Structural Connectivity Changes and Verbal Memory Recovery 10 Years After Anterior Temporal Lobe Resection
Abstract number :
2.302
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2024
Submission ID :
1043
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Marine Fleury, PhD – Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology,University College London
Lawrence Binding, PhD – Department of Clinical and Experimental Epilepsy, Institute of Neurology, Faculty of Brain Sciences, University College London
Karin Trimmel, MD, PhD – Medical University of Vienna
Sjoerd Vos, PhD – University of Western Australia
Jane de Tisi, BSc – University College London
Peter Taylor, PhD – Newcastle University
Fenglai Xiao, MD PhD – Department of Clinical and Experimental Epilepsy, Institute of Neurology, Faculty of Brain Sciences, University College London
Davide Giampiccolo, MD – Department of Clinical and Experimental Epilepsy, Institute of Neurology, Faculty of Brain Sciences, University College London
Yihe Wang, PhD – Xuan Wu Hospital
Jonathan Horsley, BSc – Newcastle University
Gavin P. Winston, PhD – Queen's University Canada
Pamela Thompson, PhD – Chalfont Epilepsy Society
Sallie Baxendale, PhD – Chalfont Epilepsy Society
Matthias J Koepp, MD PhD – Department of Clinical & Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG & Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, United Kingdom
John Duncan, MD – University College London
Meneka Sidhu, MBChB, MRCP, PhD – National Hospital for Neurology and Neurosurgery
Rationale: Episodic memory decline affects up to 40% of individuals undergoing anterior temporal lobe resection (ATLR). Long-term after ATLR, we showed improvement in verbal memory in circa 50% of people with a left-sided and 38% with a right-sided resection, and identified corresponding network changes 1–10 years postoperatively. This study investigates white matter (WM) tracts critical to long-term verbal memory function. This may guide surgical planning to mitigate memory decline.
Methods: Ten healthy controls and 24 individuals who had ATLR (12 left-sided) underwent memory assessment, structural MRI, and diffusion MRI preoperatively, 1 year, and 10 years postoperatively. Seed-to-whole-brain probabilistic tractography was performed using seeds from a prior memory fMRI connectivity study. Seeds entailed the non-resected hippocampus and the remnant/spared hippocampus and parahippocampal gyrus (termed remnant seed). Density maps of WM tracts projecting from the seeds were generated for every subject’s 10-year scan, compared between groups, and correlated with individual memory change from 1 to 10 years.
Results: Controls exhibited consistent structural connectivity between hippocampal seeds and ipsilateral temporo-occipital cortices. Ten years after left and right ATLR, structural tracts from the remnant medial temporal seed extended to both posterior ipsilateral and contralateral temporo-occipital areas. Compared to controls, left and right ATLR groups displayed significantly more WM tracts from the remnant seed to the bilateral cuneus, and ipsilateral precuneus, lingual and remnant posterior parahippocampus; all interconnected via the medial occipital longitudinal tract (MOLT). There was also increased WM density in tracts extending from the remnant medial temporal seed to the bilateral posterior cingulate cortex. At 10 years, increased WM tract density within both the MOLT and the cingulum tracts – both of which connecting the parahippocampus to either visual or subcortical areas – correlated positively with verbal memory improvement from 1 to 10 years after ATLR.
Conclusions: Ten years post-ATLR, structural connectivity changes primarily occurred within the resected hemisphere, in posterior temporo-occipital areas. Greater WM tract density within the MOLT and cingulum tracts may represent a compensatory process, possibly supporting efficient information processing and mnemonic integration in the parahippocampus and corresponding memory recovery. This suggests that sparing these tracts in surgery may be beneficial for long-term cognitive function.
Funding: This work is supported by National Institute for Health Research UCLH Biomedical Research Centre (grant 229811), The Wellcome Trust (grant 083148), Wellcome Trust Innovation Program (106882/Z/15/Z, 218380/Z/19/Z) and MRC (G0802012, MR/M00841X/1). MF and MKS are supported by the UCLH BRC and the Epilepsy Society. PT is supported by a UKRI Future Leaders Fellowship (MR/T04294X/1). This work and MKS are supported by the MRC (grant MR/X031039/1).
Neuro Imaging