Original article Functional MRI investigation of verbal working memory in adults with anorexia nervosa N.P. Lao-Kaim a,1 , V.P. Giampietro b,1 , S.C.R. Williams b,c , A. Simmons b,c , K. Tchanturia a, * a King’s College London, Institute of Psychiatry, Department of Psychological Medicine, London, United Kingdom b King’s College London, Institute of Psychiatry, Department of Neuroimaging, SE5 8AF London, United Kingdom c NIHR Biomedical Research Centre for Mental Health at South London, Maudsley NHS Foundation Trust, Institute of Psychiatry, King’s College London, London, United Kingdom 1. Introduction Anorexia nervosa (AN) is a disorder characterised by extreme dietary restraint, abnormal psychosocial functioning and poor weight-related physical morbidity. With a lack of empirical support for behavioural and pharmacological treatment of AN, further research is needed to improve understanding and development of successful interventions [65]. People with AN exhibit inefficient visuo-spatial memory and processing [36], cognitive flexibility [63], long-term memory [48], attention [17] and central coherence [38]. However, the results of studies assessing verbal working memory (vWM) in AN have been inconsistent (Table 1). WM is a limited capacity store through which information is held, maintained and manipulated in order to plan and carry out behaviour [43] and to facilitate complex processes such as comprehension, learning and reasoning [3] (Fig. 1). Specific cortical regions within the fronto-parietal brain net- work have been found to control these vWM mechanisms [49]. With relation to Baddeley and Hitch’s model [3], the left posterior parietal cortex (PP) has been implicated in phonological storage, the left inferior frontal gyrus (IFG) in sub-vocal rehearsal and the central executive is thought to reside in the dorsolateral pre- frontal cortex (DLPFC) [60]. Focal lesions in these areas give rise to vWM process-specific deficits [45] and recent neuroimaging experiments have found these same regions to show consistent abnormalities in people with AN. Voxel-based morphometric analysis of volumetric magnetic resonance imaging (MRI) [1], has localised decreases in cortical grey matter to the parietal cortex [14,25], and cerebellum [8]. The cerebellum is traditionally associated with fine motor co-ordination but has also been implicated in facilitating initial phonological encoding of verbal information [53]. Conversely, one study found a significant increase in grey matter volume in the DLPFC [8]. A timely review of positron emission tomography (PET), single photon emission computer tomography (SPECT) and functional MRI (fMRI) studies, has demonstrated a consensus of functional ‘‘disturbance’’ in the IFG, DLPFC and inferior parietal lobule (IPL) [50]. Effects between binge/purge and restrictor subtypes were similar, but laterality towards the left hemisphere for IPL European Psychiatry xxx (2013) xxx–xxx A R T I C L E I N F O Article history: Received 11 April 2013 Received in revised form 10 May 2013 Accepted 22 May 2013 Available online xxx Keywords: Eating disorders Anorexia Working memory Neuropsychology fMRI Executive function A B S T R A C T Literature regarding verbal working memory (vWM) in anorexia nervosa (AN) has been inconsistent due to a misunderstanding of the key components of vWM and introduction of confounding stimuli. Furthermore, there are no studies looking at how brain function in people with AN relates to vWM performance. The present study used functional magnetic resonance imaging (fMRI) with a letter n-back paradigm to study the effect of increasing vWM task difficulty on cortical functioning in the largest AN sample to date (n = 31). Although the AN group had low BMI and higher anxious and depressive symptomology compared to age-matched controls (HC), there were no between-group differences in accuracy and speed at any task difficulty. fMRI data revealed no regions exhibiting significant differences in activation when groups were compared at each difficulty separately and no regions showing group x condition interaction. Although there was a trend towards lower accuracy as duration of illness increased, this was not correlated with activity in regions associated with vWM. These findings indicate that vWM in AN is as efficient and performed using the same cognitive strategy as HC, and that there may not be a need for therapies to pursue remediation of this particular neurocognitive faculty. Crown Copyright ß 2013 Published by Elsevier Masson SAS. All rights reserved. * Corresponding author. PO59, King’s College London, Institute of Psychiatry, Department of Psychological Medicine, De Crespigny Park, SE5 8AF London, United Kingdom. Tel.: +44 0 207 848 0134; fax: +44 0 207 848 0182. E-mail address: kate.tchanturia@kcl.ac.uk (K. Tchanturia). 1 Both authors contributed equally to the manuscript. G Model EURPSY-3074; No. of Pages 8 Please cite this article in press as: Lao-Kaim NP, et al. Functional MRI investigation of verbal working memory in adults with anorexia nervosa. European Psychiatry (2013), http://dx.doi.org/10.1016/j.eurpsy.2013.05.003 Available online at www.sciencedirect.com 0924-9338/$ – see front matter . Crown Copyright ß 2013 Published by Elsevier Masson SAS. All rights reserved. http://dx.doi.org/10.1016/j.eurpsy.2013.05.003