Professor Cliff Abraham
Director,
Brain Health and Repair Research Centre
 Contact
Details
Tel 64 3 479 7648
Email cabraham@psy.otago.ac.nz
Cellular and Molecular Mechanisms of Synaptic Plasticity
One of the most likely mechanisms underlying memory storage
in the brain is long-lasting plasticity in the strength of
synaptic transmission between connected neurons. This plasticity
involves both long-term potentiation (LTP) and long-term depression
(LTD) of synaptic efficacy. In my research programme, funded
by the New Zealand Health Research and Marsden Councils,
the cellular and molecular mechanisms of LTP and LTD are studied
in the hippocampus, a brain structure important for certain
kinds of learning and memory.
Our studies on the molecular mechanisms of such synaptic
plasticity (done in collaboration with Professor Warren Tate,
Biochemistry and Dr Joanna Williams, Anatomy and
Structural Biology) have focused on the role that “immediate
early genes” (IEGs) play in the maintenance of LTP and
LTD across time. Related experiments have aimed at identifying
the changes in synaptic proteins, including glutamate receptors,
that accompany LTP and LTD. The regulation of LTP and LTD
persistence by environmental stimulation is also under investigation,
in collaboration with Associate Professor David Bilkey.
The mechanisms for establishing LTP and LTD including understanding
the conditions under which they can be elicited is another
major research interest. We are interested in how the
induction processes are controlled by intracellular calcium
levels, stress hormones, aging, disease-related amyloid proteins
and neurotransmitters mediating arousal and attention. A major
focus interest is the mechanisms by which the prior history
of neural activity controls the subsequent induction of synaptic
plasticity, a novel set of phenomena we have termed “metaplasticity”.
Williams, J.M., Guevremont, D., Mason-Parker, S.E., Luxmanan,
C.,
Tate, W.P., Abraham, W.C. (2007). Differential trafficking
of AMPA and
NMDA receptors during LTP in awake adult animals. Journal
of
Neuroscience, 27, 14171-14178.
Abraham, W.C. (2008). Metaplasticity tuning synapses and
networks
for plasticity. Nature Reviews Neuroscience, 9, 387-399.
Taylor, C.J., Ireland, D.R., Ballagh, I., Bourne, K., Marechal,
N.M.,
Turner, P.R., Bilkey, D.K., Tate, W.P., Abraham, W.C. (2008).
Endogenous secreted amyloid precursor protein- regulates hippocampal
NMDA receptor function, long-term potentiation and spatial
memory.
Neurobiology of Disease, 31, 250-260.
Abraham, W.C., Robins, A. (2005). Memory retention –
the synaptic stability versus plasticity dilemma. Trends
in Neurosciences, 28, 73-78.
Abraham, W. C. (2003). How long will long-term potentiation
last? Philosophical Transactions of the Royal Society
of London B, 358, 735-744.
Abraham, W. C., Logan, B., Greenwood, J. M., & Dragunow,
M. (2002). Induction and experience-dependent consolidation
of stable long-term potentiation lasting months in the hippocampus.
The Journal of Neuroscience, 22(21), 9626-9634.
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