Part Of Brain Associated With Delayed Disease Identified - Implications For Alzheimer's Disease

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Academic Journal
Main Category: Alzheimer's / Dementia
Also Included In: Neurology / Neuroscience
Article Date: 16 Dec 2011 - 9:00 PST


From experience we usually tend to anticipate the sound of thunder just moments after the strike of lightning. A new report published in the December issue of Science reveals that researchers at the Picower Institute for Learning and Memory at MIT have for the first time identified the part of the brain, which is responsible for this delayed association. The finding could have potential implications for treating Alzheimer's disease.

One of the first areas in the brain that is affected by Alzheimer's disease is the entorhinal cortex (EC). It is interesting to note that a person with early onset of Alzheimer's performs memory tasks with a delay between learning and recalling items.

Study co-author Junghyup Suh, research scientist at the Picower Institute says:

"Our findings provide new insights into how patients with Alzheimer's disease develop deficits in working memory with consequent failure of the formation of episodic memory.

In addition, by identifying the circuits responsible for the cognitive deficits in human patients with the disease, we begin to lay a potential framework for selective therapeutic intervention in Alzheimer's disease."

A temporal association, such as waiting for thunder after seeing lightning or anticipating a bee sting after hearing a buzzing insect, is a process in which the first sensory experience is separated from its associated experience by a short period in time.

Researchers established that inputs from a part of the brain called the EC layer III to the hippocampus are crucial for temporal associations. This layer, which is shaped like a seahorse, is responsible for memory formation and retrieval.

Suh said:

"This study shows for the first time that the EC is important for processing non-spatial information such as a time element of episodic memory."

The EC acts as an interface between the hippocampus and the neocortex, and is believed to be involved in the retrieval and consolidation of spatial memories as well as in fine-tuning place cells in the hippocampus.

Earlier research independent of MIT had established that different kinds of cells in the EC are linked to where an animal is in space, indicating that the EC relays spatial information to the hippocampus. Furthermore, studies have demonstrated that certain cells in the EC can fire continuously for tens of seconds. In the absence of sensory inputs, this type of continuous firing can help to maintain sensory information, such as buzzing and lightning.

Suh concludes:

"This study is among the first to examine the interactions between the hippocampus and its adjacent cortical areas in cognitive processes using genetic tools with great temporal and spatial specificity. It also opens the door to future research with regard to how the hippocampus and EC communicate, process information and guide behaviors."

Written by Petra Rattue
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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