Attentional problems are a common complaint of patients with a PTSD diagnosis, and clinical research data support this. Using the attentional network test [ 43 ], PTSD participants were found to be impaired in inhibiting irrelevant information, a function of the executive attentional network [ 76 ].
In this task, pairs of threat and neutral or positive stimuli are simultaneously presented across repeated trials. Each stimulus pair is followed by a target probe appearing at the location of either the threat stimulus congruent trials or the neutral stimulus incongruent trials. An attention bias score is calculated as the difference between the mean reaction times of these two types of trials. Early dot probe studies in PTSD in adults and children reported mixed findings.
Still others have failed to find significant attentional bias differences between PTSD and control groups, consisting of healthy individuals and a group of recent trauma survivors that included individuals both with and without acute stress disorder [ 85 , 86 ]. Attention bias was also positively correlated with PTSD symptom severity. These mechanisms are thought to contribute to the onset and maintenance of general anxiety disorders and have relevance for the study of attention bias in PTSD.
General anxiety seems to be associated with a preferential bias for negativity. The measure of attention bias has recently been refined by employing a moving average technique, rather than the previously employed binning method, to generate a more stable index that is influenced less by the number of trials in any particular study [ 90 ].
Attentional training sometimes called attention bias modification, ABM is aimed at reducing symptoms and behaviors associated with anxiety by systematically reducing negative attentional biases and training selective attention to orient away, or to disengage, from threat [ 91 ].
Attention control training, but not attention bias modification, was found to significantly reduce attention bias and reduce PTSD symptoms [ 92 ]. Thus, further study of treatment efficacy for attention bias, and its underlying neurocognitive mechanisms, seems warranted. The scientific and clinical data supporting the facts of diminished vagal and increased sympathetic activity in PTSD increased notably in the past decade and continue to mount [ 13 ].
In developing a treatment intervention, it is important to understand the signature patterns of normal and deranged stimulus processing and appraisal, and response output type, whether immobility, defense, or affiliative. Effective interventions aim to activate, deactivate, or modify one or more components of the abnormal cardiac adjustment pattern. In our clinical research, we use HRVB as a psychophysiological intervention to study the effects of psychological trauma and its potential amelioration. With practice, the individual learns how to voluntarily and quickly produce HRV coherence using RFB, focused attention, and conscious voluntary positive emotional state.
Visual feedback of HRV either quantitative display or animated challenge games is provided as participants practice techniques of attention focusing such as mindfulness , RFB, and induction of a positive emotional state.
Summaries of the evidence for the efficacy of HRVB in reducing mental and physical symptom burden are available [ 93 — 95 ]. The process begins in the upper left corner of the figure, when a stimulus in the environment is registered A normal OR is initiated in less than a second, and proceeds blue arrow to appraisal through cortical processing with an output of cardiac adjustment that depends on the appraisal: stimulus is not further perceived with return to baseline vigilance or appraisal of life threat with no escape immobilization or appraisal of affiliative engagement or appraisal of danger with freeze, fight, or flight response.
Each of the latter appraisal outcomes is associated with an autonomic state, respectively: return to preregistration baseline, bradycardia modulated by dorsal vagal nucleus, bradycardia modulated by ventral vagus and nucleus ambiguus, cardiac acceleration modulated by withdrawal of rostroventral lateral medulla, and activation of sympathetic nervous system. However, all of these studies employed some form of HRV biofeedback as the treatment intervention. The study by Lande [ 98 ] was excluded because HRV data were not included in the study report.
Furthermore, significant improvements were observed as increased digit span backwards and fewer commission errors on continuous performance testing, with a significant interaction of training with PTSD on word list learning that demonstrated combat veterans with PTSD were able to benefit from HRVB to a greater degree than veterans without PTSD. Below are some of the key findings from that study which have not been previously published anywhere else. The length of training was 6 weekly sessions. Raters were blind to the training assignment groups.
Some of the important findings from this study are summarized here and are being prepared for submission as a research article elsewhere. Data showing correlations between HRV variables and measures of PTSD in a sample this size have not, to the best of our knowledge, been previously published. Thus, as vagal tone increased, total PTSD severity decreased. The intrusive thoughts cluster was negatively correlated with log10 HF power, yet was not correlated with either of the time domain variables.
This is strong evidence that active HRVB training produced coherence in those veterans who received it. The orienting reflex could facilitate attention and perception toward a stimulus on one hand, whereas it could bias attention away from the percept on the other hand.
Our planned research on the autonomic stages of the OR in combat veterans with PTSD uses the action cascade, a software program of our own creation. The action cascade is a computerized test that presents the subject with stimulus trials that produce an experimental analog of the naturalistic stages of orienting and response: Rest, Alert, Vigilance, Orienting and Appraisal, and Response Selection and Output. Heart rate and HRV are recorded continuously and simultaneously with task performance on the action cascade by linking the physiological recorder to the computer stimulus presentation program.
Durations of the Rest, Alert, and Vigilance stages vary to reduce the anticipatory predictability of the task. The action cascade is a close analog of the defense cascade paradigm, but modified stimulus valence e. The action cascade protocol is in preliminary data collection stage at this time. Results may bridge the gap in understanding the role that ANS dysfunction plays in the adverse effects of PTSD on arousal, attention, and response disinhibition.
Our chapter has reviewed evidence underlying the theory that ANS control of cardiac adjustments to environmental stimulation is a central factor in the symptom complex of PTSD. HRV is measured and quantified in terms of power variance and the coherence ratio of parasympathetic to total variance in the tachygram. Understanding of vagus nerve as the major control point of responsivity to environmental stimulation, with inputs and outputs affecting emotions, cognition, and behavior, fits into the evolutionary framework that includes the range of response outputs—fight or flight, freezing, tonic immobility, and affiliation.
The neurovisceral integration model specifies the neuroanatomical networks of vagal afference and efference which control the rhythm of cardiac acceleration and deceleration. Dysregulation of the normal fear response by traumatization deranges the ANS and its control of HRV and subsequent defense cascade. HRVB is theoretically and intuitively beneficial in the restoration of ANS function to adaptive parasympathetic and sympathetic levels.
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