Neuroscience
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Previous studies often report that early auditory deprivation or congenital deafness contributes to cross-modal reorganization in the auditory-deprived cortex, and this cross-modal reorganization limits clinical benefit from cochlear prosthetics. However, there are inconsistencies among study results on cortical reorganization in those subjects with long-term unilateral sensorineural hearing loss (USNHL). It is also unclear whether there exists a similar cross-modal plasticity of the auditory cortex for acquired monaural deafness and early or congenital deafness. ⋯ Our results indicate that the left primary auditory cortex (non-auditory-deprived cortex) in patients with left USNHL has been reorganized by visual and sensorimotor modalities through cross-modal plasticity. Furthermore, the cross-modal reorganization also alters the directional brain functional networks. The auditory deprivation from the left or right side generates different influences on the human brain.
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Task switching is our ability to abandon an old, irrelevant task in order to perform a new, more relevant one. Data from neuropsychology and neuroimaging studies indicate hemispheric asymmetries in task switching, however the neural mechanisms subtending switching, and in particular protocols to improve switching abilities are yet to be established. The present study aimed to assess hemispheric asymmetry and practice effects in task switching by using transcranial direct current stimulation (tDCS). ⋯ The task was repeated three times in three separate sessions in order to test practice effects with and without stimulation. Results show that increased hemispheric asymmetry in dorsolateral prefrontal areas improved switching performance as measured by a better practice effect, compared to sham condition. Our results support the hypothesis of dynamic hemispheric asymmetry in task switching and reinforce the notion of utilizing brain stimulation with traditional training methods in order to enhance cognitive abilities.
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The sudden interruption of the increase of the concentration of the gamma-aminobutyric acid (GABA), determines an increase in neuronal activity. GABA withdrawal (GW) is a heuristic analogy, with withdrawal symptoms developed by other GABA receptor-agonists such as alcohol, benzodiazepines, and neurosteroids. ⋯ GW induces pre- and postsynaptic changes: a decrease in GABA synthesis/release, and the decrease in the expression and composition of GABAA receptors associated with increased calcium entry into the cell. GW is an excellent bioassay for studying partial epilepsy, epilepsy refractory to drug treatment, and a model to reverse or prevent the generation of abstinences from different drugs.
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Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. ⋯ Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.
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The relationship between recognition memory and cognitive control is an important research topic. The current study investigated how conflict control influences an individual's emotional memory. During the encoding phase, participants were required to judge the affective valence of a Chinese Chengyu word (either positive or negative) in a modified Simon paradigm and to remember the word. ⋯ The retrieval of words encoded in the incongruent condition induced greater late positive complex (LPC) amplitudes, relative to those encoded in the congruent condition on the left hemisphere. It was also observed that the recognition of positive words induced faster LPC responses than negative words when they were encoded in the incongruent condition. The present electrophysiological study illustrates that emotional memory processes may be affected by conflict control.