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Biomedical subjects

S L Rauch

Publications and source records attributed to S L Rauch.

At least 73 records · Page 4Linked to original sources
PubMed1997

Visual imagery and perception in posttraumatic stress disorder. A positron emission tomographic investigation.

BACKGROUND: Relative regional cerebral blood flow (rCBF) changes were measured in Vietnam combat veterans with and without posttraumatic stress disorder (PTSD) during exposure to combat-related stimuli. METHODS: Positron emission tomography was used to measure rCBF in 7 combat veterans with PTSD (PTSD group) and 7 healthy combat veterans (control group) who viewed and generated visual mental images of neutral, negative, and combat-related pictures. RESULTS: Unlike control subjects, subjects with PTSD had increased rCBF in ventral anterior cingulate gyrus and right amygdala when generating mental images of combat-related pictures; when viewing combat pictures, subjects with PTSD showed decreased rCBF in Broca's area. CONCLUSIONS: Results suggest that ventral anterior cingulate gyrus and right amygdala play a role in the response of combat veterans with PTSD to mental images of combat-related scenes. Reexperiencing phenomena of PTSD, which often involve emotional visual mental imagery, may be likewise associated with increased rCBF in these regions.

Amygdala↗
PubMed1997

Neuroimaging and neuropsychology of the striatum. Bridging basic science and clinical practice.

Neuroimaging and neuropsychology are complementary disciplines that provide powerful means for assessing the structure and function of corticostriatal systems. Findings from four model basal ganglia disorders--OCD, TS, HD, and PD--are reviewed. This survey is intended as a vehicle for illustrating the breadth of current clinical and research applications, as well as the potential for future advances. The perspectives brought by neuroimaging and neuropsychology serve as a natural bridge from the basic neuroscience to the clinical practice articles in this issue.

Cognition Disorders↗
PubMed1997

Current controversies and future directions in basal ganglia research. Integrating basic neuroscience and clinical investigation.

This article discusses current controversies and future directions in basal ganglia research, detailing behavioral aspects, anatomic models, neurochemistry, pharmacology, and diagnostic methods as well as surgical techniques. A neuroethologic perspective is highlighted. Furthermore, the relevant literature pertaining to contemporary molecular approaches such as brain microinjections of embryonic or genetically modified cells, for therapeutic purposes and the use of transgenic and knockout animals.

Animals↗
PubMed1997

Placebo-controlled trial of fluoxetine and phenelzine for obsessive-compulsive disorder.

OBJECTIVE: It is now well documented that fluoxetine is a viable treatment option for patients with obsessive-compulsive disorder (OCD), and there is a small body of evidence indicating that monoamine oxidase inhibitors may be effective in at least a subset of patients. The authors conducted a 10-week placebo-controlled trial of these two agents in patients who met DSM-III-R criteria for OCD. METHOD: Sixty-four subjects were randomly assigned to receive placebo, phenelzine (60 mg/day), or fluoxetine (80 mg/day). These doses were achieved by the end of week 3 of the active phase of the study. Outcomes were assessed with standardized instruments to measure OCD, mood, and anxiety. RESULTS: Fifty-four patients completed the study. There was a significant difference among the three treatments on one OCD scale, with fluoxetine-treated patients improving significantly more than those in the placebo or phenelzine group. A subgroup of OCD patients with symmetry obsessions did respond to phenelzine. CONCLUSIONS: This study provides no evidence to support the use of phenelzine in OCD except possibly for those patients with symmetry or other atypical obsessions. There was also no support for the hypothesis that patients with high levels of anxiety would respond preferentially to phenelzine.

Adult↗
PubMed1997

Probing striatal function in obsessive-compulsive disorder: a PET study of implicit sequence learning.

