Co-localisation of abnormal brain structure and function in specific language impairment

We assessed the relationship between brain structure and function in 10 individuals with specific language impairment (SLI), compared to six unaffected siblings, and 16 unrelated control participants with typical language. Voxel-based morphometry indicated that grey matter in the SLI group, relative to controls, was increased in the left inferior frontal cortex and decreased in the right caudate nucleus and superior temporal cortex bilaterally. The unaffected siblings also showed reduced grey matter in the caudate nucleus relative to controls. In an auditory covert naming task, the SLI group showed reduced activation in the left inferior frontal cortex, right putamen, and in the superior temporal cortex bilaterally. Despite spatially coincident structural and functional abnormalities in frontal and temporal areas, the relationships between structure and function in these regions were different. These findings suggest multiple structural and functional abnormalities in SLI that are differently associated with receptive and expressive language processing.     

高压氧对小鼠学习记忆及脑细胞形态结构的影响

实验用两种行为模型（旷场行为模型和Ｙ－迷宫分辨学习模型）观察了幼龄小鼠在不同压力的高压氧处理后,对新异环境的探究行为和自发活动情况,以及学习记忆能力的变化;并用ＸＹ－生物医学电脑图像分析仪分析了与学习记忆相关的脑区（大脑皮层、海马）神经元密度,细胞核面积,胞核／胞浆比值的变化。结果表明：（１）与对照组相比,吸０.１ＭＰａ高压氧的幼鼠学习记忆能力明显提高,相关脑区的神经元密度、细胞核面积、胞核／浆比均显著增加。（２）吸０.２５ＭＰａ高压氧的幼鼠学习记忆能力与对照组相比无明显变化,但其在新异环境中的自发行为明显减少。提示：慢性吸入０.１ＭＰａ高压氧有利于促进幼鼠脑的生长发育,增强脑功能活动。     

Clock drawing performance and brain morphology in mild cognitive impairment and Alzheimer's disease

The Clock Drawing Test (CDT) is a widely used instrument in the neuropsychological assessment of Alzheimer's disease (AD). As CDT performance necessitates several cognitive functions (e.g., visuospatial and constructional abilities, executive functioning), an interaction of multiple brain regions is likely. Fifty-one subjects with mild cognitive impairment, 23 with AD and 15 healthy controls underwent high-resolution magnetic resonance imaging. Optimized voxel-based morphometry (VBM) was performed to investigate the putative association between CDT performance and gray matter (GM) density throughout the entire brain. In the first step of analysis (p<.001, uncorrected), VBM revealed a reduced GM density in numerous cortical (temporal lobe, frontal lobe, parietal lobe, cerebellum) and subcortical (thalamus, basal ganglia) brain regions to be associated with poorer CDT performance. When corrected for multiple comparisons (p<.01), the associations remained significant predominantly in the left temporal and--less pronounced--the right temporal lobe. VBM demonstrated CDT performance to depend on the integrity of widely distributed cortical and subcortical areas in both brain hemispheres with accentuation in the left-sided temporal lobe region.     

Decision-making deficit of a patient with axonal damage after traumatic brain injury

Patients with traumatic brain injury (TBI) were reported to have difficulty making advantageous decisions, but the underlying deficits of the network of brain areas involved in this process were not directly examined. We report a patient with TBI who demonstrated problematic behavior in situations of risk and complexity after cerebral injury from a traffic accident. The Iowa gambling task (IGT) was used to reveal his deficits in the decision-making process. To examine underlying deficits of the network of brain areas, we examined T1-weighted structural MRI, diffusion tensor imaging (DTI) and Tc-ECD SPECT in this patient. The patient showed abnormality in IGT. DTI-MRI results showed a significant decrease in fractional anisotropy (FA) in the fasciculus between the brain stem and cortical regions via the thalamus. He showed significant decrease in gray matter volumes in the bilateral insular cortex, hypothalamus, and posterior cingulate cortex, possibly reflecting Wallerian degeneration secondary to the fasciculus abnormalities. SPECT showed significant blood flow decrease in the broad cortical areas including the ventromedial prefrontal cortex (VM). Our study showed that the patient had dysfunctional decision-making process. Microstructural abnormality in the fasciculus, likely from the traffic accident, caused reduced afferent feedback to the brain, resulting in less efficient decision-making. Our findings support the somatic-marker hypothesis (SMH), where somatic feedback to the brain influences the decision-making process.     

