Single-Neuron Correlates of Decision Confidence in the Human Medial Temporal Lobe.

The human medial temporal lobe (MTL) has been suggested to play a role in valuation. However, little is known about its role in binary decisions and metacognition. We performed two decision-making tasks while recording from neurons in the human MTL. During a break, subjects consumed their preferred food item to satiation and subsequently repeated both tasks. We identified both a persistent and a transient modulation of the neural activity. Two independent subpopulations of neurons showed a persistent correlation of their firing rates with either decision confidence or reaction times. Importantly, the changes in confidence and reaction time between experimental sets were accompanied by a correlated change in the neural activity, and this correlation lasted as long as it was relevant for the behavioral task. Previous studies have suggested a transient modulation of the neural activity in the human MTL correlated with subjective value. However, in our study, neither subjective value nor unsigned value could explain this transient activity better than the nutritional features of the stimuli, calling into question the role of the human MTL in valuation.

Skipped BSCL2 Transcript in Celia's Encephalopathy (PELD): New Insights on Fatty Acids Involvement, Senescence and Adipogenesis.

OBJECTIVE: PELD (Progressive Encephalopathy with or without Lipodystrophy or Celia's Encephalopathy) is a fatal and rare neurodegenerative syndrome associated with the BSCL2 mutation c.985C>T, that results in an aberrant transcript without the exon 7 (Celia seipin). The aim of this study was to evaluate both the process of cellular senescence and the effect of unsaturated fatty acids on preadipocytes from a homozygous c.985C>T patient. Also, the role of aberrant seipin isoform on adipogenesis was studied in adipose-derived human mesenchymal stem cells. MATERIAL AND METHODS: Cellular senescence was evaluated using ß-galactosidase staining of preadipocytes obtained from a homozygous c.985C>T patient. Moreover, these cells were cultured during 24 hours with Intralipid, a soybean oil-based commercial lipid emulsion. The expression of the different BSCL2 transcripts was measured by qPCR. Adipose-derived human mesenchymal stem cells were differentiated to a fat lineage using StemPRO adipogenesis kit, and the expression of BSCL2 transcripts and several adipogenesis-related genes was measured by qPCR. RESULTS: the treatment of preadipocytes with unsaturated fatty acids significantly reduced the expression of the BSCL2 transcript without exon 7 by 34 to 63%. On the other hand, at least in preadipocytes, this mutation does not disturb cellular senescence rate. Finally, during adipocyte differentiation of adipose-derived human mesenchymal stem cells, the expression of adipogenic genes (PPARG, LPIN1, and LPL) increased significantly over 14 days, and noteworthy is that the BSCL2 transcript without exon 7 was differentially expressed by 332 to 723% when compared to day 0, suggesting an underlying role in adipogenesis. CONCLUSIONS: our results suggest that Celia seipin is probably playing an underestimated role in adipocyte maturation, but not in senescence, and its expression can be modified by exogenous factors as fatty acids.