ABSTRACT
Purpose Two kinds of forward conditional reasoning including modus ponens (MP) and denial of the antecedent (DA) are the most common deductive reasoning in daily life. The present study aimed to explore the difference between the two neural machanisms. Materials and Methods Three kinds of tasks including MP, DA, and baseline were administrated to 14 undergraduates [7 males and 7 females, mean age (23.4±1.3) years] by using functional magnetic resonance imaging (fMRI) technique. fMRI data was analyzed. Results The reaction times were significantly slower for MP and DA than that of BS (P<0.001), while the effect was not significant for accuracy. In contrast to baseline, both MP and DA tasks activated the left inferior frontal cortex (BA 9), inferior parietal lobule (BA 40), and postcentral gyrus. Bilateral caudate significant activation was found in MP task when compared with DA, whereas the frontal, parietal, occipital lobe and anterior cingulate cortex were acivated more in the DA than in MP task. Conclusion Both forward conditional reasoning of MP and DA commonly activate the left frontoparietal cortex, while significant dissociations can be seen in the regions of caudate and bilateral frontal, parietal and occipital. These results firstly demonstrates the different neural mechanism underlying the two forward conditional reasoning, which might help to further uncover the brain mechanism of conditional reasoning.
ABSTRACT
Objective To detect changes of regional grey matter and white matter volume in patients of neuromyelitis optica (NMO) by voxel-based morphometry (VBM),and investigate its relationship with clinical variables.Methods Conventional magnetic resonance imaging (MRI) and structural threedimensional MRI were obtained from 20 NMO and 20 sex-and age-matched healthy volunteers.The comparison of grey matter and white matter volume between the two groups was analyzed by VBM tools of statistical parametric mapping (SPM) 5.Pearson correlational analysis was used to assess correlations between regional volume decrease and disease duration and expanded disability status scale (EDSS) scores in NMO patients.Results Compared with normal controls,NMO patients had grey matter atrophy in several cortical regions,such as right inferior frontal gyrus (cluster size 514),left superior temporal gyrus (282),right middle temporal gyvus (229) and right insula (211) (t =3.58-5.11,AlphaSim corrected,P ＜0.05).White matter atrophy was found in several subcortical regions in NMO patients,such as right precentral and postcentral gyrus (cluster size 457,110),left middle frontal gyrus (285),and right inferior parietal lobule (231) (t =2.90-4.25,AlphaSim corrected,P ＜ 0.05).Grey matter and white matter volume loss were not significantly correlated with clinical duration or EDSS score in NMO.Conclusion By means of VBM,regional atrophy of grey matter and white matter is found in NMO patients,which may provide evidence for brain structural abnormality in NMO.
ABSTRACT
Objective To investigate the feature of regional grey matter volume changes in relapsing-remitting multiple sclerosis (RRMS) patients by voxel-based morphometry ( VBM) and presume the possible pathophysiological basis.Methods Conventional magnetic resonance imaging (MRI) and T1-weighted three-dimensional MRI were obtained from 32 RRMS and 32 sex- and age-matched normal controls.The comparison of grey matter volume between the two groups was analyzed by statistical analysis software SPM5 and VBM.A Pearson correlational analysis was used to assess correlation between gre matter loss and disease duration,expanded disability status scale (EDSS) and visible brain lesion volume.Results Compared with normal controls,RRMS patients had extensive bilateral grey matter atrophy in thalami (left 2031 and right 1711),caudate (left 815 and right 1031) and parahippocampal gyrus (left 313 and right 467),as well as several cortical regions in frontal,temporal,parietal,and occipital lobes (t value were between 8.853 and 11.163,all P ＜ 0.01).Regional grey matter loss in bilateral thalami ( r value were - 0.596 on left and were - 0.694 on right) and right caudate ( r = - 0.409 ) were strongly negatively correlated with visible brain lesion volume in RRMS (all P ＜ 0.05 ).Conclusions By means of VBM,extensive grey matter atrophy are found in RRMS patients,especially in deep grey matter.Axonal degeneration secondary to visible brain lesions may be a key pathogenesis of grey matter atrophy in RRMS.