Modulation of prefrontal cortex activation by emotional words in recognition memory Lars Kuchinke a , Arthur M. Jacobs a , Melissa L.-H. Vo ì a , Markus Conrad a , Claudia Grubich b and Manfred Herrmann c,d a Department of Psychology, Freie UniversitÌt Berlin, b Department of Psychiatry and Psychotherapy, K˛nigin Elisabeth Herzberge Krankenhaus, Berlin, Germany, c Department of Neuropsychology and Behavioral Neurobiology, Institute for Cognitive Neuroscience and d Center for Advanced Imaging, Bremen University, Germany Correspondence and requests for reprints to Lars Kuchinke, Allgemeine Psychologie, Freie UniversitÌt Berlin, Habelschwerdter Allee 45, 14195 Berlin, Germany Tel: + 49 (0)30 83855776; fax: + 49 (0)30 83855620; e-mail: kuchinke@zedat.fu-berlin.de Sponsorship: LKwas supported by the Deutsche Forschungsgemeinschaft ( JA 823/3-1) and the research group ‘Neuroscience of Emotion’ at the Hanse Institute for Advanced Study, Delmenhorst/Bremen, Germany. Received 20 March 2006; accepted 28 March 2006 We employed event-related functional magnetic resonance imaging to examine emotional valence e¡ects on verbal recognition memory. Using a yes/no recognition task, we focussed on prefrontal cortex responses to positive, negative and neutral words. Behavioral data con¢rmed enhanced processing of emotional items and functional magnetic resonance imaging revealed di¡erent subregions in the prefrontal cortex supporting retrieval of emotional words. Activations in the right mid- ventrolateral prefrontal cortex correlated with the correct retrieval conditions for negative words, whereas the right ventromedial and orbitofrontal prefrontal cortex showed enhanced responses to positive words. Additionally, di¡erences between old and new items mainly a¡ected bilateral orbitofrontal regions when processing positive words. The results are discussed in terms of higher monitoring demands owing to familiarity-based recognition bias for emotional words. NeuroReport 17:1037^1041 c 2006 Lippincott Williams & Wilkins. Keywords: emotional valence, functional magnetic resonance imaging, negative words, neuroimaging, neutral, prefrontal cortex, positive, recognition memory Introduction Recognition memory is influenced by the affective or emotional valence of the test items. Whereas other imaging studies focus on basic processes underlying episodic retrieval of verbal information [1], the present study was designed to investigate the role of emotional valence for visual word processing in the prefrontal cortex (PFC). In particular, we examined memory performance for positively and negatively valenced words in a yes/no recognition task. Besides the role of medial temporal lobe during episodic memory retrieval [2], PFC is thought to subserve monitoring processes related to familiarity-based judgements at time of retrieval [1]. Orbitofrontal PFC activity is proposed to reflect retrieval success and bilateral mid-dorsolateral PFC was shown to be related to monitoring processes such as evaluation of the retrieved information [3]. If recognition judgements are influenced by the higher familiarity of emotional items [4], one can expect dorsolateral PFC activity to be modulated by emotional valence in the present study. In an event-related potentials (ERPs) study, Windmann and Kutas [5] related an early prefrontal negativity for unstu- died negative items judged as ‘old’ to an automatic bias for emotional material, possibly reflecting more liberal decision criteria for verifying retrieved information. So far, only a few neuroimaging studies attempt to examine the effects of emotional valence on recognition memory for single words, mainly focussing on emotional context effects in sentence processing [6] or pictorial backgrounds [7,8]. According to these studies, orbitofrontal PFC activation was observed for positive emotional contexts, suggesting a role in combina- tion with hippocampus and anterior cingulate gyrus in a network subserving the processing of memories associated with positive affect [8,9]. In contrast, left ventrolateral PFC involvement was found in retrieving items from negative contexts [6,8]. To our knowledge, no other functional magnetic reson- ance imaging (fMRI) study has examined the contribution of emotional valence to the correct retrieval of items in a standard yes/no recognition task with positive, neutral and negative words. Using an event-related design, we report that the differential effect emotional valence takes on the difference between successful and unsuccessful retrieval of old items. Additionally, we investigated the influence of emotional valence on the so-called ‘old/new’ effect (the relation between correctly classified old items and correctly rejected new items), previously associated with successful item retrieval mechanisms [5]. Both behavioural and ERP data suggest a modulation of the ‘old/new’ effect for negative as compared with neutral items. A diminished ‘old/new’ effect was found for negative items at a late time BRAIN IMAGING NEUROREPORT 0959-4965 c Lippincott Williams & Wilkins Vol 17 No 10 17 July 2006 1037 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.