Antwerp Neuroscience Seminar.
Promotion zaal (Aula UIA)
March 11, 2002
Schedule:
17.00 : A. Artola (Paris): Metaplaticity: to be or not to be plastic.
Activity-dependent synaptic plasticity is critical for learning and memory. Considerable attention has been paid to mechanisms that increase or decrease synaptic efficacy, referred to as long-term potentiation (LTP) and depression (LTD), respectively. There is a wide agreement that the direction and the degree of the synaptic change are a function of postsynaptic depolarization: LTD is obtained following low levels of postsynaptic depolarization whereas LTP is produced by a stronger depolarization. It is now becoming apparent that synaptic changes also depend on previous synaptic activity. This plasticity of synaptic plasticity, referred to as "metaplasticity", is due to variations in the level of postsynaptic depolarization required for inducing a change in synaptic strength. In potentiated synapses, the induction of LTD is facilitated whereas that of LTP is inhibited; and vice et versa in depressed synapses. These concomitant and opposite changes in the induction of LTD and LTP tend to keep synaptic transmission within a dynamic range. Similar changes have been observed in several pathological situations such as stress and diabetes mellitus. It is therefore possible that metaplasticity is involved in cognitive deficits that are associated with these disorders.