Stephen J. Goldberg, Ph.D.
Retired January, 2007
Office Phone: 561-732-5281
- B.A., Biology, Antioch College (1965)
- Ph.D., Biology, Clark University (1971)
- Postdoctoral training University of California at Los Angeles in neurophysiology
RESEARCH AND SCHOLARLY INTERESTS
We investigated, and still publish on, the neurophysiological and mechanical properties of brain stem motor units involved in two separate motor control systems: (1) tongue and (2) eye movements. One component of a motor unit, the motoneuron, was studied through intracellular and extracellular recording and stimulation. We examined motoneuron conduction velocity, physical size and shape as well as synaptic inputs. Input resistance and rheobase were occasionally examined. The other component of a motor unit, the muscle fibers innervated by a single motoneuron, was studied using a force transducer. We measured muscle mechanics in response to intracellular and extracellular stimulation of the motoneuron. Muscle twitch contraction, tetany, fusion frequency and fatigue were delineated. We wanted to know what correlations exist between motoneuron physiological and muscle fiber contractile measures. Also, we compared the motor unit types seen in the brain stem to those found in the spinal cord by other investigators. Additionally, morphological studies were done in both the eye movement and tongue motor systems. We were interested in discerning the basic mechanisms of brain stem controlled movement and thereby contributing to our understanding of neuromuscular disorders.
A critical finding for the development of tongue movement is that reduced movement (caused by “artificial rearing” (postnatal)) has anatomical and physiological consequences later in life.
A critical finding for the eye movement system is that the eyes can move accurately and quickly with far fewer motoneurons than are present in normal mammals. This provides a measure of protection against injury and disease.
- Goldberg, S. J., Meredith, M. A. and Shall, M. S. Extraocular motor unit and whole-muscle responses in the lateral rectus muscle of the squirrel monkey. Journal of Neuroscience. 18:10629-10639, 1998.
- Goldberg, S. J. and Shall, M. S. Motor units of extraocular muscles: recent findings. Progress in Brain Research. 123:221-232, 1999.
- Sutlive, T. G., Shall, M. S., McClung, J. R. and Goldberg, S. J. Contractile properties of the tongue's genioglossus muscle and motor units in the rat. Muscle Nerve. 23:416-425, 2000.
- McClung, J.R., Allman, B.L., Dimitrova, D.M. and Goldberg, S.J. Extraocular connective tissues: a role in human eye movements? Invest. Ophthalmol. Vis. Sci. 47:202-205, 2006.
- Smith, J.C., Moore, W.A., Goldberg, S.J. and Shall, M.S. Contractile properties and myosin heavy chain composition of rat tongue retrusor musculature show changes in early adulthood after 19 days of artificial rearing. J. Appl. Physiol. 101:1053-1059, 2006.