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Raquel E Gur

Publications and source records attributed to Raquel E Gur.

69 records · Page 4Linked to original sources
PubMed2002

Neuropsychological functioning in elderly patients with schizophrenia and Alzheimer's disease.

Cognitive functioning was compared in elderly patients with schizophrenia, elderly patients with probable Alzheimer's disease (AD), and matched healthy controls using a brief neuropsychological battery. Both schizophrenia and AD patients demonstrated marked impairment as compared to controls, with the profile of neuropsychological deficits in both disorders appearing remarkably similar. Only visual confrontation naming, verbal delayed recall, and rate of forgetting (i.e. savings score) significantly differentiated between the two patient groups, with AD patients showing poorer overall recall and more rapid forgetting of verbal information over delay. In addition, schizophrenia subjects showed a significantly greater deficit in visual confrontation naming than the AD group. The relationship of neuropsychological function and clinical symptoms of schizophrenia subjects was also examined. Results showed that word list learning, delayed recall, and rate of forgetting correlated most strongly with positive and negative symptoms. Recent neuropathological studies have indicated abnormalities in specific subfields of the hippocampal formation in schizophrenia that are also severely affected in AD. Though the specific histopathology of the two disorders differs, abnormalities in the common sites may underlie the common neuropsychological profile.

Age Factors↗
PubMed2002

A method for obtaining 3-dimensional facial expressions and its standardization for use in neurocognitive studies.

Facial expressions of emotion are increasingly being used in neuroscience as probes for functional imaging and as stimuli for studying hemispheric specialization for face and emotion processing. Available facial stimuli are 2-dimensional and therefore, their orientation is fixed and poorly suited for examining asymmetries, they are often obtained under poorly specified conditions, usually posed, lack ethnic diversity, and are of restricted age range. We describe a method for accurately acquiring and reconstructing the geometry of the human face and for display of this reconstruction in a 3-dimensional format. We applied the method in a sample of 70 actors and 69 actresses expressing happiness, sadness, anger, fear and disgust, as well as neutral expressions. Each emotion was expressed under three levels of intensity and under both posed and evoked conditions. Resulting images are of high technical quality and are accurately identified by raters. The stimuli can be downloaded in digital form as 'movies' where angle and orientation can be manipulated for inclusion in functional imaging probes or in tests that can be administered as measures of individual differences in facial emotion processing. The database of emotional expressions can also be used as a standard for comparison with clinical populations.

Adolescent↗
PubMed2002

Brain activation during facial emotion processing.

Functional neuroimaging studies have helped identify neural systems involved in cognitive processing and more recently have indicated limbic activation to emotional stimuli. Some functional magnetic resonance imaging (fMRI) studies have reported increased amygdala response during exposure to emotional stimuli while others have not shown such activation. The present study was designed to test the hypothesis that activation of the amygdala is related to the relevance of the emotional valence of stimuli. Healthy young participants (7 men, 7 women) were studied in a high-field (4 tesla) scanner using blood oxygenation-level dependent (BOLD) signal changes in a blocked "box car" design. They viewed facial displays of happiness, sadness, anger, fear, and disgust as well as neutral faces obtained from professional actors and actresses of diverse ethnicity and age. Their task alternated between emotion discrimination (indicating whether the emotion was positive or negative) and age discrimination (indicating whether the poser was older or younger than 30). Blocks contained the same proportion of emotional and neutral faces. Limbic response was greater during the emotion than during the age discrimination conditions. The response was most pronounced in the amygdala, but was also present in the hippocampus and circumscribed voxels in other limbic regions. These results support the central role of the amygdala in emotion processing, and indicate its sensitivity to the task relevance of the emotional display.

Adult↗
PubMed2002

Surgically implantable long-term antipsychotic delivery systems for the treatment of schizophrenia.

Non-adherence with medication remains a major correctable cause for poor outcome in schizophrenia. We describe a surgically implantable preparation of haloperidol with the aim that patients will have superior outcomes with improved medication adherence from implants. In contrast to depot formulations, implantable pellets could last many months, providing symptomatic improvement for periods of time never before possible. Additionally, in the event of unacceptable side effects, implants could be removed, offering a degree of reversibility not available with depot formulations. A surgically-implantable formulation of haloperidol has been created using biodegradable polymers. Implants have been characterized for in-vitro kinetics, as well as in-vivo bioactivity in rodents. Haloperidol implants demonstrate steady release of drug for 5 months. Animals treated with haloperidol implants display increased striatal D2 receptor expression as well as increased apomorphine stimulated locomotion. Surgically-implantable formulations are a viable approach to provide long-term delivery of antipsychotic medications to patients with psychotic disorders.

Animals↗
PubMed2002

Neuropsychological profiles delineate distinct profiles of schizophrenia, an interaction between memory and executive function, and uneven distribution of clinical subtypes.

