Showing papers on "Superior frontal gyrus published in 2006"
TL;DR: A hybrid model of the anatomical and functional organization of the lateral SFG for WM is supported, according to which this region is involved in higher levels of WM processing but remains oriented towards spatial cognition, although the domain specificity is not exclusive and is overridden by an increase in executive demand, regardless of the domain being processed.
Abstract: The superior frontal gyrus (SFG) is thought to contribute to higher cognitive functions and particularly to working memory (WM), although the nature of its involvement remains a matter of debate. To resolve this issue, methodological tools such as lesion studies are needed to complement the functional imaging approach. We have conducted the first lesion study to investigate the role of the SFG in WM and address the following questions: do lesions of the SFG impair WM and, if so, what is the nature of the WM impairment? To answer these questions, we compared the performance of eight patients with a left prefrontal lesion restricted to the SFG with that of a group of 11 healthy control subjects and two groups of patients with focal brain lesions [prefrontal lesions sparing the SFG (n = 5) and right parietal lesions (n = 4)] in a series of WM tasks. The WM tasks (derived from the classical n-back paradigm) allowed us to study the impact of the SFG lesions on domain (verbal, spatial, face) and complexity (1-, 2- and 3-back) processing within WM. As expected, patients with a left SFG lesion exhibited a WM deficit when compared with all control groups, and the impairment increased with the complexity of the tasks. This complexity effect was significantly more marked for the spatial domain. Voxel-to-voxel mapping of each subject's performance showed that the lateral and posterior portion of the SFG (mostly Brodmann area 8, rostral to the frontal eye field) was the subregion that contributed the most to the WM impairment. These data led us to conclude that (i) the lateral and posterior portion of the left SFG is a key component of the neural network of WM; (ii) the participation of this region in WM is triggered by the highest level of executive processing; (iii) the left SFG is also involved in spatially oriented processing. Our findings support a hybrid model of the anatomical and functional organization of the lateral SFG for WM, according to which this region is involved in higher levels of WM processing (monitoring and manipulation) but remains oriented towards spatial cognition, although the domain specificity is not exclusive and is overridden by an increase in executive demand, regardless of the domain being processed. From a clinical perspective, this study provides new information on the impact of left SFG lesions on cognition that will be of use to neurologists and neurosurgeons.
674 citations
TL;DR: Functional magnetic resonance imaging findings suggest that different kinds of moral judgment are preferentially supported by distinguishable brain systems.
Abstract: The traditional philosophical doctrines of Consequentialism, Doing and Allowing, and Double Effect prescribe that moral judgments and decisions should be based on consequences, action (as opposed to inaction), and intention. This study uses functional magnetic resonance imaging to investigate how these three factors affect brain processes associated with moral judgments. We find the following: (1) Moral scenarios involving only a choice between consequences with different amounts of harm elicit activity in similar areas of the brain as analogous nonmoral scenarios; (2) Compared to analogous nonmoral scenarios, moral scenarios in which action and inaction result in the same amount of harm elicit more activity in areas associated with cognition (such as the dorsolateral prefrontal cortex) and less activity in areas associated with emotion (such as the orbitofrontal cortex and temporal pole); (3) Compared to analogous nonmoral scenarios, conflicts between goals of minimizing harm and of refraining from harmful action elicit more activity in areas associated with emotion (orbitofrontal cortex and temporal pole) and less activity in areas associated with cognition (including the angular gyrus and superior frontal gyrus); (4) Compared to moral scenarios involving only unintentional harm, moral scenarios involving intentional harm elicit more activity in areas associated with emotion (orbitofrontal cortex and temporal pole) and less activity in areas associated with cognition (including the angular gyrus and superior frontal gyrus). These findings suggest that different kinds of moral judgment are preferentially supported by distinguishable brain systems.
337 citations
TL;DR: Gender differences of cortical thickness are examined using a 3-D surface-based method that enables more accurate measurement in deep sulci and localized regional mapping compared to volumetric analyses to support a hypothesis of sexual dimorphism.
