Neuropsychologia 47 (2009) 980–987 Contents lists available at ScienceDirect Neuropsychologia journal homepage: www.elsevier.com/locate/neuropsychologia Reduced heat pain thresholds after sad-mood induction are associated with changes in thalamic activity Gerd Wagner, Mandy Koschke, Tanja Leuf, Ralf Schlösser, Karl-Jürgen Bär ∗ Department of Psychiatry and Psychotherapy, Friedrich Schiller University Jena, Philosophenweg 3, 07743 Jena, Germany article info Article history: Received 5 June 2008 Received in revised form 15 October 2008 Accepted 27 October 2008 Available online 5 November 2008 Keywords: Pain perception threshold Major depression Mood induction fMRI abstract Negative affective states influence pain processing in healthy subjects in terms of augmented pain expe- rience. Furthermore, our previous studies revealed that patients with major depressive disorder showed increased heat pain thresholds on the skin. Potential neurofunctional correlates of this finding were located within the fronto-thalamic network. The aim of the present study was to investigate the neu- rofunctional underpinnings of the influence of sad mood upon heat pain processing in healthy subjects. For this purpose, we used a combination of the Velten Mood Induction procedure and a piece of music to induce sad affect. Initially we assessed heat pain threshold after successful induction of sad mood outside the MR scanner in Experiment 1. We found a highly significant reduction in heat pain threshold on the left hand and a trend for the right. In Experiment 2, we applied thermal pain stimuli on the left hand (37, 42, and 45 ◦ C) in an MRI scanner. Subjects were scanned twice, one group before and after sad-mood induction and another group before and after neutral-mood induction, respectively. Our main finding was a significant group × mood- induction interaction bilaterally in the ventrolateral nucleus of the thalamus indicating a BOLD signal increase after sad-mood induction and a BOLD signal decrease in the control group. We present evidence that induced sad affect leads to reduced heat pain thresholds in healthy subjects. This is probably due to altered lateral thalamic activity, which is potentially associated with changed attentional processes. © 2008 Elsevier Ltd. All rights reserved. 1. Introduction The complex sensory experience of pain involves cognitive, behavioural and emotional aspects which are closely interrelated. A model for the interaction between different components has been proposed, which involves a dual pathway of affective pain process- ing (Price, 2000). In addition to direct activation by the spinothala- mic pathway, a corticolimbic pathway may play a role in integrating sensory pain characteristics with information from other sensory systems as well as learning and memory. This adds a cognitive aspect regarding the long-term consequences to affective pain pro- cessing. In addition, it has been pointed out that direct pathways from the thalamus to the amygdala and related structures may exist (Price, 2000). The interrelation between emotion and pain is mul- tifactorial and there is strong experimental evidence that emotion modulates pain perception in healthy subjects as well as in patients with psychiatric disorders (Bär et al., 2006; Jochum et al., 2006). Several experimental approaches assessed the influence of emo- tion on pain in healthy subjects. Positive as well as negative emotion ∗ Corresponding author. Tel.: +49 3641 935282; fax: +49 3641 936217. E-mail address: Karl-Juergen.Baer@med.uni-jena.de (K.-J. Bär). induction by affective material like pictures produces differen- tial pain processing (Meagher, Arnau, & Rhudy, 2001). Willoughby, Hailey, Mulkana, and Rowe (2002) presented evidence that healthy subjects had significantly lower tolerance times in the cold-pressor task and higher pain catastrophizing scores after negative sad- mood induction. Pain catastrophizing is defined as a set of negative emotional and cognitive processes during the experience of pain, which characterizes pain as awful, horrible and unbearable. In the study of Willoughby et al. (2002), it was assessed by administering the Pain Catastrophizing Scale (PCS; Sullivan, Bishop, & Pivik, 1995). Furthermore, it was shown that viewing depressive statements reduces cold-pressor tolerance while viewing elation statements enhances pain tolerance (Zelman, 1991). In our previous studies with depressed patients, we could observe that patients with major depressive disorder showed hypoalgesia for thermal or electrical pain on the skin (Bär et al., 2005). By means of fMRI, we tested the neurofunctional underpin- nings of this type of hypoalgesia for thermal pain and observed a relative hyperactivation in a fronto-thalamic brain network (Bär et al., 2007).@@ To further elucidate the influence of emotional states upon pain processing, we investigated the neurofunctional correlates of the interaction between sad affect and thermal pain in healthy subjects. 0028-3932/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.neuropsychologia.2008.10.021