How does an animal's nervous system select and generate
behavior for each circumstance the animal faces? Our research addresses
this general question through neurophysiological and
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. The programs for generating
these movements and for "choosing" among them reside in the spinal
cord: the animal can produce these movements
when all input from the brain is removed. This means that we can
focus attention on a relatively small subset of the central nervous
system and study the electrical activity and the morphology of
individual spinal cord neurons that are involved in selecting and
generating each type of movement. We can then reveal the kinds of
neural circuitry that allow the spinal cord to select and generate
Feel free to contact me if you are interested in doing research in my lab as a graduate student or postdoctoral fellow:
Johnson, K. P., Tran, S. M., Siegrist, E. A., Paidimarri, K. B., Elson, M. S., Berkowitz, A. (2017) Turtle flexion reflex motor patterns show windup, mediated partly by L-type calcium channels. Frontiers in Neural Circuits 11: 83, doi: 10.3389/fncir.2017.00083.
Hao, Z.-Z. and Berkowitz, A. (2017) Shared components of rhythm generation for locomotion and scratching exist prior to motoneurons. Frontiers in Neural Circuits, 11: 54, doi: 10.3389/fncir.2017.00054 (recommended by F1000)
Elson, M. S. and Berkowitz, A. (2016) Flexion reflex can interrupt and reset the swimming rhythm. J. Neurosci. 36: 2819 –2826.
Hao, Z.-Z., Meier, M. L., and Berkowitz, A. (2014) Rostral spinal cord segments are sufficient to generate a rhythm for both locomotion and scratching, but affect their hip extensor phases differently. J. Neurophysiol. 112: 147-155.
Holmes, J. R. and Berkowitz, A. (2014) Dendritic orientation and branching distinguish a class of multifunctional turtle spinal interneurons. Frontiers in Neural Circuits doi: 10.3389/fncir.2014.00136.
Berkowitz, A. (2013) Control of locomotion and scratching in turtles. In: Encyclopedia of Computational Neurosciences, SpringerReference.com, Article ID: 348107; Chapter ID: 42.
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/icbicr041).
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.
Berkowitz, A. (2010) Shared and specialized spinal interneurons for turtle limb movements. Annals of the NY Academy of Sciences 1198: 119-132.
Berkowitz, A. (2009) Population Coding. In: Larry R. Squire, Ed., Encyclopedia of Neuroscience, Academic Press, Oxford, pp. 757-764.
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.
Berkowitz, A. (2005) Physiology and morphology indicate that individual spinal interneurons contribute to diverse limb movements. J. Neurophysiol. 94:4455-4470.
Berkowitz, A. (2004) Propriospinal projections to the ventral horn of the rostral and caudal hindlimb enlargement in turtles. Brain Res. 1014:164-176.
Berkowitz, A. (2002a) Both shared and specialized neural circuitry for scratching and swimming in turtles. J. Comp. Physiol. A 188:225-234.
Berkowitz, A. (2002b) Endogenous biotin staining in a subset of spinal neuronal cell bodies: a potential confounding factor for neuroanatomical studies. Brain Res. 938:98-102.
Berkowitz, A. (2001a) Broadly tuned spinal neurons for each form of fictive scratching in spinal turtles. J. Neurophysiol. 86:1017-1025.
Berkowitz, A. (2001b) Rhythmicity of spinal neurons activated during each form of fictive scratching in spinal turtles. J. Neurophysiol. 86:1026-1036.
Berkowitz, A. and Stein, P.S.G. (1994a) Activity of descending propriospinal axons in the turtle hindlimb enlargement during two forms of fictive scratching: Broad tuning to regions of the body surface. J. Neurosci. 14:5089-5104.
Berkowitz, A. and Stein, P.S.G. (1994b) Activity of descending propriospinal axons in the turtle hindlimb enlargement during two forms of fictive scratching: Phase analyses. J. Neurosci. 14:5105-5119.
Berkowitz, A. and Stein, P.S.G. (1994c) Descending propriospinal axons in the hindlimb enlargement of the red-eared turtle: Cells of origin and funicular courses. J. Comp. Neurol. 346:321-336.
Berkowitz, A. and Laurent, G. (1996a) Local control of leg movements and motor patterns during grooming in locusts. J. Neurosci. 16:8067-8078.
Berkowitz, A. and Laurent, G. (1996b) Central generation of grooming motor patterns and interlimb coordination in locusts. J. Neurosci. 16:8079-8091.
Berkowitz, A. (1996a) Our genes, ourselves? BioScience 46:42-51.
Berkowitz, A. (1996b) Networks of neurons, networks of genes. Neuron 17:199-202.
Vu, E.T., Berkowitz, A., and Krasne, F.B. (1997) Postexcitatory inhibition of the crayfish lateral giant neuron: a mechanism for sensory temporal filtering. J. Neurosci. 17:8867-8879.
Berkowitz, A., Vu, E.T., and Krasne, F.B. (1998) Specificity of
neural circuits that inhibit escape in crayfish. Ann. NY Acad. Sci.
Current research in the Berkowitz laboratory is supported by a grant from the National Science Foundation and an award from the Oklahoma Center for the Advancement of Science and Technology.