The neuroanatomical substrate of lexical-semantic decline in MCI APOE ε4 carriers and noncarriers

Lexical-semantic competency in mild cognitive impairment (MCI) ε4 carriers was used as an endophenotype, and gray matter volume in MCI ε4 carriers/noncarriers and in noncarrier controls was compared. Residual gray matter volumes were correlated with age of acquisition values for words from a category fluency task, an index of semantic competency. MCI patients had significantly impoverished lexical-semantic output compared with controls, more marked in MCI ε4 carriers. Smaller volumes in the left hippocampus, bilateral regions of the uncus, and posterior cingulate cortex were associated with a tendency to retrieve earlier acquired words in the category fluency task in MCI ε4 carriers, whereas poor semantic performance in MCI noncarriers was associated with smaller volumes in the left uncus, bilateral regions of the parahippocampal gyrus, and hippocampus, and also in a large number of neocortical regions. There was a significant semantic competency by genotype interaction in the left perirhinal cortex, in a number of left frontal and temporal areas and in the right inferior parietal lobule and precuneus. MCI ε4 carriers, when compared with noncarriers, had lower gray matter volume values confined to the right precuneus and the cerebellum bilaterally, but the converse comparison showed that MCI noncarriers had lower values in extensive frontal, temporal, and parietal regions of the neocortex. Similar brain volumetric variations linked to genotype were found in minimal-to-mild AD. The results suggest a relatively specific impact of apolipoprotein E (APOE) ε4 burden and underline the value of linguistic assessment in preclinical diagnosis.     

Differential cortical atrophy in subgroups of mild cognitive impairment

OBJECTIVE: To compare gray matter brain volumes in patients diagnosed with subtypes of mild cognitive impairment (MCI) (those with a focal amnestic disorder and those with more diffuse cognitive dysfunction) with those of elderly controls. DESIGN: Magnetic resonance imaging volumetric study of MCI subgroups (MCI-amnestic [MCI-A], and MCI-multiple cognitive domain [MCI-MCD]) using a whole brain voxel-based analysis. SETTING: Referral dementia clinic.Patients Thirty-seven patients with MCI (age range, 49-85 years; MCI-A, n = 9; MCI-MCD, n = 28) and 47 control subjects (age range, 55-81 years). MAIN OUTCOME MEASURES: Volumetric anatomical magnetic resonance imaging differences between MCI subgroups and normal controls, and between patients with MCI who progressed to dementia. Magnetic resonance imaging scans were analyzed using statistical software SPM99. RESULTS: Overall, the patients with MCI had significantly decreased volume in the hippocampus and middle temporal gyrus, bilaterally, compared with control subjects. Compared with patients with MCI-MCD, patients with MCI-A had significant volume loss of the left entorhinal cortex and inferior parietal lobe. Compared with patients with MCI-A, patients with MCI-MCD had significantly reduced volume of the right inferior frontal gyrus, right middle temporal gyrus, and bilateral superior temporal gyrus. Patients with MCI who progressed to Alzheimer disease during follow-up (mean interval 2 years, maximum 4.5 years), showed greater atrophy in the left entorhinal cortex, bilateral superior temporal gyri, and right inferior frontal gyrus compared with those who did not progress. CONCLUSIONS: These data provide evidence of distinct brain structural abnormalities in 2 groups of patients with MCI. While both have mesial temporal and cortical volume loss, those with a focal memory deficit have more involvement of the mesial temporal structures and less involvement of the neocortical heteromodal association areas than those patients with MCI with diffuse cognitive dysfunction. Thus, MCI may represent a more heterogeneous group than currently conceived, possibly reflecting 2 different etiological processes to dementia. These data also suggest that these structural abnormalities precede the development of Alzheimer disease.     

Combining neuropsychological and structural neuroimaging indicators of conversion to Alzheimer's disease in amnestic mild cognitive impairment

