Here we tested whether this effect can be observed in the absence of some of the visual areas showing a preferential response to faces as typically identified in neuroimaging. Event-related potentials were recorded in response to faces, cars, and their phase-scrambled versions in a well-known brain damaged case of prosopagnosia
(PS). Despite the patient’s right inferior occipital gyrus lesion encompassing the most posterior cortical area showing preferential response to faces (“occipital face area”), we identified an early face-sensitive component over the right occipito temporal hemisphere of the patient that was identified as the N170. A second experiment supported this conclusion, showing the typical N170 increase of latency and amplitude in response to inverted faces. In contrast, MK 2206 there was no N170 in the left hemisphere, where PS has a lesion to the middle fusi form gyrus and shows no evidence of face preferential response in neuroimaging( no left “fusiform face area”). These results were replicated by a magnetoencephalographic investigation of the patient, disclosing a selleck kinase inhibitor M170 component only in the right
hemisphere. These observations indicate that face preferential activation in the inferior occipital cortex is not necessary to elicit early visual responses associated with face perception (N170/M170) on the human scalp. These results further suggest that when the right inferior occipital cortex is damaged, the integrity of the middle fusiform gyrus and/or the superior temporal sulcus – two areas showing face-preferential responses in the patient’s right hemisphere – might be necessary to generate the N170 effect.”
“Mitochondrial reactive oxygen species regulate many important biological Selleckchem SNX-5422 processes. We studied H2O2 formation by nonsynaptic brain mitochondria in response to the addition of low concentrations of glutamate, an excitatory neurotransmitter. We demonstrated that glutamate at concentrations from 10 to 50 mu M stimulated the H2O2 generation in mitochondria up to 4-fold, in a dose-dependent manner. The effect of glutamate was observed
only in the presence of Ca2+ (20 mu M) in the incubation medium, and the rate of calcium uptake by the brain mitochondria was increased by up to 50% by glutamate. Glutamate-dependent effects were sensitive to the NMDA receptor inhibitors MK-801 (10 mu M) and D-AP5 (20 mu M) and the inhibitory neurotransmitter glycine (5 mM). We have shown that the H2O2 formation caused by glutamate is associated with complex II and is dependent on the mitochondrial potential. We have found that nonsynaptic brain mitochondria are a target of direct glutamate signaling, which can specifically activate H2O2 formation through mitochondrial respiratory chain complex II. The H2O2 formation induced by glutamate can be blocked by glycine, an inhibitory neurotransmitter that prevents the deleterious effects of glutamate in brain mitochondria. (C) 2013 Elsevier Inc. All rights reserved.
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