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Biomedical subjects

Israel Liberzon

Publications and source records attributed to Israel Liberzon.

35 records · Page 2Linked to original sources
PubMed2004

Functional neuroimaging studies of human emotions.

Neuroimaging studies with positron emission tomography and functional magnetic resonance imaging have begun to describe the functional neuroanatomy of human emotion. Taken separately, specific studies vary in task dimensions and in type(s) of emotion studied, and are limited by statistical power and sensitivity. By examining findings across studies in a meta-analysis, we sought to determine if common or segregated patterns of activations exist in different emotions and across various emotional tasks. We surveyed over 55 positron emission tomography and functional magnetic resonance imaging activation studies, which investigated emotion in healthy subjects. This paper will review observations in several regions of interest in limbic (eg, amygdala, anterior cingulate cortex) and paralimbic (eg, medial prefrontal cortex, insula) brain regions in emotional responding.

Affect↗
PubMed2003

Topiramate attenuates exaggerated acoustic startle in an animal model of PTSD.

RATIONALE: Exaggerated acoustic startle is a prominent symptom of post-traumatic stress disorder (PTSD); however, its physiological basis is not well understood, and there are few available treatments. Neurobiological research has suggested that anti-kindling agents and/or glutamate antagonists can attenuate the acoustic startle response (ASR) in animal models. The anticonvulsant topiramate is an AMPA antagonist that also demonstrates potent anti-kindling effects and may, therefore, have promise in treating trauma-enhanced ASR. OBJECTIVE: To evaluate the ability of topiramate to attenuate stress-induced increases in ASR in a previously validated animal model of PTSD. METHODS: Male Sprague-Dawley rats ( n=36) served as controls or received single prolonged stress (SPS). SPS consisted of 2 h restraint, forced swim and ether anesthesia, then a 7-day "undisturbed" period. Animals then received vehicle, 10 mg/kg or 30 mg/kg of topiramate orally, twice daily for 7 days. ASR was assessed for all animals before and after the study, in light and dark environments. RESULTS: SPS produced a sustained increase in the ASR in both environments, an effect that was significantly reduced by topiramate. Meanwhile the ASR of control animals remained unaffected by topiramate. CONCLUSIONS: The current results provide one of the few demonstrations of a single stress episode producing sustained enhancement of ASR. In addition, topiramate demonstrates promise in treating exaggerated acoustic startle symptoms in PTSD or other stress-related disorders.

Acoustic Stimulation↗
PubMed2003

Habituation of rostral anterior cingulate cortex to repeated emotionally salient pictures.

Habituation of the neural response to repeated stimuli has been well demonstrated for subcortical limbic regions responding to emotionally salient stimuli. Although the rostral or affective division of the anterior cingulate cortex (rACC) is also engaged during emotional processing, little is known about the temporal dynamics of this region in sustained evaluation of emotional salience. Using a test/retest design, the present study assessed habituation in the human brain with functional magnetic resonance imaging. Eight healthy subjects were exposed to two repeated runs of aversive, neutral, and blank images. Activation of the rACC to negatively valenced pictures occurred only in the first session, and this activation was significantly greater in the first relative to the second session. Additionally, medial prefrontal cortex, hippocampal, and amygdalar activations were noted during the first, but not second, presentation of aversive pictures. These findings highlight the phasic activity of the rACC in emotional processing consistent with habituation.

Adult↗
PubMed2003

Activation of the medial prefrontal cortex and extended amygdala by individual ratings of emotional arousal: a fMRI study.

BACKGROUND: Significant differences between individual responses to emotional stimuli can be important for the study of emotion. We investigated whether incorporating individual ratings of emotional arousal in the analysis of functional magnetic resonance imaging (fMRI) data improves the detection of activation in the medial prefrontal cortex (MPFC) and sublenticular extended amygdala (SLEA), areas implicated in the processing of emotional salience. METHODS: Healthy subjects viewed counterbalanced blocks of aversive, nonaversive, and blank images. Outside the scanner, they rated the intensity of emotional arousal (salience) of each presented picture. RESULTS: Incorporating the subject's response to each stimulus by using individualized regressors produced more robust activations within MPFC and SLEA compared with a simple boxcar regressor, identical for all subjects. CONCLUSIONS: Our findings demonstrate that individual behavioral data are useful in improving detection of activation in block-design functional imaging studies.

Adult↗
PubMed2003

Subjective rating of emotionally salient stimuli modulates neural activity.