Morphometric and neuropsychological retrospective studies of amnestic mild cognitive impairment (MCI) have demonstrated that regional atrophies and cognitive impairments may differentiate stable from progressing MCI. No measure has proved helpful prospectively. In this study, twenty five amnestic MCI patients and 25 healthy controls underwent structural MRI and comprehensive neuropsychological assessment. The groups' grey matter volumes were compared with voxel based morphometry and were also correlated with scores obtained on paired associates learning and category fluency tasks. MCI patients had significantly reduced grey matter volume in left mediotemporal and other neocortical regions compared with controls. Atrophy in perirhinal and anterior inferior temporal cortex was associated with poor scores on both category fluency and paired associates learning tasks. After 36 months, 44% of the MCI sample converted to dementia. Converter and non-converter MCI subgroups differed in paired associates learning and in category fluency scores, and showed limited differences in grey matter loss in the hippocampal complex. Variable atrophy in the hippocampus was not a relevant element in the converter/non converter distinction, but converters had significant volumetric reductions in the perhirinal cortex and in other anterior temporal and frontal neocortical areas. A high proportion of converters (91%) could be identified from baseline data using a combination of measures of regional atrophy in left temporal association cortex and poor scores on paired associates learning and category fluency tasks. This combined approach may offer a better option than using each measure alone to prospectively identify individuals at more immediate risk of conversion to dementia in the MCI population. The clinical advantage of this combination of structural MRI and neuropsychological measures in predicting conversion to dementia will need additional prospective validation.     

Abstracts from british neuropsychological society meeting 26-27 April 2000, London,UK

Accumulating evidence indicates action naming may rely more on frontal-subcortical circuits, and noun naming may rely more on temporal cortex. Therefore, noun versus action fluency might distinguish frontal and subcortical dementias from cortical dementias primarily affecting temporal and/or parietal cortex such as Alzheimer's disease (AD). We hypothesized patients with subcortical dementia, e.g., normal pressure hydrocephalus (NPH) and patients with dementias predominantly affecting frontal cortex, e.g., behavioral variant frontotemporal dementia (bv-FTD) and progressive nonfluent aphasia (PNFA) have more difficulty on action fluency versus noun fluency (e.g., animal naming). Patients with AD, who have temporo parietal cortical dysfunction, should have more difficulty on noun versus verb fluency. A total of 234 participants, including healthy controls (n = 20) and patients diagnosed with NPH (n =144), AD (n = 33), bv-FTD (n = 22) or PNFA (n =15) were administered animal fluency, action fluency, and letter fluency tasks, and the Mini-Mental State Examination (MMSE, to control for dementia severity). NPH and bv-FTD/PNFA patients had significantly higher MMSE scores and animal fluency than AD patients (after adjusting for age), but their action fluency tended to be lower than in AD. Only NPH and bvFTD/PNFA patients showed significantly lower action verb than animal fluency. Results provide novel evidence that action naming relies more on frontal-subcortical circuits while noun naming relies more on temporoparietal cortex, indicating action verb fluency may be more sensitive than noun fluency, particularly for detecting frontal-subcortical dysfunction.     

Common and unique gray matter correlates of episodic memory dysfunction in frontotemporal dementia and alzheimer's disease

Conflicting evidence exists regarding the integrity of episodic memory in the behavioral variant of frontotemporal dementia (bvFTD). Recent converging evidence suggests that episodic memory in progressive cases of bvFTD is compromised to the same extent as in Alzheimer's disease (AD). The underlying neural substrates of these episodic memory deficits, however, likely differ contingent on dementia type. In this study we sought to elucidate the neural substrates of episodic memory performance, across recall and recognition tasks, in both patient groups using voxel‐based morphometry (VBM) analyses. We predicted that episodic memory dysfunction would be apparent in both patient groups but would relate to divergent patterns of neural atrophy specific to each dementia type. We assessed episodic memory, across verbal and visual domains, in 19 bvFTD, 18 AD patients, and 19 age‐ and education‐matched controls. Behaviorally, patient groups were indistinguishable for immediate and delayed recall, across verbal and visual domains. Whole‐brain VBM analyses revealed regions commonly implicated in episodic retrieval across groups, namely the right temporal pole, right frontal lobe, left paracingulate gyrus, and right anterior hippocampus. Divergent neural networks specific to each group were also identified. Whereas a widespread network including posterior regions such as the posterior cingulate cortex, parietal and occipital cortices was exclusively implicated in AD, the frontal and anterior temporal lobes underpinned the episodic memory deficits in bvFTD. Our results point to distinct neural changes underlying episodic memory decline specific to each dementia syndrome. Hum Brain Mapp 35:1422–1435, 2014. © 201 Wiley Periodicals, Inc.     

