RAPID COMMUNICATION Hippocampal Volume Predicts Fluid Intelligence in Musically Trained People Mathias S. Oechslin, 1,2,3 *C eline Descloux, 4 Alexandre Croquelois, 4 Julien Chanal, 2 Dimitri Van De Ville, 1,5,6 Franc¸oisLazeyras, 5 and Clara E. James 1,2,7 ABSTRACT: Recently, age-related hippocampal (HP) volume loss could be associated with a decrease in general fluid intelligence (gF). In the present study we investigated whether and how extensive mu- sical training modulates human HP volume and gF performance. Pre- viously, some studies demonstrated positive effects of musical training on higher cognitive functions such as learning and memory, associated with neural adaptations beyond the auditory domain. In order to detect possible associations between musical training and gF, we bilaterally segmented the HP formation and assessed the indi- vidual gF performance of people with different levels of musical ex- pertise. Multiple regression analyses revealed that HP volume predicts gF in musicians but not in nonmusicians; in particular, bilat- erally enhanced HP volume is associated with increased gF exclu- sively in musically trained people (amateurs and experts). This result suggests that musical training facilitates the recruitment of cognitive resources, which are essential for gF and linked to HP functioning. Musical training, even at a moderate level of intensity, can thus be considered as a potential strategy to decelerate age-related effects of cognitive decline. V C 2013 Wiley Periodicals, Inc. KEY WORDS: expertise; musicians; hippocampus; cognition; fluid intelligence; brain plasticity INTRODUCTION The hippocampal (HP) formation is a highly plas- tic brain structure that generates neurons over the whole lifespan (Lledo et al., 2006). Investigations on HP function in healthy human adults could demon- strate that age-related HP volume loss predicts decrease in general fluid intelligence (gF) performance (Reuben et al., 2011). Therefore, it is of pertinent in- terest to ascertain possible interventions that could countervail HP volume loss and thus decelerate this effect of cognitive decline. Different positive factors, such as cognitive stimulation, meditation and physical exercises may modify HP structure and volume (review by Fotuhi et al., 2012). Musical activities con- stitute another promising influential factor due to the highly complex multimodal features of musical performance. Extensive musical practice promotes functional and structural brain plasticity in auditory areas (auditory cortex: Schneider et al., 2002; Hyde et al., 2009; Meyer et al., 2012b; Oechslin et al., 2010b), auditory pathway microstructure (arcute fasciculus: Bengtsson et al., 2005; Oechslin et al., 2010a; Halwani et al., 2011), the motor system (somatosensory cortex: Elbert et al., 1995; corpus callosum: Schmithorst and Wilke, 2002; primary motor cortex: Hyde et al., 2009; corticospinal tract: Imfeld et al., 2009) and in areas involved in multisensory integration (Lee and Noppeney, 2011; Luo et al., 2012; James et al., in press). Previous reviews outlined the full panoply of training induced cortical adaptations; highlighting the role of the musical brain as one of the most promi- nent models in neuroscience to study brain plasticity (Schellenberg, 2001; M€ unte et al., 2002; J € ancke, 2009; Trainor et al., 2009; Kraus and Chandrase- karan, 2010; Wan and Schlaug, 2010; Besson et al., 2011; Pantev and Herholz, 2011; Penhune, 2011; Herholz and Zatorre, 2012; Meyer et al., 2012a; Schulze and Koelsch, 2012). With respect to auditory cognition, it has been demonstrated that musical training changes the 1 Geneva Neuroscience Center, University of Geneva, CH-1211 Geneva 4, Switzerland; 2 Faculty of Psychology and Educational Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland; 3 International Normal Aging and Plasticity Center (INAPIC), University of Zurich, CH-8006, Zurich, Switzerland; 4 Department of Cell Biology and Morphology, University of Lausanne, CH-1015 Lausanne, Switzerland; 5 Department of Radiology and Medical Informatics, H^ opitaux Universitaires de Gene `ve, CH-1211 Geneva 4, Switzerland; 6 Institute of Bioengineering,  Ecole Polytechnique F ed erale de Lausanne, CH-1015 Lausanne, Switzerland; 7 School of Health Geneva, University of Applied Sciences Western Switzerland, CH-1206 Geneva, Switzerland Grant sponsor: Swiss National Science Foundation (part of a multibrain imaging project entitled Behavioral, neuro-functional, and neuro- anatomical correlates of experience dependent music perception); Grant number: 100014-125050. *Correspondence to: Mathias S. Oechslin, International Normal Aging and Plasticity Imaging Center (INAPIC), University of Zurich, Binzm€ uh- lestrasse 14/25, 8050 Zurich, Switzerland. E-mail: mathias.oechslin@uzh.ch Accepted for publication 12 March 2013 DOI 10.1002/hipo.22120 Published online 29 April 2013 in Wiley Online Library (wileyonlinelibrary.com). V C 2013 WILEY PERIODICALS, INC. HIPPOCAMPUS 23:552–558 (2013)