Decreased cerebral blood flow in the limbic and prefrontal cortex using SPECT imaging in a cohort of completed suicides

Suicide has a high comorbidity with impulsivity and depression, and finding imaging biomarkers indicative of patients at high risk for suicidal behavior is invaluable to the clinician. Using single-photon emission computed tomography (SPECT) imaging, we have previously reported regional cerebral blood flow (rCBF) decreases in the medial prefrontal cortex, ventral tegmental area and subgenual cingulate cortex (Brodmann area 25 (BA 25)), a region found to be hypoperfused with treatment-resistant depression. From 2007 to 2010, we have extended our analysis to include nine additional completed suicides. In all, 27 healthy, age- and gender-matched subjects from a previously acquired healthy brain study served as controls to our 21 completed suicides. All 21 suicides had been previously diagnosed with depression according to Diagnostic and Statistical Manual of Mental Disorder-IV criterion. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare the differences in technetium-99m hexamethylpropylene amine oxime brain uptake between the groups. Factor analysis of the data identified the top 10 regions of hypoperfusion in the suicidal group, including the bilateral superior frontal lobes, the right precuneus, the rolandic operculum, postcentral gyrus, left caudate and insular cortex. We also demonstrate more focal decreases in rCBF in the subgenual cingulate cortex (BA 25) in 18 subjects, supporting our previous hypothesis that hypoperfusion of BA 25 may be a risk factor for suicide in depressed patients. This work suggests that SPECT might be useful in predicting risk for suicide completion in subjects with depression or treatment-resistant depression. Further investigation of this work is necessary to better understand the predictive value of this finding

Connectivity between mPFC and PCC predicts post‐choice attitude change: The self‐referential processing hypothesis of choice justification

Prior research shows that after making a choice, decision makers shift their attitudes in a choice‐congruous direction. Although this post‐choice attitude change effect is robust, the neural mechanisms underlying it are poorly understood. Here, we tested the hypothesis that decision makers elaborate on their choice in reference to self‐knowledge to justify the choice they have made. This self‐referential processing of the choice is thought to play a pivotal role in the post‐choice attitude change. Twenty‐four young American adults made a series of choices. They also rated their attitudes toward the choice options before and after the choices. In support of the current hypothesis, we found that changes in functional connectivity between two putative self‐regions (medial prefrontal cortex and posterior cingulate cortex/precuneus]) during the post‐choice (vs. pre‐choice) rating of the chosen options predicted the post‐choice shift of the attitudes toward the chosen options. This finding is the first to suggest that cognitive integration of various self‐relevant cognitions is instrumental in fostering post‐choice attitude change. Hum Brain Mapp 37:3810–3820, 2016. © 2016 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134093/1/hbm23277_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134093/2/hbm23277.pd

Exploring Sex Differences in the Neural Correlates of Self-and Other-Referential Gender Stereotyping

While general self-referential processes and their neural underpinnings have been extensively investigated with neuroimaging tools, limited data is available on sex differences regarding self- and other-referential processing. To fill this gap, we measured 17 healthy women and men who performed a self- vs. other-appraisal task during functional magnetic resonance imaging (fMRI) using gender-stereotypical adjectives. During the self-appraisal task, typical male (e.g., “dominant,” “competitive”) and female adjectives (e.g., “communicative,” “sensitive”) were presented and participants were asked whether these adjectives applied to themselves. During the other-appraisal task, a prototypical male (Brad Pitt) and female actor (Julia Roberts) was presented and participants were asked again to judge whether typical male and female adjectives applied to these actors. Regarding self-referential processes, women ascribed significantly more female compared to male traits to themselves. At the same time both women and men indicated a stronger desire to exhibit male over female traits. While fMRI did not detect general sex differences in the self- and other-conditions, some subtle differences were revealed between the sexes: both in right putamen and bilateral amygdala stronger gender-congruent activation was found which was however not associated with behavioral measures like the number of self-ascribed female or male attributes. Furthermore, sex hormone levels showed some associations with brain activation pointing to a different pattern in women and men. Finally, the self- vs. other-condition in general led to stronger activation of the anterior cingulate cortex while the other- vs. self-condition activated the right precuneus more strongly which is in line with previous findings. To conclude, our data lend support for subtle sex differences during processing of stereotypical gender attributes. However, it remains unclear whether such differences have a behavioral relevance. We also point to several limitations of this study including the small sample size and the lack of control for potentially different hormonal states in women

Understanding the Link Between Brain Activation, Choice, and Attitude Change for European Americans and East Asians.