Amnestic mild cognitive impairment in Parkinson's disease: A brain perfusion SPECT study

The purpose of this study was to investigate cortical dysfunction in Parkinson's disease (PD) patients with amnestic deficit (PD‐MCI). Perfusion single photon emission computed tomography was performed in 15 PD‐MCI patients and compared (statistical parametric mapping [SPM2]) with three groups, i.e., healthy subjects (CTR), cognitively intact PD patients (PD), and common amnestic MCI patients (aMCI). Age, depression, and UPDRS‐III scores were considered as confounding variables. PD‐MCI group (P < 0.05, false discovery rate–corrected for multiple comparisons) showed relative hypoperfusion in bilateral posterior parietal lobe and in right occipital lobe in comparison to CTR. As compared to aMCI, MCI‐PD demonstrated hypoperfusion in bilateral posterior parietal and occipital areas, mainly right cuneus and angular gyrus, and left precuneus and middle occipital gyrus. With a less conservative threshold (uncorrected P < 0.01), MCI‐PD showed hypoperfusion in a left parietal region, mainly including precuneus and inferior parietal lobule, and in a right temporal‐parietal‐occipital region, including middle occipital and superior temporal gyri, and cuneus‐precuneus, as compared to PD. aMCI versus PD‐MCI showed hypoperfusion in bilateral medial temporal lobe, anterior cingulate, and left orbitofrontal cortex. PD‐MCI patients with amnestic deficit showed cortical dysfunction in bilateral posterior parietal and occipital lobes, a pattern that can be especially recognized versus both controls and common aMCI patients, and to a lesser extent versus cognitively intact PD. The relevance of this pattern in predicting dementia should be evaluated in longitudinal studies. © 2008 Movement Disorder Society     

Volumes of lateral temporal and parietal structures distinguish between healthy aging, mild cognitive impairment, and Alzheimer's disease

Distinguishing amnestic mild cognitive impairment (MCI) from Alzheimer's disease (AD) and healthy aging depends mainly on clinical evaluation, and, ultimately, on investigator's judgment. Clinical evaluation in vivo is based primarily on cognitive assessments. The present study explores the potential of volumetric magnetic resonance imaging of parietal and lateral temporal brain structures to support the diagnosis of AD and to distinguish AD patients from patients with MCI and healthy control subjects (HCS). 52 age-matched HCS, 18 patients with MCI, and 59 patients with probable late onset AD were investigated. Using computational, neuromorphometric procedures gray matter (GM) was automatically parcellated into 28 local regions of interest, the volumes of which were computed. The left hippocampus (sensitivity/specificity: 80.8-90.4%/55.6-86.4%) and the right hippocampus (73.1-90.4%/66.7-84.7%) provided highest diagnostic accuracy in separating all three diagnostic groups. Promising diagnostic values for distinguishing MCI from HCS were found for the left superior parietal gyrus (61.5%/55.6%) and left supramarginal gyrus (65.4%/66.7%), and for distinguishing subjects with MCI from AD patients for the right middle temporal gyrus (77.8%/79.7%), left inferior temporal gyrus (83.3%/72.9%), and right superior temporal gyrus (77.8%/71.2%). The left superior temporal pole (92.3%/84.7%), left parahippocampal gyrus (86.5%/81.4%), left Heschl's gyrus (86.5%/79.7%), and the right superior temporal pole (82.7%/78.0%) revealed most promising diagnostic values for distinguishing AD patients from HCS. Data revealed that lateral temporal and parietal GM volumes distinguish between HCS, MCI, and AD as accurate as hippocampal volumes do; hence, these volumes can be used in the diagnostic procedure. Results also suggest that cognitive functions associated with these brain regions, e.g., language and visuospatial abilities, may be tested more extensively to obtain additional information that might enhance the diagnostic accuracy further.     

Distinct neuroanatomical substrates and cognitive mechanisms of figure copy performance in Alzheimer's disease and behavioral variant frontotemporal dementia

Figure copy is the most common method of visual spatial assessment in dementia evaluations, but performance on this test may be multifactorial. We examined the neuroanatomical substrates of figure copy performance in 46 patients with Alzheimer's disease (AD) and 48 patients with the behavioral variant of Frontotemporal dementia (bvFTD). A group of 94 neurologically healthy controls were studied for comparison. In AD, poor figure copy correlated significantly with right parietal cortex volumes but not with right dorsolateral prefrontal cortex volumes, whereas in bvFTD, figure copy performance correlated significantly with right dorsolateral prefrontal cortex volumes and there was only a trend with right parietal cortex volumes. The cognitive processes associated with figure copy performance also differed by diagnostic group such that figure copy was associated with spatial perception and attention in AD and with spatial planning and working memory in bvFTD. Spatial planning accounted for unique variance in the figure copy performance of bvFTD even after accounting for spatial perception, attention, and working memory. These results suggest that figure copy performance in AD and bvFTD is not anatomically specific and is differentially impacted by bottom-up and top-down aspects of visual spatial processing. Alternative methods of visual spatial assessment for dementia evaluations are proposed.     

