Coordinated behaviors are composed of sequential or parallel processes (cognitive, sensory, associative, etc.) that often lead to motor output.  The basal ganglia (BG), a collection of several deep brain nuclei, are thought to interact extensively with multiple motor structures (e.g. cortex and thalamus) during these processes.  Increasing evidence supports the notion that at least some of these nuclei, including the globus pallidus (J. Neurophysiol., 2001, 85:998-1004) may encode information about the behavioral settings and motivational conditions in which movements are generated.  However, little is known about how the BG are coordinated and assembled to support behavior or how changes in motor, cognitive, and emotive features arise that are hallmarks of BG diseases (i.e. Parkinson’s disease). 

To examine the role of basal ganglia neurons in sensorimotor processing we use single and multiple electrodes are used to record from neurons in the BG nuclei (i.e. putamen, globus pallidus external and internal segments, subthalamic nucleus) in monkeys performing a set of learned behaviors.  During these tasks, we quantify neural activity associated with eye and limb movements and behavioral variables (e.g. target instructions, reward delivery).  These experiments provide a unique opportunity to characterize behaviorally-associated neuronal discharge in multiple BG nuclei in a group of monkeys performing identical behaviors, yielding novel insight into neural interactions in the BG network.  The outcome of these studies has potential clinical relevance in the understanding of cognitive and motor deficits inherent to disease processes consequential to basal ganglia dysfunction such as Parkinson’s disease, Huntington’s Chorea, or Schizophrenia.

A second line of research established in 2005 will enable the parallel evaluation of patients diagnosed with Parkinson’s disease and age-matched control subjects during the performance of tasks executed by our non-human primate subjects.  These data will be used to address key questions about the ability of PD patients to incorporate multisensory cues to guide voluntary movements.

Sensorimotor Integration

Gdowski, M.J., Miller, L.E., Townsend, K.A., Bastianen, C.A., and Houk, J.C.  Comparison of Globus Pallidus Internal and External Segments During Visually and Memory Guided Forearm Movements. Society for Neuroscience Abstracts 400.2, 2005.

Gdowski, M.J., Miller, L.E., Nenonene, E., Parrish, T., Houk, J.C. 2001, Context-dependency in the Globus Pallidus Internal Segment During Targeted Arm Movements. J. Neurophysi. 85: 998-1004.

Gdowski, M.J., Nenonene, E.K., Miller, L.E., Houk, J.C. 2000, Diversity of Signaling Patterns in the External and Internal Segments of the Globus Pallidus. Soc. Neurosci. Abst., 26: 457.2.

Gdowski, M.J., Nenonene, E., Miller, L.E., Houk, J.C., 1999 Response Properties of Neurons in the Internal Segment of the Globus Pallidus. Soc. Neurosci. Abst., 25:765.13.

Neural and Pathological Consequences of Disease

Luciano, M.G., Skarupa, D.J., Booth, A.M., Wood, A.S., Brant, C.L., Gdowski, M.J. 2001, Cerebrovascular Adaptation in Chronic Hydrocephalus. J. Cereb. Blood Flow and Metab., 21(3):285-94.

Johnson, M.J., Ayzman, I., Wood, A.S., Tkach, J.A., Klauschie, J., Skarupa, D.J., McAllister, J.P., and Luciano, M.G. 1999, Development and Characterization of an adult model of obstructive hydrocephalus. J. Neurosci. Meth., 91(1-2):55-65.

Mangano, F.T., McAllister, J.P., II, Jones, H.C., Johnson, M.J., Kriebel, R.M. 1998, The microglial response to progressive hydrocephalus in a model of inherited aqueductal stenosis. Neurol. Res., 20(8):697-704.

Temporal Coordination of Neuronal Activity

Johnson, M.J. and Alloway, K.D 1996, Cross-correlation analysis reveals laminar differences in thalamocortical interactions in the somatosensory system.J. Neurophysi., 75: 1444-57.

Johnson, M.J.and Alloway, K.D. 1995, Evidence for synchronous activation of neurons located in different layers of primary somatosensory cortex. Somatosensory and Motor Research, 12: 235-47.