Herbert P. Killackey

Associate Execute Vice Chancellor, Anatomy & Neurobiology
School of Medicine

Professor, Neurobiology and Behavior
School of Biological Sciences

PH.D., Duke University, 1969

Phone: (949) 824-7371
Fax: (949) 824-2438
Email: hkillack@uci.edu

University of California, Irvine
2205 BS II
509 Administration
Mail Code: 4550
Irvine, CA 92697

Developmental neuroanatomy
URL www.ucihs.uci.edu/anatomy/killackey.html
The cerebral neocortex is the brain structure that has undergone the greatest expansion in the course of mammalian evolution. It is also the neuronal organ most intimately associated with functions that are uniquely human. The long-term goal of my laboratory's research program is to contribute to the understanding of the morphological organization and development of this structure at the level of the light microscope. It is at this level of analysis that the enormous complexity of the neocortex is most readily apparent. The goals of this research program are approached by two slightly different but interrelated avenues of research on morphological patterns of neuronal connectivity. The focus of
both avenues is the somatosensory cortex, the region in which tactile information from the body surface is processed.

Our first line of research is aimed at determining the factors that play a role in establishing orderly maps of the peripheral receptor surface within the somatosensory cortex. Our experiments suggest that the formation of such maps involves two different sets of interactions between groups of neurons. The first factors are intrinsic interactions between groups of neurons at different levels of the neuroaxis. These interactions play a role in the formation of broad topographic relations. The second factors are extrinsic in that they are ultimately derived from the periphery and can be passed along by the neural axis to the somatosensory cortex. Extrinsic factors refine topographic organization into a detailed somatotopic map.

Our second line of research is aimed at the cortical projection neuron. These neurons interconnect a given cortical area with both other cortical areas and other parts of the central nervous system. During the course of development, classes of these neurons undergo major changes in their distribution pattern. For example, early in development, one major class of cortical projection neurons sends one neuronal process to the other hemisphere and a second to a region within the same hemisphere. In the adult, a given neuron projects to only one of these targets. Ongoing experiments are aimed at elucidating the "rules" by which this "choice" of ultimate targets is reached.
Publications Lane RD, Stojic RS, Killackey HP, Rhoades RW. Source of inappropriate receptive fields in cortical somatotopic maps from rats that sustained neonatal forelimb removal. Journal of Neurophysiology 1999 Feb;81(2):625-33.
  Stojic AS, Lane RD, Killackey HP, Qadri BA, Rhoades RW.
Thalamocortical and intracortical projections to the forelimb-stump SI representation of rats that sustained neonatal forelimb removal. Journal of Comparative Neurology 1998 Nov 16;401(2):187-204.
  Rhoades RW, Strang V, Bennett-Clarke CA, Killackey HP, Chiaia NL. Sensitive period for lesion-induced reorganization of intracortical projections within the vibrissae representation rats primary somatosensory cortex. Journal of Comparative Neurology 1997 Dec 8;389(1):185-92.
  Lane RD, Killackey HP, Rhoades RW. Blockade of GABAergic inhibition reveals reordered cortical somatotopic maps in rats that sustained neonatal forelimb removal. J Neurophysiology 1997 May;77(5):2723-35.
  Catalano, S.M., Robertson, R.T., and Killackey, H.P. Individual axonal morphology and thalamocortical topography in developing rat somatosensory cortex. Journal of Comparative Neurology 1996;367, 36-53
  Catalano, S.M., Robertson, R.T., and Killackey, H.P.Rapid alteration of thalamocortical axon morphology follows peripheral damage in the neonatal rat. Proceedings of the National Academy of Sciences U.S.A. 1995;92, 2549-2552.
  Killackey, H.P., Rhoades, R.W. and
Bennett-Clarke, C.A. The formation of a cortical somatotopic map. Trends In Neuroscience 1995;18, 402-407
  Killackey, H.P. (1994) Evolution of the human brain: A neuroanatomical perspective. In: The Cognitive Neurosciences. M. Gazzaniga (ed.) MIT press, 1243-1253.
Link to this profile http://www.faculty.uci.edu/profile.cfm?faculty_id=2559
Last updated 03/15/2002