Related Experiment Video
Updated: Jan 18, 2026

Block Building Task Identifies Distinct Groups of Left/Right-hand Choice Patterns After Unilateral Peripheral Nerve Injury
Published on: March 21, 2025
Cerebral circuits involved in preferential hand posture representation for action
V Piombino1, M D'Alonzo2, F Castro3
1Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Università Campus Bio-Medico di Roma, Rome, Italy; Department of Psychology and Life Sciences, Faculty of Humanities, Charles University, Prague, Czechia.
Objective:
The thumb-down/fingers-up (standard) posture was shown to be the configuration in which the hand is preferentially represented by the brain. This supra-modal representation results in improved sensorimotor performances. This study aims at identifying the cortical circuit responsible for this advantage.
Methods:
Different TMS coil orientations (antero-posterior, latero-medial, postero-anterior) - activating different cortical circuits- have been used to test cortico-spinal and cortico-cortical connections in different postures. Additionally, pair-pulse TMS protocols were used to explore inhibitory and facilitatory mechanisms within the primary motor cortex (M1) that might contribute to the observed postural advantage.
Results:
A significant corticospinal excitability difference in nMEPs between standard and inverse posture was observed with antero-posterior TMS (p = 0.003), activating cortico-cortical connections from premotor cortex (PM) and with postero-anterior TMS (p = 0.042), favoring local cortical connections. Latero-medial stimulation, activating direct corticospinal connections, did not show a preference. A MEPs analysis further revealed a significant effect exclusively for antero-posterior stimulation (p < 0.003). Intracortical facilitation and inhibition were unaffected by hand postures.
Conclusions:
The postural advantage of the thumb-down/fingers-up hand configuration is associated with a neural circuit involving PM cortex projecting to M1, activated by antero-posterior and postero-anterior TMS.
Significance:
The corticospinal evoked activity to different TMS protocols gave cues on the neural basis of body representation and favored posture.
Related Concept Videos
Motor and Sensory Areas of the Cortex
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex....
Major Somatic Sensory Pathways
Somatosensory, Motor, and Association Cortex
Somatosensation
Indirect Motor Pathways
The vestibulospinal tract originates in the vestibular nuclei of the brainstem. The vestibular system detects changes in...
Direct Motor Pathways
The corticospinal tract is responsible for the voluntary movement of the limbs and trunk. It originates in the cerebral cortex of the brain and descends through the cerebrum's internal capsule and...

