Behavioural Brain Research 223 (2011) 280–286 Contents lists available at ScienceDirect Behavioural Brain Research jo u r n al hom epa ge: www.elsevier.com/locate/bbr Research report Non-effective increase of fMRI-activation for motor performance in elder individuals M. Loibl, W. Beutling, E. Kaza, M. Lotze ∗ Functional Imaging Unit, Center for Diagnostic Radiology and Neuroradiology, University of Greifswald, Greifswald, Germany a r t i c l e i n f o Article history: Received 24 February 2011 Received in revised form 20 April 2011 Accepted 25 April 2011 Available online 6 May 2011 Keywords: Age Motor compensation Motor recruitment a b s t r a c t Motor performance declines with increasing age and it has been proposed that elder people might com- pensate for these deficits with increased cerebral activation. However, it is not known, whether increased activation – especially in motor areas of the contralateral and the ipsilateral cerebral hemisphere – might effectively contribute to motor performance or whether it is an ineffective way to counteract age related deficits in the motor system. We tested this question by mapping brain activation during performance of differentially demanding motor tasks in 18 young (mean 25.39 years) and 17 elderly (mean 66.65 years) healthy individuals. We tested a wide range of hand motor tasks from passive wrist movements, fist clenching at different frequencies, to a somatosensory-guided finger pinch task. In the elderly group functional activation was generally increased for all tasks with comparable motor performance for ipsi- lateral primary and secondary motor areas. The young group showed increased contralateral primary motor cortex activation for the more difficult somatosensory guided precision grip task. We correlated motor performance of the task with high difficulty and comparable performance with fMRI-activation. Elder participants showed a negative correlation for the ipsilateral supplementary motor area (SMA) and for the ipsilateral sensorimotor cortex (SM1). Young participants showed a positive correlation for contralateral SMA and SM1. Our data suggest an increased cerebral recruitment reflects an inefficient response to an age-related higher difficulty of task and is not an effective way to counteract age-related deficits in the motor system. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Motor performance decreases linearly in individuals older than 60 years for less demanding tasks and nonlinearly for complex movements [20]. The decline in motor performance with increasing age is associated with a structural decline in the neuromuscular sys- tem [4,10] and central neuronal changes [14]. For other domains, it has been demonstrated that cortical representation in elderly peo- ple, as investigated with functional magnetic resonance imaging (fMRI), differs from that in younger persons, even when the level of performance is matched [1]. Generally, task-related activation appears to be more focused and lateralized in younger individuals and more diffuse and bilateral in older individuals [1,26]. For the motor domain the reduction of functional lateralization, especially as a result of ipsilateral activation, correlates with age [16]. For the elderly functional mapping studies on simple motor tasks revealed increased activation in contralateral primary and ∗ Corresponding author at: Functional Imaging Unit, Center for Diagnostic Radi- ology and Neuroradiology, University of Greifswald, Friedrich-Löffler-Straße 23a, D-17487 Greifswald, Germany. Tel.: +49 3834 866899; fax: +49 3834 866898. E-mail address: martin.lotze@uni-greifswald.de (M. Lotze). secondary motor regions (M1, dPMC, SMA [9,14] and parietal cor- tex [9,14], but also in ipsilateral M1 [15,16,18,28], dPMC [15,18], and SMA [2,15]. These studies with younger and older individuals were based on experiments testing activation differences during the perfor- mance of simple motor tasks. However, highly demanding motor tasks are the first to show a decline in aged individuals [20] and should therefore be more distinguishable between groups. As an example of a more challenging motor paradigm, Heuninckx et al. [8] used an interlimb coordination task and found a positive corre- lation between performance and BOLD-signal of areas additionally activated by the elderly. The authors conclude that age-related changes are compensational and increased activation in the older participants is associated with better performance. This effective compensation hypothesis emphasizes that increased activation, especially in non-motor-areas, is associated with increased per- formance, and is therefore able to compensate for motor deficits. In older individuals, additionally activated areas – especially non- motor regions – should correlate positively with performance. However, in this study, the performance level between groups differed and is therefore only comparable in certain aspects. In contrast, a compensation of decreased motor ability should be suc- cessful in simple, repetitive motor tasks. It might be insufficient 0166-4328/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.bbr.2011.04.040