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Dr. Prasun Kumar Roy
Computational Neuroscience & Neuroimaging Lab, School of Biomed. Engg.
Area of Interest: 
Brain Research, Neuroscience, Neurotchnology, Medical Imaging (MRI, fMRI), Cognitive Processing

As a medical doctor, Professor Roy was trained in radiology at the Institute of Postgraduate Medical Education and Research, Calcutta University, and was an ICRF scholar at Royal Marsden Hospital, University of London. He has been a postdoctoral Research Scientist at University of Connecticut, Visiting faculty at University of California- Berkeley and Visiting Associate Professor at Medical College of Wisconsin. His research interests are diagnostic and therapeutic neuroimaging, computational systems biology, and cellular and molecular radiology. His teaching experience spans medical imaging and radiology, foundational neuroscience, biostatistics and research methodology.

Research Summary

Using the techniques of computational neurobiology and imaging, the aim of the laboratory is to study flow processes pertinent to the brain, such as that of information, energy, chemicals, drugs or cells, and use the approach for obtaining basic understanding and clinical applications, regarding the neurological system, both in health and disease.

Research Perspective:
What is the most characteristic feature of a system that can be observed most readily? Evidently, it is flow, the flux of change or motion, namely the dynamics of the system. It is the study of flows pertaining to the brain----whether that of information, energy, chemicals, drugs or cells----which is the unitary principle of the investigations carried out in our unit. Indeed, the electrical flux or the digital spike is the most fundamental currency in neural systems, and furnishes the primary insight of how the brain works, thinks and computes. The aim of the laboratory is to use the methodology of computational biology and neuroimaging to

  • Harness fresh understanding into how the brain processes information in health and disease
  • Evolve novel perspectives for developing multimodal diagnostic and therapeutic approaches to neurological and psychiatric disorders.

Across the brain, point-by-point, the flows can be characterized by biophysical or biochemical parameters, such as conductivity (for energy flow), diffusivity (for chemical flow), deformability (for tissue displacement) or permeability (for cellular flow). To decipher the aforesaid biological flow dynamics, we use a variety of imaging systems that are available at the National Neuroimaging Facility that has beenset up at NBRC. The systems include structural/functional MRI (Magnetic resonance imaging) including Flow spin tagging, EEG (Electro-encephalography), ERP (Evoked response potential map) or TMS (Transcranial magnetic stimulation) and psychometric analysis. Thereby we have developed several approaches to obtain incisive comprehension into various conditions as shown below.

  • Alzheimer's disease: Using elastoporosity analysis of tissue by MRI, the differential diagnosis of various behavioral stages of Alzheimer's disease and its predecessor Mild Cognitive Impairment, can be well distinguished, since redox potential and associated fibrillogenesis increasingly actuates the shear strain of the amyloid sheet.

  • Electrical Firing Source Localization in Epilepsy: Synchronization of MRI, fMRI, Conductivity tensor imaging (CTI) and EEG is used to map the electrical dipole source of epileptic firing focus deep inside brain, that can be targetted radiosurgically in intractable epilepsy, while temporal lobe activation can be shown by fMRI mapping when the individual is subjected to rapid breathing or hyperventilation.

  • Cognitive processing by bimodal information transmission: Using fMRI analysis of verbal production, the bimodal form of information transmission can be mapped, which can be characterized by word association output during speaking (namely syntagmatic and paradigmatic responses), corresponding to syntactic and semantic processing, respectively.

From a therapeutic neuroimaging aspect, we investigate the possibility of modulating cellular flow and its dynamics during different disorders. From MRI diffusion tensor imaging, we have delineated cell permeation tensor, that enables one to map the tracts of cell flow across the brain, in two conditions:

  • Malignant Glioma cell invasion in brain tumours, whose map we use to optimize perturbative radiotherapy and targetted chemotherapy, so as to eliminate residual tumour cells

  • Neural Progenitor cell migration from adult subventricular zone to stroke penumbra, this enables the accurate quantification and scheduling of erythropoetin drug administration to optimize therapeutic neurogenesis, by modulating a nuclear factor (NFkB) pathway.

The major long-term brain disorders in India, in order of incidence, are Epilepsy, Stroke, Dementia and Movement disorders

Needless to say, the newer methodology of computational systems biology and molecular radiology now furnishes unmatched potentiality to carry out both fundamental and applied research, especially since many delicate biophysical and biochemical processes can be well tracked in the awake behaving brain of anyone.