Anatomy of the hippocampus

Location of the hippocampus

The medial temporal lobe of the brain.

What is the hippocampus? VIDEO

• Small sea-horse structure

Formation of Hippocampus

• hippocampus proper

• dentate gyrus

• subiculum

• entorhinal cortex
  

Hippocampus proper

• CA1

• CA2

• CA3

• Cornu Ammonis (Ammon’s horn)

Hippocampus—-Cortical structure watch video

• allacortext or achicortext

• 3 layers

Entorhinal cortex

• perforant path

• integrated cortical information

• no unimodal information

• only polymodal information

Hippocampus Proper—Major Output

subiculum —> back to EC

Subcortical —> Emotional strucutre

Hippocampal circuitry

Intrinsic circuitry

• Trisynaptic loop

• entorhinal cortex to dentate gyrus

• dentate gyrus to CA3

• CA3 - CA1

• Trisynaptic loop

• Responsible for generating hippocampal theta waves

• Trisynaptic loop section 1

• From EC to Section 1, the Dentate Gyrus (GD)

  • Pp—perforant path—nerve fiber bundle that connects the entorhinal cortex to the hippocampus

Trisynaptic loop section 2

• From Section 1 to Section 2

  • mf—mossy fiber—axon that carries info about movement, sensory input, and cortical plans for action in the brain and spinal cord

  • Section 2—the name of CA3

    • Carbonic anhydrase 3.

Trisynaptic loop section 3

• From Section 2 to Section 3

  • sc=schaffer collaterals —a group of nerve fibers that connect CA3 and CA1 regions of the hippocampus

  • To the EC

Importance of episodic memory

LEC—-lateral enthornila —process details of an individuals object, sensory aspect of a scene—what

MED—medial entorhinal—spatial information, overall location of __—-where

ALL integrated in the hippocampus