Proteomic analysis of human frontal and temporal cortex using iTRAQ-based 2D LCMS/MS

Background:The human brain is the most complex organ in the body,and it is important to have a better understanding of how the protein composition in the brain regions contributes to the pathogenesis of associated neurological disorders.Methods:In this study,a comparative analysis of the frontal and temporal cortex proteomes was conducted by isobaric tags of relative and absolute quantification(iTRAQ)labeling and two-dimensional liquid chromatographytandem mass spectrometry(2D LC-MS/MS).Brain protein was taken from relatively normal tissue that could not be avoided of damage during emergent surgery of the TBI(traumatic brain injury)patients admitted in Beijing Tiantan Hospital from 2014 to 2017.Eight cases were included.Four frontal lobes and 4 temporal lobes proteome were analyzed and the proteins were quantitated.Gene Ontology(GO),Ingenuity Pathway Analysis(IPA),and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis were used to analyze the biological function of identified proteins,unchanged proteins,and differentially expressed proteins(DEPs).Results:A total number of 2127 protein groups were identified in the frontal and temporal lobe proteomes.A total of 1709 proteins could be quantitated in both the frontal and temporal cortex.Among 90 DEPs,14 proteins were screened highly expressed in the temporal cortex,including MAPT,SNCG,ATP5IF1,GAP43,HSPE1,STMN1,NDUFS6,LDHB,SNCB,NDUFA7,MRPS36,EPDR1,CISD1,and RALA.In addition,compared to proteins expressed in the frontal cortex,14 proteins including EDC4,NIT2,VWF,ASTN1,TGM2,SSB,CLU,HBA1,STOM,CRP,LRG1,SAA2,S100A4,and VTN were a low expression in the temporal cortex.The biological process enrichment showed that unchanged proteins between the frontal and temporal cortex mainly take part in regulated exocytosis,axon guidance,and vesicle-mediated transport.The KEGG pathway analysis showed that unchanged proteins between the frontal and temporal cortex mainly take part in oxidative phosphorylation,carbon metabolism,Huntington’s disease,and Parkinson’s disease.Conclusions:The majority of proteins are unchanged between the frontal and temporal cortex,and unchanged proteins are closely related to its function.Among DEPs,MATP(tau)is upregulated in the temporal cortex,closely related to Alzheimer’s disease(AD),and is one of the targets for the treatment of AD.CLU is downregulated in the temporal cortex which functions as an extracellular chaperone that prevents aggregation of non-native proteins.It was suggested that the temporal lobe may not be the“functional dumb area”of the traditional view,but could be involved in important neural metabolic circuits.

Correlation between special brain area and blood perfusion in patients with cerebral infarction at convalescent period Feasibility for quantitative determination and estimation of learning and memory function

BACKGROUND： Presently, clinic memory scale is used to evaluate learning memory ability in most studies, and the influence of difference in measurement condition of individuals exists. OBJECTIVE： To study the correlation between regional cerebral blood flow （rCBF） perfusion and learning memory function in special brain regions of patients with cerebral infarction at convalescent period, and to try to find out a method which can quantitatively evaluate learning ability. DESIGN： Case observation, and correlation analysis. SETTINGS： Shandong Institute for Behavioral Medicine; the Affiliated Hospital of Jining Medical College. PARTICIPANTS： Totally 70 patients with cerebral infarction admitted to Department of Neurology, Jining Medical College between January 2004 and December 2005 were involved. The involved patients, 58 male and 12 female, were averaged （52±3） years, and they were all right handed. They all met the diagnosis criteria instituted by the Fourth National Conference on Cerebrovascular Disease, and were confirmed as cerebral infarction by skull CT or MRI. Informed consents of detected items were obtained from all the patients and relatives. METHODS： When the patients were at convalescent period, their learning and memory ability were measured with “ clinic memory scale （set A）”. The 18 patients whose total mark over 100 were regarded as good learning memory function group; The 23 cases whose total mark less than 70 were regarded as poor learning memory function group. RCBF of hippocampus, nucleus amygdalae, temporal cortex and prefrontal lobe of patients between two groups were measured and compared by single photon emission computed tomography （SPECT）. The total scores of the 18 good learning memory patients and 23 poor learning memory patients were taken as dependent variable Y, and their rCBFs of hippocampus, nucleus amygdale, temporal cortex and prefrontal lobe respectively as independent variable X for linear correlation analysis. MAIN OUTCOME MEASURES： Correlation of rCBF in different brain regions and learning memory ability in patients with cerebral infarction. RESULTS： ①The rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex of good learning memory function group were significantly higher than those of poor learning memory function group （P 〈 0.05）. ②In the good learning memory function group, rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex were significantly positively correlated with memory scale scores （ r = 0.961, 0.926, 0.954, 0.907, P 〈 0.05 ） , and also in the poor learning memory function group （r = 0.979, 0.976, 0.991, 0.953, P 〈 0.05 ） . CONCLUSION： The rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex of patients with cerebral infarction are significantly positively correlated with memory scale scores. Predicting learning memory ability of patients by quantitative determination of rCBF provides a quantitative and objective method for evaluating learning memory ability.