How do people make difficult choices, and how does the decision process influence subsequent attitudes towards the choice options? Moreover, does culture influence decision-making and attitude change? My dissertation addresses these questions using neuroimaging data from individuals who evaluated choice options before and after making difficult choices either for the self or a close friend. In Study 1, I measured neural activation during decision-making and found that brain regions involved in self-processing and reward processing predicted attitude change for European Americans but not East Asians. Moreover, regions involved in conflict detection and negative arousal were recruited when people made difficult (versus easy) choices for the self and a close friend, whereas mentalizing regions were recruited when people made difficult choices for a close friend (versus self choices). In Study 2, I found that post-choice connectivity between regions involved in self-processing predicted attitude change. In Study 3, I found that European Americans represented information about choice outcome (chosen versus rejected) in self-processing regions, whereas East Asians represented information about choice outcome in mentalizing regions. Both European Americans and East Asians represented information about choice target (self versus friend) in both self-processing and mentalizing brain regions. The current work provides evidence for key brain regions and networks that support decision-making and attitude change for both the self and close others. This research advances understanding of how culture shapes the way in which people evaluate choice options and make choice.PHDPsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/135786/1/tompson_1.pd

Neural networks involved in self-judgement in young and elderly adults

peer reviewedRecent studies have shown that both young and elderly subjects activate the ventromedial prefrontal cortex (VMPFC) when they make self-referential judgements. However, the VMPFC might interact with different brain regions during self-referencing in the two groups. In this study, based on data from Ruby et al (2009), we have explored this issue using psychophysiological interaction analyses. Young and elderly participants had to judge adjectives describing personality traits in reference to the self versus a close friend or relative (the other), taking either a first-person or a third-person perspective. The physiological factor was the VMPFC activity observed in all participants during self judgement, and the psychological factor was the self versus other referential process. The main effect of first-person perspective in both groups revealed that the VMPFC was coactivated with the left parahippocampal gyrus and the precuneus for self versus other judgments. The main effect of age showed a stronger correlation between activity in the VMPFC and the lingual gyrus in young compared to elderly subjects. Finally, in the interaction, the VMPFC was specifically co-activated with the orbitofrontal gyrus and the precentral gyrus when elderly subjects took a first-person perspective for self judgements. No significant result was observed for the interaction in young subjects. These findings show that, although the VMPFC is engaged by both young and older adults when making self-referential judgements, this brain structure interacts differently with other brain regions as a function of age and perspective. These differences might reflect a tendency by older people to engage in more emotional/social processing than younger adults when making self-referential judgements with a first-person perspectiv

Perception of self and others in healthy ageing

Processing information related to the self and inferring the mental state of another person is known to involve the ventromedial prefrontal cortex (VMPFC) in both younger and older adults (Stone et al., 2008; Kelley et al., 2002; Hynes et al., 2006; Ruby et al., 2009). According to the dorsolateral prefrontal (DLPF) theory of cognitive ageing, processing of the self should not be affected by healthy adult ageing as functions related to the VMPFC remain relatively preserved compared to functions related to the DLPF cortex (MacPherson et al., 2002). Similarly, no age difference should emerge in those tasks thought to tap functions of the VMPFC. The aim of this PhD is to investigate the effect of healthy adult ageing on the ability to process information related to the self and others. A series of experiments was designed to compare the performance of younger and older adults on tasks that investigate processing and retrieval of self-related information (e.g. behaviour prediction, personality judgement, mental state inferences, self-referential). The tasks differ in the extent to which they rely on cognitive effort. The results show that ageing does not affect self-related judgements. A further series of experiments designed to investigate affective and cognitive Theory of Mind (ToM) show that the affective performance, thought to rely on VMPFC activity, is not affected by age. In contrast, the performance of older participants differs from that of younger adults on cognitive ToM task, thought to involve DLPFC brain areas. A final experiment investigated the ability to make self versus other related judgments in a confabulating patient. The results show that the ability to reflect on the self but not on others was intact. In summary, the findings demonstrate that processing self-information and making ToM inferences remains intact in older individuals and is not overtly impaired by confabulation