Studies using emotionally salient stimuli have demonstrated neural activation in limbic and paralimbic brain regions. In some studies, subjects passively perceive evocative stimuli, while in other studies, they perform specific cognitive tasks. Evidence is emerging that even a simple cognitive task performed on emotionally salient stimuli can affect neural activation in emotion-associated brain regions. We tested the hypothesis that rating the subjective experience of an aversive visual stimulus would decrease limbic/paralimbic activation and increase activity in medial frontal regions. Ten healthy subjects underwent (15)O PET scans while they viewed pictures of aversive (AV) and nonaversive (NA) content, taken from the International Affective Picture System. Subjects appraised pictures on a scale of pleasantness/unpleasantness during one set of scans (RTNG), and they passively viewed pictures during another set (PSVW). After each scan, emotional responses were assessed. RTNG was associated with significantly less intensity of sadness and significantly less activation (AV - NA) of the right insula/amygdala and left insula, relative to PSVW. RTNG also activated the dorsal medial prefrontal cortex and the anterior cingulate sulcus, which were not differentially activated during PSVW. For both RTNG and PSVW, subjects activated the left fusiform gyrus. The results support the proposition that task instructions about how subjects should process evocative stimuli can affect neural activity.

Amygdala↗
PubMed2003

Valence, gender, and lateralization of functional brain anatomy in emotion: a meta-analysis of findings from neuroimaging.

We performed quantitative meta-analyses on 65 neuroimaging studies of emotion. In an earlier report (NeuroImage 16 (2002), 331). we examined the effects of induction method, specific emotions, and cognitive demand in emotional tasks. This paper focuses on the effects of emotional valence (positive vs negative and approach vs withdrawal) and gender on regional brain activations, with particular emphasis on hypotheses concerning lateralization of brain function in emotion. Overall, we found no support for the hypothesis of overall right-lateralization of emotional function, and limited support for valence-specific lateralization of emotional activity in frontal cortex. In addition, we found that males showed more lateralization of emotional activity, and females showed more brainstem activation in affective paradigms. The study provides evidence that lateralization of emotional activity is more complex and region-specific than predicted by previous theories of emotion and the brain.

Brain↗
PubMed2003

Brain-imaging studies of posttraumatic stress disorder.

Brain-imaging studies of posttraumatic stress disorder (PTSD) have rapidly increased in recent years. Structural studies have identified potential smaller volumes of the hippocampus of traumatized and/or PTSD subjects. Functional activation studies have implicated hyperactive or altered functioning of brain regions, such as the amygdala and the insula, and a failure to engage emotional regulatory structures, such as the medial prefrontal and anterior cingulate cortex. Recent neurochemical investigations have suggested that neuromodulatory systems (eg, gamma-aminobutyric acid, micro-opioid) may underlie these aberrant brain activation patterns. This article reviews the literature on structural, functional, and neurochemical brain-imaging studies of PTSD.

Brain↗
PubMed2003

Neural correlates of traumatic recall in posttraumatic stress disorder.

Functional activation studies of posttraumatic stress disorder (PTSD) using symptom provocation paradigms have implicated dysfunction in limbic and paralimbic brain regions. Increased or altered cerebral blood flow has been observed in amygdala and insula. Decreased or absent activity has been seen in medial prefrontal and anterior cingulate cortex (ACC). These brain regions comprise a neural circuit that has been demonstrated as important for emotional processing and emotional regulation. We studied combat veterans with PTSD (n=16), combat veterans without PTSD (combat controls, n=15), and age-matched healthy control subjects (n=15) with [O-15] H2O PET under a script-driven imagery paradigm of personalized traumatic/stressful and emotionally neutral events. Preliminary findings show that PTSD patients and combat controls had differential blood flow patterns during emotional recall in amygdala, insula and medial prefrontal cortex. Consistent with and extending prior findings, these preliminary results replicate differential patterns of activation in limbic and paralimbic regions of PTSD patients and trauma exposed controls suggesting that these neural substrates may be involved in the deficits in emotional processing in PTSD on one hand, and in resilience to trauma on the other.

Animals↗
PubMed2002

A functional anatomic study of emotion in schizophrenia.

