Left prefrontal cortex control of novel occurrences during recollection: a psychopharmacological study using scopolamine and event-related fMRI.
Recollection and familiarity represent two processes involved in episodic memory retrieval. We investigated how scopolamine (an antagonist of acetylcholine muscarinic receptors) influenced brain activity during memory retrieval, using a paradigm that separated recollection and familiarity. Eighteen healthy volunteers were recruited in a randomized, placebo-controlled, double-blind design using event-related fMRI. Participants were required to perform a verbal recognition memory task within the scanner, either under placebo or scopolamine conditions. Depending on the subcondition, participants were required to make a simple recognition decision (old/new items) or base their decision on more specific information related to prior experience (target/non-target/new items). We show a drug modulation in left prefrontal and perirhinal cortex during recollection. Such an effect was specifically driven by novelty and showed an inverse correlation with accuracy performance. Additionally, we show a direct correlation between drug-related signal change in left prefrontal and perirhinal cortices. We discuss the findings in terms of acetylcholine mediation of the familiarity/novelty signal through perirhinal cortex and the control of the relative signal strength through prefrontal cortex.
Bozzali
M
M
Institute of Cognitive Neuroscience, University College London, UK. m.bozzali@fil.ion.ucl.ac.uk
MacPherson
S E
SE
Dolan
R J
RJ
Shallice
T
T
D000328:Adult; D003116:Color; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects; D011932:Reading; D012601:Scopolamine / Q000494:pharmacology*; D013028:Space Perception / Q000502:physiology; D013238:Stereotaxic Techniques
D018727:Muscarinic Antagonists; D012601:Scopolamine; D010100:Oxygen