Cognitive Brain Research 12 (2001) 199–206 www.elsevier.com / locate / bres Research report Encoding and retrieval related cerebral activation in continuous verbal recognition a, b a b b * Frank Jessen , Sebastian Flacke , Dirk-Oliver Granath , Christoph Manka , Lukas Scheef , c b a Andreas Papassotiropoulos , Hans H. Schild , Reinhard Heun a Department of Psychiatry, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany b Department of Radiology, University of Bonn, Bonn, Germany c Department of Psychiatry Research, University of Zurich, Zurich, Switzerland Accepted 20 March 2001 Abstract The differential neuronal activation related to encoding of novel and recognition of previously studied items and the effect of retrieval effort on neuronal activation were assessed in a event-related functional magnetic resonance imaging experiment. A verbal continuous recognition task with two repetitions of the target items was used. The interpretation of the results was focused on brain areas that have been previously reported to be involved in explicit memory. Encoding of novel words in comparison with the first repetition was associated with a stronger activation in the left parahippocampal and inferior frontal gyrus. Encoding of novel words compared to the second repetition was related to a greater bifrontal activation. Recognition of studied items was associated with greater activation in the medial and bilateral inferior parietal lobe at first repetition and in the medial and left inferior parietal lobe at second repetition in comparison with encoding of the novel items. Recognition at first repetition compared to recognition at second repetition was associated with greater bilateral frontal activation. The results are discussed in relation to current concepts of spatial differentiation of memory function and findings from event-related potentials studies of continuous recognition.  2001 Elsevier Science B.V. All rights reserved. Theme: Neural basis of behavior Topic: Learning and memory: systems and functions Keywords: Encoding; Recognition; Parahippocampal gyrus; Frontal cortex; Parietal cortex; Event-related fMRI 1. Introduction different trial types in a single experiment. In the present study we used event-related fMRI to directly compare Functional neuroimaging studies have demonstrated a intermixed encoding and recognition of identical stimuli network of medio-temporal, frontal and parietal areas that presented in a continuous recognition task. subserve explicit encoding and recognition of previously The continuous recognition task has been widely em- studied material [5,10]. With regard to the medial temporal ployed in event-related potential (ERP) studies and robust lobe and the frontal lobe, models of spatial differentiation differential effects of novel and repeated items, in terms of between encoding and retrieval have been proposed an increased negativity after the first presentation and a [28,32,39,44]. However, both conditions have primarily more positive ERP-waveform after the repeated pre- been investigated in separate studies with different sub- sentation of target items, have been reported [11,12,34,35]. jects, tasks and technical applications. The development of Intracranial ERP studies have provided evidence for event-related functional magnetic resonance imaging generators of the novel / repeated effects in various brain (fMRI) [4,14] now provides the basis to investigate regions [16–20,41,42]. In the present study, we included two repetitions of the target items, contradictory to standard continuous recogni- *Corresponding author. Tel.: 149-228-2875-743; fax: 149-228-2876- tion tasks, where the target item is repeated only once. 097. E-mail address: jessen@uni-bonn.de (F. Jessen). This enabled us to address the issue of neuronal activation 0926-6410 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0926-6410(01)00046-5