Positron emission tomography was employed to contrast the brain activation pattern in patients with obsessive-compulsive disorder (OCD) to that of matched control subjects while they performed an implicit learning task. Although patients and control subjects evidenced comparable learning, imaging data from control subjects indicated bilateral inferior striatal activation, whereas OCD patients did not activate right or left inferior striatum and instead showed bilateral medial temporal activation. The findings further implicate corticostriatal dysfunction in obsessive-compulsive disorder. Furthermore, when OCD patients are confronted with stimuli that call for recruitment of corticostriatal systems, they instead appear to access brain regions normally associated with explicit (conscious) information processing.

Adult↗
PubMed1997

Phenomenological differences appearing with repetitive behaviours in obsessive-compulsive disorder and Gilles de la Tourette's syndrome.

BACKGROUND: Obsessive-compulsive disorder (OCD) is heterogeneous, with some forms related to Gilles de la Tourette's syndrome (GTS). This is a phenomenological study designed to investigate the nature of these possible OCD subtypes and the relationship between OCD and GTS. METHOD: We evaluated 20 adult outpatients with OCD, 21 with GTS, and 20 with OCD plus GTS using a semi-structured interview designed to assess cognitive, sensory and autonomic phenomena preceding repetitive behaviours. RESULTS: More cognitions and autonomic anxiety and fewer sensory phenomena were reported in OCD than in GTS. Like the GTS group, the OCD plus GTS group reported more sensory phenomena and fewer cognitions than the OCD group. CONCLUSIONS: The presence or absence of cognitions, sensory phenomena, and autonomic anxiety distinguishes repetitive behaviours in patients with OCD from those with OCD plus GTS, and GTS. These subjective experiences may be useful in subtyping OCD and may represent valid predictors of prognosis and treatment response.

Adolescent↗
PubMed1997

Striatal recruitment during an implicit sequence learning task as measured by functional magnetic resonance imaging.

Prior research has repeatedly implicated the striatum in implicit sequence learning; however, imaging findings have been inconclusive with respect to the sub-territories and laterality involved. Using functional magnetic resonance imaging (fMRI), we studied brain activation profiles associated with performance of the serial reaction time task (SRT) in 10 normal right-handed males. Behavioral results indicate that significant implicit learning occurred, uncontaminated by significant explicit knowledge. Concatenated fMRI data from the entire cohort revealed significant right-lateralized activation in both the caudate and putamen. Analysis of fMRI data from individual subjects showed inter-individual variability as to the precise territories involved, including right as well as left caudate and putamen. Interestingly, all seven subjects who manifested robust learning effects exhibited significant activation within the putamen. Moreover, among those seven subjects, the magnitude of signal intensity change within the putamen correlated significantly with the magnitude of reaction time advantage achieved. These findings demonstrate right-sided striatal activation across subjects during implicit sequence learning, but also highlight interindividual variability with respect to the laterality and striatal subterritories involved. In particular, results from individual subjects suggest that, during the SRT, the reaction time advantage garnered via implicit sequence learning might be predominantly associated with activity within the putamen.

Adult↗
PubMed1996

Neural effects of visualizing and perceiving aversive stimuli: a PET investigation.

Cerebral blood flow was recorded (using positron emission tomography) while middle-aged subjects viewed or visualized pictures of neutral or aversive stimuli, and then determined whether auditorily presented statements correctly described the stimuli. Visualizing aversive stimuli enhanced cerebral blood flow, relative to visualizing neutral stimuli, in areas 17 (right) and 18 (bilateral), as well as the anterior insula (bilateral) and middle frontal cortex (left). Areas 17 and 18 have been identified as supporting the representations that underlie the experience of imagery, and the anterior insula is a major cortical recipient of input from the autonomic nervous system. Perceiving aversive stimuli enhanced cerebral blood flow, relative to neutral stimuli, in area 46, the angular gyrus and area 19, area 47, and the middle temporal gyrus (all in the left hemisphere). All of these areas have previously been implicated in visual object identification. It is striking that negative emotion did not modulate activation in any areas in the same way during imagery and perception.

Brain↗
PubMed1996

The role of hippocampus and frontal cortex in age-related memory changes: a PET study.