The association between the propensity to experience meaningful coincidence and brain anatomy in healthy females: The moderating role of coping skills

When two events co-occur within a specific time interval, some people experience ‘meaningful coincidence’. This may be a consequence of the mind searching for causal structure in reality. In cases of negative events, it may be a coping strategy for managing stress. The present voxel-based morphometry (VBM) study investigated neural correlates of the propensity to experience meaningful coincidence (PEMC). VBM data from 115 females (mean age: 26 years) were correlated with self-reported PEMC and the use of certain coping strategies (e.g. seeking support, positive focusing). PEMC was negatively correlated with grey matter volume (GMV) in the medial prefrontal cortex, the inferior frontal gyrus, and the superior/inferior parietal cortex. Moderation analyses indicated that the negative association between GMV in the mentioned brain regions and PEMC was only present in participants with average or below-average coping skills. The identified fronto-parietal regions are part of an integrated neural network implicated in the detection of causality and cognitive control.     

The neural basis of syntactic deficits in primary progressive aphasia

Patients with primary progressive aphasia (PPA) vary considerably in terms of which brain regions are impacted, as well as in the extent to which syntactic processing is impaired. Here we review the literature on the neural basis of syntactic deficits in PPA. Structural and functional imaging studies have most consistently associated syntactic deficits with damage to left inferior frontal cortex. Posterior perisylvian regions have been implicated in some studies. Damage to the superior longitudinal fasciculus, including its arcuate component, has been linked with syntactic deficits, even after gray matter atrophy is taken into account. These findings suggest that syntactic processing depends on left frontal and posterior perisylvian regions, as well as intact connectivity between them. In contrast, anterior temporal regions, and the ventral tracts that link frontal and temporal language regions, appear to be less important for syntax, since they are damaged in many PPA patients with spared syntactic processing.     

Support for anterior temporal involvement in semantic error production in aphasia: new evidence from VLSM

Semantic errors in aphasia (e.g., naming a horse as “dog”) frequently arise from faulty mapping of concepts onto lexical items. A recent study by our group used voxel-based lesion-symptom mapping (VLSM) methods with 64 patients with chronic aphasia to identify voxels that carry an association with semantic errors. The strongest associations were found in the left anterior temporal lobe (L-ATL), in the mid- to anterior MTG region. The absence of findings in Wernicke’s area was surprising, as were indications that ATL voxels made an essential contribution to the post-semantic stage of lexical access. In this follow-up study, we sought to validate these results by re-defining semantic errors in a manner that was less theory dependent and more consistent with prior lesion studies. As this change also increased the robustness of the dependent variable, it made it possible to perform additional statistical analyses that further refined the interpretation. The results strengthen the evidence for a causal relationship between ATL damage and lexically-based semantic errors in naming and lend confidence to the conclusion that chronic lesions in Wernicke’s area are not causally implicated in semantic error production.     

Neuroanatomy of childhood disruptive behavior disorders

Our aims were to (1) examine possible neuroanatomical abnormalities associated with the Disruptive Behavior Disorders (DBDs) as a group and (2) assess neuroanatomical anomalies specific to each DBD (i.e., conduct disorder [CD] and oppositional defiant disorder). Cortical thickness analysis and voxel-based morphometry were analyzed in 47 8-year-old boys (22 DBDs with and without CD and/or ODD and 25 healthy controls) from Magnetic Resonance Imaging brain scans. DBD symptoms were assessed using the Dominic-R. In DBD subjects relative to controls, we found (1) a decreased overall mean cortical thickness; (2) thinning of the cingulate, prefrontal and insular cortices; and (3) decreased gray matter density (GMd) in the same brain regions. We also found that scores on the Dominic-R were negatively correlated with GMd in the prefrontal and precuneus/superior temporal regions. There was a subdiagnostic main effect for CD, related to thinning of the middle/medial frontal, and for ODD in the left rectal/orbitofrontal. Findings suggest that thinning and decreased GMd of the insula disorganizes prefrontal circuits, diminishing the inhibitory influence of the prefrontal cortex on anger, aggression, cruelty, and impulsivity, and increasing a person's likelihood of aggressive behavior. These findings have implications for pathophysiologic models of the DBDs, their diagnostic classification system, and for designing more effective intervention programs.     

Finding the g-factor in brain structure using the method of correlated vectors

It is unclear whether brain mechanisms underlying human intelligence are distributed throughout the brain or mainly concentrated in the frontal lobes. Data are inconsistent possibly due, at least in part, to the different ways the construct of intelligence is measured. Here we apply the method of correlated vectors to determine how the general factor of intelligence (g) is related to regional gray matter and white matter volumes. This is a re-analysis of an earlier study showing regional gray matter and white matter volume is correlated to Full Scale IQ (FSIQ). However, it is well-known that FSIQ taps several cognitive abilities and skills in addition to g. The results now show that the g factor accounts for several but not all FSIQ/gray matter correlations distributed throughout the brain and these areas may differ for young and older adults.