Pattern separation, the process by which similar experiences can be stored as distinct memories, has been ascribed to the dentate gyrus (DG) of the hippocampus. The DG is the target of noradrenergic modulation directly and indirectly via the basolateral amygdala. We tested the hypothesis that noradrenergic activation (tested using salivary alpha-amylase) potentiates DG function, enhancing pattern separation, by showing participants fearful stimuli in a pre-training task and then testing their capacity for pattern separation in a later test. Consistent with our hypothesis, we found that increased levels of salivary alphaamylase were positively correlated with enhanced pattern separation performance even after accounting for general enhancements in recognition.
Loneliness, the subjective experience of social isolation, may reflect, in part, underlying neural processing of social signals. Aging may exacerbate loneliness due to decreased social networks and increased social isolation, or it may reduce loneliness due to preferential attentional processing of positive information and increased interactions with emotionally close partners. Here, we conducted a functional magnetic resonance imaging (fMRI) study of loneliness in younger (N = 50, 26 female, M = 20.4) and older (N = 49, 30 female, M = 62.9) adults. Compared to younger adults, older adults were less lonely and dwelled longer on faces, regardless of valence. Previous studies in younger adults found that loneliness was negatively correlated with ventral striatal (VS) activation to pleasant social pictures of strangers yet positively correlated with VS activation to faces of close others. In the present study, we observed no association between loneliness and VS activation to social pictures of strangers in either age group. Further, unlike previous studies, we observed no association between social network size and amygdala activation to social stimuli. Additional research is needed to examine the effect of loneliness and social network size on neural processing of different dimensions of social stimuli.
Background and Aims: Physiologic measurement of myocardial perfusion in the immediate postangioplasty period may complement the angiographic assessment of the outcome of the procedure and improve our ability to identify patients at increased risk for a suboptimal late result. Immediate in-lab identification of patients at risk for late coronary restenosis would allow the interventionalist to implement alternate interventional and/or pharmacologic strategies aimed at improving the long-term outcome of angioplasty. The present single-center pilot study was undertaken to examine prospectively the value of intracoronary Doppler flow measurements immediately postangioplasty for predicting long-term patency of the dilated coronary artery. Patients and Methods: Coronary average peak flow velocity (APV) at rest and during hyperemia (6-18 µg intracoronary adenosine) and coronary flow reserve in the distal coronary segment were measured in 24 consecutive patients 10-15 min after successful elective coronary angioplasty. Volume flow (Q) was calculated as APV/2· coronary cross-sectional area •heart rate. Coronary arterial vessels and narrowings were measured by quantitative angiography using a geometric based method and automated edge detection. The present study reports the findings in the 16 patients undergoing conventional balloon angioplasty for whom hard endpoint angiographic data were available 4.9 ± 1.5 months after angioplasty. Results: A linear relation was present between angiographically measured minimal luminal dimension immediately postangioplasty and the late angiographic result of the procedure (r = 0.71, p = 0.0005). A greater acute gain during angioplasty was predictive of a larger luminal dimension at late angiographic follow-up (p = 0.006). There was no relation between the immediate postangioplasty Doppler flow measurements and the late angiographic result of the procedure. Late luminal dimension was not related to immediate postangioplasty basal or hyperemia APV, nor to immediate postangioplasty basal or hyperemic volume flow or to coronary flow reserve (all NS). Conclusions: In this single-center study, intracoronary blood flow and Doppler-derived coronary flow reserve immediately postpercutaneous transluminal coronary angioplasty were not predictive of long-term vessel patency or late coronary restenosis. The immediate angiographic result of angioplasty did correlate with the late result of the procedure.
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