267 citations
TL;DR: Investigating changes in functional connectivity of the right middle fusiform gyrus in subjects with mild cognitive impairment (MCI) during performance of a face-matching task demonstrates that functional connectivity can be an effective marker for the detection of changes in brain function in MCI subjects.
Abstract: Cognitive function requires a high level of functional interaction between regions of a network supporting cognition. Assuming that brain activation changes denote an advanced state of disease progression, changes in functional connectivity may precede changes in brain activation. The objective of this study was to investigate changes in functional connectivity of the right middle fusiform gyrus (FG) in subjects with mild cognitive impairment (MCI) during performance of a face-matching task. The right middle FG is a key area for processing face stimuli. Brain activity was measured using functional MRI. There were 16 MCI subjects and 19 age-matched healthy controls. The linear correlation coefficient was utilized as a measure of functional connectivity between the right middle FG and all other voxels in the brain. There were no statistical differences found in task performance or activation between groups. The right middle FG of the healthy control and MCI groups showed strong bilateral positive linear correlation with the visual cortex, inferior and superior parietal lobules, dorsolateral prefrontal cortex (DLPFC) and anterior cingulate. The healthy controls showed higher positive linear correlation of the right middle FG to the visual cortex, parietal lobes and right DLPFC than the MCI group, whereas the latter had higher positive linear correlation in the left cuneus. In the healthy controls, the right middle FG had negative linear correlation with right medial frontal gyrus and superior temporal gyrus and with left inferior parietal lobule (IPL), angular gyrus, superior frontal gyrus and anterior cingulate gyrus, but the MCI group had negative linear correlation with the left IPL, angular gyrus, precuneus, anterior cingulate, and to right middle temporal gyrus and posterior cingulate gyrus. In the negatively linearly correlated regions, the MCI group had reduced functional connectivity to the frontal areas, right superior temporal gyrus and left IPL. Different regions of the cuneus and IPL had increased functional connectivity in either group. The putative presence of Alzheimer's disease neuropathology in MCI affects functional connectivity from the right middle FG to the visual areas and medial frontal areas. In addition, higher linear correlation in the MCI group in the parietal lobe may indicate the initial appearance of compensatory processes. The results demonstrate that functional connectivity can be an effective marker for the detection of changes in brain function in MCI subjects.
229 citations
TL;DR: Findings suggest a functional relationship among men between higher blood pressure, lower regional grey matter volume, and poorer cognitive function that is independent of other risk factors and confounding medical conditions.
137 citations
TL;DR: The results demonstrate comparable brain activation in men and women in association with mental rotation and verbal fluency function with differential performance, and provide support for sex differences in brain–behaviour relationships.
Abstract: To explicate the neural correlates of sex differences in visuospatial and verbal fluency tasks, we examined behavioural performance and blood-oxygenation-level-dependent (BOLD) regional brain activity, using functional magnetic resonance imaging, during a three-dimensional (3D) mental rotation task and a compressed sequence overt verbal fluency task in a group of healthy men (n=9) and women (n=10; tested during the low-oestrogen phase of the menstrual cycle). Men outperformed women on the mental rotation task, and women outperformed men on the verbal fluency task. For the mental rotation task, men and women activated areas in the right superior parietal lobe and the bilateral middle occipital gyrus in association with the rotation condition. In addition, men activated the left middle temporal gyrus and the right angular gyrus. For verbal fluency, men activated areas in the bilateral superior frontal gyrus, right cingulate gyrus, left precentral gyrus, left medial frontal gyrus, left inferior frontal gyrus, thalamus, left parahippocampal gyrus and bilateral lingual gyrus, and women activated areas in the bilateral inferior frontal gyrus and left caudate. Despite observing task related activation in the hypothesised areas in men and women, no areas significantly differentiated the two sexes. Our results demonstrate comparable brain activation in men and women in association with mental rotation and verbal fluency function with differential performance, and provide support for sex differences in brain–behaviour relationships.
136 citations
TL;DR: After childhood TBI, neural correlates of personality change evolve between 6 and 12 months and 12 to 24 months after injury, and the data implicate the dorsal prefrontal cortex and frontal lobe white matter in the emergence of Personality change involving the effortful or conscious regulation of affective states.
