Unformatted text preview: cortex (ERC).! Properties of Amnesia Due to Medial Temporal Lobe Damage!
Squire, Stark, & Clark (2004) Annual Review of Neuroscience!
8) Impairment is multimodal.
Memory impairment is selective; affects only long-term declarative memory.
Other cognitive functioning appears intact, including perception, intelligence, and
The impairment appears to involve the encoding & storage of information but not
the retrieval of information.
However, memories do not appear to be stored directly within the MTL, but rather
that it is involved in the reactivation of cortical processes.
The temporal gradient of retrograde amnesia can be attributed to a consolidation
The hippocampus is the ultimate recipient of convergent projections from adjacent
cortical structures, meaning that the MTL may play a special role in relating or
combining various forms of information.
There is mixed evidence regarding functional dissociations within the MTL
system. 1) Memory damage is multimodal. Doesn't matter whether it is visual or auditory, all of these things are affected
4) if the damage is restricted to MTL as in H.M. we can no longer form any new memories, but can still remember prior to surgery. Thus retrieval is not
5) Storage somewhere in the cortex, not in MTL
6) There is some sort of consolidation period. Things right before surgery was also forgotten.
7) MTL plays a special role in integrating all sorts of elements
8) Next Slide Functional Dissociations within the Medial Temporal Lobe! Libby, Ekstrom, Ragland, & Ranganath (2012)
Journal of Neuroscience!
- Animal tracer studies and fMRI functional connectivity studies (i.e., how well the BOLD signal from
different regions are synchronized with each other) reveal that the perirhinal cortex (PRC) and the
parahippocampal cortex (PHC) subserve different regions of the hippocampus.!
- Some researchers attribute these anatomical dissociations to functional dissociations (e.g., recollection
31:00 Shows that the anterior portion of hippocampus in MTL seems to be functional connected with anterior regions of the cortex, where the posterior region
- These of the MTL have a different connectivity pattern. They appear to be more the neocortex (or association cortex. How
of the hippocampusstudies also demonstrate the extensive connections with connected with posterior regions of the cortex).! are they
functional dissociated from each other, and has been related to recollection & familiarity (recollection is vivid memory of remembering someone). These are
thought to be linked in MTL, but could also be a link between episodic and semantic memory. PFC damage doesn't lead to amnesia, but does cause memory
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- Fall '11
- temporal lobe, medial temporal lobe, memory impairment, different underlying brain