Using salient pictures with aversive (AV) and non-aversive (NA) content, we probed limbic-emotional function in schizophrenia, testing specific hypotheses that the amygdala would exhibit abnormal activity and a relationship with positive symptoms. Fourteen schizophrenic patients and 13 healthy comparison subjects viewed pictures during [15O] water positron emission tomography (PET). Both groups reported identical subjective experience of the aversive stimuli and both activated right insula (AV-NA). The schizophrenic group showed greater activation of the medial prefrontal cortex (MPFC) for the AV-NA comparison. Control subjects activated bilateral amygdaloid and orbitofrontal regions for NA relative to a blank condition (simple visual fixation, BL), whereas schizophrenic subjects only activated left orbitofrontal cortex. Activity in the left amygdala correlated with positive symptoms in the patients. Both groups activated visual cortex, and the schizophrenic subjects exhibited less modulation throughout visual cortex for NA-BL, as well as more focused deficits in the left fusiform and left mid-occipital gyrus for AV-NA, possibly related to decreased eye movements in the schizophrenic patients. Overall, the data are consistent with a general failure to process salient stimuli in schizophrenia, and the findings support the involvement of the amygdala in the positive symptoms of schizophrenia.

Adult↗
PubMed2002

Extended amygdala and emotional salience: a PET activation study of positive and negative affect.

Functional neuroimaging studies have implicated amygdaloid and basal forebrain regions, including sublenticular extended amygdala (SLEA), in the mediation of aversive emotional responses. However, it is not clear whether SLEA responds to 'aversiveness' or to general stimulus salience. We predicted that both pleasant and aversive stimuli would activate this region. Using [(15)O] water PET, we studied 10 healthy subjects while viewing pleasant, aversive, neutral, and blank images. Each subject underwent eight scans, which were processed and averaged with standard statistical methods. Both positive and negative stimuli activated regions in SLEA. Both positive and negative content activated the visual cortex, relative to neutral content. Aversive stimuli deactivated the left frontal pole, relative to positive and neutral stimuli. These findings demonstrate that both positive and negative emotional content evokes processing in the sublenticular/extended amygdala region, suggesting that this region is involved in general emotional processing, such as detection or attribution of salience.

Adolescent↗
PubMed2002

mu-Opioid receptors and limbic responses to aversive emotional stimuli.

Functional neuroimaging studies implicate limbic and paralimbic activity in emotional responses, but few studies have sought to understand neurochemical mechanisms which modulate these responses. We have used positron emission tomography to measure mu-opioid receptor binding, and cerebral blood flow in the same subjects, and demonstrated that the baseline binding potential and the regional cerebral blood flow in the left inferior temporal pole are functionally related. Higher baseline mu-opioid receptor binding potential was associated with lower regional cerebral blood flow in this region during presentation of emotionally salient stimuli. This is consistent with an inhibitory/anxiolytic role of the endogenous opioid system in limbic regions of the temporal lobe and basal forebrain.

Adult↗
PubMed2002

Functional neuroanatomy of emotion: a meta-analysis of emotion activation studies in PET and fMRI.

Neuroimagingstudies with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have begun to describe the functional neuroanatomy of emotion. Taken separately, specific studies vary in task dimensions and in type(s) of emotion studied and are limited by statistical power and sensitivity. By examining findings across studies, we sought to determine if common or segregated patterns of activations exist across various emotional tasks. We reviewed 55 PET and fMRI activation studies (yielding 761 individual peaks) which investigated emotion in healthy subjects. Peak activation coordinates were transformed into a standard space and plotted onto canonical 3-D brain renderings. We divided the brain into 20 nonoverlapping regions, and characterized each region by its responsiveness across individual emotions (positive, negative, happiness, fear, anger, sadness, disgust), to different induction methods (visual, auditory, recall/imagery), and in emotional tasks with and without cognitive demand. Our review yielded the following summary observations: (1) The medial prefrontal cortex had a general role in emotional processing; (2) fear specifically engaged the amygdala; (3) sadness was associated with activity in the subcallosal cingulate; (4) emotional induction by visual stimuli activated the occipital cortex and the amygdala; (5) induction by emotional recall/imagery recruited the anterior cingulate and insula; (6) emotional tasks with cognitive demand also involved the anterior cingulate and insula. This review provides a critical comparison of findings across individual studies and suggests that separate brain regions are involved in different aspects of emotion.

Brain↗
PubMed1991

Post-ECT Dyskinesia.

Three depressed individuals who developed a transient dyskinesia after right unilateral, nondominant electroconvulsive therapy (ECT) are described. The patients responded well to ECT in terms of their affective disorders, and were discharged free of permanent ECT-induced movement disorder symptoms. Risk factors and possible neurochemical changes underlying this phenomenon are discussed.

