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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
| Factors influencing the strength of
synapses |
| Julian Jack, University
Laboratory of Physiology, Oxford, UK |
| The strength of synapses may be adjusted by a
variety of factors, of which the mechanisms of short-term and long-term plasticity,
including homeostatic mechanisms, are obvious examples. An additional factor that has been
implicated for some nerve cells is dendritic location, so that synapses further from the
firing zone may be locally more powerful. It is likely that there may be other factors as
well. In order to explore this issue further, two approaches will be presented. The first
is to consider, from theoretical modelling, what constraints may operate in terms of
efficiency : it is well known that voltage feedback on the current flowing through a
conductance may limit the magnitude of the resulting effect. Similar considerations apply
to the consequent ion concentration changes in both the synaptic cleft and the local
intracellular compartment. The second approach is empirical and relies on quantal analysis
of individual inputs. Comparisons of both the variation in synaptic strength within a
functionally homogeneous input and the distribution of synaptic strengths of different
functional inputs to the same cell will be presented. |
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