Archive for the ‘Cellular learning’ Category
Trk signaling as a backprop mechanism?
Thursday, June 24th, 2004From this week’s Nature, the Poo lab shows how BDNF-induced plasticity in the optic tectum can lead to “back-propogated” changes in AMPA receptor density one synapse back in retinal ganglion cells. Click below for the full abstract
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Two new Hebbian rules in vitro
Tuesday, February 10th, 2004Mu-Ming Poo’s lab (which in 1998 found a very impressive result in hippocampal culture where excitatory synapses are potentiated when a Hebb-like protocol is used on the pre- and post-synaptic cell) has recently added two new Hebbian rules also found in hippocampal cell culture.
The first one applies to inhibitory hippocampal synapses (Neuron, Aug 2003) and the second one applies to spike trains in the mossy fiber pathway (Neuron, Feb 2004). The relative spike timing between the pre and post cells results in different amounts of potentiation/depression depending on the synapse type.
Some questions: Are there many different STDP rules? Or, are we missing the bigger picture (ie. a more general rule) of which these are all only specific examples? (Remember, this is just in hippocampus!)