The purpose of this study was to examine the neuroanatomical correlates of explicit retrieval of episodic memories in older and young adults. We used an experimental paradigm that allowed us to separate the effort involved in attempting to retrieve a recently studied word from the actual recollection of the item. Both older and younger adults showed hippocampal blood flow increases in association with recollection of a studied word. In contrast, younger but not older adults showed bilateral blood flow increases in anterior prefrontal cortex during retrieval attempts: older adults showed more posterior frontal lobe activations during attempted retrieval. We conclude that the hippocampus activations may reflect a commonality in the way that older and younger adults remember past events, whereas differences in frontal activation may reflect age-related changes in their retrieval strategies.

Adult↗
PubMed1996

Conscious recollection and the human hippocampal formation: evidence from positron emission tomography.

We used positron emission tomography (PET) to examine the role of the hippocampal formation in implicit and explicit memory. Human volunteers studied a list of familiar words, and then they either provided the first word that came to mind in response to three-letter cues (implicit memory) or tried to recall studied words in response to the same cues (explicit memory). There was no evidence of hippocampal activation in association with implicit memory. However, priming effects on the implicit memory test were associated with decreased activity in extrastriate visual cortex. On the explicit memory test, subjects recalled many target words in one condition and recalled few words in a second condition, despite trying to remember them. Comparisons between the two conditions showed that blood-flow increases in the hippocampal formation are specifically associated with the conscious recollection of studied words, whereas blood-flow increases in frontal regions are associated with efforts to retrieve target words. Our results help to clarify some puzzles concerning the role of the hippocampal formation in human memory.

Adult↗
PubMed1996

A symptom provocation study of posttraumatic stress disorder using positron emission tomography and script-driven imagery.

BACKGROUND: Previous studies have used symptom provocation and positron emission tomography to delineate the brain systems that mediate various anxiety states. Using an analogous approach, the goal of this study was to measure regional cerebral blood flow changes associated with posttraumatic stress disorder (PTSD) symptoms. METHODS: Eight patients with PTSD, screened as physiologically responsive to a script-driven imagery symptom provocation paradigm, were exposed sequentially to audiotaped traumatic and neutral scripts in conjunction with positron emission tomography. Heart rate and subjective measures of emotional state were obtained for each condition. Statistical mapping techniques were used to determine locations of significant brain activation. RESULTS: Increases in normalized blood flow were found for the traumatic as compared with control conditions in right-sided limbic, paralimbic, and visual areas; decreases were found in left inferior frontal and middle temporal cortex. CONCLUSIONS: The results suggest that emotions associated with the PTSD symptomatic state are mediated by the limbic and paralimbic systems within the right hemisphere. Activation of visual cortex may correspond to the visual component of PTSD reexperiencing phenomena.

Adult↗
PubMed1996

Functional magnetic resonance imaging of symptom provocation in obsessive-compulsive disorder.

BACKGROUND: The new technique of functional magnetic resonance imaging was used to investigate the mediating neuroanatomy of obsessive-compulsive disorder symptoms. METHODS: Ten patients with obsessive-compulsive disorder and 5 normal subjects were studied via functional magnetic resonance imaging during control and provoked conditions. Data analysis entailed parametric and nonparametric statistical mapping. RESULTS: Statistical maps (nonparametric; P < 10(-3)) showed activation for 70% or more of patients with obsessive-compulsive disorder in medial orbitofrontal, lateral frontal, anterior temporal, anterior cingulate, and insular cortex, as well as caudate, lenticulate, and amygdala. No normal subjects exhibited activation in any brain region. CONCLUSIONS: Results of functional magnetic resonance imaging were consistent with past studies of obsessive-compulsive disorder that used other functional neuroimaging modalities. However, paralimbic and limbic activations were more prominent in the present study.

Adult↗
PubMed1996

Cerebral structural abnormalities in obsessive-compulsive disorder. A quantitative morphometric magnetic resonance imaging study.

