limbic system 1 Flashcards
What is the papez circuit?
hippocampus → hypothalamus → thalamus → cortex → hippocampus
amygdla is not in circuit
Where does the septal nuclei lie?
Septal nuclei lie between septum pellucidum and fornix + anterior commissure
They are mostly anterior (rostral) to the columns of the fornix
What does the fornix split into and where?
How does the septal nuclei communicate with the fornix?
At the anterior commissure, fornix spilts into pre- & post- commissural fibers
Septal nuclei communicate with fornix via precommissural fibers
What are the septal recipricol connections?
cingulate gyrus, habenula, hypothalamus, hippocampus, and amygdala
Habenula and the hypothalamus communicates with the brainstem
Septal self-stimulation in experimental animals has demonstrated an effect that is preferred over any other behavior (including eating) until the animal dies.
How is the cingulate cortex organized?
motor- anterior
somatosensory- posterior
Cingulum is a 2-way association bundle; limbic circuit fibers go to hippocampus
What is the location of the mammillary bodies?
What fibers does the fornix carry and to where?
Mammillary bodies (nuclei) lie at the posterior end of the hypothalamus
The fornix carries hippoocampal efferents to the mammillary body
What is Koraskoff syndrome?
degeneration of the mammilarry bodies due to chronic alcoholism
this has been implicated in amnesia
mammillary bodies and thalamic nucleus in the same coronal plane
Mammillothalamic tract is vertical to this orientation
Where is the medial temporal lobe located?
Where is the amygdala located?
Where hippocampal formation located?
Medial temporal lobe-superficial to the parahippocampal gyrus and uncus
amygdala is deep to the uncus
hippocampal formation is deep to the parahippocampal gyrus
What is the anterior half of he parahippocampal gyrus called?
What is it function?
Anterior 1/2 of parahippocampal gyrus is entorhinal cortex (Brodmann area 28)
This cortex receives most cingular fibers and is the major input to hippocampus
Amygdala and dentate gyrus after parahippocampal gyrus is removed
What dominates the medial temporal lobe?
scroll like hippocampal formation
describe the scrolling of the hippocampal formation of the temporal lobe?
Embryonic scrolling of cortex occurs along medial temporal lobe
Cortex becomes folded and buried medial & superior to parahippocampal gyrus
The scrolled, buried cortex is the hippocampal formation
Where is the subiculum, hippocampus proper, dentate gyrus on the temporal hippocampal formation?
The hippocampal formation is “S” shaped
subiculum (bottom of S; transitional between entorhinal cortex and hippocampus)
hippocampus proper (top of the “S”; mostly adjacent to ventricle)
dentate gyrus ( “U” shaped, resting on subiculum; cupping end of “S”)
What doe sthe hippocampus border?
What is the dentate gyrus is indented by?
Hippocampus borders the temporal horn of the lateral ventricle
Dentate gyrus is indented by vessels
What are the layers of the hippocampal formation and how are the sectors subdivided?
The parts of the hippocampal formation are layered cortex
Layers transition through subiculum from 6 to 3
Hippocampus is subdivided into sectors CA1 - CA4 (CA4 is minor)
Dentate gyrus
What is CA1 extremely susceptible to?
hypoxia-ischemia
