Imaging the contributions of the hippocampus to memory
Research type
Research Study
Full title
Dissecting the cognitive roles of hippocampus and other temporal lobe structures
IRAS ID
172472
Contact name
Natalie Voets
Contact email
Sponsor organisation
Emory University
Duration of Study in the UK
8 years, 0 months, 30 days
Research summary
Research Summary:
Up to 30% of patients with epilepsy have seizures that cannot be controlled with medications. The majority of these patients will have epilepsy starting in the temporal lobe of the brain. For these patients, brain surgery removing the tissue where seizures start can effectively control their epilepsy. However, surgery involving the anteromedial temporal lobe of the brain can result in verbal memory and naming problems following surgery (resection) in the language-dominant (typically left) hemisphere and in visual memory problems after surgery in the non-dominant (typically right) hemisphere. Recently, we showed that traditional surgery also frequently produces recognition or naming problems for several object types (e.g. famous faces, animals) and related functions (e.g. proper noun fluency). These problems, not previously recognised as clinical risks, can compound the burden of memory deficits in these patients, affecting their quality of life.We propose that these newly recognised deficits reflect "disconnection syndromes" resulting from collateral damage incurred when surgically reaching the mesial temporal region. Using MRI, this study will relate damage resulting from surgical resection extent/location - specifically the involvement of white matter fibre pathways in the temporal lobe - to performance on our cognitive measures and traditional memory and naming tests in patients undergoing standard temporal lobe resection. All eligible patients undergoing brain surgery in Oxford, as well as healthy volunteers, will be invited for 2 MRI scans.
This study is a sub-part of a larger study (funded by the NIH, led/sponsored by Emory University, USA). This study will contribute data related to standard surgical approaches on memory, to be compared to US data on memory after a surgical laser approach. The primary aim is to improve our understanding of the contribution of specific brain structures (the hippocampus), and associated white matter fibre pathways in the temporal lobe, to memory and language performance.
Summary of Results:
This multi-site study (predominantly performed in the United States of America) aimed to look at cognitive outcomes in patients with drug treatment-resistant epilepsy depending on the impact of brain surgery on specific anatomical structures in the brain. Specifically, we predicted that surgical damage to certain connection pathways in the brain might be at the source of language and memory deterioration after surgery. The UK sub-site contributed only a few additional patients to the wider study. The results of the wider study (publications linked below) indicate better naming and language outcomes following surgery that spares more of the brain's white matter nerve fibres.REC name
South Central - Oxford B Research Ethics Committee
REC reference
15/SC/0636
Date of REC Opinion
2 Dec 2015
REC opinion
Further Information Favourable Opinion