Neuropsychological performance in 151 patients with schizophrenia was examined using cluster analysis to identify neurocognitive subtypes. Hierarchical and iterative partitioning methods identified four clusters using an extended neuropsychological battery. Consistent with previous findings two extreme clusters were characterized by near normative performance and profound global dysfunction, respectively. The two remaining neurocognitive clusters displayed moderate-severe dysfunction and were differentiated by unique patterns of abstraction and flexibility, attention, spatial memory, and sensory-perception. Analysis of variance revealed an interaction between global memory and executive function for clusters III and IV. Although limited cluster differences were found relative to clinical and historical data, the distribution of previously defined clinical subtypes was uneven among neurocognitive clusters. Paranoid patients were significantly more likely to be classified into cluster II and disproportionately absent from clusters I and IV. Patients with negative and disorganized clinical subtypes comprised a disproportionate component of clusters I and IV but were less likely to be classified in cluster II. This suggests greater correspondence than previously postulated between systems responsible for clinical symptomatology and those moderating neurocognitive dysfunction.

Adult↗
PubMed2002

Sex differences in temporo-limbic and frontal brain volumes of healthy adults.

Sex differences have been observed in neurobehavioral measures and in neuroanatomic studies. Men and women differ in emotion processing, including perception, experience and expression, most notably reflected in greater male aggression. We examine temporo-limbic and prefrontal structures volumetrically in a large well-characterized sample of healthy adults, applying morphometric methods across cerebral regions that regulate emotions. Quantitative magnetic resonance imaging (MRI) was performed in 116 healthy adults, 57 men and 59 women, age range 18-49 years. We used reliable methods of region of interest identification to examine sex differences in volume of temporo-limbic and frontal regions. An automated tissue segmentation procedure was used to obtain separate measurements for gray and white matter. After correcting for cranial volume, men and women had identical volumes of amygdala and hippocampus, as well as dorsal prefrontal cortex. However, women had larger orbital frontal cortices than men, resulting in highly significant difference in the ratio of orbital gray to amygdala volume (P = 0.002). The larger volume of cortex devoted to emotional modulation may relate to behavioral evidence for sex differences in emotion processing.

Adolescent↗
PubMed2002

An fMRI study of facial emotion processing in patients with schizophrenia.

OBJECTIVE: Emotion processing deficits are notable in schizophrenia. The authors evaluated cerebral blood flow response in schizophrenia patients during facial emotion processing to test the hypothesis of diminished limbic activation related to emotional relevance of facial stimuli. METHOD: Fourteen patients with schizophrenia and 14 matched comparison subjects viewed facial displays of happiness, sadness, anger, fear, and disgust as well as neutral faces. Functional magnetic resonance imaging was used to measure blood-oxygen-level-dependent signal changes as the subjects alternated between tasks of discriminating emotional valence (positive versus negative) and age (over 30 versus under 30) of the faces with an interleaved crosshair reference condition. RESULTS: The groups did not differ in performance on either task. For both tasks, healthy participants showed activation in the fusiform gyrus, occipital lobe, and inferior frontal cortex relative to the resting baseline condition. The increase was greater in the amygdala and hippocampus during the emotional valence discrimination task than during the age discrimination task. In the patients with schizophrenia, minimal focal response was observed for all tasks relative to the resting baseline condition. Contrasting patients and comparison subjects on the emotional valence discrimination task revealed voxels in the left amygdala and bilateral hippocampus in which the comparison subjects had significantly greater activation. CONCLUSIONS: Failure to activate limbic regions during emotional valence discrimination may explain emotion processing deficits in patients with schizophrenia. While the lack of limbic recruitment did not significantly impair simple valence discrimination performance in this clinically stable group, it may impact performance of more demanding tasks.

Affect↗
PubMed2002

Working memory for complex figures: an fMRI comparison of letter and fractal n-back tasks.

n-back letter and fractal tasks were administered to 11 participants during functional magnetic resonance imaging to test process specificity theories of prefrontal cortex (PFC) function and assess task validity. Tasks were matched on accuracy, but fractal n-back responses were slower and more conservative. Maintenance (1-back minus 0-back) activated inferior parietal and dorsolateral PFC, with additional activation in right ventrolateral PFC during letter n-back and left lingual gyrus during fractal n-back. Maintenance plus manipulation (2-back minus 0-back) activated inferior parietal, Broca's area, insula, and dorsolateral and ventral PFC, with greater right dorsolateral PFC activation for letter n-back. Manipulation only (2-back minus 1-back) produced additional and equivalent dorsolateral PFC and anterior cingulate activation in both tasks. Results support fractal n-back validity and indicate substantial overlap in working memory functions of dorsal and ventral PFC.

Adult↗
PubMed2002

Memory-delineated subtypes of schizophrenia: relationship to clinical, neuroanatomical, and neurophysiological measures.

Memory performance was examined in patients with schizophrenia to determine whether subgroups conforming to cortical and subcortical dementias could be identified and, if so, whether subgroups differed on clinical, neuroanatomical, and neurophysiological measures. A cluster analysis of California Verbal Learning Test performance classified patients into 3 subgroups. Two groups exhibited memory deficits consistent with the cortical-subcortical distinction, whereas 1 group was unimpaired. Cortical patients tended to be male, and they had earlier illness onset, reduced temporal lobe gray matter, and hypometabolism. Subcortical patients had ventricular enlargement and more negative symptoms. Unimpaired patients had fewer negative symptoms and dorsal medial prefrontal hypermetabolism. The authors conclude that categorizing patients on the basis of memory deficits may yield neurobiologically meaningful disease subtypes.

