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Major depression disorder (MDD) is a serious mental illness with high disability rate and high recurrence rate, accompanied by cognitive impairment including language processing. This article reviews neurophysiological evidences of abnormal semantic processing in MDD patients in recent years. Electrophysiological data indicates that abnormal semantic processing in the patients begins in the early stages of perceptual processing and persists in subsequent cognitive processing stages with hemispheric lateralization. Brain imaging studies show that the patients have abnormal activation levels in the medial prefrontal cortex and inferior frontal gyrus. The current research paradigms cannot separate semantic processing from other cognitive processes, and more research is needed.
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As a vital part of human body, the brain executes junior and senior function through coordination and interaction of different functional regions. Modern scientific research showed that there were many human brain functional networks in the resting-state. The rest-ing-state functional magnetic resonance imaging technology, which was getting more and more mature, taking opportunities for brain func-tional networks and was widely used in nervous and mental diseases, providing new methods and ideas for the diagnosis and assessment of nervous and mental diseases. This paper focused on the brain mechanism research methods based on resting-state networks and its applica-tion in nervous and mental diseases.
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@#The behavioral performance and mechanism of spatial acalculia were reviewed in this paper. Meanwhile, the brain mechanism and cognitive impairment are also preliminarily introduced.
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@#Objective To investigate errors and mechanism of acalculia in patients with brain injury.Methods Forty patients with brain injury and forty-eight normal adults who were matched in age and years of education were tested with EC301 standardized battery. Patients were divided into the left-brain damaged (LBD) group (n=20), right-brain damaged (RBD) group (n=9) and bilateral brain damaged (BBD) group (n=11). The data of all subjects were statistical analyzed.Results Both total scores and scores of 27 out of 31 items were remarkable lower in patients than those in the normal control group ( P<0.05). The total scores and items' scores for number sequences, numerical transcodings were significantly lower in LBD group than those in RBD group ( P<0.05). Total scores and each items' score did not significantly differ between BBD group and LBD group, or between BBD group and RBD group ( P>0.05).Conclusion The abilities of number processing and calculation are impaired in patients with brain injury. There is either association or dissociation in terms of performance of acalculia and aphasia in LBD patients. Visuospatial impairment is related to performance of acalculia in RBD patients.
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The function of memory plays an important role in the operation of whole brain function. Memory is related wile almost structures of cortex and subcortex in order to perform this purpose. Therefore, it is very important to study the brain mechanism of memory understanding not only the function of memory also general processing of brain information or brain function. Longterm memory is encoded in the neuronal connectivities of the brain. The most successful models of human memory in their operations are the models of distributed and self organized associative memory, which are founded in the principle of simulaneous convergence in network formation. Memory is not perceived as the qualities inherent in physical objects or events, but as a set of ralations previously established in a neural net by simultaneousy occurring experiences. When it is easily found any correlation with existing neural networks through analysis of network structures, memory is automatically encoded in cerebral cortex. However, in the emergence of informations which are complicated to classify and correlated with existing networks, and conflictual with other networks, those informations are sent to the subcortex including hippocampus. Memory is stored in the form of templates distributed across several different cortical regions. The hippocampus provides detailed maps far the conjoint binding and calling up of widely distributed informations. With a large of knowledges about the distribution of correlated networks, they find the most correlated networks and transform the existing networks into new one. Then hippocampus consolidats new farmed network. Amygdala may enable the emotions to influence the information processing and memory as well as providing the visceral informations to them. Cortico-striatal-pallido-thalamo-cortical loop also play an important role in memory function with analysis of language and concept. In case of difficulty of processing in spite of parallel process of informations, frontal lobe organizes theses complicated informations of network analysis through temporal processing. With understanding of brain mechanism of memory and information processing, the brain mechanism of mental phenomena including psychopathology can be conjectured in terms of neurobiology and neruopsychology. Because the psychoanalysis means the memory in unconsciousness in psychoanalysis, the studies of brain mechanism of memory may provide a precise insight to the human mind and it's disorders.