Visual, acoustic, and olfactory stimuli associated with a highly
charged emotional situation take on the affective qualities
of that situation. Where the emotional meaning of a given sensory
experience is stored is a matter of debate.
Tiziana Sacco and Benedetto Sacchetti have found that e
xcitotoxic lesions of auditory, visual, or olfactory secondary sensory cortices impaired remote, but not recent, fear memories in rats. Amnesia was modality-specific and not due to an interference with sensory or emotional processes. In these sites, memory
persistence was dependent on ongoing protein kinase M
activity
and was associated with an increased activity of layers II–IV,
thus suggesting a synaptic strengthening of corticocortical
connections. Lesions of the same areas left intact the memory
of sensory stimuli not associated with any emotional charge.
Tiziana Sacco and Benedetto Sacchetti propose that secondary sensory cortices support memory storage
and retrieval of sensory stimuli that have acquired a behavioral
salience with the experience.
