title: Associative Recognition Memory Awareness Improved by Theta-Burst Stimulation of Frontopolar Cortex.
abstract: Neuroimaging and lesion studies have implicated specific prefrontal cortex locations in subjective memory awareness. Based on this evidence, a rostrocaudal organization has been proposed whereby increasingly anterior prefrontal regions are increasingly involved in memory awareness. We used theta-burst transcranial magnetic stimulation (TBS) to temporarily modulate dorsolateral versus frontopolar prefrontal cortex to test for distinct causal roles in memory awareness. In three sessions, participants received TBS bilaterally to frontopolar cortex, dorsolateral prefrontal cortex, or a control location prior to performing an associative-recognition task involving judgments of memory awareness. Objective memory performance (i.e., accuracy) did not differ based on stimulation location. In contrast, frontopolar stimulation significantly influenced several measures of memory awareness. During study, judgments of learning were more accurate such that lower ratings were given to items that were subsequently forgotten selectively following frontopolar TBS. Confidence ratings during test were also higher for correct trials following frontopolar TBS. Finally, trial-by-trial correspondence between overt performance and subjective awareness during study demonstrated a linear increase across control, dorsolateral, and frontopolar TBS locations, supporting a rostrocaudal hierarchy of prefrontal contributions to memory awareness. These findings indicate that frontopolar cortex contributes causally to memory awareness, which was improved selectively by anatomically targeted TBS.
authors.affiliation: Department of Medical Social Sciences, Ken & Ruth Davee Department of Neurology, Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Ryals
authors.affiliation: Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA.
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Rogers
authors.affiliation: Department of Medical Social Sciences, Ken & Ruth Davee Department of Neurology, Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Evan Z
authors.initials: EZ
authors.lastname: Gross
authors.affiliation: Department of Medical Social Sciences, Ken & Ruth Davee Department of Neurology, Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Polnaszek
authors.affiliation: Department of Medical Social Sciences, Ken & Ruth Davee Department of Neurology, Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Joel L
authors.initials: JL
authors.lastname: Voss
mesh_terms: D000328:Adult; D001245:Association Learning / Q000502:physiology*; D001364:Awareness / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology / Q000502:physiology*; D006801:Humans; D007600:Judgment / Q000502:physiology; D007858:Learning / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D021641:Recognition, Psychology / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D055815:Young Adult
keywords: confidence; judgments of learning; metamemory; prefrontal cortex; transcranial magnetic stimulation