title: The effect of motor familiarity during simple finger opposition tasks.
abstract: Humans are more familiar with performing (and observing) index-thumb than with any other finger to thumb grasping and the effect of familiarity has not been tested specifically with simple and intransitive actions. The study of simple and intransitive motor actions (i.e. simple actions without need of object interaction) provides the opportunity to investigate specifically the brain motor regions reducing the effect of non-motor aspects that are related with more complex and/or transitive motor actions. The aim of this study is to evaluate brain activity patterns during the execution of simple and intransitive finger movements with different degrees of familiarity. With this in mind, a functional Magnetic Resonance Imaging (fMRI) study was performed in which participants were asked to execute finger to thumb opposition tasks with all the different fingers (index, middle, ring and little) with a fixed frequency (1 Hz) determined by a visual cue. This movement is considered as the pantomime of a precision grasping action. Significant activity was identified in the Sensory Motor Cortex (SMC), posterior parietal and premotor regions for all simple conditions (index-finger>control, middle-finger>control, ring-finger>control and little-finger>control). However, a linear trend contrast (index<middle<ring<little) demonstrated that there was a linear increase of activity in the SMC (mainly in the Precentral Gyrus) while the finger used to perform the action was further from the thumb. Therefore, the execution of less familiar simple intransitive movements seems to lead to a stronger activation of the SMC than familiar ones. Posterior parietal and premotor regions did not show the aforementioned stronger activation. The most important implication of this study is the identification of differences in brain activity during the execution of simple intransitive movements with different degrees of familiarity.
authors.affiliation: Department of Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain. jplata5@hotmail.com.|Hospital Universitario de Canarias, Department of Neurosurgery, Calle Ofra s/n La Cuesta, CP 38320, La Laguna, S/C de Tenerife, Spain. jplata5@hotmail.com.
authors.forename: Julio
authors.initials: J
authors.lastname: Plata Bello
authors.affiliation: Department of Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain.|Servicio de Resonancia Magnética para Investigaciones Biomédicas (SRMIB), University of La Laguna, San Cristóbal de La Laguna, Spain.
authors.forename: Cristián
authors.initials: C
authors.lastname: Modroño
authors.affiliation: Department of Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain.|Servicio de Resonancia Magnética para Investigaciones Biomédicas (SRMIB), University of La Laguna, San Cristóbal de La Laguna, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Marcano
authors.affiliation: Department of Physiology, Faculty of Medicine, University of La Laguna, San Cristóbal de La Laguna, Spain.|Servicio de Resonancia Magnética para Investigaciones Biomédicas (SRMIB), University of La Laguna, San Cristóbal de La Laguna, Spain.
authors.forename: José Luis
authors.initials: JL
authors.lastname: González-Mora
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003463:Cues; D005260:Female; D005385:Fingers / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
keywords: Action execution; Familiarity; Precision grasping; Simple actions