Dissociating Amygdalohippocampal vs. Parahippocampal Contributions to Verbal Declarative Memory: Lesion-Symptom Mapping in Patients with Mesial Temporal Lobe Epilepsy
Abstract number :
1.372
Submission category :
11. Behavior/Neuropsychology/Language / 11A. Adult
Year :
2019
Submission ID :
2421365
Source :
www.aesnet.org
Presentation date :
12/7/2019 6:00:00 PM
Published date :
Nov 25, 2019, 12:14 PM
Authors :
Ezequiel Gleichgerrcht, Medical University of South Carolina; Deqiang Qiu, Emory University; Jon T. Willie, Emory University; Nigel P. Pedersen, Emory University; Kelsey C. Hewitt, Emory University; Natalie Voets, Oxford University; Robert E. Gross, Emory
Rationale: By exploring statistical associations between task performance and damage to different brain areas, lesion-symptom mapping (LSM) can help elucidate brain structures that are critical for a given behavior. This approach has been limited in studying the neurobiology of memory given the scarcity of lesions of the medial temporal lobe with common brain insults such as ischemic stroke. However, stereotactic laser amygdalohippocampotomy (SLAH) is a growing surgical technique for the treatment of medically refractory mesial temporal lobe epilepsy (MTLE) which produces discrete brain lesion in said region. Methods: We performed region of interest (ROI)-based LSM in 42 patients (age 42±14.2; 36% male) with unilateral MTLE who underwent ipsilateral (45% left-sided) SLAH. We analyzed the acquisition, immediate recall, and delayed recall standardized Z scores on the Rey Auditory Verbal Learning Task at 12 months post-surgery. ROIs were determined based on the Automated Anatomical Labeling atlas. Family-wise errors were controlled by means of permutation thresholding. Results: There were no significant differences in lesion volume between left- and right-sided SLAH (p = .33). LSM revealed that verbal memory acquisition (learning phase) was critically associated with damage to the left amygdala (z = -2.6) and left hippocampus (z = -1.97) while both immediate and delayed recall phases of the task were associated with left parahippocampal damage (z = -2.3). No voxel or ROI within this area was specifically associated with worsening or improvement of memory task performance. Conclusions: Our findings reveal an amygdalohippocampal vs. parahippocampal dissociation for consolidation vs. retrieval phases of verbal declarative memory, providing structural confirmation of observations previously gathered from functional studies. These findings have both theoretical implications for the neurobiology of memory as well as clinical implications for surgical planning and post-operatively assessment of patients with temporal lobe epilepsy. Funding: No funding
Behavior/Neuropsychology/Language