BACKGROUND: A previous pilot study of only posterior brain regions found lower white-matter volume in patients with obsessive-compulsive disorder than in normal control subjects. We used new cohorts of patients and matched normal control subjects to study whole-brain volume differences between these groups with magnetic resonance imaging-based morphometry. METHODS: Ten female patients with obsessive-compulsive disorder and 10 female control subjects, matched for handedness, age, weight, education, and verbal IQ, underwent magnetic resonance imaging with a 3-dimensional volumetric protocol. Scans were blindly normalized and segmented by means of well-characterized semiautomated intensity contour mapping and differential intensity contour algorithms. Brain structures investigated included the cerebral hemispheres, cerebral cortex, diencephalon, caudate, putamen, globus pallidus, hippocampus amygdala, third and fourth ventricles, corpus callosum, operculum, cerebellum, and brain stem. Anterior to posterior neocortical regions, including precallosum, anterior pericallosum, posterior pericallosum, and retrocallosum, with adjacent white matter were also measured. Volumes found different between groups were correlated with Yale-Brown Obsessive Compulsive Scale score and Rey-Osterieth Complex Figure Test measures. RESULTS: Confirming results of our earlier pilot study and expanding the findings to the whole brain, patients with obsessive-compulsive disorder had significantly less total white matter but, in addition, significantly greater total cortex and opercular volumes. Severity of obsessive-compulsive disorder and nonverbal immediate memory correlated with opercular volume. CONCLUSIONS: Replication of volumetric white-matter differences suggests a widely distributed structural brain abnormality in obsessive-compulsive disorder. Whereas determining the etiogenesis may require research at a microscopic level, understanding its functional significance can be further explored via functional neuroimaging and neuropsychological studies.

Adult↗
PubMed1996

Functional MRI and the study of OCD: from symptom provocation to cognitive-behavioral probes of cortico-striatal systems and the amygdala.

Functional magnetic resonance imaging (fMRI) first appeared in 1991. Since that time there has been a burgeoning use of the technology by psychiatric researchers and neuroscientists. Our group first used fMRI to study obessive compulsive disorder (OCD) with a symptom provocation paradigm and then moved to the use of circuitry-specific cognitive-behavioral probes. The techniques we utilized for the symptom provocation study remain valid today, but have been supplemented by a wide array of new tools. Functional MRI continues to be a rapidly developing technology which could become the gold standard for neuroimaging research in psychiatry. With this in mind, this paper focuses on the past, present, and future applications of fMRI to one model illness, namely OCD. We examine the strengths and limitations of our initial OCD symptom provocation study and then evaluate the use of fMRI with cognitive-behavioral probes of cortico-striatal circuitry and limbic (amygdala) circuitry. We conclude with a brief summary of foreseeable developments which will influence the implementation of fMRI for psychiatric neuroscience in general.

Arousal↗
PubMed1996

Encoding words and pictures: a positron emission tomography study.

Subjects viewed words, pictures, crosshairs, or a large X flanked by two smaller xs on either side while their brain activity was monitored using positron emission tomography (PET). When activation from the pictures, crosshairs, or Xs condition was subtracted from activation in the words condition, the left angular gyrus and Broca's area were found to be activated. In the comparison of words and pictures, additional language areas were activated. These results provide support for the classical neurological model of reading. The results also suggest that a "word form area" is near the margin of the left angular gyrus.

Adolescent↗
PubMed1996

Response and habituation of the human amygdala during visual processing of facial expression.

We measured amygdala activity in human volunteers during rapid visual presentations of fearful, happy, and neutral faces using functional magnetic resonance imaging (fMRI). The first experiment involved a fixed order of conditions both within and across runs, while the second one used a fully counterbalanced order in addition to a low level baseline of simple visual stimuli. In both experiments, the amygdala was preferentially activated in response to fearful versus neutral faces. In the counterbalanced experiment, the amygdala also responded preferentially to happy versus neutral faces, suggesting a possible generalized response to emotionally valenced stimuli. Rapid habituation effects were prominent in both experiments. Thus, the human amygdala responds preferentially to emotionally valenced faces and rapidly habituates to them.

Adult↗