Seminar Computational Intelligence F (708.116)
Institut f�r Grundlagen der Informationsverarbeitung
Assoc. Prof. Dr. Robert Legenstein
Office hours: by appointment (via e-mail)
Location: IGI-seminar room,
Inffeldgasse 16b/I, 8010 Graz
on March 15th 2012, every Thursday, 16.15 -
Content of the seminar:In this seminar, we will discuss
new results on synaptic plasticity. Most theoretical models of
synaptic plasticity focus on point neuron models. However,
cortical pyramidal neurons have quite stereotypical dendritic
branches with nonlinear effects such as dendritic spikes of
various types. Also, synaptic input from different sources target
different dendritic locations, and synaptic plasticity rules
depend on the dendritic location of the synapse. Collectively,
these findings suggests that pyramidal neurons (in particular:
cortical Layer 5 pyramidal neurons) are specialized plastic
processors that integrate information and adapt to information
from different sources in a specific way.
We will furthermore look at new results about modulation of
plasticity by dopamine and inhibition, as well as clustered
||about: "Conditional modulation of
spike-timing-dependent plasticity for olfactory learning"
||about: "Observation on
clustered synaptic plasticity and highly structured input
||about: "A clustered
plasticity model of long-term memory engrams"
||about: "Learning with two
sites of synaptic integration"
about: "A new cellular mechanism for coupling inputs
arriving at different cortical layers"
mechanisms controlling spike-timing-dependent synaptic
about: "Synaptic integration in tuft dendrites of layer 5
pyramidal neurons: A new unifying principle"
||about: "Micro-rewiring as a substrate for learning"
||about: "Supervised and unsupervised learning with two
sites of synaptic integration"
||about: "Active dentrites: adaptation to spike-based
inhibitory circuits and the control of fear memory"
||about: "Dopamine gates LTP induction in lateral
amygdala by suppressing feedforward inhibition"
Papers on plasticity in Layer 5 Pyramids (L5Ps):
||Kampa BM, Letzkus JJ, and Stuart GJ.
Dendritic mechanisms controlling spike-timing-dependent
synaptic plasticity. Trends in Neurosciences,
||This is a very readable
paper. It builds on
Talks on these papers should be preceded
||Letzkus JJ, Kampa BM, and Stuart GJ.
Learning rules for spike timing-dependent plasticity depend
on dendritic synapse location. J Neurosci. 2006 Oct
||This paper provides
||Larkum ME, Zhu JJ, and Sakmann B. A
new cellular mechanism for coupling inputs arriving at
different cortical layers. Nature, 398:338-341,
||which describes the BAC
firing mechanism, and
||Larkum ME, Nevian T, Sandler M,
Polsky A, and Schiller J. Synaptic integration in tuft
dendrites of layer 5 pyramidal neurons: A new unifying
principle. Science, 325:756-760, 2009.
||Here, the authors describe
an inspiring hypothesis about computation in L5Ps.
The following papers may have modeled some of the
consequences of these mechanisms (needs to be checked):
Modulation of plasticity by dopamine and inhibition:
||Xu TX and Yao WD. D1 and D2 dopamine
receptors in separate circuits cooperate to drive
associative long-term potentiation in the prefrontal
cortex. Proc Natl Acad Sci U S A. 2010 Sep
||This paper suggests that
DA affects syn. plasticity in L5Ps in PFC by reducing the
impact of inhibitory neurons, that otherwise prevent
||Bissi�re S, Humeau Y, and L�thi A.
Dopamine gates LTP induction in lateral amygdala by
suppressing feedforward inhibition. Nat Neurosci. 2003
||This paper tells us a
similar story for Amygdala.
||Ehrlich I, Humeau Y, Grenier F,
Ciocchi S, Herry C, and L�thi A. Amygdala inhibitory
circuits and the control of fear memory. Neuron. 2009 Jun
||A review paper on this
||Cassenaer S and Laurent G.
Conditional modulation of spike-timing-dependent plasticity
for olfactory learning. Nature, 25 January
Papers on clustered plasticity:
||Magee JC. Observations on clustered
synaptic plasticity and highly structured input
Neuron. 2011 Dec
||The paper provides a nice
recent review of "clustered plasticity". It is quite short,
so it should be complemented by more detailed papers such
||DeBello WM. Micro-rewiring as a
substrate for learning, TINS 2008.
||Govindarajan A, Kelleher RJ, and
Tonegawa S. A clustered plasticity model of long-term
memory engrams. Nature Reviews Neuroscience, 7:575-583,
Theoretical model for dendritic computation: