Neuroscience Letters 512 (2012) 94–98 Contents lists available at SciVerse ScienceDirect Neuroscience Letters j our nal ho me p ag e: www.elsevier.com/locate/neulet Regional brain responses to pleasant and unpleasant IAPS pictures: Different networks Faten M. Aldhafeeri a,b,∗ , Ian Mackenzie c , Tony Kay c , Jamaan Alghamdi a,d , Vanessa Sluming a,e a School of Health Sciences, The University of Liverpool, UK b Ministry of Health, Radiology Department, Saudi Arabia c Aintree University NHS Foundation Trust, Liverpool, UK d King Abdul Aziz University, Physics Department, Saudi Arabia e Magnetic Resonance and Image Analysis Research Centre (MARIARC), Liverpool, UK a r t i c l e i n f o Article history: Received 13 September 2011 Received in revised form 17 January 2012 Accepted 26 January 2012 Keywords: Emotions IAPS Amygdala fMRI a b s t r a c t Purpose: The purpose of this study was to investigate the brain circuitry involved in the processing of both positive and negative emotions in normal healthy subjects. Method: we have recruited 15 healthy volunteers (9 males and 6 females, age range 30–60). In this block-design fMRI study, we compared the blood oxygen level dependant (BOLD) signal change as response to pleasant and unpleasant IAPS pic- tures, each compared to a neutral condition. Results: Pleasant pictures versus neutral condition contrast demonstrated significant activation (p FDRcorrected <0.05) in bilateral pre-frontal cortex (PFC), anterior and posterior cingulate gyri and temporal lobe. Unpleasant pictures relative to neutral condition exhibit sig- nificant activation (p FDRcorrected <0.05) in amygdala, hippocampus, parahippocampal gyri, temporal lobe, visual cortex, fusiform gyri, PFC and anterior cingulate gyrus. Conclusion: Amygdala is mainly involved in the processing of negative emotions. Although an overlap in regions involved in the processing of pleasant and unpleasant IAPS pictures exists, the neural network for each is unique. © 2012 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Emotional processing in the human brain has been an area of interest and argument for many researchers in the past decades. Neuroimaging studies have suggested that emotional circuits in the brain may preferentially involve the prefrontal cortex, anterior cin- gulate gyrus, parietal cortex, amygdala, and cerebellum. Scientists agree, despite of ambiguity in such neural mechanism, that there is brain specialisation in emotional processing. It is proposed that the amygdala is a fundamental structure in the processing of negative, fearful and aversive emotions [4,9,28]. Generally, the pre-frontal cortex (PFC) is found to be involved in emotional processing [4,22]. Its involvement is thought to be related to cognitive functions as an appraisal process of the emotional stimuli [19,22]. Both PFC and the amygdala are considered key components in emotional cognition, behaviour and processing [8]. However, the question regarding the exact brain circuitry involved in positive and negative emotions remains unanswered. Functional neuroimaging studies have provided valuable infor- mation about the neuroanatomy and neurophysiology of emotions ∗ Corresponding author at: School of Health Sciences, Department of Medical Imaging, Thompson Yates Building, The University of Liverpool, L69 3GB, UK. Tel.: +44 7701055501. E-mail address: F.M.Aldhafeeri@liverpool.ac.uk (F.M. Aldhafeeri). using visual and auditory emotionally evocative stimuli. Different types of stimuli were standardised in order to be exploited for the neurofunctional studies of emotions. Most of such studies investigating emotional processing map in the human brain have employed emotional faces, pictures and words as emotional visual stimuli [4,29,30]. Others have employed music and aversive sounds as emotional evocative acoustic stimuli [24,41]. Differences in emotionally involved brain regions between studies do exist because of many reasons including the use of different emotional stimuli and different methodological approaches [6]. One of the main interests of many neuroscientists is identifying whether positive and negative emotions employ similar or different brain regions. This interest arises from the need to create a cognitive model of emotions in healthy adults, thus, it will be possible to understand neural correlates of psychiatric conditions involving emotional aspects in humans. The standardised emotionally evocative International Affective Picture System (IAPS) have been widely employed in the neuro- functional studies of emotion [5,33]. In parallel, facial expression visual stimuli are also being utilised in functional studies of emo- tions. Both types of stimuli were found to target similar brain regions associated with emotion processing [4]. The importance of experimental neurofunctional studies of emotions in healthy adults is embodied in establishing a neurophysioloical model of positive and negative emotions. Hence, recognising and diagnosing psychi- atric disorders related to emotions will be possible. Furthermore, 0304-3940/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2012.01.064