Neuroscience
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The amygdala plays a key role in gathering social cues to context-appropriate responses that require refined motor behavior, involving either direct or indirect connections with sensorimotor-related areas. Although, several studies investigated the structural and functional limbic connectivity of the amygdala both in animals and in humans, less is known about the limbic modulation on sensorimotor-related areas. However, recent evidences suggest the amygdala as a possible cornerstone in the limbic-motor interface. ⋯ On the other hand, our connectomic analysis revealed a close interplay between the amygdala and the inferior parietal lobule, followed by the postcentral gyrus, the precentral gyrus and the paracentral lobule. The findings of the present study are in line with previous literature and reinforce the idea of the existence of a limbic-motor interface, which is likely to be involved in the emotional modulation of complex functions such as spatial perception and movement computation. Considering that these pathways may play an important role, not on in physiological conditions, but also in pathological context, further studies should be fostered in order to confirm the existence of a limbic-motor interface and its precise functional meaning.
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For the past two decades, we have advanced in our understanding of the mechanisms implicated in the formation of brain circuits. The connection between the cortex and thalamus has deserved much attention, as thalamocortical connectivity is crucial for sensory processing and motor learning. ⋯ In this review, I will summarize the most relevant discoveries that have been made in this field, from development to early plasticity processes covering three major aspects: axon guidance, thalamic influence on sensory cortical specification, and the role of spontaneous thalamic activity. I will emphasize how the implementation of new tools has helped the field to progress and what I consider to be open questions and the perspective for the future.
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Alzheimer's disease (AD) has been considered as a metabolic dysfunction disease associated with impaired insulin signaling. Determining the mechanisms underlying insulin signaling dysfunction and resistance in AD will be important for its treatment. Impaired clearance of amyloid-β peptide (Aβ) significantly contributes to amyloid accumulation, which is typically observed in the brain of AD patients. ⋯ These results suggest that insulin exposure enhanced Aβ degradation via an increase in NEP secretion and IDE expression in astrocytes, via activation of the ERK-mediated pathway. The inhibition of insulin signaling pathways delayed Aβ degradation by attenuating alterations in NEP and IDE levels and competition with insulin and Aβ. Our results provide further insight into the pathological relevance of insulin resistance in AD development.
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In this study the timing of electromagnetic signals recorded during incongruent and congruent audiovisual (AV) stimulation in 14 Italian healthy volunteers was examined. In a previous study (Proverbio et al., 2016) we investigated the McGurk effect in the Italian language and found out which visual and auditory inputs provided the most compelling illusory effects (e.g., bilabial phonemes presented acoustically and paired with non-labials, especially alveolar-nasal and velar-occlusive phonemes). In this study EEG was recorded from 128 scalp sites while participants observed a female and a male actor uttering 288 syllables selected on the basis of the previous investigation (lasting approximately 600 ms) and responded to rare targets (/re/, /ri/, /ro/, /ru/). ⋯ A pMMN (phonological Mismatch Negativity) to incongruent AV stimuli was identified 500 ms after voice onset time. This automatic response indexed the detection of an incongruity between the labial and phonetic information. SwLORETA (Low-Resolution Electromagnetic Tomography) analysis applied to the difference voltage incongruent-congruent in the same time window revealed that the strongest sources of this activity were the right superior temporal (STG) and superior frontal gyri, which supports their involvement in AV integration.
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We explored resting-state brain activity and its potential links to clinical parameters in schizophrenic patients with tardive dyskinesia (TD) using fractional amplitude of low-frequency fluctuations (fALFF). Resting-state functional magnetic resonance imaging data were acquired from 32 schizophrenic patients with TD (TD group), 31 without TD (NTD group), and 32 healthy controls (HC group). Clinical parameters including psychopathological symptoms, severity of TD, and cognitive function were assessed using the Positive and Negative Syndrome Scale, Abnormal Involuntary Movement Scale (AIMS), and Repeatable Battery for the Assessment of Neuropsychological Status, respectively. ⋯ The AIMS total score was negatively correlated to the visuospatial/constructional score (r = -0.53, p = 0.005). Our findings suggested that resting-state brain activity changes were associated with TD in schizophrenic patients. There was an association between the decreased brain activity in the occipital lobe and the delayed memory cognition impairment in this population.