A tale of two hemispheres: Do the left and right medial temporal lobes play different roles in perception and recognition of verbal and non-verbal stimuli?
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1
Neuroscience Research Australia / University of New South Wales, Australia
i. Background
Episodic memory begins with perception. The medial temporal lobes (MTL) contain structures which are crucial for episodic memory processing but an increasing number of reports implicate the MTL in perceptual processing. It is unclear however, how MTL substructures contribute to the perception and memory of different kinds of stimuli.
ii. Methods
Twenty young healthy adults, participated in two fMRI experiments aimed at investigating MTL contributions to perception (experiment one) and recognition (experiment two) of verbal and non-verbal stimuli. In a third experiment, we utilised voxel based morphometry to identify regions of brain atrophy associated with poor performance on these tasks in twenty patients with Alzheimer’s disease and semantic dementia.
iii. Results
The results of experiment one and two revealed that for verbal stimuli, the left perirhinal cortex and left hippocampus were recruited during perception and recognition respectively. In contrast, the right perirhinal cortex was asymmetrically recruited during both perception and recognition of non-verbal stimuli. Experiment 3 revealed that atrophy in the left perirhinal cortex and hippocampus was associated with poor performance on the verbal memory task and atrophy in the right perirhinal cortex was associated with poor performance on the non-verbal task.
iv. Discussion
Our results suggest that i) structures of the MTL are recruited during both perception and recognition memory, ii) there is a functional asymmetry with left and right MTL structures recruited for verbal and non-verbal stimuli respectively and iii) atrophy in the MTL regions implicated in our functional imaging results is associated with impaired task performance in patients with dementia. These results have important implications for current theoretical models of episodic memory and perception.
Keywords:
recognition memory,
Visual Perception,
Medial Temporal Lobes,
perirhinal cortex,
Hippocampus,
verbal memory,
non-verbal memory
Conference:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013.
Presentation Type:
Oral
Topic:
Memory
Citation:
Dalton
MA,
Hornberger
M,
Hodges
JR and
Piguet
O
(2013). A tale of two hemispheres: Do the left and right medial temporal lobes play different roles in perception and recognition of verbal and non-verbal stimuli?.
Conference Abstract:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference.
doi: 10.3389/conf.fnhum.2013.212.00173
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Received:
15 Oct 2013;
Published Online:
25 Nov 2013.
*
Correspondence:
Mr. Marshall A Dalton, Neuroscience Research Australia / University of New South Wales, Sydney, Australia, m.dalton@neura.edu.au