Articles written in Journal of Biosciences
Volume 27 Issue 1 February 2002 pp 35-52
Schizophrenia is a severe neuropsychiatric disorder with a polygenic mode of inheritance which is also governed by non-genetic factors. Candidate genes identified on the basis of biochemical and pharmacological evidence are being tested for linkage and association studies. Neurotransmitters, especially dopamine and serotonin have been widely implicated in its etiology. Genome scan of all human chromosomes with closely spaced polymorphic markers is being used for linkage studies. The completion and availability of the first draft of Human Genome Sequence has provided a treasure-trove that can be utilized to gain insight into the so far inaccessible regions of the human genome. Significant technological advances for identification of single nucleotide polymorphisms (SNPs) and use of microarrays have further strengthened research methodologies for genetic analysis of complex traits. In this review, we summarize the evolution of schizophrenia genetics from the past to the present, current trends and future direction of research.
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 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.