Novelty processing in younger and older adults measured using an adapted visual novelty oddball  task

Studies using event-related potential (ERP) suggests that the hippocampus, a medial temporal lobe (MTL) structure, can distinguish new and old stimuli. However, it remains unclear whether age deficits in MTL processes contribute to age deficits in novelty processing. The present study aimed to investigate this knowledge gap and to confirm previous findings reported by Schomaker et al. (2021) regarding the role of the MTL in novelty detection and later processing. Twenty-one patients with epilepsy with unilateral MTL resection and twenty-four matched healthy controls performed an adapted visual novelty oddball task, with two streams of stimuli presented left and right of a fixation cross, while their electroencephalogram (EEG) was recorded. The participants had to respond to infrequent target stimuli while ignoring standard and novel stimuli. Novelty detection, indexed by the N2, was reduced by MTL resections, shown by a smaller N2 for patients compared to healthy controls. Novelty...Show moreStudies using event-related potential (ERP) suggests that the hippocampus, a medial temporal lobe (MTL) structure, can distinguish new and old stimuli. However, it remains unclear whether age deficits in MTL processes contribute to age deficits in novelty processing. The present study aimed to investigate this knowledge gap and to confirm previous findings reported by Schomaker et al. (2021) regarding the role of the MTL in novelty detection and later processing. Twenty-one patients with epilepsy with unilateral MTL resection and twenty-four matched healthy controls performed an adapted visual novelty oddball task, with two streams of stimuli presented left and right of a fixation cross, while their electroencephalogram (EEG) was recorded. The participants had to respond to infrequent target stimuli while ignoring standard and novel stimuli. Novelty detection, indexed by the N2, was reduced by MTL resections, shown by a smaller N2 for patients compared to healthy controls. Novelty processing, indexed by the P3, was not reduced in patients, shown by a larger P3 for patients compared to healthy controls. However, this might be due to collapsing of data in the patient group, since resection side was outside the scope of this study. Target processing, indexed by the P3b, was unaffected by MTL resections: no differences were found between patients and healthy controls. These results suggest that MTL structures, including the hippocampus and the amygdala, play a role in novelty processing. In contrast, MTL structures do not play a role in target processing since this was unaffected by MTL resections.Show less

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Novelty processing in younger and older adults measured using an adapted visual novelty oddball task