The long-term goals of the research in our laboratory are to elucidate the neural mechanisms underlying cognitive processes in motor behavior and to understand the intrinsic mechanisms of the cerebral cortex. We pursue experimental psychological studies, neurophysiological recordings, functional magnetic resonance imaging (MRI) at high field (4 Tesla), and neural network modeling (using supercomputers) to achieve these goals.
We carry out psychological studies in both human subjects and rhesus monkeys. The tasks are cognitive-motor in nature and employ paradigms of mental rotation, memory scanning, and visuomotor control of isometric force trajectories generated by the arm. Functional MRI in human subjects distinguishes the patterns of activation of brain areas during performance of these tasks. Electrophysiological recordings of the activity of single cells in motor and other areas of the cerebral cortex are then conducted in behaving monkeys in order to elucidate the brain mechanisms involved in these tasks. This experimental arrangement provides for a direct study of the relations between neuronal populations and behavior. We model the activity in these neuronal populations using a massively interconnected neural network to produce dynamically evolving trajectories under external guidance and from memory. Finally, we use information theory as a metrics-free analytical tool.
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Sakellaridi S, Christova P, Christopoulos V, Leuthold AC, Peponis J, Georgopoulos AP. Neural mechanisms underlying the exploration of small city maps using magnetoencephalography. Exp Brain Res. 2015 Aug 8.
Sakellaridi S, Christova P, Christopoulos VN, Vialard A, Peponis J, Georgopoulos AP. Cognitive mechanisms underlying instructed choice exploration of small city maps. Front Neurosci. 2015 Mar 20;9:60.
Scott NM, Sera MD, Georgopoulos AP. An information theory analysis of spatial decisions in cognitive development. Front Neurosci. 2015 Feb 4;9:14.
Georgopoulos AP, Carpenter AF. Coding of movements in the motor cortex. Curr Opin Neurobiol. 2015 Jan 31;33C:34-39.
James LM, Belitskaya-Lévy I, Lu Y, Wang H, Engdahl BE, Leuthold AC, Georgopoulos AP. Development and application of a diagnostic algorithm for posttraumatic stress disorder. Psychiatry Res. 2015 Jan 30;231(1):1-7.
Merchant H, Crowe DA, Fortes AF, Georgopoulos AP. Motor directional tuning across brain areas: directional resonance and the role of inhibition for directional accuracy. Front Neurosci. 2014 Aug 11;8:245.
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. The Minnesota Women Healthy Aging Project. Minn Med. 2012 Jan;95(1):49-51.
Tan H-RM, Leuthold AC, Lee DN, Lynch JK, Georgopoulos AP. Neural mechanisms of movement speed and tau as revealed by magnetoencephalography. Exp Brain Res. 2009 Jun;195(4):541-52.
Jerde TA, Lewis SM, Goerke U, Gourtzelidis P, Tzagarakis C, Lynch J, Moeller S, Van de Moortele PF, Adriany G, Trangle J, Ugurbil K, Georgopoulos AP. Ultra-high field parallel imaging of the superior parietal lobule during mental maze solving. Exp Brain Res. 2008 Jun;187
Georgopoulos AP, Karageorgiou E, Leuthold AC, Lewis SM, Lynch JK, Alonso AA, Aslam Z, Carpenter AF, Georgopoulos A, Hemmy LS, Koutlas IG, Langheim FJ, McCarten JR, McPherson SE, Pardo JV, Pardo PJ, Parry GJ, Rottunda SJ, Segal BM, Sponheim SR, Stanwyck JJ, Stephane M, Westermeyer JJ. Synchronous neural interactions assessed by magnetoencephalography: a functional biomarker for brain disorders. J Neural Eng. 2007 Dec;4(4):349-355.
Georgopoulos AP, Karageorgiou E. Neurostatistics: Applications, challenges and expectations. Stat Med. 2007 Nov 29.
Georgopoulos AP, Stefanis CN. Local shaping of function in the motor cortex: motor contrast, directional tuning. Brain Res Rev. 2007 Oct;55(2):383-9.
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.
Wilson TW, Leuthold AC, Moran JE, Pardo PJ, Lewis SM, Georgopoulos AP. Reading in a deep orthography: neuromagnetic evidence for dual-mechanisms. Exp Brain Res. 2007 Jun;180(2):247-62.
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.
Pardo PJ, Georgopoulos AP, Kenny JT, Stuve TA, Findling RL, Schulz SC. Classification of adolescent psychotic disorders using linear discriminant analysis. Schizophr Res. 2006 Oct;87(1-3):297-306.
Langheim FJ, Leuthold AC, Georgopoulos AP. Synchronous dynamic brain networks revealed by magnetoencephalography. Proc Natl Acad Sci U S A. 2006 Jan 10;103(2):455-9.
Merchant H, Georgopoulos AP. Neurophysiology of perceptual and motor aspects of interception. J Neurophysiol. 2006 Jan;95(1):1-13.
Langheim FJ, Merkle AN, Leuthold AC, Lewis SM, Georgopoulos AP. Dipole analysis of magnetoencephalographic data during continuous shape copying. Exp Brain Res. 2006 Apr;170(4):513-21.
Former Graduate Students:
Bruno Averbeck (Ph.D. 2001, Neuroscience, University of Minnesota).
David Crowe (Ph.D. 2001, Neuroscience, University of Minnesota).
Antonio Fortes (Ph.D. 2005, Neuroscience, University of Minnesota).
Trenton Jerde (Ph.D. 2004, Neuroscience, University of Minnesota).
Fred Langheim (Ph.D. 2004, Neuroscience, University of Minnesota).
Thomas Naselaris (Ph.D. 2005, Neuroscience, University of Minnesota).
Nicholas Port (Ph.D. 1997, Neuroscience, University of Minnesota).