Complex organization of human primary motor cortex: a high-resolution fMRI study.
A traditional view of the human motor cortex is that it contains an overlapping sequence of body part representations from the tongue in a ventral location to the foot in a dorsal location. In this study, high-resolution functional MRI (1.5x1.5x2 mm) was used to examine the somatotopic map in the lateral motor cortex of humans, to determine whether it followed the traditional somatotopic order or whether it contained any violations of that somatotopic order. The arm and hand representation had a complex organization in which the arm was relatively emphasized in two areas: one dorsal and the other ventral to a region that emphasized the fingers. This violation of a traditional somatotopic order suggests that the motor cortex is not merely a map of the body but is topographically shaped by other influences, perhaps including correlations in the use of body parts in the motor repertoire.
Meier
Jeffrey D
JD
Department of Psychology, Green Hall, Princeton University, Princeton, NJ 08544, USA.
Aflalo
Tyson N
TN
Kastner
Sabine
S
Graziano
Michael S A
MS
D000328:Adult; D001931:Brain Mapping; D003463:Cues; D003627:Data Interpretation, Statistical; D004525:Efferent Pathways / Q000033:anatomy & histology / Q000502:physiology; D005385:Fingers / Q000294:innervation / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008046:Lip / Q000294:innervation / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D012044:Regression Analysis; D034941:Upper Extremity / Q000294:innervation / Q000502:physiology