Procedural learning in schizophrenia investigated with functional magnetic resonance imaging

A cerebral basis for the acquisition and retention of procedural knowledge in schizophrenia was examined with 1.5 T functional MRI during an embedded sequence Serial Reaction Time Task (SRTT) in 10 chronic medicated patients and 15 healthy controls. Comparable procedural learning was observed in both groups, suggesting that the impairment reported in previous schizophrenia samples may not be robust. Consistent with previous fMRI reports, procedural learning in the control group was associated with activity in the dorsal striatum, anterior cingulate, parietal cortex and frontal cortex. Greater procedural learning related activity was observed in the control relative to the schizophrenia group in the bilateral frontal, left parietal and bilateral caudate regions. Patients did not activate frontal or parietal areas while responding to the embedded sequence within the SRTT, but greater activation during procedural learning was observed relative to the control sample in the right anterior cingulate, left globus pallidus and the right superior temporal gyrus. Thus, despite comparable instantiation of procedural learning in schizophrenia, the cerebral activation associated with this cognitive skill was abnormal. The paucity of activity in bilateral frontal cortex, left parietal cortex and bilateral caudate nucleus may represent cerebral dysfunction associated with schizophrenia, whereas the hyperactivation of the right superior temporal gyrus, the right anterior cingulate cortex and the left globus pallidus may represent a compensatory cerebral action capable of facilitating near-normal task performance. The results are thus consistent with a neurodevelopmental pathology impinging on fronto-subcortical circuitry.     

Regional structural hypo‐ and hyperconnectivity of frontal–striatal and frontal–thalamic pathways in behavioral variant frontotemporal dementia

Behavioral variant frontotemporal dementia (bvFTD) has been predominantly considered as a frontotemporal cortical disease, with limited direct investigation of frontal–subcortical connections. We aim to characterize the grey and white matter components of frontal–thalamic and frontal–striatal circuits in bvFTD. Twenty‐four patients with bvFTD and 24 healthy controls underwent morphological and diffusion imaging. Subcortical structures were manually segmented according to published protocols. Probabilistic pathways were reconstructed separately from the dorsolateral, orbitofrontal and medial prefrontal cortex to the striatum and thalamus. Patients with bvFTD had smaller cortical and subcortical volumes, lower fractional anisotropy, and higher mean diffusivity metrics, which is consistent with disruptions in frontal–striatal–thalamic pathways. Unexpectedly, regional volumes of the striatum and thalamus connected to the medial prefrontal cortex were significantly larger in bvFTD (by 135% in the striatum, p = .032, and 217% in the thalamus, p = .004), despite smaller dorsolateral prefrontal cortex connected regional volumes (by 67% in the striatum, p = .002, and 65% in the thalamus, p = .020), and inconsistent changes in orbitofrontal cortex connected regions. These unanticipated findings may represent compensatory or maladaptive remodeling in bvFTD networks. Comparisons are made to other neuropsychiatric disorders suggesting a common mechanism of changes in frontal–subcortical networks; however, longitudinal studies are necessary to test this hypothesis.     

Overweight adolescents’ brain response to sweetened beverages mirrors addiction pathways

Many adolescents struggle with overweight/obesity, which exponentially increases in the transition to adulthood. Overweight/obesity places youth at risk for serious health conditions, including type 2 diabetes. In adults, neural substrates implicated in addiction (e.g., orbitofrontal cortex (OFC), striatum, amygdala, and ventral tegmental area) have been found to be relevant to risk for overweight/obesity. In this study, we examined three hypotheses to disentangle the potential overlap between addiction and overweight/obesity processing by examining (1) brain response to high vs. low calorie beverages, (2) the strength of correspondence between biometrics, including body mass index (BMI) and insulin resistance, and brain response and (3) the relationship between a measure of food addiction and brain response using an established fMRI gustatory cue exposure task with a sample of overweight/obese youth (M age = 16.46; M BMI = 33.1). Greater BOLD response was observed across the OFC, inferior frontal gyrus (IFG), nucleus accumbens, right amygdala, and additional frontoparietal and temporal regions in neural processing of high vs. low calorie beverages. Further, BMI scores positively correlated with BOLD activation in the high calorie > low calorie contrast in the right postcentral gyrus and central operculum. Insulin resistance positively correlated with BOLD activation across the bilateral middle/superior temporal gyrus, left OFC, and superior parietal lobe. No relationships were observed between measures of food addiction and brain response. These findings support the activation of parallel addiction-related neural pathways in adolescents’ high calorie processing, while also suggesting the importance of refining conceptual and neurocognitive models to fit this developmental period.     

