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mesial_temporal_lobe

Mesial temporal lobe

The mesial temporal lobe is, as the name suggests, located on the medial aspect of the temporal lobe and is distinct from the rest of the lobe which is comprised of neocortex.

The term encompasses five structures:

Amygdala

Hippocampus

Uncus

Dentate gyrus

Parahippocampal gyrus. The medial temporal lobe includes a system of anatomically related structures that are essential for declarative memory.

The system consists of the hippocampal region and the adjacent perirhinal, entorhinal cortex, and parahippocampal cortices.

This system (a) is principally concerned with memory, (b) operates with neocortex to establish and maintain long-term memory, and c ultimately, through a process of consolidation, becomes independent of long-term memory, though questions remain about the role of perirhinal and parahippocampal cortices in this process and about spatial memory in rodents. Data from neurophysiology, neuroimaging, and neuroanatomy point to a division of labor within the medial temporal lobe. However, the available data do not support simple dichotomies between the functions of the hippocampus and the adjacent medial temporal cortex, such as associative versus nonassociative memory, episodic versus semantic memory, and recollection versus familiarity 1).


The intraventricular elements are the hippocampus, fimbria, amygdala, and choroidal fissure; the extraventricular elements are the uncus and parahippocampal gyrus and dentate gyrus.

Not only is the knowledge of these relations useful to angiographically characterize the mesial temporal region, but it has also proven to be of extreme value during microsurgeries involving this region as applied to amygdalohippocampectomy 2).


Statistical analysis demonstrated that the left medial temporal lobe and right anterior temporal lobe were specifically associated with high expression of mutant p53. Kaplan-Meier curves showed that tumors located in these regions were associated with significantly worse progression free survival compared with tumors occurring elsewhere, providing new evidence that genetic changes during cancer may have anatomic specificity. Additionally, suggests that tumor location identified on structural MR images could potentially be used for customized presurgical outcome prediction 3).

Pathology

1)
Squire LR, Stark CE, Clark RE. The medial temporal lobe. Annu Rev Neurosci. 2004;27:279-306. Review. PubMed PMID: 15217334.
2)
Wen HT, Rhoton AL Jr, de Oliveira E, Cardoso AC, Tedeschi H, Baccanelli M, Marino R Jr. Microsurgical anatomy of the temporal lobe: part 1: mesial temporal lobe anatomy and its vascular relationships as applied to amygdalohippocampectomy. Neurosurgery. 1999 Sep;45(3):549-91; discussion 591-2. PubMed PMID: 10493377.
3)
Wang YY, Zhang T, Li SW, Qian TY, Fan X, Peng XX, Ma J, Wang L, Jiang T. Mapping p53 Mutations in Low-Grade Glioma: A Voxel-Based Neuroimaging Analysis. AJNR Am J Neuroradiol. 2015 Jan;36(1):70-6. doi: 10.3174/ajnr.A4065. Epub 2014 Aug 7. PubMed PMID: 25104286.
mesial_temporal_lobe.txt · Last modified: 2019/03/13 21:54 by administrador