Ionic mechanisms of neuronal excitability

Information in the nervous system is transmitted by electrical signals (action potentials) within neurons and by chemical signals between neurons. The research interests of this lab are in studying the biophysical properties of voltage- and ligand-gated ion channels intrinsic to neurons, as well as in understanding the physiological consequences of the different patterns of activity characteristic of specific neurons.

We are currently studying neurons of the cerebellum, a brain region that participates in controlling movements. Projects in the lab focus on the ionic mechanisms of high-frequency firing in Purkinje neurons, the transmission of synaptic signals from Purkinje to cerebellar nuclear cells, and the response of cerebellar nuclear cells to different patterns of synaptic input. These types of studies will be useful for the development of accurate computer models of neuronal activity, as well as for cellular-level interpretations of systems-level studies of cerebellar function.

e-mail Dr. Raman
ph: 847.467.7912
fax: 847.491.5211

Selected References:

• Grieco, T.M., Malhotra, J.D., Chen, C., Isom, L.L., and Raman, I.M. (2005). Open-channel block by the cytoplasmic tail of sodium channel beta 4 as a mechanism for resurgent sodium current. Neuron. 45: 233-244.

• Khaliq, Z.M. and Raman, I.M. (2005). Axonal propagation of simple and complex spikes in cerebellar Purkinje neurons. Journal of Neuroscience. 25(2): 454-63.

• Pugh, J.R. and Raman, I.M. (2005). GABAA receptor kinetics in the cerebellar nuclei: Evidence for detection of transmitter from distant release sites. Biophysical Journal. 88 (3): 1740-54.

• Telgkamp, P., Padgett, D.E., Ledoux, V.A., Woolley, C.S., Raman, I.M. (2004). Maintenance of high-frequency transmission at Purkinje to cerebellar nuclear synapses by spillover from boutons with multiple release sites. Neuron. 41(1): 113-26.

• Grieco, T.M., Raman, I.M. (2004). Production of resurgent current in NaV1.6-null Purkinje neurons by slowing sodium channel inactivation with beta-pompilidotoxin. Journal of Neuroscience. 24(1): 35-42.

• Khaliq, Z.M., Gouwens, N.W., Raman, I.M. (2003). The contribution of resurgent sodium current to high-frequency firing in Purkinje neurons: an experimental and modeling study. Journal of Neuroscience. 23(12): 4899-912.

• Telgkamp, P., Raman, I.M. (2002). Depression of inhibitory synaptic transmission between Purkinje cells and neurons of the cerebellar nuclei. Journal of Neuroscience. 22(19): 8447-57.

Other Links:

• link to more detailed research description

• Northwestern University Institute for Neuroscience