Adult↗
PubMed1997

Reliability, performance characteristics, construct validity, and an initial clinical application of a visual object learning test (VOLT).

Whereas verbal learning has received considerable attention by cognitive neuropsychology, spatial object learning has been more resistant to study. The paucity of visual learning data has hampered attempts to clarify if visual learning has unique features with specialized neural substrates. In schizophrenia, severe verbal learning impairment has been established, but lack of comparable visual learning measures has thwarted the dissociation of verbal and visual abilities. The Visual Object Learning Test (VOLT) was developed to examine aspects of visual-spatial learning and memory in a manner analogous to available verbal tests. Studies were performed to establish normative performance characteristics, convergent and divergent validity, and the sensitivity of the VOLT to detection of individual differences in normal (through sex and age) and pathologic variability (through persons with schizophrenia). The results indicated excellent internal consistency, convergent and divergent validity, and sensitivity to the effects of aging and pathology. Persons with schizophrenia were impaired in both learning and retention. The authors conclude that memory impairment in schizophrenia may not be specific to verbal learning.

Adolescent↗
PubMedDate not supplied

Age-related differences in brain activation during emotional face processing.

Advancing age is associated with significant declines on neurobehavioral tasks that demand substantial mental effort. Functional imaging studies of mental abilities indicate that older adults faced with cognitive challenges tend to activate more regions, particularly frontal, than their younger counterparts, and that this recruitment of additional regions may reflect an attempt to compensate for inefficiency in cortical networks. The neural basis of emotion processing in aging has received little attention, and the goal of the present study was to use functional magnetic resonance imaging (fMRI) to examine the influence of age on facial emotion processing and activation in cortical and limbic regions. Participants (eight old and eight young adults) viewed facial displays of happiness, sadness, anger, fear, disgust, and neutrality in alternating blocks of emotion and age discrimination. We predicted that in response to an emotion discrimination task, older adults would demonstrate increased use of frontal regions relative to younger adults, perhaps combined with diminished use of regions recruited by younger adults, such as temporo-limbic regions. During the emotion discrimination task, young participants activated, visual, frontal and limbic regions, whereas older participants activated parietal, temporal and frontal regions. A direct comparison between emotion and age discrimination revealed that while younger adults activated the amygdala and surrounding temporo-limbic regions, older adults activated left frontal regions. The results of this study suggest that older adults may rely on different cortical networks to perceive emotional facial expressions than do their younger counterparts.

Adult↗
PubMedDate not supplied

Relationship between clock-drawing and neuropsychological and functional status in elderly institutionalized patients with schizophrenia.

OBJECTIVE: The authors sought to examine the usefulness of the clock-drawing test (CDT) as a measure of general cognitive and adaptive functioning in elderly patients with schizophrenia. METHODS: CDT performance of elderly institutionalized patients with schizophrenia were contrasted with a comparison group, similar in age. Cognitive and functional status was examined using an expanded battery from the Consortium to Establish a Registry for Alzheimer's disease and the Psychogeriatric Dependency Rating Scale. RESULTS: Patients (N=21) performed more poorly overall on the CDT than the comparison group (N=21), with greater clock number and hand errors. Production of the clock's gestalt did not differ between groups. In patients, overall CDT performance and clock hand placement were significantly correlated with general cognitive functioning, memory, visuoconstruction, and word-list generation. CDT global and hand placement performances corresponded to patients' general orientation. CONCLUSIONS: Impaired CDT performance in elderly patients with schizophrenia is not attributable to normal aging. Also, the CDT uniquely relates to an array of cognitive abilities in this population, validating its multicognitive character and implicating multiple brain regions. The CDT's tolerability and brevity make it attractive for use in geriatric schizophrenia.

Adaptation, Psychological↗
PubMedDate not supplied

Brain region and sex differences in age association with brain volume: a quantitative MRI study of healthy young adults.

There is evidence that some brain regions show age-associated volume decline and that men undergo more accelerated cerebral aging than women. However, limited information is available on age-associated changes during young adulthood. The authors performed quantitative magnetic resonance imaging in 116 healthy young adults (57 men, 59 women; age range: 18-49 years) to evaluate the relationship of age and sex with volumes of frontal and temporal regions, including selected limbic structures and the basal ganglia. Regardless of sex, increasing age was moderately associated with decrease in total gray matter (GM) and mildly with increase in sulcal cerebrospinal fluid (CSF). Associations of age with reduced GM volume were observed in all frontal and temporal cortical regions and some basal ganglia structures, but were generally less prominent in subcortical regions. The associations were stronger for men than women in the dorsolateral prefrontal cortex. Thus, in young, healthy adults, age-associated changes are selective as well as sex-specific, with men experiencing greater volume decrement across age-groups than women, particularly in the dorsolateral prefrontal regions. Reduced GM and increased CSF in this age range suggests that the aging process is a continuum, with changes evident before senescence. Thus, the biological changes commonly attributed to "aging" do, in fact, begin much earlier in the life-cycle.

Adult↗