Articles written in Journal of Biosciences
Volume 40 Issue 2 June 2015 pp 355-364 Articles
Empathy deficit is a core feature of schizophrenia which may lead to social dysfunction. The present study was carried out to investigate functional and structural abnormalities associated with empathy in patients with schizophrenia using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). A sample of 14 schizophrenia patients and 14 healthy control subjects matched for age, sex and education were examined with structural high-resolution T1-weighted MRI; fMRI images were obtained during empathy task in the same session. The analysis was carried out using SPM8 software. On behavioural assessment, schizophrenic patients (83.00±29.04) showed less scores for sadness compared to healthy controls (128.70±22.26) (𝑝 < 0.001). fMRI results also showed reduced clusters of activation in the bilateral fusiform gyrus, left lingual gyrus, left middle and inferior occipital gyrus in schizophrenic subjects as compared to controls during empathy task. In the same brain areas, VBM results also showed reduced grey and white matter volumes. The present study provides an evidence for an association between structural alterations and disturbed functional brain activation during empathy task in persons affected with schizophrenia. These findings suggest a biological basis for social cognition deficits in schizophrenics.
Volume 40 Issue 5 December 2015 pp 909-919 Articles
It is not clearly known as to why some people identify camouflaged objects with ease compared with others. The literature suggests that Field-Independent individuals detect camouflaged object better than their Field-Dependent counterparts, without having evidence at the neural activation level. A paradigm was designed to obtain neural correlates of camouflage detection, with real-life photographs, using functional magnetic resonance imaging. Twenty-three healthy human subjects were stratified as Field-Independent (Fl) and Field-Dependent (FD), with Witkins Embedded Figure Test. FIs performed better than FDs (marginal significance; 𝑝=0.054) during camouflage detection task. fMRI revealed differential activation pattern between Fl and FD subjects for this task. One sample T-test showed greater activation in terms of cluster size in FDs, whereas FIs showed additional areas for the same task. On direct comparison of the two groups, Fl subjects showed additional activation in parts of primary visual cortex, thalamus, cerebellum, inferior and middle frontal gyrus. Conversely, FDs showed greater activation in inferior frontal gyms, precentral gyms, putamen, caudate nucleus and superior parietal lobule as compared to FIs. The results give preliminary evidence to the differential neural activation underlying the variances in cognitive styles of the two groups.
Volume 41 Issue 3 September 2016 pp 419-426
Neuropsychological studies have reported that attention, memory, language, motor and emotion processing areimpaired in schizophrenia. It is known that schizophrenia involves structural alterations in the white matter of brainthat contribute to the pathophysiology of the disorder. Uncinate fasciculus (UNC), a bundle of white matter fibres,plays an important role in the pathology of this disorder and involved in cognitive functions such as memory, languageand emotion processing. Therefore, the present study aimed to investigate microstructural changes in UNC fibre inschizophrenia patients relative to controls and its correlation with neuropsychological scores.Diffusion tensor imaging (DTI) and Hindi version of Penn Computerised Neuropsychological Battery test wasperformed in 14 schizophrenia patients and 14 controls. DTI measures [fractional anisotropy (FA) and meandiffusivity (MD)] from UNC fibre were calculated and a comparison was made between patients and controls.Pearson’s correlation was performed between neuropsychological scores and DTI measures.Schizophrenia patientsshowed significantly reduced FA values in UNC fibre compared to controls. In schizophrenia patients, a positivecorrelation of attention, spatial memory, sensorimotor dexterity and emotion with FA was observed. These findingssuggest that microstructural changes in UNC fibre may contribute to underlying dysfunction in the cognitive functionsassociated with schizophrenia.
Volume 43 Issue 5 December 2018 pp 877-886 Article
Worries preoccupy the working memory capacity in anxious individuals, thereby affecting their performance during tasksthat require efficient attention regulation. According to the attentional control theory (ACT), trait anxiety affects theprocessing efficiency, i.e. the effort required for task performance, more than the accuracy of task performance. Weinvestigated the relation between trait anxiety and neural response for a reasoning task in healthy subjects. Functionalmagnetic resonance imaging (fMRI) was carried out on 22 healthy participants and blood oxygenation level dependent(BOLD) contrast estimates were extracted from a priori regions of interest (ROIs) that were earlier implicated in reasoning(i.e., bilaterally caudate head, globus pallidus, thalamus, prefrontal cortex [rostral, dorsal and ventral regions], inferiorparietal lobule and middle occipital gyrus). Controlling for the effects of age, gender, state anxiety and depressivesymptoms, for equivalent levels of task performance, trait anxiety of the participants was found to be associated with anincrease in task related BOLD activation in right globus pallidus, left thalamus and left middle occipital gyrus. Our resultssuggest a reduced processing efficiency for reasoning in high trait anxiety subjects and provides important brain–behaviourrelationships with respect to sub-clinical anxiety.