Displaying 1 - 2 of 2
The medial prefrontal cortex (mPFC), hippocampus, and amygdala are implicated in the regulation of affect and physiological processes, including hypothalamic-pituitary-adrenal (HPA) axis function. Anhedonia is likely associated with dysregulation of these processes. Dense-array resting electroencephalographic and cortisol were obtained from healthy and anhedonic groups. Low-resolution electromagnetic tomography was used to compute intracerebral current density. For the control group, voxelwise analyses found a relationship between current density in beta and gamma bands and steeper cortisol slope (indicative of more adaptive HPA axis functioning) in regions of the hippocampus, parahippocampal gyrus, and mPFC. For the anhedonic group, the mPFC finding was absent. Anhedonia may be characterized by disruptions of mPFC-mediated neuroendocrine regulation, which could constitute a vulnerability to the development of stress-related disorders.
The nature of the affective deficit that characterizes social anhedonia is not well understood. Emotionally evocative visual stimuli were presented to undergraduates identified as anhedonic or normal, based on their scores on the revised Social Anhedonia Scale. The affective stimuli were chosen to elicit positive and negative emotion; a subset of slides were specifically chosen to include social-interpersonal content. In the acoustic startle paradigm, participants were administered startle probes (50-ms 95 dB white noise bursts) while viewing images from the International Affective Picture System. Socially anhedonic individuals did not differ from normally hedonic individuals in terms of their physiological response to the stimuli, regardless of the nature of the content of the stimuli. However, on the self-report measures of trait affectivity, the socially anhedonic individuals reported significantly lower levels of positive affect and higher levels of negative affect. These findings suggest that the affective deficits reported by socially anhedonic individuals are not global in nature.