Professor of Biology
Dr. Berkowitz's Web Page
Current Research Interests and Subject Areas Available for Graduate Research
How does an animal’s nervous system select and generate an appropriate behavior for each circumstance the animal faces? My research addresses this general question through neurophysiological, neuroanatomical, and pharmacological experiments on an especially suitable model system: the turtle spinal cord. The turtle spinal cord can produce three distinct types of rhythmic scratching movements of a hindlimb, each targeted to a different region of the body, as well as two types of rhythmic swimming movements of the hindlimbs, and limb withdrawal (flexion reflex). The programs for generating these movements and for choosing among them reside in the spinal cord: the animal can produce these movements appropriately even when all input from the brain is cut off. This means we can focus attention on a relatively small subset of the central nervous system and study the electrical activity, morphology, and pharmacology of individual spinal cord neurons, to reveal the kinds of neural circuitry that allow the spinal cord to select and generate appropriate movements. We have found in recent years that the spinal cord selects and generates these distinct movements using a combination of multifunctional and specialized spinal cord interneurons.
My lab’s research currently focuses on the following questions:
1) What mechanisms do multifunctional interneurons use to contribute to multiple kinds of limb movements? In particular, what neurotransmitter(s) is used by transverse interneurons (Berkowitz et al. 2006), are they excitatory or inhibitory, and do they synapse directly on motor neurons?
2) What mechanisms do scratch-specialized interneurons (Berkowitz 2002, 2008) use to affect scratching but not swimming?
3) What mechanisms do flexion reflex-selective interneurons (Berkowitz 2007) use to affect flexion reflex (limb withdrawal), but not swimming or scratching?
4) How are the specialized interneurons inhibited during competing behaviors?
To learn more about this research, visit Dr. Berkowitz's Web Page.
Ph.D., Washington University, St. Louis
A.B., University of Chicago
Director, Cellular & Behavioral Neurobiology Graduate Program, University of Oklahoma
Mui, J.W., Willis, K.L., Hao, Z.-Z., and Berkowitz, A. (2012) Distributions of active spinal cord neurons during swimming and scratching motor patterns. J. Comp. Physiol. A 198: 877-889.
Hao, Z.-Z., Spardy, L.E., Nguyen, E., Rubin, J.E., and Berkowitz, A. (2011) Strong interactions between spinal cord networks for locomotion and scratching. J. Neurophysiol. 106:1766-1781.
Berkowitz, A. and Hao, Z.-Z. (2011) Partly shared spinal cord networks for locomotion and scratching. Integrative and Comparative Biology 51: 890-902; doi: 10.1093/icb/icr041.
Berkowitz, A., Roberts, A., and Soffe, S. R. (2010) Roles for multifunctional and specialized spinal interneurons during motor pattern generation in tadpoles, zebrafish larvae, and turtles. Frontiers in Behavioral Neuroscience 4: 36 (doi: 10.3389/frbeh.2010.00036).
Berkowitz, A. (2010) Shared and specialized spinal interneurons for turtle limb movements. Annals of the NY Academy of Sciences 1198: 119-132.
Berkowitz, A. (2008) Physiology and morphology of shared and specialized spinal interneurons for locomotion and scratching. J. Neurophysiol. 99:2887-2901.
Berkowitz, A. (2007) Spinal interneurons that are selectively activated during fictive flexion reflex. J. Neurosci. 27:4634-4641.
Berkowitz, A., Yosten, G.L.C., and Ballard, R.M. (2006) Somato-dendritic morphology predicts physiology for neurons that contribute to several kinds of limb movements. J. Neurophysiol. 95:2821-2831.
Berkowitz, A. (2005) Physiology and morphology indicate that individual spinal interneurons contribute to diverse limb movements. J. Neurophysiol. 94:4455-4470.
Berkowitz, A. (2002) Both shared and specialized spinal circuitry for scratching and swimming in turtles. J. Comp. Physiol. A 188:225-234.