George F. Martin, Ph.D.
Distinguished University Professor Emeritus
young.591@osu.edu
614-292-1667
614-292-7659
Appointments:
Distinguished University Professer, Department of Biomedical Informatics-Division
of Anatomy
Education:
Ph.D.: University of Alabama
Research Area:
Comparative Neurology,Developmental Neurobiology
and Developmental Plasticity of the Spinal Cord
Current Research:
The spinal cord of adult mammals, including that of man, does not regenerate
after injury and axons fail to grow across the lesion site. The results include
paralysis and loss of sensation below the site of injury. It seems reasonable
to suggest, however, that the ability to regenerate might be present during
development when the spinal cord is immature and axons are programmed for
growth. We have asked whether the mammalian spinal cord is capable of regeneration
during early development, whether descending and ascending axons grow through
the lesion and, if so, whether the critical period for such growth is the
same for all of them. We are also interested in the functional outcome(s)
of developmental plasticity. For example, do adult animals subjected to spinal
cord transection during the critical period for developmental plasticity have
normal use of the hindlimbs in locomotion and/or normal sensation caudal to
the lesion. In other words, do axons which grow across the lesion site support
normal function? We employ the North American opossum, Didelphis virginiana,
for such studies because it is born in a fetal-like state, 12 days after conception,
and is available in the mother's pouch where it can be manipulated experimentally
without intrauterine surgery. In addition, the developmental history of major
spinal axons is known in the opossum. A long term goal of our studies is to
identify the mechanism which support regeneration of the injured spinal cord
during development and those which inhibit it with increasing maturation.
Techniques Available:
We use a number of techniques to study developmental plasticity and recovery
of function. These include surgical and injection methods, the use of retrograde
and orthograde tracing methods to identify axons experimentally, immunohistochemistry
alone and in combination with axonal tracing methods, histological methods
for identifying nerve cells and their processes, light and darkfield microscopy,
fluorescence microscopy, computer based plotting and quantitation of labeled
neurons and axons, computerized three-dimensional reconstruction of microscopic
images, and behavioral analysis (in conjunction with Drs. Basso and Bresnahan).
Representative Publications:
Martin GF, Ghooray GT, Wang XM, Xu XM, Zou XC: (1995) Models of spinal
cord regeneration. pp 175-201, vol. 103 in F.J. Seil, Ed., Progress in
Brain Research, Elsevier, Amsterdam.
Wang XM, Terman JR, Martin GF: (1996) Evidence for growth of supraspinal axons through the lesion after transection of the thoracic spinal cord with the developing opossum, Didelphis virginiana. J Comp Neurol, 371:104-115.
Terman JR, Wang XM, Martin GF: (1996) Growth of dorsal spinocerebellar axons through a lesion of their spinal pathway during early development in the North American opossum, Didelphis virginiana. Dev Brain Res, 93:33-48.
Wang XM, Qin YQ, Terman JR, Martin GF: (1997) Development and developmental plasticity of the fasciculus gracilis in the North American opossum (Didelphis virginiana). Dev Brain Res, 98:151-163.
Wang XM, Basso DM, Terman JR, Bresnahan JC, Martin GF: (1998) Adult opossums (Didelphis virginiana) demonstrate near normal locomotion after spinal cord transection as ????. Exp. Neurobio., 151:50-69.
Terman JR, Wang XM, Martin GF: (1999) Developmental plasticity of ascending spinal axons. Dev Brain Res, 112:65-77