Abstract: Phenomenology and predictive factors of personality change due to traumatic brain injury (TBI) 6 to 24 months after injury was investigated in children, ages 5 to 14 years, enrolled from consecutive admissions and followed prospectively for 2 years. Injury and preinjury psychosocial variables were assessed. Personality change occurred in 13% of participants between 6 and 12 months after injury and 12% in the second year after injury. Severity of injury consistently predicted personality change, and preinjury adaptive function predicted personality change only in the second year postinjury. Lesions of the superior frontal gyrus were associated with personality change between 6 and 12 months following injury, after controlling for severity of injury and the presence of other brain lesions. Only lesions in the frontal lobe white matter were significantly related to personality change in the second year after injury. After childhood TBI, neural correlates of personality change evolve between 6 and 12 months and 12 to 24 months after injury. The data implicate the dorsal prefrontal cortex and frontal lobe white matter in the emergence of personality change involving the effortful or conscious regulation of affective states.
96 citations
TL;DR: The results substantiate evidence from animal studies indicating an important role for the anterior cingulate cortex in suprahypothalamic feedback regulation of the HPA axis and have implications for disorders in which disorders of the posterior cingulating cortex are frequently observed, such as depression and Alzheimer's disease.
Abstract: Context: Studies in animals suggest that the limbic prefrontal cortex, including the anterior cingulate cortex, is involved in regulation of the hypothalamic-pituitary-adrenal (HPA) axis, but human data are lacking. Objective: This study tested the hypothesis that smaller anterior cingulate cortex volumes are associated with HPA axis dysregulation in healthy older men. Design and Participants: Comparison was made of volumes of bilateral anterior cingulate cortex, hippocampus, and superior frontal gyrus (control region) volumes in two groups of 10 healthy men, aged 65–70 yr, who showed nonsuppression or suppression of cortisol levels in response to low dose (250 μg) dexamethasone. Analysis of brain volumes was performed blind to the cortisol levels. Setting: This study was performed at a tertiary care clinical research center. Results: Nonsuppressors had significantly smaller left anterior cingulate cortex volumes than suppressors (5757 vs. 7817 mm3; P = 0.01). Right anterior cingulate cortex, bilateral hi...
96 citations
TL;DR: To evaluate the effect of antipsychotic medication on RGS4 expression levels, a subset of treated and untreated cases that were off antippsychotic medication for at least 3 months prior to death are compared.
Abstract: The regulator of G protein signaling (RGS) molecules are a class of proteins that modulate the signaling activity of G-protein coupled receptors. Regulator of G protein signaling 4 (RGS4) is of particular interest in schizophrenia since it is associated with the dopamine (DA) receptor, its expression is altered in affected CNS tissue, and polymorphisms in the RGS4 gene are being examined as risk factors for the disease (Morris et al.2004, Am J Med Genet B Neuropsychiatr Genet 125:50–53; Prasad et al.2005, Mol Psychiatry 10:213–219; Williams et al.2004, Biol Psychiatry 55:192–195). To further test for the involvement of RGS4 expression in schizophrenia, we examined a selection of different cortical and subcortical regions in human brain for alterations in RGS4 mRNA and protein expression. To evaluate the effect of antipsychotic medication on RGS4 expression levels, we compared a subset of treated and untreated cases that were off antipsychotic medication for at least 3 months prior to death. We report a significant decrease in RGS4 mRNA levels in the cingulate gyrus, superior frontal gyrus, and the insular cortex of all schizophrenia cases when compared with controls. A decrease in RGS4 mRNA was also observed in the caudate, but only in the medicated schizophrenia cases. Measurement of protein levels using Western blot demonstrated that RGS4 protein is decreased in the frontal cortex of schizophrenia cases. Synapse 59:472–479, 2006. © 2006 Wiley-Liss, Inc.
