Shyam Diwakar

Publications (22) View all

• Source

  Available from: Shyam Diwakar

  Article: Sakshat Labs: India's virtual proteomics initiative.

  Sandipan Ray, Nicole R Koshy, Shyam Diwakar, Bipin Nair, Sanjeeva Srivastava
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  ABSTRACT: The first Virtual Proteomics Lab of India has been developed at the IIT Bombay as a part of the "Sakshat" Lab Project, established to develop openly accessible, high-quality educational materials on science and technology.
  PLoS Biology 07/2012; 10(7):e1001353. · 11.45 Impact Factor
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  Available from: Shyam Diwakar

  Chapter: Biotechnology Virtual Labs: Facilitating Laboratory Access Anytime-Anywhere for Classroom Education

  Shyam Diwakar, Krishnashree Achuthan, Prema Nedungadi, Bipin Nair
  02/2012; , ISBN: 978-953-51-0096-6
• Article: Modeling spike-train processing in the cerebellum granular layer and changes in plasticity reveal single neuron effects in neural ensembles.

  Chaitanya Medini, Bipin Nair, Egidio D'Angelo, Giovanni Naldi, Shyam Diwakar
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  ABSTRACT: The cerebellum input stage has been known to perform combinatorial operations on input signals. In this paper, two types of mathematical models were used to reproduce the role of feed-forward inhibition and computation in the granular layer microcircuitry to investigate spike train processing. A simple spiking model and a biophysically-detailed model of the network were used to study signal recoding in the granular layer and to test observations like center-surround organization and time-window hypothesis in addition to effects of induced plasticity. Simulations suggest that simple neuron models may be used to abstract timing phenomenon in large networks, however detailed models were needed to reconstruct population coding via evoked local field potentials (LFP) and for simulating changes in synaptic plasticity. Our results also indicated that spatio-temporal code of the granular network is mainly controlled by the feed-forward inhibition from the Golgi cell synapses. Spike amplitude and total number of spikes were modulated by LTP and LTD. Reconstructing granular layer evoked-LFP suggests that granular layer propagates the nonlinearities of individual neurons. Simulations indicate that granular layer network operates a robust population code for a wide range of intervals, controlled by the Golgi cell inhibition and is regulated by the post-synaptic excitability.
  Computational Intelligence and Neuroscience 01/2012; 2012:359529.
• Article: A modeling based study on the origin and nature of evoked post-synaptic local field potentials in granular layer.

  Harilal Parasuram, Bipin Nair, Giovanni Naldi, Egidio D'Angelo, Shyam Diwakar
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  ABSTRACT: Understanding population activities of underlying neurons reveal emergent behavior as patterns of information flow in neural circuits. Evoked local field potentials (LFPs) arise from complex interactions of spatial distribution of current sources, time dynamics, and spatial distribution of dipoles apart underlying conductive properties of the extracellular medium. We reconstructed LFP to test and parameterize the molecular mechanisms of cellular function with network properties. The sensitivity of LFP to local excitatory and inhibitory connections was tested using two novel techniques. In the first, we used a single granule neuron as a model kernel for reconstructing population activity. The second technique consisted using a detailed network model. LTP and LTD regulating the spatiotemporal pattern of granular layer responses to mossy fiber inputs was studied. The effect of changes in synaptic release probability and modulation in intrinsic excitability of granule cell on LFP was studied. The study revealed cellular function and plasticity were represented in LFP wave revealing the activity of underlying neurons. Changes to single cell properties during LTP and LTD were reflected in the LFP wave suggesting the sparse recoding function of granule neurons as spatial pattern generators. Both modeling approaches generated LFP in vitro (Mapelli and D'Angelo, 2007) and in vivo (Roggeri et al., 2008) waveforms as reported in experiments and predict that the expression mechanisms revealed in vitro can explain the LFP changes associated with LTP and LTD in vivo.
  Journal of Physiology-Paris 08/2011; 105(1-3):71-82. · 1.31 Impact Factor
• Conference Proceeding: Taking Project Tiger to the Classroom: A Virtual Lab Case Study.

  Harilal Parasuram, Bipin Nair, Krishnashree Achuthan, Shyam Diwakar
  Advances in Computing and Communications - First International Conference, ACC 2011, Kochi, India, July 22-24, 2011. Proceedings; 01/2011