Abstract Details

Title Mapping the Neural Basis of Declarative Verbal Memory: Evidence from Mesial Temporal Lobe Lesions

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) P3 - Poster Session 3 (5:30 PM-6:30 PM)

Poster/Presentation
Number 9-014

Objective

To identify the neural substrates supporting different phases of declarative verbal memory.

Background Current neuroanatomical models of declarative memory stipulate a concerted role between the hippocampus and its adjacent structures to support encoding, storage, and recovery of information in the human brain. Much of our understanding of these processes is the result of functional neuroimaging studies (e.g. fMRI), which register brain activation while participants complete a given task. These techniques have allowed us to identify some of the neurobiological underpinnings of cognition but they only provide indirect measures of neural activation, making it impossible to reliably discern which brain areas are truly crucial for a given function. A solution to this problem can be found in lesion-symptom mapping (LSM), an approach by which behavioral performance is statistically related to damaged brain tissue, hence detecting brain structures that are critical for a given behavior. To date, LSM studies of memory function have been limited likely due to the scarcity of discrete lesions of the medial temporal lobe with common brain insults such as ischemic stroke. Stereotactic laser amygdalohippocampotomy (SLAH) is a growing surgical technique for the treatment of medically refractory mesial temporal lobe epilepsy (MRMTLE) which produces a confined brain lesion in such region.

Design/Methods We performed voxel-based LSM in thirteen patients (age 40±18.4; 30% male) with MRMTLE and left-predominant language (as confirmed by fMRI or Wada or both) who underwent left-sided SLAH. We analyzed the acquisition, immediate recall, and delayed recall standardized Z scores on the Rey Auditory Verbal Learning Task at 6 months post-surgery.

Results LSM revealed that acquisition was critically associated with hippocampal damage while both immediate and delayed recall phases of the task were associated with entorhinal damage.

Conclusions Our results suggest a dissociation of hippocampal vs. parahippocampal integrity for consolidation vs. retrieval aspects of declarative memory, respectively.

Authors/Disclosures
Ezequiel Gleichgerrcht, MD (Emory University) PRESENTER	Dr. Gleichgerrcht has nothing to disclose.
Leonardo F. Bonilha, MD (University of South Carolina)	Dr. Bonilha has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Nigel P. Pedersen, MBBS (University of California, Davis)	No disclosure on file
David W. Loring, PhD, FAAN	Dr. Loring has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Springer Nature. Dr. Loring has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for ILAE. The institution of Dr. Loring has received research support from NIH. Dr. Loring has received publishing royalties from a publication relating to health care.
Jon T. Willie, MD, PhD (Emory University)	Jon T. Willie, MD, PhD has received personal compensation in the range of $0-$499 for serving as a Consultant for AiM Medical. Jon T. Willie, MD, PhD has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Medtronic. Jon T. Willie, MD, PhD has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Neuropace.
Robert Gross	No disclosure on file
Daniel Drane, PhD (Emory University School of Medicine)	Dr. Drane has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Medical Directors Solutions, Inc. The institution of Dr. Drane has received research support from NIH/NINDS. The institution of Dr. Drane has received research support from Medtronic, Inc..

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