Limbic System Flashcards
Limbic System includes
hippocampal formation, amygdala, septal nuclei, cingulate cortex, entorhinal cortex, perirhinal cortex, parahippocampal cortex
Hippocampal Formation is located in the
temporal lobe
Hippocampal components:
Subiculum, Hippocampus proper, Dentate gyrus
WHat 2 hippocampal structures form an interlocking C
Hippocampal proper and dentate gyrus
Paleocortex and the hippocampus
Old cortex, 3-layered structure
Inside out Hippocampus meaning
the cortical layers begin with an inner molecular layer and outer polymorphic layer
The middle layer varies between dentate and hippocampus
Hippocampus - pyramidal, dentate gyrus - granule
CA3
area of hippocampus that is capped by the dentate gyrus
Alveus
the polymorphic layer of the hippocampus (white matter of neocortex) that forms the fornix
Subiculum
transitional layer between hippocampus and parahippocampal gyrus (6-layer)
Functions of the hippocampus
Short-term memory loss and inability to learn new tasks or facts
Anterograde memory loss
after lesion to hippocampus, short-term memories cannot be retained
Korsakoff’s Syndrome
Alcoholism and thiamine deficiency cause mammillary body destruction, patients cannot form new memories
Fornix
major pathway of exit/entrance to the hippocampus
Fimbria of fornix
travel posteriorly as a tight bundle of fibers of the alveus
Crura of the Hippocampus
extension of the fimbria that extends superiorly to the hippocampal commissure
Hippocampal commissure
provides 1 of 2 major pathways for hippocampi communication
Body of the Fornix
single fiber bundle from the hippocampal commissure to the anterior commissure
As the fornix reaches the anterior commissure, the fornix spits into 3:
Precommissural fornix, Decussation at the anterior commissure, and the Postcommissural fornix
Precommissural fornix fibers project to
Septal nuclei, ventral striatum, and cingulate cortex
Fibers decussating in the anterior commissure
provides the other major pathway for hippocampi communication between contralateral hippocampus
Postcommissural fornix fibers project to
Mammillary bodies and anterior nucleus of thalamus
Amygdala Location
mediodorsal portion of temporal lobe (deep to uncut, anterior to hippocampus)
Amygdala function
integrative center for emotions, emotional behavior, and motivation