91 citations
TL;DR: This result indicates that PTSD patients have alterations in cerebral perfusion of limbic regions and the frontal and temporal cortex without re-exposure to accident-related stimuli, and supports the hypothesis of the involvement of limbsic regions, which might be associated with the regulation of emotion and memory, in the pathophysiology of PTSD.
85 citations
TL;DR: As task difficulty increased, the magnitude of task-induced deactivations increased in the medial prefrontal/superior frontal gyrus and middle/posterior cingulate cortex in younger and older adults, and in the middle cingulates cortex in older adults with and without AD.
TL;DR: The JME patients showed complex structural abnormalities in the corpus callosum, frontal lobe and hippocampus, and also a decreased gray matter concentration of the prefrontal region, which all suggests there is an abnormal neural network in the JME brain.
Abstract: OBJECTIVE We aimed to find structural brain abnormalities in juvenile myoclonic epilepsy (JME) patients MATERIALS AND METHODS The volumes of the cerebrum, hippocampus and frontal lobe and the area of the corpus callosum's subdivisions were all semiautomatically measured, and then optimized voxel-based morphometry (VBM) was performed in 19 JME patients and 19 age/gender matched normal controls RESULTS The rostrum and rostral body of the corpus callosum and the left hippocampus were significantly smaller than those of the normal controls, whereas the volume of the JME's left frontal lobe was significantly larger than that of the controls The area of the rostral body had a significant positive correlation with the age of seizure onset (r = 056, p = 0012), and the volume of the right frontal lobe had a significant negative correlation with the duration of disease (r = -051, p = 0025) On the VBM, the gray matter concentration of the prefrontal lobe (bilateral gyri rectus, anterior orbital gyri, left anterior middle frontal gyrus and right anterior superior frontal gyrus) was decreased in the JME group (corrected p < 005) CONCLUSION The JME patients showed complex structural abnormalities in the corpus callosum, frontal lobe and hippocampus, and also a decreased gray matter concentration of the prefrontal region, which all suggests there is an abnormal neural network in the JME brain
TL;DR: It is concluded that ADC may be a more sensitive measure than ventricular volume assessments for use in future studies of early prediction of schizophrenia.
Abstract: A novel magnetic resonance imaging method was used to determine whether it is feasible to detect early signs of cortical atrophy among individuals who are at high risk for developing schizophrenia. Fifteen individuals at high-risk for schizophrenia and 15 of their first degree relatives diagnosed with schizophrenia were compared with controls (n=25) who did not have a family history of psychiatric illness or psychiatric hospitalizations. On the basis of a voxelwise analysis of apparent diffusion coefficient (ADC) maps derived from diffusion weighted magnetic resonance imaging, these individuals showed evidence of deficits in four separate regions of the brain, all on the left side only: parahippocampal gyrus, lingual gyrus, superior frontal gyrus, and middle frontal gyrus. However, conventional volumetric quantification of ventricular space to detect atrophy failed to reveal differences between high-risk subjects and controls. It is concluded that ADC may be a more sensitive measure than ventricular volume assessments for use in future studies of early prediction of schizophrenia.
TL;DR: A reliable method of parcellating the SFG, IFG and MFG, which constitute the DLPFC, a brain region involved in a variety of neuropsychiatric conditions is described.
Abstract: Precise rules for locating the anatomical boundaries of the dorsolateral prefrontal cortex (DLPFC) or its subdivisions, i.e., superior, inferior and middle frontal gyri (SFG, IFG and MFG) on magnetic resonance images (MRI), have not been defined. The present study describes the inter-rater reliability of manual segmentation of the SFG, IFG and MFG using guidelines based on sulcal–gyral anatomical boundaries as well as the cytoarchitectonic features of the sub-regions of the prefrontal cortex (PFC). Variations in the application of these guidelines in different subjects to account for normal sulcal variability were developed using the atlas of Ono et al. (Ono, M., Kubik, S., Abernathey, C.D., 1990. Atlas of the Cerebral Sulci. Georg Thieme Verlag, New York). Based on previous cytoarchitectonic studies, the coronal plane of the anterior termination of olfactory sulcus (ATOS) was used as a landmark for delimiting the boundary between the frontal pole (FP) and the frontal gyri. The left hemisphere gray-matter volumes of the SFG, IFG and MFG were determined using a set of 10 MRIs (5 normal and 5 schizophrenia subjects) by two trained raters independently. The intra-class correlation coefficients (ICC) for the SFG, IFG and MFG volumes by the two raters were 0.97, 0.94 and 0.93, respectively. Thus, we describe a reliable method of parcellating the SFG, IFG and MFG, which constitute the DLPFC, a brain region involved in a variety of neuropsychiatric conditions.
