Limbic System

Olfactory Bulbs location

Piriform Cortex Location

Amygdala Function and Impacts of Deteriorating

• FEAR and rage

• maybe memory, has reciprocal connections w hippocampus

• deteriorates in fronto-temporo dementia

Amygdala Location

Hippocampus Location

Hint from class?

Gray banana = hippocampus

Hippocampal proper

The C-shaped structure of the hippocampus

Significance of Henry Molaison

H.M. was having constant grand-mal seizures (epileptic activity). Removal of his bilateral hippocampus reduced his seizures but also gave him memory issues.

What do H.M.’s brain scans show

A loss of volume in the temporal lobe, where the hippocampus is found

Memory Issues and that H.M. had

anterograde amnesia: Did not remember facts or episodes (memories) that happened after his surgery, cannot form new memories

temporally-graded retrograde amnesia: had trouble remembering things right before his accident, memory was better further back in time

Does the hippocampus impact procedural learning?

No! H.M. had no deficits in procedural learning. The hippocampus does not impact motor learning, but does impact knowledge.

I get better at playing pacman but cannot remember what pacman is

The hippocampus does NOT store

long term memories

Where can we find mamillary bodies

posterior to optic chiasm

The limbic system (flowchart)

What structure is this

septal nuclei

What structure is this

fornix

Limbic system, alternative visualization

Septal nuclei are responsible for

Emotion (pleasure, reward)

example: Removing them made rats scream and aggressive. Stimulating this area w lever presses is always chosen over food reward.

Function of mamillary bodies

For new long-term memories

Deteriorate in long-term alcoholics.

Korsakoff’s psychosis/syndrome

caused by thiamine deficiency, developed in chronic alcoholism

= deteriorated mamillary bodies and anterograde amnesia

Patient video had man with strong math skills but poor memory of hospital, length of his stay, anything he was asked to remember

Piriform cortex is made up of:

1. Entorhinal cortex = landmark of hippocampus

2. Uncus = landmark of amygdala

amygdala and hippocampus are above these structures

Parts of the Limbic System