PubMed Health⌕ Search

Biomedical subjects

W D Killgore

Publications and source records attributed to W D Killgore.

18 recordsLinked to original sources
PubMed2001

Sex differences in amygdala activation during the perception of facial affect.

The cognitive and affective systems of the cerebral cortex are often more lateralized in males than females, but it is unclear whether these differences extend to subcortical systems. We used fMRI to examine sex differences in lateralized amygdala activity during happy and fearful face perception. Amygdala activation differed for men and women depending on the valence of the expression. Overall, males were more lateralized than females, but the direction differed between valence conditions. Happy faces produced greater right than left amygdala activation for males but not females. Both sexes showed greater left amygdala activation for fearful faces. These findings suggest that the lateralization of affective function may extend beyond the cortex to subcortical regions such as the amygdala.

Adult↗
PubMed2001

Sex-specific developmental changes in amygdala responses to affective faces.

It is hypothesized that adolescent development involves a redistribution of cerebral functions from lower subcortical structures to higher regions of the prefrontal cortex to provide greater self-control over emotional behavior. We further hypothesized that this redistribution is likely to be moderated by sex-specific hormonal changes. To examine developmental sex differences in affective processing, 19 children and adolescents underwent fMRI while viewing photographs of faces expressing fear. Males and females differed in the pattern of their amygdala vs prefrontal activation during adolescent maturation. With age, females showed a progressive increase in prefrontal relative to amygdala activation in the left hemisphere, whereas males failed to show a significant age related difference. There appear to be sex differences in the functional maturation of affect-related prefrontal-amygdala circuits during adolescence.

Adolescent↗
PubMed2000

Functional activation of the left amygdala and hippocampus during associative encoding.

The human hippocampus is critical to episodic encoding, but the role of the amygdala in memory is less clear. Animal research suggests a role for the amygdala in associative memory, but this has not been examined systematically in humans. Using fMRI, we compared amygdala and hippocampus activation for seven healthy subjects during two visual encoding tasks: serially presented single faces and faces presented as pairs. Single faces activated bilateral hippocampi, but not the amygdala. Paired faces activated bilateral amygdala, but only the left hippocampus. Subtraction of the two conditions revealed greater activation within the left amygdala and hippocampus during paired face encoding, suggesting that associative encoding activates a left-lateralized limbic network including the hippocampus and amygdala.

Adult↗
PubMed2000

fMRI during affect discrimination in bipolar affective disorder.

OBJECTIVE: It has been hypothesized that disturbances in affect may represent distinct etiologic factors for bipolar affective disorder. The neural mechanisms mediating affective processes and their relationship to brain development and the pathophysiology of bipolar affective disorder remain to be clarified. Recent advances in neuroimaging techniques have made possible the non-invasive examination of specific brain regions during cortical challenge paradigms. This study reports findings based on fMRI data acquired during fearful and happy affect recognition paradigms in patients with bipolar affective disorder and in healthy adult subjects. METHODS: Prior to the scan, subjects were instructed to view the stimuli and to identify the type of facial expression presented. Echo planar scanning was performed on a 1.5 Tesla scanner which had been retrofitted with a whole body echo planar coil, using a head coil. RESULTS: The data indicate that in adult subjects with bipolar affective disorder, there is a reduction in dorsolateral prefrontal cortex activation and an increase in amygdalar activation in response to fearful facial affect. In a healthy comparison group, signal intensity changes were not found in these regions. In addition, although the patients with bipolar affective disorder completed the task demands, they demonstrated an impaired ability to correctly identify fearful facial affect but not the happy facial affect displayed. CONCLUSION: These findings are consistent with the hypothesis that in some patients with bipolar affective disorder, there may be a reduction of frontal cortical function which may be associated with affective as well as attentional processing deficits.

Adult↗
PubMed2000

Using the WMS-III to detect malingering: empirical validation of the rarely missed index (RMI).

To detect malingering during memory assessment, we evaluated item response biases to the Logical Memory Delayed Recognition (LMDR) subtest of the WMS-III. In a sample of 50 healthy volunteers who were completely naïve to the content of the Logical Memory stories, 6 LMDR items were correctly endorsed above chance probabilities. These 6 rarely missed items significantly discriminated 51 patients with neurological impairment from 36 volunteers who attempted to feign head injury and poor cognitive performance. A weighted combination of the 6 items was summed to form a single Rarely Missed Index (RMI). The RMI accurately classified over 98% of participants and demonstrated high sensitivity (97%) and specificity (100%) in discriminating between analog malingerers and patients. Because the RMI is calculated directly from the LMDR items, it has the advantage of requiring no additional administration time or materials, and thus may serve as a quick screen for dissimulation that can be obtained without additional testing.