Early stage of radiological expertise modulates resting-state local coherence in the inferior temporal lobe

Background The visual system and its inherent functions undergo experience-dependent changes through the lifespan,enabling acquisition of new skills.Previous fMRI studies using tasks reported increased specialization in a number of cortical regions subserving visual expertise.Although ample studies focused on representation of long-term visual expertise in the brain,i.e.in terms of year,monthly-based early-stage representation of visual expertise remains unstudied.Given that spontaneous neuronal oscillations actively encode previous experience,we propose brain representations in the resting state is fundamentally important.Objective The current study aimed to investigate how monthly-based early-stage visual expertise are represented in the resting state using the expertise model of radiologists.Methods In particular,we investigated the altered local clustering pattern of spontaneous brain activity using regional homogeneity(ReHo).A cohort group of radiology interns(n=22)after one-month training in X-ray department and matched laypersons(n=22)were recruited after rigorous behavioral assessment.Results The results showed higher ReHo in the right hippocampus(HIP)and the right ventral anterior temporal lobe(vATL)(corrected by Alphasim correction,P<0.05).Moreover,ReHo in the right HIP correlated with the number of cases reviewed during intern radiologists’training(corrected by Alphasim correction,P<0.05).Conclusions In sum,our results demonstrated that the early stage of visual expertise is more concerned with stabilizing visual feature and domain-specific knowledge into long-term memory.The results provided novel evidence regarding how early-stage visual expertise is represented in the resting brain,which help further elaborate how human visual expertise is acquired.We propose that our current study may provide novel ideas for developing new training protocols in medical schools.

Neural plasticity in high-level visual cortex underlying object perceptual learning

With intensive training, human can achieve impressive behavioral improvement on various perceptual tasks. This phenomenon, termed perceptual learning, has long been considered as a hallmark of the plasticity of sensory neural system. Not surprisingly, high-level vision, such as object perception, can also be improved by perceptual learning. Here we review recent psychophysical, electrophysiological, and neuroimaging studies investigating the effects of training on object selective cortex, such as monkey inferior temporal cortex and human lateral occipital area. Evidences show that learning leads to an increase in object selectivity at the single neuron level and/or the neuronal population level. These findings indicate that high-level visual cortex in humans is highly plastic and visual experience can strongly shape neural functions of these areas. At the end of the review, we discuss several important future directions in this area.

Topography of Visual Features in the Human Ventral Visual Pathway

Visual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway(ventral occipital-temporal cortex,VOTC),which shows a well-documented object domain structure.An on-going question is what type of information is processed in the higher-order VOTC that underlies such observations,with recent evidence suggesting effects of certain visual features.Combining computational vision models,fMRI experiment using a parametric-modulation approach,and natural image statistics of common objects,we depicted the neural distribution of a comprehensive set of visual features in the VOTC,identifying voxel sensitivities with specific feature sets across geometry/shape,Fourier power,and color.The visual feature combination pattern in the VOTC is significantly explained by their relationships to different types of response-action computation(fight-or-flight,navigation,and manipulation),as derived from behavioral ratings and natural image statistics.These results offer a comprehensive visual feature map in the VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.