Saturday, September 25, 2010

The Reverberating Theory of the Memory Trace

Not a lot of histories of the theory of the memory trace floating around. Today, I loaded up the microfilm for Gomulicki' s "The Development and Present Status of the Trace Theory of Memory", which seemed like a well-received history on the subject, as far as things on this kind of topic are 'received' at all. It'll be nice when someone finally renders this in pdf. At any rate...

One topic that was well-represented was the reverberating theory of the memory trace, according to which you hold on to a memory so long as its effect keeps cycling in you somewhere, somehow, physiologically. From Aristotle to Nicolas Rashevksy:

Aristotle offered the first physiological theory of the memory trace, where "sensory impressions were transmitted from the sense-organs to the heart by movements in the pneuma--movements that persisted, though on a decreased scale, after the external stimuli had ceased. The persistence of the movements of the pneuma was held to constitute the physical basis of memory, forgetting being due to the gradual subsidence of the movements..." (p. 2) Then, some time later...

Rafael Lorento de Nó's "most important discovery as far as memory theory is concerned is the existence, in addition to the long-known open neural circuits (nerve 'pathways' and 'arcs'), of closed chains of several neurons, within which an impulse once set up can continue to circulate almost indefinitely without assistance from new afferent impulses." (p. 33)

From Nó's findings, Nicolas Rashevsky developed the theory of reverberating circuits, wherein the memory trace would persist so long as the activity trapped in one of Nó's closed loops persisted. The consensus among the historians I've seen discuss the reverberating theory is that no one was ever able to gather any evidence for it. Of course, at present, synaptic theories dominate. But it was an interesting idea and it seems to fit with reverberating models of active maintenance.