NRSC 2249 - Neuroanatomical correlates of memory stages

hippocampus: memory encoding

• scanned during encoding of word lists:

  • correct recall activated:

    • hippocampus

    • posterior parahippocampal cortex

    • frontal cortex

• hippocampal activity at encoding correlated with better recollection

hippocampus: memory retrieval

• subjects studied word lists before scan

• asked to differentiate between recall vs. familiarity

  • active for recall

  • not active for familiarity

perirhinal cortex: familiarity

• encoding similar to hippocampus

• also activated during recognition based on familiarity

pathways of memory: what

unimodal association areas (cortex) → anterior perirhinal cortex → hippocampal formation

paths of memory: where

multimodal association areas (cortex) → posterior perirhinal cortex → hippocampal formation

anterior hippocampus (MTL)

object recognition memory

posterior hippocampus (MTL)

spatial memory

amygdala (MTL)

emotional memories

diencephalon

Korsakoff’s syndrome

memory networks: anterior temporal (AT)

• hub in entorhinal/perirhinal

• emotion and memory regulation

• familiarity, recognition

memory networks: posterior medial (PM)

• hub in parahippocampal

• internally directed thought

• recollection (episodic)

  • memory for scenes, spatial layouts

hippocampus: spatial memory

• rodent study in radial arm maze

• intact hippocampus → preferential discrimination of arms with food

• hippocampal lesions → inefficient exploration, failure to remember and utilize spatial information

place cells (hippocampus)

• fundamental in constructing spatial cognitive maps

• activate in specific locations

grid cells (hippocampus)

• fundamental in constructing spatial cognitive maps

• fire at periodic locations within an environment that creates a grid-like pattern

hippocampus: human spatial memory

• spatial navigation tasks

  • posterior hippocampus larger in taxi drivers with experience

• specific to spatial tasks