TL;DR: There was a consistently higher number of nuclear and non-nuclear aggregates in the superior frontal gyrus than in the motor cortex, suggesting that there is a consistent regional difference in the density of aggregates and that this consistency is not reflected in the variable symptomatology between cases.
Abstract: Insoluble protein aggregates have been considered a pathological hallmark of Huntington's disease and other polyglutamine disorders. In this study the number of aggregates was assessed in the superior frontal gyrus and motor cortex of seven Huntington's disease patients and was compared with the symptoms (motor/ mood) these patients displayed during the course of the disease. Regardless of the pattern of symptoms present in the patients, there was a consistently higher number of nuclear and non-nuclear aggregates in the superior frontal gyrus than in the motor cortex. This suggests that there is a consistent regional difference in the density of aggregates and that this consistency is not reflected in the variable symptomatology between cases.
TL;DR: Findings suggest that stimulation of the Elixir Field is not only associated with activation of the sensory motor cortex but also with cortical regions that mediate planning, attention, and memory.
Abstract: Elixir Field, or Dan Tian, is the area where energy is stored and nourished in the body according to traditional Chinese medicine (TCM). Although Dan Tian stimulation is a major concept in Qigong healing and has been practiced for thousands of years, and while there are some recent empirical evidence of its effect, its neurophysiological basis remains unknown. We used functional magnetic resonance imaging (fMRI) to study brain activations associated with external stimulation of the lower Elixir Field in ten normal subjects, and compared the results with the stimulation of their right hands. While right-hand stimulation resulted in left postcentral gyrus activation, stimulation of the lower Elixir Field resulted in bilateral activations including the medial and superior frontal gyrus, middle and superior temporal gyrus, thalamus, insula, and cingulate gyrus. These findings suggest that stimulation of the Elixir Field is not only associated with activation of the sensory motor cortex but also with cortical regions that mediate planning, attention, and memory.
TL;DR: To demonstrate the Bereitschaftspotentials, movement-related cortical potentials with respect to the middle finger extension were recorded in seven patients with refractory epilepsy who underwent subdural implantation of platinum electrode grids and/or strips covering the high lateral frontal convexity.
TL;DR: The sexual arousal by visual stimulation may activate the anterior parahippocampal gyrus of the left limbic lobe, the superior temporal g Cyrus of both temporal lobes, the precuneus of the right parietal lobe,the medial frontal gyrusOf the left frontal g Cyrus, and the middle occipital gyrusof the right Occipital lobe.
Abstract: Purpose: Low resolution brain electromagnetic tomography (LORETA) is a kind of functional imaging technique and it is also an up-to-date technique for conducting electroencephalography (EEG) analysis. We tried to investigate the locations on the cerebral cortex that are activated by visually stimulated sexual arousal. Materials and Methods: Thirty-three male volunteers (age range: 24.7±1.7 years) among all the right-handed medical students at our university were enrolled in this study. The EEGs included the segments recorded during resting, watching a music-video, intermission and watching a porno-video. The LORETA images of the cross-spectral analysis were obtained with using segments of LORETA-KEY (KEY Institute for Brain-Mind Research, Switzerland) software. Results: In the statistical nonparam etric m aps (SnPM) of each spectrum and the delta, theta and alpha waves did not show the increased current density. The beta 1, 2 and 3 activity showed the point of maximal current densities in the anterior parahippocampal gyrus of the left limbic lobe and the superior temporal gyrus of both temporal lobes, the superior temporal gyrus of the right temporal lobe, the precuneus of the right parietal lobe, the medial frontal gyrus of the left frontal lobe, the middle occipital gyrus of the right occipital lobe, the superior temporal gyrus of both temporal lobes and the superior frontal gyrus of the right frontal lobe. Conclusions: The sexual arousal by visual stimulation may activate the anterior parahippocampal gyrus of the left limbic lobe, the superior temporal gyrus of both temporal lobes, the precuneus of the right parietal lobe, the medial frontal gyrus of the left frontal gyrus, and the middle occipital gyrus of the right occipital lobe. (Korean J Urol 2006;47:779-785)
24 Jul 2006
TL;DR: A fully automated method for identifying the gyri in three-dimensional (3-D) human brain magnetic resonance (MR) images is proposed and Experimental results showed that the proposed method correctly segmented the appropriate gyri.