Brain imaging evidence of preclinical Alzheimer's disease in normal aging

OBJECTIVE: This study was designed to test the hypothesis that baseline glucose metabolism and medial temporal lobe brain volumes are predictive of cognitive decline in normal older people. METHODS: We performed positron emission tomography using [18F]fluorodeoxyglucose and structural magnetic resonance imaging at baseline in 60 cognitively normal community-dwelling older subjects who were part of a longitudinal cohort study. Subjects were followed for a mean of 3.8 years, with approximately annual evaluation of global cognition (the Modified Mini-Mental State Examination) and episodic memory (delayed recall). Baseline brain volumes and glucose metabolism were evaluated in relation to the rate of change in cognitive test scores. RESULTS: Six subjects developed incident dementia or cognitive impairment (converters). Baseline positron emission tomography scans showed regions in left and right angular gyrus, left mid-temporal gyrus, and left middle frontal gyrus that predicted the rate of change on the Modified Mini-Mental State Examination (p < 0.001). The left hemisphere temporal and parietal regions remained significant when converters were excluded. Both hippocampal (p = 0.03) and entorhinal cortical volumes (p = 0.01) predicted decline on delayed recall over time, and entorhinal cortical volumes remained significant when converters were excluded (p = 0.02). These brain volumes did not predict Modified Mini-Mental State Examination decline. INTERPRETATION: These results indicate that temporal and parietal glucose metabolism predict decline in global cognitive function, and medial temporal brain volumes predict memory decline in normal older people. The anatomical location of these findings suggests detection of preclinical Alzheimer's disease pathology.     

Sex and performance level effects on brain activation during a verbal fluency task: A functional magnetic resonance imaging study

Neuroimaging studies investigating the neural correlates of verbal fluency (VF) focused on sex differences without taking into account behavioural variation. Nevertheless, group differences in this verbal ability might account for neurocognitive differences elicited between men and women. The aim of this study was to test sex and performance level effects and the combination of these on cerebral activation. Four samples of 11 healthy students (N = 44) selected on the basis of sex and contrasted VF scores, high fluency (HF) versus low fluency (LF), performed a covert phonological VF task during scans. Within- and between-group analyses were conducted. Consistent with previous studies, for each sample, the whole-group analysis reported activation in the inferior frontal gyrus (IFG), insula, anterior cingulate cortex (ACC), medial frontal gyrus (mFG), superior (SPL) and inferior parietal lobules (IPL), inferior visual areas, cerebellum, thalamus and basal ganglia. Between-group analyses showed an interaction between sexes and performances in the right precuneus, left ACC, right IFG and left dorsolateral prefrontal cortex (dlPFC). HF men showed more activation than LF ones in the right precuneus and left dlPFC. LF men showed more activation in the right IFG than HF ones and LF women elicited more activation in the left ACC than HF ones. A sex main effect was found regardless of performance in the left inferior temporal gyrus (ITG), cerebellum, anterior and posterior cingulate cortexes and in the right superior frontal gyrus (SFG) and dlPFC, lingual gyrus and ACC, with men eliciting significantly greater activations than women. A performance main effect was found for the left ACC and the left cerebellum regardless of sex. LF subjects had stronger activations than HF ones in the ACC whereas HF subjects showed stronger activations in the cerebellum. Activity in three discrete subregions of the ACC is related to sex, performance and their interaction, respectively. Our findings emphasize the need to consider sex and performance level in functional imaging studies of VF.     

Language-related brain function during word repetition in post-stroke aphasics

We compared fMRI findings (using SPM99) obtained with repetition task in normal subjects with those of two patients with Broca's and Wernicke's aphasia who received speech therapy and showed complete recovery. Both aphasic patients with left hemisphere damage who showed complete recovery exhibited activation of only the compensatory area in the right hemisphere during the repetition task. Recovery from Broca's aphasia involves reorganization and neuromodulation between the external temporopolar area and the anterior superior temporal area of the superior temporal gyrus, putamen and the inferior frontal gyrus, while that from Wernicke's aphasia involves reorganization and neuromodulation between the superior temporal gyrus of the temporal region, the posterior supramarginal gyrus and inferior parietal lobule of the parietal region.     

