Memory Storage Flashcards
What do patients with lesions have memory loss of?
Patients with medial-temporal lobe (MTL) lesions, most famously Henry Molaison (patient HM), show retrograde memory loss that is temporally graded, so that recent memory loss is greater than earlier memory loss.
What is their memory loss restricted to?
This temporal gradient is restricted to explicit memory, leaving implicit memory intact and stable over time (Scoville and Milner, 1957)
What do lesions in the hippocampal formation indicate?
extensive temporally-graded retrograde amnesia
What do patients with lesions indicate?
as time passes after learning, there is gradual reorganization within long-term memory storage whereby the importance of the hippocampal formation gradually diminishes and a more permanent memory system develops that is independent of this region.
Temporary storage of information is achieved by
rapidly established and short-lived modifications within the hippocampal system
witthin CA3
What would be the role of MTL in memory storage?
MTL forms a temporary memory trace needed for explicit memories until they are consolidated elsewhere in the brain, presumably in the neocortex
How would MTL store memory in neocortex?
The role of the medial temporal lobe is to store sufficient information to point to and activate the relevant sites in neocortex, rather than to store the entire memory representation itself. These changes allow the medial temporal lobe to bind together the multiple neocortical sites that store the representation of a whole event.
When does consolidation occur?
Consolidation occurs when the neocortical representations are repeatedly co-activated by the
medial temporal lobe
What happens during consolidation?
gradual and long-lasting changes occur in the connectivity within necortex. Eventually, these connections become strong enough that the medial temporal lobe is not needed to recreate the original representation