Journal Article↗
PubMedDate not supplied

Cortisol level and perinatal outcome in pregnant women with posttraumatic stress disorder: a pilot study.

Posttraumatic stress disorder (PTSD) affects 12% of women in the United States and could affect childbearing via behavioral and neuroendocrine mechanisms. This pilot study collected preliminary data about the extent to which the low cortisol profile found in patients with PTSD also occurs in the hormonal context of pregnancy, as well as the association between PTSD and less optimal processes and outcomes of pregnancy. Standardized psychiatric diagnostic telephone interviews, salivary cortisol assays, and medical records review were evaluated in a community sample of 25 women pregnant with their first child. Higher PTSD symptom counts correlated with worse overall perinatal outcomes summarized by an Optimality Index Score (n = 22; r = -.725; P < .001). The women whose symptoms met diagnostic criteria for PTSD or partial PTSD had lower peak basal salivary cortisol concentrations (n = 14; mean = .4584 versus .8123; P = .010). Further research on the effects of PTSD on pregnancy processes and outcomes is warranted. Differences in cortisol levels were consistent with the pattern seen in nonpregnant women with PTSD. This finding suggests that salivary cortisol would be a useful biological measure to include in perinatal research on PTSD and childbearing.

Abortion, Spontaneous↗
PubMedDate not supplied

Psychopharmacological treatment in PTSD: a critical review.

INTRODUCTION: Posttraumatic stress disorder (PTSD) is a prevalent psychiatric disorder that is heterogeneous in its nature, and often presents with other psychiatric comorbidities. As a result, empirical research on effective pharmacotherapy for PTSD has produced complex findings. This article reviews the existing research literature on pharmacological treatments for PTSD, identifies the most effective treatments, and where possible examines their mechanism of action with respect to the neurobiology of PTSD. METHODS: We examined reports of clinical trials of psychotropic agents carried out with PTSD patients and published in peer-reviewed journals, as well as reports from presentations at scientific meetings between 1966 and 2001. RESULTS: Numerous medications are effective in treating PTSD. These include tricyclic antidepressants, monoamine oxidase inhibitors, and serotonin reuptake inhibitors. Considering reported overall efficacy and side effects profiles, selective serotonin reuptake inhibitors emerge as the preferred first line treatment for PTSD. Mood stabilizers, atypical neuroleptics, adrenergic agents, and newer antidepressants also show promise, but require further controlled trials to clarify their place in the pharmacopoeia for PTSD. DISCUSSION: There is clear evidence for effective pharmacotherapy of PTSD. Future improvements in the treatment of this disorder await further clinical trials and neurobiological research.

Clinical Trials as Topic↗
PubMedDate not supplied

The development of persistent pain and psychological morbidity after motor vehicle collision: integrating the potential role of stress response systems into a biopsychosocial model.

OBJECTIVES: Persistent pain and psychological sequelae are common after motor vehicle collision (MVC), but their etiology remains poorly understood. Such common sequelae include whiplash-associated disorders (WAD), fibromyalgia, and posttraumatic stress disorder (PTSD). Increasing evidence suggests that these disorders share overlapping epidemiologic and clinical features. A model is proposed in which central neurobiological systems, including physiologic systems and neuroanatomical structures involved in the stress response, are an important substrate for the development of all 3 disorders and interact with psychosocial and other factors to influence chronic symptom development. METHODS: Epidemiologic and clinical characteristics regarding the development of these disorders after MVC are reviewed. Evidence suggesting a role for stress response systems in the development of these disorders is presented. RESULTS: Contemporary evidence supports a model of chronic symptom development that incorporates the potential for interactions between past experience, acute stress responses to trauma, post-MVC behavior, and cognitive/psychosocial consequences to alter activity within brain regions which process pain and to result in persistent pain, as well as psychological sequelae, after MVC. Such a model incorporates factors identified in prior biopsychosocial theories and places them in the landscape of our rapidly developing understanding of stress systems and CNS pain-modulating pathways. CONCLUSION: New models are needed to stimulate deeper examination of the interacting influences of initial tissue damage, acute pain, psychosocial contingencies, and central stress pathways during chronic symptom development after MVC. Deeper understanding could contribute to improved treatment approaches to reduce the immense personal and societal burdens of common trauma-related disorders.

Accidents, Traffic↗