Intrinsic cortical circuitry—the pattern of synaptic connections between morphologically distinct neurons within a local cortical region—is essentially unknown, although its structure is crucial for understanding of how neuronal functional modules such as cortical columns are formed, and it ultimately determines what specific cortical processing is performed by the underlying region. My current research interests are focused on two related issues: (i) deciphering the local cortical circuitry from the spatial structure of axonal and dendritic arbors of pre- and post-synaptic cell-pairs and their distribution across cortical layers, and (ii) understanding how these local circuits give rise to functional modules, and how they shape the underlying cortical dynamics.
We investigate these problems using analytical and computational approaches, particularly, very large-scale cortical network simulations on massively parallel supercomputers.
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Christopoulos VN, Boeff DV, Evans CD, Crowe DA, Amirikian B, Georgopoulos A, Georgopoulos AP. A network analysis of developing brain cultures. J Neural Eng. 2012 Aug;9(4):046008.
Georgopoulos AP, Merchant H, Naselaris T, Amirikian B. Mapping of the preferred direction in the motor cortex. Proc Natl Acad Sci U S A. 2007 Jun 26;104(26):11068-72.
Naselaris T, Merchant H, Amirikian B, Georgopoulos AP. Large-scale organization of preferred directions in the motor cortex. I. Motor cortical hyperacuity for forward reaching. J Neurophysiol. 2006 Dec;96(6):3231-6.
Naselaris T, Merchant H, Amirikian B, Georgopoulos AP. Large-scale organization of preferred directions in the motor cortex. II. Analysis of local distributions. J Neurophysiol. 2006 Dec;96(6):3237-47.
Amirikian B. A phenomenological theory of spatially structured local synaptic connectivity. PLoS Comput Biol. 2005 Jun;1(1):e11.
Lewis SM, Jerde TA, Tzagarakis C, Gourtzelidis P, Georgopoulos MA, Tsekos N, Amirikian B, Kim SG, Ugurbil K, Georgopoulos AP. Logarithmic transformation for high-field BOLD fMRI data. Exp Brain Res. 2005 Sep;165(4):447-53.
Naselaris T, Merchant H, Amirikian B, Georgopoulos AP. Spatial reconstruction of trajectories of an array of recording microelectrodes. J Neurophysiol. 2005 Apr;93(4):2318-30.
Amirikian B, Georgopoulos AP (2003) Motor cortex: Coding and decoding of directional operations. In: The Handbook of Brain Theory and Neural Networks, ed. M Arbib, 2nd edition, MA, MIT Press Cambridge, pp. 690–696.
Amirikian B, Georgopoulos AP (2003) Modular organization of directionally tuned cells in the motor cortex: Is there a short-range order? Proc. Natl. Acad. Sci. USA, 100:12474–12479.