Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [11C] Harmine Positron Emission Tomography Study

Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [¹¹C] harmine PET to measure MAO-A total distribution volume (MAO-A V_T), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A V_T were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F_2,33=6.8, P=0.003; OFC and VS MAO-A V_T each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F_7,28=2.7, P=0.029). In ASPD, VS MAO-A V_T was consistently negatively correlated with self-report and behavioral measures of impulsivity (r=−0.50 to −0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity.     

Effect of intracoronary nitroglycerin on myocardial blood flow and distribution in pacing-induced angina pectoris. Quantitative assessment by single-photon emission tomography

Changes in regional coronary flow after administration of intracoronary nitroglycerin were assessed by measuring total coronary blood flow (using coronary sinus flow catheters) and its regional distribution (by quantitative single-photon emission tomography of injected radioactive microspheres). After pacing to angina, 10 patients with coronary artery disease received serial selective left coronary injections of technetium-99m microspheres, 40 micrograms of nitroglycerin, and indium-111 microspheres. Significant changes in coronary flow distribution were determined by subtracting prenitroglycerin from postnitroglycerin tomographic profiles. Perfusion of each myocardial segment was classified as normal mildly, moderately or severely compromised, based on upstream coronary anatomy. The overall increase in coronary flow was 23% in the normal territories and 33%, 44% and 15% (p less than 0.05), in the mildly, moderately and severely compromised territories, respectively, compared with control values. Thus, intracoronary nitroglycerin increased coronary blood flow to all perfusion territories. The increase in distribution of coronary flow was greatest in the mildly and moderately compromised regions and the least in the most severely compromised regions; this is probably a reflection of the underlying coronary reserve.     

Depression self-management support: A systematic review

Objective

To systematically review empirical evidence regarding the efficacy of depression self-management support (SMS) interventions for improving depression symptomatology and preventing relapse.

Methods

Pubmed and PsycINFO databases were searched for relevant articles on depression SMS interventions. Scanning of references in the articles and relevant reviews and communications with field experts yielded additional articles. Two independent reviewers analyzed the articles for inclusion and data was extracted from the selected articles.

Results

13 papers met the inclusion criteria and reported the results of six separate studies, including three pilot studies. The results were mostly positive. A majority of the trials assessing depression severity changes found SMS to be superior to care as usual. SMS interventions were found to improve self-management behaviors and self-efficacy. Mixed results were found concerning relapse rates. Promising results were found on assessments of functional status. Based on the findings, cost-effectiveness remains unclear.

Conclusion

SMS has been mostly examined through pilot studies with insufficient power. The results are promising, but larger randomized controlled trials are needed.

Practice implications

SMS interventions can be administered by non-physician professionals and are well accepted by patients, but more research is needed before we can recommend implementing specific depression SMS approaches in primary care.     

Distinct neural correlates of visual long-term memory for spatial location and object identity: a positron emission tomography study in humans.

The purpose of the present study was to investigate by using positron emission tomography (PET) whether the cortical pathways that are involved in visual perception of spatial location and object identity are also differentially implicated in retrieval of these types of information from episodic long-term memory. Subjects studied a set of displays consisting of three unique representational line drawings arranged in different spatial configurations. Later, while undergoing PET scanning, subjects' memory for spatial location and identity of the objects in the displays was tested and compared to a perceptual baseline task involving the same displays. In comparison to the baseline task, each of the memory tasks activated both the dorsal and the ventral pathways in the right hemisphere but not to an equal extent. There was also activation of the right prefrontal cortex. When PET scans of the memory tasks were compared to each other, areas of activation were very circumscribed and restricted to the right hemisphere: For retrieval of object identity, the area was in the inferior temporal cortex in the region of the fusiform gyrus (area 37), whereas for retrieval of spatial location, it was in the inferior parietal lobule in the region of the supramarginal gyrus (area 40). Thus, our study shows that distinct neural pathways are activated during retrieval of information about spatial location and object identity from long-term memory.     

General and specific brain regions involved in encoding and retrieval of events: what, where, and when.

Remembering an event involves not only what happened, but also where and when it occurred. We measured regional cerebral blood flow by positron emission tomography during initial encoding and subsequent retrieval of item, location, and time information. Multivariate image analysis showed that left frontal brain regions were always activated during encoding, and right superior frontal regions were always activated at retrieval. Pairwise image subtraction analyses revealed information-specific activations at (i) encoding, item information in left hippocampal, location information in right parietal, and time information in left fusiform regions; and (ii) retrieval, item in right inferior frontal and temporal, location in left frontal, and time in anterior cingulate cortices. These results point to the existence of general encoding and retrieval networks of episodic memory whose operations are augmented by unique brain areas recruited for processing specific aspects of remembered events.