Neuroscience
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Understanding and predicting the intentions of others through limb movements are vital to social interaction. The processing of biological motion is unique from the processing of motion of inanimate objects. Presently, there is controversy over whether visual consciousness of biological motion is regulated by visual attention. ⋯ Late processing was localized to frontal-parietal regions, such as the right dorsal superior frontal gyrus, the left medial superior frontal gyrus, and the occipito-temporal regions. Congruency-related processing occurred in the 246-260-ms window and was localized to the right superior occipital gyrus. In summary, due to its complexity, biological motion awareness has a unique neural basis.
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Understanding brain processing mechanisms from the perception of speech sounds to high-level semantic processing is vital for effective human-robot communication. In this study, 128-channel electroencephalograph (EEG) signals were recorded when subjects were listening to real and pseudowords in Mandarin. By using an EEG source reconstruction method and a sliding-window Granger causality analysis, we analyzed the dynamic brain connectivity patterns. ⋯ This may be related to semantic processing and integration. The involvement of both bottom-up input and top-down modulation in real word processing may support the previously proposed TRACE model. In sum, the findings of this study suggest that representations of speech involve dynamic interactions among distributed brain regions that communicate through time-specific functional networks.
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Emotional Stability Interacts with Cortisol Levels before fMRI on Brain Processing of Fearful Faces.
Functional-Magnetic-Imaging (fMRI) is widely adopted to investigate neurophysiological correlates of emotion processing (EP). However, studies have reported that scanning procedures in neuroimaging protocols may increase or cause anxiety and psychological distress related with the scanning, thus inducing peripheral cortisol release. These phenomena may in turn impact on brain EP. ⋯ In the context of lower ES, the opposite Δc-brain activity relationship was found. Our results suggest that the stressful potential of fMRI interacts with personality traits in modulating brain activity during EP. These findings should be taken into account when interpreting neuroimaging studies especially exploring brain physiology during EP.
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The glare illusion enhances the perceived brightness of a central white area surrounded by a luminance gradient, without any actual change in light intensity. In this study, we measured the varied brightness and neurophysiological responses of electroencephalography (EEG) and pupil size with the several luminance contrast patterns of the glare illusion to address the question of whether the illusory brightness changes to the glare illusion process in the early visual cortex. We hypothesized that if the illusory brightness enhancement was created in the early stages of visual processing, the neural response would be similar to how it processes an actual change in light intensity. ⋯ We found the SSVEP amplitude was lower in the glare illusion than in the control condition, especially under high luminance contrast conditions. Furthermore, we found the probable mechanisms of the inhibited SSVEP amplitude to the high luminance contrast of glare illusion based on the greater pupil constriction, thereby decreasing the amount of light entering the pupil. Thus, the brightness enhancement in the glare illusion is already represented at the primary stage of visual processing linked to the larger pupil constriction.
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Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting the corticospinal tract and leading to motor neuron death. According to a recent study, magnetic resonance imaging-visible changes suggestive of neurodegeneration seem absent in the motor cortex of G93A-SOD1 ALS mice. However, it has not yet been ascertained whether the cortical neural activity is intact, or alterations are present, perhaps even from an early stage. ⋯ The extracellular Na+, Ca2+, K+ and Cl- concentrations were elevated, pointing to perturbations in the culture micro-environment. Our findings highlight remarkable early changes in ALS cortical neuron activity and physiology. These changes suggest that the causative factors of hyperexcitability and associated toxicity could become established much earlier than the appearance of disease symptoms, with implications for the discovery of new hypothetical therapeutic targets.