Abstract
In many regions of the cerebral cortex, Ca2+ influx through NMDA (N-methyl-D-aspartate) sensitive glutamate receptors (NMDA receptors) can trigger two forms of synaptic plasticity: long-term depression (LTD) and long-term potentiation (LTP). LTD is induced by low levels of postsynaptic NMDA-receptor activation, for instance in response to low-frequency stimulation, whereas LTP is induced by the stronger activation that occurs following high-frequency stimulation. Theoretical studies have shown that the properties of synaptic LTD and LTP can account for many aspects of experience-dependent plasticity in the developing visual cortex, provided that the LTD-LTP crossover point (the modification threshold, θ(m)) varies as a function of the history of cortical activity. Here we provide direct experimental evidence that the value of θ(m) depends on sensory experience. We find in visual cortex of light-deprived rats that LTP is enhanced and LTD diminished over a range of stimulation frequencies, and that these effects can be reversed by as little as two days of light exposure. Our findings support the idea that a variable synaptic-modification threshold allows synaptic weights in neural networks to achieve a stable equilibrium.
Original language | English (US) |
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Pages (from-to) | 526-528 |
Number of pages | 3 |
Journal | Nature |
Volume | 381 |
Issue number | 6582 |
DOIs | |
State | Published - 1996 |
Externally published | Yes |
ASJC Scopus subject areas
- General