Space and Memory A two-way street

Example #2: memory in synapses

Memory-related processes involve spatial sensory/motor pathways

Example #1 Memory in activity Example #2 Memory in synapses Example #3 Parietal cortex Example #4 Hippocampus

Example #2 Memory in synapses Information can also be stored via changes in

synaptic efficacy Often occurs in (spatial) sensory/motor

pathways

Model system: Vestibulo-ocular reflex

Counter-rotation of the eyes when the head turns Serves to keep visual image stable on retina Must be calibrated

Head

Eye No change in retinal image

Head

Eye No change in retinal image

These turns must be matched!

Gain of VOR

Gain = Eye turn Head turn

E.g. desired gain = 1 if: -- Looking at something far away (head and eye rotate about different axes) -- Not wearing glasses!

Glasses change size of visual scene

VOR gain must be adjusted when you get new glasses

Changes occur within pathway that senses the head turn and moves the eye

Notably: Vestibular nuclei Cerebellum

Cerebellum Vestibular nuclei (inside brainstem)

VOR gain must be adjusted when you get new glasses

Changes occur within pathway that senses the head turn and moves the eye

Notably: Vestibular nuclei Cerebellum

Synapses Changes in the gain of the VOR are thought to be accomplished by changes in the strength of synapses

and are implemented in vestibular-oculomotor pathway

Next Up:

A two-way street Example #3: space and memory in parietal cortex