The antimuscarinic agent biperiden selectively impairs recognition of abstract figures without affecting the processing of non‐words

Abstract

Objectives The present study investigated the effects of biperiden, a muscarinic type 1 antagonist, on the recognition performance of pre‐experimentally unfamiliar abstract figures and non‐words in healthy young volunteers. The aim was to examine whether 4 mg biperiden could model the recognition memory impairment seen in healthy aging. Methods A double‐blind, placebo‐controlled, two‐way crossover study was conducted. We used a three‐phase (deep memorization, shallow memorization, and recognition) old/new discrimination paradigm in which memory strength was manipulated. Strong memories were induced by deep encoding and repetition. Deep encoding was encouraged by redrawing the abstract figures and mentioning existing rhyme words for the non‐words (semantic processing). Weak memories were created by merely instructing the participants to study the stimuli (shallow memorization). Results Biperiden impaired recognition accuracy and prolonged reaction times of the drawn and the studied abstract figures. However, participants were biased towards “old” responses in the placebo condition. The recognition of the new abstract figures was unaffected by the drug. Biperiden did not affect the recognition of the non‐words. Conclusions Although biperiden may model age‐related deficits in episodic memory, the current findings indicate that biperiden does not mimic age‐related deficits in recognition performance.

Age Effects on Old/New Recognition Memory Involving Abstract Figures and Non-words

“…In agreement with previous results using the current paradigm, it was found that recognition performance was affected by memory strength in both age groups to a similar extent (Toth et al, 2021a ). In contrast, the recognition of the new items was comparable to the semantically processed non-words but was worse for the drawn abstract figures (Toth et al, 2021a , b ). Finally, our overall results were in line with our expectation concerning the age-independent memory advantage of deeper LOP and repetition over shallow LOP without repetition (Craik and Lockhart, 1972 ; Craik and Tulving, 1975 ; Craik, 2002 ; Newell and Andrews, 2004 ).…”