Comparative Studies of Brain Development
Acomys cahirinus (the "spiny mouse")
Acomys (a mouse indigenous to the Sinai
desert) is in the same
evolutionary group as the lab rat or mouse (Muridae). The more common
animals are born in a very immature state (they are "altricial", see
pup at left above) while Acomys is born with its
ears and eyes open
and easily moves about within hours of birth. It is rare when two
related animals have such divergent developments. In a series of
(listed below) we compared patterns of brain growth between these
Since every evolutionary change occurs as a result of a modification in
development, the work addressed both issues.
- Brunjes, P. C. Olfactory bulb maturation in Acomys
cahirinus: Is neural growth similar in precocial and altricial murids?
Developmental Brain Research 8, 335-341, 1983.
- Brunjes, P. C. Hippocampal maturation in the precocial
murid rodent Acomys cahirinus. Brain, Behavior and Evolution 24, 58-74,
- Brunjes, P. C. A stereological study of neocortical
maturation in the precocial mouse Acomys cahirinus.
Developmental Brain Research 19, 279-287, 1985.
- Brunjes. P. C. Plasticity and precocity: Odor deprivation
and brain development in the precocial mouse Acomys cahirinus. Neuroscience
24, 579-582, 1988.
- Tessitore, C. T., & Brunjes, P. C. A comparative
study of myelination in precocial and altricial murid rodents. Developmental
Brain Research 43, 139-147, 1988.
- Brunjes, P. C. A comparative study of prenatal development
in the olfactory bulb, neocortex and hippocampal region of the
precocial mouse Acomys cahirinus and the rat. Developmental
Brain Research 49, 7-25, 1989.
- Brunjes, P. C., Korol, D. L., and Stern, K. G. Prenatal
neurogenesis in the telencephalon of the precocial mouse Acomys
cahirinus. Neuroscience Letters 107, 114-119,
- Brunjes, P. C. The precocial mouse Acomys cahirinus. Psychobiology
18, 339-350, 1990.
Monodelphis domestica (gray,
Monodelphis (a Brazilian opossum), like most marsupials, gives
birth after a
very short gestation (13 days) to very immature pups (the neural tube
the telencephalic regions about 24 hours before birth). Unlike other
Monodelphis has no pouch: pups simply find a nipple on the mother's
firmly attach-- litters hang like grapes off of the the mother. As a
they allow easy examination of very early stages of brain development.
advantage of these features in the studies listed below.
- Brunjes, P. C., Jazaeri, A. and Sutherland, M. J. Olfactory
bulb organization and development in Monodelphis domestica (the grey,
short-tailed opossum). Journal of Comparative Neurology 320, 544-554,
- Philpot, B. D., Jazaeri, A. A., and Brunjes, P. C. The
development of serotonergic projections to the olfactory bulb of
Monodelphis domestica (the grey, short-tailed opossum). Developmental
Brain Research, 77, 265-270, 1994.
- Cummings, D., and Brunjes, P. C. Migrating luteinizing
hormone-releasing hormone (LHRH) neurons and processes co-localize with
a glial substrate that expresses S100. Developmental Brain Research 88,
- Philpot, B. D., Klintsova, A. Y., and Brunjes, P. C.
Oligodendrocyte/myelin immunoreactivity in the developing olfactory
system. Neuroscience 67 1009-1019, 1995.
- Malun, D., and Brunjes, P. The development of olfactory
glomeruli: temporal and spatial interactions between olfactory receptor
axons and mitral cells in opossums and rats. Journal of Comparative
Neurology 368 1-16, 1996.
- Cummings, D., Malun, D., and Brunjes, P. The development of
the anterior commissure in the grey, short-tailed opossum Monodelphis
domestica: Midline extracellular space and glia coincide with early
axon decussation. Journal of Neurobiology 32, 403-414, 1997.
- Cummings, D. M., Knab, B. R., and Brunjes, P. C. The
effects of unilateral olfactory deprivation on the developing opossum,
Monodelphis domestica. Journal of. Neurobiology 33, 429-438, 1997.
- Couper-Leo, J., and Brunjes, P. C. Developmental analysis
of the peripheral olfactory organ of the opossum Monodelphis domestica.
Developmental Brain Research 114, 43-48, 1999.
Fish are the most abundant and diverse of the vertebrates. In
two sets of
studies we examined several aspects of the development of their
systems, including the ability of their olfactory nerves to regenerate
being cut and the early expression of the genes used to code olfactory
- Stewart, J. S., and Brunjes, P. C. Olfactory bulb and
sensory epithelium in goldfish: morphological alterations accompanying
growth. Developmental Brain Research 54, 187-194, 1990.
- Stewart, J. S., and Brunjes, P. C. Spatial organization and
plasticity of the primary and secondary olfactory projections in
goldfish. Brain Research 628, 243-253, 1993.
- Byrd, C. A., and Brunjes, P. C. Organization of the
olfactory system in adult zebrafish: histological, immunohistochemical
and quantitative analyses. Journal of Comparative Neurology. 358
- Byrd, C. A,, Jones, J. T.., Quattro, J. M., Rogers, M. E.,
Brunjes, P. C., and Vogt, R. G. Ontogeny of odorant receptor gene
expression in zebrafish, Danio rerio. Journal of Neurobiology 29
- Byrd, C.A., Brunjes,P.C. Addition of new cells to the
olfactory bulb of adult zebrafish Ann. NY Acad. Sci. 855:274-276 , 1998.
- Poling, K. R., and Brunjes, P. C., Sensory deafferentation
and olfactory bulb morphology in the zebrafish and related species.
Brain Research, 21, 135-141, 2000.