Lower pattern recognition memory scores in anorexia nervosa

Abstract

Background There is extensive evidence for volumetric reductions in the hippocampus in patients with anorexia nervosa (AN), however the impact on function is unclear. Pattern separation and recognition are hippocampus-dependent forms of learning thought to underlie stimulus discrimination. Methods The present study used the Mnemonic Similarity Task to investigate pattern separation and recognition for the first time in patients with AN (N = 46) and healthy controls (N = 56). An Analysis of Covariance examined between-group differences, controlling for age, antidepressant use and method of task delivery (remote vs. in person). Results When controlling for covariates, pattern recognition memory scores were lower in the AN group with a medium effect size (d = 0.51). In contrast, there was a small effect whereby patients with AN had a greater pattern separation score than controls (d = 0.34), albeit this difference was not significant at the p = 0.05 threshold (p = 0.133). Furthermore, pattern separation and recognition memory abilities were not related to age, body mass index, eating disorder psychopathology or trait anxiety levels. Conclusions This preliminary study provides initial evidence for an imbalance in pattern separation and recognition abilities in AN, a hippocampus-dependent cognitive ability. Further studies should endeavour to investigate pattern separation and recognition performance further in AN, as well as investigate other hippocampus-dependent functions.

Every mistake is a treasure: Lessons learned from the TRIANGLE trial for anorexia nervosa

“…Other opportunities may include personalization based on biomarkers: for example, recent evidence suggests that alterations in the gut microbiome may warrant strategies such as adjustments to refeeding processes, diet compositions, supplements (including pre‐ or probiotics), and target weights in AN treatment (Herpertz‐Dahlmann et al, 2017), although this research remains in somewhat early stages and further work is required (Malcolm & Phillipou, 2021). There may also be opportunities to explore novel psychopharmacological (e.g., ketamine, psilocybin) and psychotherapeutic (e.g., cognitive remediation, exposure) approaches that could mitigate neuroplasticity deficiencies resulting from AN (Keeler et al, 2023). Efforts to individualize care may empower patients, giving them an opportunity to have more voice in their treatment and to draw upon their own lived experience to conceptualize their illness and recovery (Rankin et al, 2023).…”

Longitudinal changes in brain-derived neurotrophic factor (BDNF) but not cytokines contribute to hippocampal recovery in anorexia nervosa above increases in body mass index

“…Nevertheless, novel therapeutics (e.g. ketamine [Keeler, Kan, Treasure, & Himmerich, 2023;Keeler, Treasure, Juruena, Kan, & Himmerich, 2021b]) may target BDNF levels in people with AN in order to bolster neuroplasticity and learning, although it should be noted that BDNF has been documented to have suppressive effects on appetite (Rios, 2013;Stanek et al, 2008), which is undesirable in this population (Trinh, Keller, Herpertz-Dahlmann, & Seitz, 2023).…”

Ketamine as a Treatment for Anorexia Nervosa: A Narrative Review

“…Patients with AN often have difficulties in several aspects of cognition that may be linked to reduced neuroplasticity and hippocampal function, such as memory, learning and cognitive flexibility. Apparent deficits in memory in AN include overgeneralising autobiographical memories [147,148], poor immediate and delayed recall of story details [149], recall of locations [150] and pattern recognition memory [151]. Patients with AN have a negative bias when constructing future-directed thoughts compared to healthy controls [152], which may be related to a negative bias in memory retrieval [153]; it has been hypothesised that generating future-directed thoughts is reliant on the flexible recombination of events from the past [154].…”