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Biomedical subjects

Ruben C Gur

Publications and source records attributed to Ruben C Gur.

58 records · Page 4Linked to original sources
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

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↗