Comparison of fMRI correlates of successful episodic memory encoding in temporal lobe epilepsy patients and healthy controls

Paul F. Hill, Danielle R. King, Bradley C. Lega, Michael D. Rugg

Research output: Contribution to journalArticle

Abstract

Intra-cranial electroencephalographic brain recordings (iEEG) provide a powerful tool for investigating the neural processes supporting episodic memory encoding and form the basis of experimental therapies aimed at improving memory dysfunction. However, given the invasiveness of iEEG, investigations are constrained to patients with drug-resistant epilepsy for whom such recordings are clinically indicated. Particularly in the case of temporal lobe epilepsy (TLE), neuropathology and the possibility of functional reorganization are potential constraints on the generalizability of intra-cerebral findings and pose challenges to the development of therapies for memory disorders stemming from other etiologies. Here, samples of TLE (N ​= ​16; all of whom had undergone iEEG) and age-matched healthy control (N ​= ​19) participants underwent fMRI as they studied lists of concrete nouns. fMRI BOLD responses elicited by the study words were segregated according to subsequent performance on tests of delayed free recall and recognition memory. Subsequent memory effects predictive of both successful recall and recognition memory were evident in several neural regions, most prominently in the left inferior frontal gyrus, and did not demonstrate any group differences. Behaviorally, the groups did not differ in overall recall performance or in the strength of temporal contiguity effects. However, group differences in serial position effects and false alarm rates were evident during the free recall and recognition memory tasks, respectively. Despite these behavioral differences, neuropathology associated with temporal lobe epilepsy was apparently insufficient to give rise to detectable differences in the functional neuroanatomy of episodic memory encoding relative to neurologically healthy controls. The findings provide reassurance that iEEG findings derived from experimental paradigms similar to those employed here generalize to the neurotypical population.

Original languageEnglish (US)
Article number116397
JournalNeuroImage
Volume207
DOIs
StatePublished - Feb 15 2020

Keywords

  • Encoding
  • Episodic memory
  • Temporal lobe epilepsy

ASJC Scopus subject areas

  • Neurology
  • Cognitive Neuroscience

Fingerprint Dive into the research topics of 'Comparison of fMRI correlates of successful episodic memory encoding in temporal lobe epilepsy patients and healthy controls'. Together they form a unique fingerprint.

  • Cite this