Adolescent↗
PubMed2000

Evidence for a third factor on the Positive and Negative Affect Schedule in a college student sample.

The Positive and Negative Affect Schedule (PANAS) was originally developed to measure two orthogonal dimensions of affect. The present study examined the factor structure of the PANAS in a sample of 302 undergraduates. maximum Likelihood factor analysis was used to compare two- and three-factor solutions to self-rated affect. The two-factor solution resulted in confirmation of the two factors of Positive and Negative Affect hypothesized to underlie the schedule. When, however, a three-factor solution was specified, the Positive Affect factor was retained, while the Negative Affect factor split into two lower-order factors generally consistent with the Upset and Afraid factors described by Mehrabian in 1997. These findings highlight the need for research to consider the possible influence of a third affective dimension, such as Dominance-Submissiveness on self-rated affective experience.

Affect↗
PubMed2000

Sex differences in identifying the facial affect of normal and mirror-reversed faces.

The influences of sex and lateralized visual hemispace bias in the judgment of the emotional valence of faces during a free viewing condition are evaluated. 73 subjects (aged 18 to 52 yr.) viewed videotaped facial expressions of emotion in normal and mirror-reversed orientation and classified each face as a positive, negative, or neutral expression. There was a significant interaction between the sex of the rater and the orientation of the face that influenced the proportion of correct classifications. Male and female perceivers did not differ in the accuracy of their affect judgments for faces viewed in normal orientation, whereas reversal of the orientation of the faces resulted in a significant enhancement of accuracy judgments for the males but not the females. The results suggest greater cerebral lateralization of perceptual processes in males.

Adolescent↗
PubMed2000

Item response biases on the logical memory delayed recognition subtest of the Wechsler Memory Scale-III.

We hypothesized that the wording and sequential order of the WMS-III Logical Memory recognition questions may bias subjects toward correct or incorrect responses on specific items. Therefore, we classified each item according to one of three potential sources of bias (yeasaying to proper names, priming of "yes" responses by previous items with similar content, naysaying to unlikely occurrences) and administered the items to 31 subjects who were completely naïve to the story content. The items predicted to have correct endorsement biases were answered correctly at greater than chance frequencies, while items predicted to be biased toward incorrect answers were missed more frequently than expected by chance. The same sources of bias were tested in an independent clinical sample of 36 neurological patients who were administered the WMS-III in the standard manner. In these patients biases appeared robust enough to be detected in the performances of clinical patients during a neuropsychological evaluation. With further research, such biases may provide avenues for detecting malingering.

Adult↗
PubMed2000

Academic and research interest in several approaches to psychotherapy: a computerized search of literature in the past 16 years.

A computerized search of published abstracts in PsychInfo was conducted to obtain the frequency of annual citations since 1984 for six forms of psychotherapy. Cognitive-Behavioral therapies showed the most rapid increase over the past 16 years. Family therapies, in contrast, showed a significant decline in the number of abstract citations since 1990. At present, brief, empirically tested treatments appear to be generating the greatest discussion in the academic and scientific literature.

Cognitive Behavioral Therapy↗
PubMed1999

Functional MRI and the Wada test provide complementary information for predicting post-operative seizure control.

Prediction of post-surgical seizure relief and potential cognitive deficits secondary to anterior temporal lobectomy (ATL) are important to pre-surgical planning. Although the intracarotid amobarbital test (IAT) is predictive of post-ATL seizure outcome, development of non-invasive and more precise means for determining post-ATL seizure relief are needed. We previously reported on a technique utilizing functional MRI (fMRI) to evaluate the relative functional adequacy of mesial temporal lobe structures in preparation for ATL. In the present study, we report follow-up outcome data on eight temporal lobe epilepsy (TLE) patients 1-year post-ATL who were evaluated pre-surgically using IAT and fMRI. Functional memory lateralization using fMRI predicted post-ATL seizure outcome as effectively as the IAT. In general, asymmetry of functional mTL activation favouring the non-epileptic hemisphere was associated with seizure-free status at 1-year follow-up. Moreover, when combined, fMRI and IAT provided complementary data that resulted in improved prediction of post-operative seizure control compared with either procedure alone.

Adolescent↗
PubMed1999

Affective valence and arousal in self-rated depression and anxiety.