Structural changes in the gray matter of unmedicated patients with obsessive-compulsive disorder: a voxel-based morphometric study

The aim of the current study was to use whole brain voxel-based morphometry（VBM）to assess the gray matter（GM）changes in unmedicated patients with obsessive-compulsive disorder（OCD）compared with normal controls.We compared the GM volumes in28 patients with 22 matched healthy controls using a1.5T MRI.Three-dimensional T1-weighted magnetic resonance images were obtained from all participants.VBM was performed to detect GM volume differences between the two groups.We detected increased regional GM volumes in the bilateral middle temporal gyri,bilateral middle occipital gyri,bilateral globus pallidus,right inferior parietal gyrus,left superior parietal gyrus,right parahippocampus,right supramarginal gyrus,right medial superior frontal gyrus,and left inferior frontal opercular cortex in the OCD patients relative to controls（P〈0.001,uncorrected,cluster size〉100 voxels）.No decreased GM volume was found in the OCD group compared with normal controls.Our findings suggest that structural changes in the GM are not limited to fronto-striato-thalamic circuits in the pathogenesis of OCD.Temporo-parietal cortex may also play an important role.     

Functional MR evaluation of temporal and frontal language dominance compared with the Wada test

OBJECTIVE: To evaluate the reliability of temporal and frontal functional MRI (fMRI) activation for the assessment of language dominance, as compared with the Wada test. PATIENTS AND METHODS: Ten patients with temporal lobe epilepsy were studied using blood oxygen level dependent fMRI and echoplanar imaging (1.5-T). Three tasks were used: semantic verbal fluency, covert sentence repetition, and story listening. Data were analyzed using pixel by pixel autocorrelation and cross-correlation. fMRI laterality indices were defined for several regions of interest as the ratio (L - R)/(L + R), L being the number of activated voxels in the left hemisphere and R in the right hemisphere. Wada laterality indices were defined as the difference in the percentages of errors in language tests between left and right carotid injections. RESULTS: Semantic verbal fluency: The asymmetry of frontal activation was correlated with Wada laterality indices. The strongest correlation was observed in the precentral/middle frontal gyrus/inferior frontal sulcus area. Story listening: The asymmetry of frontal, but not temporal, activation was correlated with Wada laterality indices. Covert sentence repetition: No correlation was observed. CONCLUSIONS: There was a good congruence between hemispheric dominance for language as assessed with the Wada test and fMRI laterality indices in the frontal but not in the temporal lobes. The story listening and the covert sentence repetition tasks increased the sensitivity of detection of posterior language sites that may be useful for brain lesion surgery.     

Increased cortical recruitment in Huntington's disease using a Simon task

Cognitive deficits in Huntington's disease (HD) have been attributed to neuronal degeneration within the striatum; however, postmortem and structural imaging studies have revealed more widespread morphological changes. To examine the impact of HD-related changes in regions outside the striatum, we used functional magnetic resonance imaging (fMRI) in HD to examine brain activation patterns using a Simon task that required a button press response to either congruent or incongruent arrow stimuli. Twenty mild to moderate stage HD patients and 17 healthy controls were scanned using a 3T GE scanner. Data analysis involved the use of statistical parametric mapping software with a random effects analysis model to investigate group differences brain activation patterns compared to baseline. HD patients recruited frontal and parietal cortical regions to perform the task, and also showed significantly greater activation, compared to controls, in the caudal anterior cingulate, insula, inferior parietal lobules, superior temporal gyrus bilaterally, right inferior frontal gyrus, right precuneus/superior parietal lobule, left precentral gyrus, and left dorsal premotor cortex. The significantly increased activation in anterior cingulate-frontal-motor-parietal cortex in HD may represent a primary dysfunction due to direct cell loss or damage in cortical regions, and/or a secondary compensatory mechanism of increased cortical recruitment due to primary striatal deficits.     

