Effects of acetylcholine on neuronal properties in entorhinal cortex.

James G Heys,Christopher F Shay,Yusuke Tsuno,Nathan W Schultheiss,Michael E Hasselmo

doi:10.3389/fnbeh.2012.00032

Abstract

The entorhinal cortex (EC) receives prominent cholinergic innervation from the medial septum and the vertical limb of the diagonal band of Broca (MSDB). To understand how cholinergic neurotransmission can modulate behavior, research has been directed toward identification of the specific cellular mechanisms in EC that can be modulated through cholinergic activity. This review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory. In particular, the study of stellate cells (SCs) in medial entorhinal has resulted in discovery of correlations between physiological properties of these neurons and properties of the unique spatial representation that is demonstrated through unit recordings of neurons in medial entorhinal cortex (mEC) from awake-behaving animals. A separate line of investigation has demonstrated persistent firing behavior among neurons in EC that is enhanced by cholinergic activity and could underlie working memory. There is also evidence that acetylcholine plays a role in modulation of synaptic transmission that could also enhance mnemonic function in EC. Finally, the local circuits of EC demonstrate a variety of interneuron physiology, which is also subject to cholinergic modulation. Together these effects alter the dynamics of EC to underlie the functional role of acetylcholine in memory.

Highlights

Effects of acetylcholine on neuronal properties in entorhinal cortexThis review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory
There is strong evidence to support the claim that acetylcholine modulates the physiology and the function of the entorhinal cortex (EC)
This review focuses upon modulation in the EC that can be largely attributed to activation of the muscarinic sensitive acetylcholine receptor. muscarinic acetylcholine receptor activation (mAChR) are G-protein coupled receptors that are expressed in the central nervous system as one of five subtypes in the central nervous system (M1–M5) and can be grouped into two more general classes, M1-like which are associated with the Gq subtype G-protein coupled receptor and M2-like which are linked with the Gi sub-type

Summary

Effects of acetylcholine on neuronal properties in entorhinal cortex

This review focuses on intrinsic cellular properties of neurons in EC that may underlie functions such as working memory, spatial processing, and episodic memory. A separate line of investigation has demonstrated persistent firing behavior among neurons in EC that is enhanced by cholinergic activity and could underlie working memory. There is evidence that acetylcholine plays a role in modulation of synaptic transmission that could enhance mnemonic function in EC. The local circuits of EC demonstrate a variety of interneuron physiology, which is subject to cholinergic modulation. Together these effects alter the dynamics of EC to underlie the functional role of acetylcholine in memory

INTRODUCTION

Findings

Acetylcholine and cortical networks