To evaluate the predictive utility of Russell's two-dimensional model of affect to the experience of depression and anxiety, self-report ratings of pleasure and arousal were obtained from 200 undergraduates using the Affect Grid. Ratings of Pleasure and Arousal each accounted for significant variance in predicting depression scores on the Beck Depression Inventory and Profile of Mood States. Only ratings of Pleasure, however, were predictive of Anxiety scores on the Profile of Mood States, whereas the relationship between Arousal ratings and Anxiety scores was more complex, demonstrating possible moderation by variables consistent with a third dimension of Dominance-Submissiveness, as postulated by other investigators.

Adult↗
PubMed1999

Sex differences in asymmetrically perceiving the intensity of facial expressions.

Emotional facial expressions are often asymmetrical, with the left half of the face typically displaying the stronger affective intensity cues. During facial perception, however, most right-handed individuals are biased toward facial affect cues projecting to their own left visual hemifield. Consequently, mirror-reversed faces are typically rated as more emotionally intense than when presented normally. Mirror-reversal permits the most intense side of the expresser's face to project to the visual hemifield biased for processing facial affect cues. This study replicated the mirror-reversal effect in 21 men and 49 women (aged 18-52 yr.) using a videotaped free viewing presentation but also showed the effect of facial orientation is moderated by the sex of the perceiver. The mirror-reversal effect was significant only for men but not for women, suggesting possible sex differences in cerebral organization of systems for facial perception.

Adolescent↗
PubMed1999

Prediction of Boston Naming Test performance from vocabulary scores: preliminary guidelines for interpretation.

Patients with limited education or underdeveloped vocabulary skills may perform below the normal range on the Boston Naming Test when compared to the original published norms, even in the absence of brain damage. To reduce the frequency of false positive dysnomic classifications of patients with limited vocabulary skills, we developed a score adjustment to account for the significant shared variance between scores on this test and the WAIS-R Vocabulary subtest. Vocabulary significantly predicted performance on the Boston Naming Test (r = .65, p < .0001) in a sample of 62 outpatients who had no objective evidence of brain damage. Linear regression was used to derive expected performance on the Boston Naming Test from Vocabulary scaled scores. Relative to the original published norms, scores based on the Vocabulary subtest cut-offs produced fewer false positives and more accurately classified group membership for patients with and without objectively verified brain damage. These performance predictions are offered as tentative guidelines to assist clinicians in evaluating the presence of naming deficits by controlling for the variance associated with knowledge of vocabulary.

Adolescent↗
PubMed1999

Hemispheric laterality and self-rated personality traits.

Cerebral hemispheric lateralization and personality traits were evaluated in 154 undergraduate and nonclinical volunteers. Personality ratings did not differ significantly between groups defined on the basis of hand, eye, or ear preference.

Adult↗
PubMed1999

Empirically derived factor indices for the Beck Depression Inventory.

Factor analytic studies of the Beck Depression Inventory routinely yield a small number of factors that parsimoniously summarize the 21 items of the inventory. To improve the utility of such factor data within clinical or applied research settings, the present study aimed to develop a set of empirically derived depression indices based on the factor structure of the Beck Depression Inventory. In Study 1, principal-axis factor analysis of the responses of 303 undergraduate students yielded a 2-factor solution that accounted for 33% of the common variance. Easily calculated factor indices were developed to reflect individual performance on each factor, and normative data from the sample were used to establish preliminary guidelines for evaluating severity on each index. In Study 2, analyses of the factor-index scores obtained from a clinical sample of 55 medical patients supported the utility of the index scores for discriminating among various aspects of dysphoric experience.

Adult↗
PubMed1999

The visual analogue mood scale: can a single-item scale accurately classify depressive mood state?

Visual analogue mood scales provide extremely rapid, single-item assessment of affective states. This study examined discrimination on a single-item visual analogue depression scale between dysphoric or mildly depressed and nondepressed individuals in a sample of 284 college students. The visual analogue mood scale significantly discriminated subjects by mood category and achieved comparable hit rate, sensitivity, and specificity relative to other well validated mood scales.

Adolescent↗
PubMed1998

The Affect Grid: a moderately valid, nonspecific measure of pleasure and arousal.

The Affect Grid was first published in 1989 as a single-item measure of the two affect dimensions of pleasure-displeasure and arousal-sleepiness; however, over the past decade no subsequent validation studies have been published and no further mention of this potentially useful measure has appeared in the literature. In this study, scores on the Affect Grid were obtained from 284 college students and correlated with scores on the Beck Depression Inventory, Positive and Negative Affect Schedule, and the Profile of Mood States. Factor analytic and correlational findings suggest that the Affect Grid is a moderately valid measure of the general dimensions of pleasure and arousal but has little specificity in discriminating among various qualities of affective experience.

Adolescent↗