Parametric analysis of rate-dependent hemodynamic response functions of cortical and subcortical brain structures during auditorily cued finger tapping: a fMRI study

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2003-03, Vol.18 (3), p.731-739
• Main Authors: Riecker, Axel, Wildgruber, Dirk, Mathiak, Klaus, Grodd, Wolfgang, Ackermann, Hermann
• Format: Article
• Language: English
• Subjects: Adult; Attention - physiology; Basal ganglia; Basal Ganglia - blood supply; Basal Ganglia - physiology; Brain; Brain Mapping; Cerebellum; Cerebellum - blood supply; Cerebellum - physiology; Cerebral Cortex - blood supply; Cerebral Cortex - physiology; Cues; Disorder; Female; Finger tapping; Functional magnetic resonance imaging; Hemodynamic response function; Hemodynamics - physiology; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Motor Activity - physiology; Movement rate; Oxygen Consumption - physiology; Parametric analysis; Pitch Perception - physiology; Reaction Time - physiology; Supplementary motor area
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/S1053-8119(03)00003-X

A multitude of functional imaging studies revealed a mass activation effect at the level of the sensorimotor cortex during repetitive finger-tapping or finger-to-thumb opposition tasks in terms of either a stepwise or a monotonic relationship between movement rate and hemodynamic response. With respect to subcortical structures of the centralmotor system, there is, by contrast, some preliminary evidence for nonlinear rate/response functions within basal ganglia and cerebellum. To further specify these hemodynamic mechanisms, functional magnetic resonance imaging (fMRI) was performed during a finger-tapping task in response to acoustic stimuli (six different frequencies: 2.0, 2.5, 3.0, 4.0, 5.0 and 6.0 Hz; applied via headphones). Passive listening to the same auditory stimuli served as a control condition. Statistical evaluation of the obtained data considered two approaches: categorical and parametric analysis. As expected, the magnitude of the elicited hemodynamic response within left sensorimotor cortex (plateau phase at frequencies above 4 Hz) and mesiofrontal cortex paralleled movement rate. The observed bipartite mesial response pattern, most presumably, reflects functional compartmentalization of supplementary motor area (SMA) in a rostral component (pre-SMA) and in a caudal (SMA proper) component. At the level of the cerebellum, two significant hemodynamic responses within the hemisphere ipsilateral to the hand engaged into finger tapping (anterior/posterior quadrangular lobule and posterior quadrangular lobule) could be observed. Both activation foci exhibited a stepwise rate/response function. In accordance with clinical data, these data indicate different cerebellar contributions to motor control at frequencies below or above about 3 Hz, respectively. Caudate nucleus, putamen, and external pallidum of the left hemisphere displayed, by contrast, a negative linear rate/response relationship. The physiological significance of these latter findings remains to be clarified.