|
| |
WORKSHOP ON:
CENTRAL PROBLEMS IN SINGLE CELL COMPUTATION
16-18 September 2002
By invitation only
Venue
B10 Seminar Room, Alexandra House, 17 Queen Square, London, WC1N 3AR
| Dendritic spikes control the induction
of LTP at distal CA1 synapses |
| Nelson Spruston, Northwestern
University, USA |
| CA1 dendrites are capable of at least three
distinct forms of excitability: backpropagating action potentials, dendritically initiated
Na spikes, and dendritically initiated Ca spikes. Backpropagating action potentials have
been shown to provide an important link between axonal action potential firing and the
induction of LTP at Schaffer collateral synapses. However, because backpropagating action
potentials are small by time they reach the distal dendrites, we proposed that LTP
induction at synapses furthest from the soma (e.g. the direct input from entorhinal cortex
to CA1) may require generation of local dendritic spikes. In support of this idea, we
found that LTP of distal synapses was not dependent on backpropagating action potentials.
Furthermore, we found that the amount of LTP induced by synaptic stimulation in a
theta-burst pattern was strongly correlated with dendritic spiking during the induction
stimulus. We were also able to induce LTP that was not dependent on backpropagating action
potentials by stimulating more proximal synapses (Schaffer collateral inputs from CA3)
strongly enough to trigger dendritic spikes. These findings suggest that dendritic spikes
are an important signal for the induction of LTP, which can occur independently of action
potential firing in the axon. |
| For more information on our work please see
paper by Golding, Staff and Spruston published in Nature Vol 418,
18 July 2002. Click here to download. |
|
