Biomedical subjects

Heather E McNeely

Publications and source records attributed to Heather E McNeely.

6 recordsLinked to original sources

PubMed2006

Elevated putamen D(2) receptor binding potential in major depression with motor retardation: an [11C]raclopride positron emission tomography study.

OBJECTIVE: Several antidepressants raise striatal dopamine, but the role of striatal dopamine during major depressive episodes is unclear. Striatal [(11)C]raclopride binding potential measured with positron emission tomography is an index of D(2) type receptors and is sensitive to extracellular dopamine levels (higher D(2) binding potential occurs when dopamine is lower). It was hypothesized that putamen D(2) binding potential would be higher during major depressive episodes featuring motor retardation. METHOD: Drug-free, nonsmoking subjects experiencing a major depressive episode (N=21) underwent [(11)C]raclopride PET imaging as did 21 healthy age-matched comparison subjects. Motor retardation was measured with the finger tapping test. RESULTS: The depressed subjects exhibiting motor retardation had significantly higher D(2) binding potential in both the left and right putamen than did healthy subjects, and putamen D(2) binding potential correlated significantly with motor speed in the depressed subjects. CONCLUSIONS: The results argue that extracellular dopamine is lower in subjects experiencing a major depressive episode that features motor retardation. This depression subtype should preferentially benefit from dopamine-increasing medications and should be targeted in future clinical trials of dopamine reuptake inhibitors.

Adult↗

PubMed2006

An open trial of light therapy in adult attention-deficit/hyperactivity disorder.

OBJECTIVE: In adults with attention-deficit/ hyperactivity disorder (ADHD), a delayed sleep/ activity rhythm and/or seasonal mood symptoms may contribute significantly to core pathology and disability. This study examined whether a chronobiologically based treatment, i.e., morning bright light therapy (LT), might have utility as an adjunctive treatment for adult ADHD in the fall/ winter period. METHOD: Twenty-nine adults with DSM-IV ADHD were administered a standard 3-week open trial of LT during the fall or winter months. Primary outcome measures included percentage reduction on the Brown Adult ADD Scale and the Conners' Adult ADHD Scale. Secondary measures were decrease in depression scores according to the Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorder version; improvements on various neuropsychological tests; and shift toward an earlier circadian preference as measured by the Horne-Ostberg Morningness-Eveningness questionnaire. Regression analyses determined which variables at baseline best predicted improvement on a given outcome measure and which variables changed in parallel with one another. The study was conducted from November 2003 through February 2004. RESULTS: Morning bright light therapy was associated with a significant decrease in both subjective and objective measures of core ADHD pathology, improved mood symptoms, and a significant phase advance in circadian preference. Multiple regression showed that the shift toward an earlier circadian preference with LT was the strongest predictor of improvement on both subjective and objective ADHD measures. Neither baseline global seasonality scores nor baseline depression scores strongly predicted LT effects on most measures of ADHD. CONCLUSION: These findings suggest that during the fall/winter period, LT may be a useful adjunct in many adults with ADHD. Strikingly, the strongest correlate of improvement in core ADHD pathology was a phase advance in circadian preference rather than alleviation of comorbid seasonal affective disorder, suggesting important clinical benefits of LT beyond the treatment of seasonal affective disorder.

Adolescent↗

PubMed2005

Deep brain stimulation for treatment-resistant depression.

Treatment-resistant depression is a severely disabling disorder with no proven treatment options once multiple medications, psychotherapy, and electroconvulsive therapy have failed. Based on our preliminary observation that the subgenual cingulate region (Brodmann area 25) is metabolically overactive in treatment-resistant depression, we studied whether the application of chronic deep brain stimulation to modulate BA25 could reduce this elevated activity and produce clinical benefit in six patients with refractory depression. Chronic stimulation of white matter tracts adjacent to the subgenual cingulate gyrus was associated with a striking and sustained remission of depression in four of six patients. Antidepressant effects were associated with a marked reduction in local cerebral blood flow as well as changes in downstream limbic and cortical sites, measured using positron emission tomography. These results suggest that disrupting focal pathological activity in limbic-cortical circuits using electrical stimulation of the subgenual cingulate white matter can effectively reverse symptoms in otherwise treatment-resistant depression.

Adult↗

PubMed2004

ERP indices of emotionality and semantic cohesiveness during recognition judgments.

Event-related potentials (ERPs) were used to examine the impact of emotionality on false recognition. In Experiment 1, participants discriminated previously studied words from neutral and negatively valenced emotional foils. Emotional words elicited a more positive ERP than did neutral words and emotional foils were falsely recognized more often than neutral foils. In Experiment 2, the hypothesis that emotionality-based false recognition is due to the semantic cohesiveness of emotional words was tested by including a highly associated but emotionally neutral category (animals). It was emotional and not animal foils that elicited greater positivity in the ERP and increased false positive response. These data provide little support for semantic cohesiveness as the basis for false recognition effects, but are consistent with the view that the salience of emotional words can be falsely attributed to familiarity in the context of a recognition task.

Adult↗

PubMed2003

Neurophysiological evidence for disturbances of conflict processing in patients with schizophrenia.

Deficits in cognition are a hallmark of schizophrenia. In the present study, the authors investigated the effects of schizophrenia on the neural correlates of conflict processing in a single-trial version of the Stroop task by using event-related brain potentials. Relative to matched controls, patients with schizophrenia showed increased Stroop interference in response time, but this effect was eliminated when the effect of response slowing was controlled. In controls, conflict processing was associated with a negative wave peaking between 400 and 500 ms (N450) and conflict sustained potential (SP) peaking between 600 and 800 ms after stimulus onset. In patients with schizophrenia, the amplitude of the N450 was significantly attenuated and the conflict SP was absent. These results provide evidence for the existence of altered neural processes associated with conflict processing that may be associated with dysfunction of the anterior cingulate and prefrontal cortex in patients with schizophrenia.

Adult↗

PubMed2002

Neurophysiological evidence of error-monitoring deficits in patients with schizophrenia.

The present study was designed to investigate the time-course of neural activity underlying the disruption of response monitoring in patients with schizophrenia. Event-related brain potentials were recorded from 12 patients with schizophrenia and from 12 age-matched controls while they performed a computerized version of the Stroop color-naming task. In control participants, but not in patients with schizophrenia, intrusion errors elicited an error-related negativity (ERN) that peaked at approximately 40 ms after the response and was maximum over the central region of the scalp. Brain electrical source analysis revealed an anterior cingulate generator for the ERN. Patients also showed reduced error-related slowing of response time following intrusion errors. These findings provide neuro-physiological evidence indicating that deficits in error monitoring in schizophrenia arise from a disruption of error-detection processes, possibly attributable to anterior cingulate dysfunction.

Adult↗