Abstract
Almost all theoretical and experimental studies of the mechanisms
underlying learning and memory focus on synaptic efficacy and make the
implicit assumption that changes in synaptic efficacy are both
necessary and sufficient to account for learning and memory. However,
network dynamics depends on the complex interaction between intrinsic
membrane properties and synaptic strengths and time courses.
Furthermore, neuronal activity itself modifies not only synaptic
efficacy but also the intrinsic membrane properties of neurons. This
paper presents examples demonstrating that neurons with complex
temporal dynamics can provide short-term “memory” mechanisms that
rely solely on intrinsic neuronal properties. Additionally, we discuss
the potential role that activity may play in long-term modification of
intrinsic neuronal properties. While not replacing synaptic plasticity
as a powerful learning mechanism, these examples suggest that memory in
networks results from an ongoing interplay between changes in synaptic
efficacy and intrinsic membrane properties.