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doi:10.1093/scan/nsn027 SCAN (2008) 1 of 15
Amygdala activation during reading of emotional adjectivesan advantage for pleasant content
Cornelia Herbert,1 Thomas Ethofer,2,3 Silke Anders,2 Markus Junghofer,4 Dirk Wildgruber,3 Wolfgang Grodd,2 and Johanna Kissler1
1
Department of Psychology,University of Konstanz, Konstanz, 2 Section Experimental MR of the CNS, Department of Neuroradiology, ¨ ¨ ¨ ¨ University of Tubingen, Tubingen, 3 Department of Psychiatry, University of Tubingen, Tubingen, and 4 Institute for Biomagnetism and ¨ ¨ Biosignalanalysis, University of Munster, Munster, Germany
This event-related functional magnetic resonance imaging (fMRI) study investigated brain activityelicited by emotional adjectives during silent reading without specific processing instructions. Fifteen healthy volunteers were asked to read a set of randomly presented high-arousing emotional (pleasant and unpleasant) and low-arousing neutral adjectives. Silent reading of emotional in contrast to neutral adjectives evoked enhanced activations in visual, limbic and prefrontal brain regions. Inparticular, reading pleasant adjectives produced a more robust activation pattern in the left amygdala and the left extrastriate visual cortex than did reading unpleasant or neutral adjectives. Moreover, extrastriate visual cortex and amygdala activity were significantly correlated during reading of pleasant adjectives. Furthermore, pleasant adjectives were better remembered than unpleasant andneutral adjectives in a surprise free recall test conducted after scanning. Thus, visual processing was biased towards pleasant words and involved the amygdala, underscoring recent theoretical views of a general role of the human amygdala in relevance detection for both pleasant and unpleasant stimuli. Results indicate preferential processing of pleasant information in healthy young adults and can beaccounted for within the framework of appraisal theory. Keywords: emotion; perception; re-entrant processing; reading; amygdala; extrastriate cortex; neuroimaging
Emotional stimuli are of particular importance for an individual and demand priority access to perception and atten¨ tion (Lang et al., 1997; Ohman et al., 2001). Human lesion and neuroimaging studies suggest that the amygdala, aphylogenetically old brain structure located in the mediotemporal lobes, plays a key role in the facilitated processing of emotionally significant visual stimuli (e.g. Adolphs et al., 1999; Vuilleumier et al., 2004). Over the years many studies have shown amygdala involvement in the processing of threatening and fear-relevant stimuli, such as fearful faces ¨ or pictures of human and animal attack (seee.g. Ohman and Mineka, 2001; Adolphs, 2002; Vuilleumier, 2002). This has led to an initial conceptualization of the amygdala as a structure specialized in the detection of unpleasant and fear¨ relevant material, possibly even a ‘fear-module’ (Ohman and Mineka, 2001). But increased amygdala activation has subsequently also been found in response to happy faces (Williams et al., 2005) andemotionally arousing pleasant scenes and objects (see e.g. Zald, 2003 for a review) as well as for pleasantly and unpleasantly arousing vocalizations (Fecteau et al., 2007). A general role of the human amygdala beyond the processing of threat-related and fear-relevant
Received 18 July 2008; Accepted 29 July 2008 We thank Gregory A. Miller for helpful comments on a previous version of this article. Researchwas supported by the Heidelberg Academy of Sciences (Mind and Brain Programme), the Deutsche Forschungsgemeinschaft and the Center for Young Scientists at the University of Konstanz, Germany. Correspondence should be addressed to Johanna Kissler, Department of Psychology, Box D25, University of Konstanz, 78457 Konstanz, Germany. E-mail: johanna.kissler@uni-konstanz.de.
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