Abnormal functional connectivity in patients with vascular cognitive impairment, no dementia: a resting-state functional magnetic resonance imaging study

The functional connectivity (FC) method was used to investigate the changes in the resting state of patients with vascular cognitive impairment, no dementia (VCIND). Resting-state functional magnetic resonance images (fMRIs) were acquired from 16 patients with subcortical ischemic vascular disease (SIVD) who fulfilled the criteria for VCIND, as well as 18 age- and sex-matched subjects with SIVD with no cognitive impairment (control group). Posterior cingulate cortex connectivity was gathered by investigating synchronic low-frequency fMRI signal fluctuations with a temporal correlation method. Compared with the control group, the patients showed FC decrease in the left middle temporal gyrus, the left anterior cingulate/left middle frontal gyrus, the right caudate, the right middle frontal gyrus, and the left medial frontal gyrus/paracentral lobule. There were also some regions that showed increased connectivity. These regions included the right inferior temporal gyrus, the left middle temporal gyrus, the left precentral gyrus, and the left superior parietal lobule. Our findings revealed the change in resting-state patterns of neuronal activity in patients with VCIND. This change may be caused by subcortical white matter lesions that destroyed direct and indirect fiber tract connectivity across the cerebral white matter and influenced the cortical FC and hypoperfusion resulted from small vascular disease. The results of the increased connectivity may be evoked by the compensatory recruitment and plasticity mechanism. Our findings suggest that the simplicity and noninvasiveness of this method makes it a potential tool to help thoroughly understand the pathogenesis of VCIND.     

Different localizations underlying cortical gelastic epilepsy: Case series and review of literature

BackgroundGelastic seizures (GS) are classically observed with hypothalamic hamartomas but they can also be associated with cortical epileptogenic foci.ObjectiveTo study the different cortical localizations associated with GS.MethodsWe reviewed the data from all patients with cortical GS investigated in our epilepsy unit from 1974 to 2012 and in the literature from 1956 to 2013.ResultsSixteen cases were identified in our database and 77 in the literature. Investigations provided confident focus localization in 9 and 18, respectively. In our series, the identified foci were located in the mesial temporal structures (2 left, 1 right), lateral temporal cortex (1 right), superior frontal gyrus (1 left), and operculoinsular region [3 right (orbitofrontal or frontal operculum extending into the anterior insula) and 1 left (frontal operculum extending into the anterior insula)]. In the literature, the identified foci (13 right/5 left) were located in the temporal lobe of 4 (1 right inferior, 1 right medial and inferior, 1 right posterior middle, inferior extending posteriorly to the lingual gyrus, and 1 left middle, inferior, and medial), in the frontal lobe of 12 [10 (6 right/4 left) medial (i.e., superior, medial frontal, and/or anterior cingulate gyri), 1 lateral (right anterior inferior frontal gyrus), and 1 right medioposterior orbitofrontal cortex] and in the parietal lobe of 2 (1 left superior parietal lobule and 1 right parietal operculum) patients.ConclusionIctal laughter is a poorly lateralizing and localizing feature as it may be encountered in patients with a focus in the left or right frontal, temporal, parietal, or insular lobe.     

太溪和丘墟穴捻针时不同脑功能区的激活

A number of previous studies of acupuncture acupoint specificity have used sham acupoints,sham acupuncture or meridian acupoints at a great distance from each other as controls in functional MRI (fMRI) experiments.However,few studies have compared different meridian acupoints within the same segment,which are associated with similarly intense needle sensations.We performed fMRI on 12 healthy young volunteers and observed differences in brain activation elicited by acupuncture of the Taixi (KI 3) and Qiuxu (GB 40) acupoints.Acupuncture was applied at the Taixi and Qiuxu acupoints,using a multiple-block fMRI design with three blocks,involving three alternations of resting and task phases.After scanning,needle sensation was assessed.The behavioral results revealed that the subjective needle sensation was similar between the Taixi and Qiuxu acupoints.The fMRI results revealed that acupuncture at the right Taixi acupoint activated the right superior temporal gyrus (BA 22),left middle frontal gyrus (BA 46) and inferior frontal gyrus (BA 45),bilateral parietal lobe postcentral gyrus (BA 2),right parietal lobe (BA 3),and left parietal lobe (BA 40).Acupuncture at the right Qiuxu acupoint activated the left superior temporal gyrus (BA 42),right parietal lobe postcentral gyrus (BA 40,BA 43),right inferior frontal gyrus (BA 47),bilateral superior temporal gyrus (BA 22),and right insula BA13.These results suggest that the right Taixi and Qiuxu acupoints activated different brain areas.