Abstract: Atrophy of the human brain is observed as the progress of dementia. The atrophy occurs at the different rate on each gyrus. Estimating the atrophy for each gyrus helps us for the purpose of distinguishing diagnosis. To estimate the atrophy for each gyrus, gyri on the cortical surface should be identified. This paper aims to propose a fully automated method for identifying the gyri in three-dimensional (3-D) human brain magnetic resonance (MR) images. To clarify the effectiveness of the proposed method, it was applied to identify the superior frontal gyrus, the middle frontal gyrus, the precentral gyrus and the central gyrus. Experimental results showed that the proposed method correctly segmented the appropriate gyri.
Journal Article•
TL;DR: The results suggest that the glucose metabolism in prefrontal lobes, temporal lobe, limbic system and basal ganglia is decreased in geriatric depressed patients.
Abstract: Objective To investigate brain ~(18)F-fluorodeoxyglucose(FDG) position emission tomography(PET) mapping in geriatric depression patients.Methods This is a case control study.PET with ~(18)F-FDG was performed in six geriatric depression patients and ten healthy controls.The two groups were matched with age,sex and the Mini-Mental State Examination(MMSE) score.The voxel level regional glucose metabolic rate were analyzed with the Statistical Parametric Mapping(SPM2) software.Results(The regional) glucose metabolism rates in bilateral caudate,superior temporal gyrus,inferior frontal gyrus,middle frontal gyrus,right extra-nuclear,superior frontal gyrus,lingual gyrus and left cingulate gyrus,superior temporal gyrus,sub-gyral and precentral gyrus were decreased in geriatric depression patients than in controls(P0.005).There was no significant difference in brain regions with increased glucose metabolism between two groups.Conclusion These results suggest that the glucose metabolism in prefrontal lobes,temporal lobe,limbic system and basal ganglia is decreased in geriatric depressed patients.
Journal Article•
TL;DR: If the extent of recovery from severe aphasia is related to activation in the right hemisphere as suggested by previous report Speech therapy for patients with aphasIA should aim to activate theright hemisphere, functional magnetic resonance imaging findings obtained with repetition tasks in healthy subjects are compared.
Abstract: We have previously reported that two patients who showed complete recovery from Brocas and Wernickes aphasia exhibited activation of only compensatory areas of the right hemisphere during repetition tasks. In the present study we compared functional magnetic resonance imaging (fMRI) findings obtained with repetition tasks in healthy subjects. When subjects silently repeated sentencesthe only recognized areas of activation in the right hemisphere were the superior temporal gyrus middle temporal gyrus and precentral gyrus. When sentences were repeated aloudrecognized areas of activation in the right hemisphere were the superior temporal gyrus middle temporal gyrus superior frontal gyrus middle frontal gyrus inferior frontal gyrus and precentral gyrus. Activated areas in the left hemisphere were similar when sentences were repeated aloud or silently:the superior temporal gyrusmiddle temporal gyrussuperior frontal gyrusmiddle frontal gyrusinferior frontal gyrusand precentral gyrus. If the extent of recovery from severe aphasia is related to activation in the right hemisphere as suggested by previous reportsspeech therapy for patients with aphasia should aim to activate the right hemisphere. (Jikeikai Med J 2006;53:81-6