Mapping function of hand proprioception in the human motor cortex (ProMap)
Main funder
Funder's project number: 361732
Funds granted by main funder (€)
- 549 251,00
Funding program
Project timetable
Project start date: 01/09/2024
Project end date: 31/08/2028
Summary
It is still unknown how the brain is able to achieve the incredible repertoire of human motor actions with multifaceted purposes spanning from locomotion to complex fine-motor actions of the hand. This motor control is likely based on the vast somatosensory feedback from the locomotor system, i.e., from mechanoreceptors in the muscles, tendons, joints and skin. These receptors signaling the internal state of the moving body are called proprioceptors, and thus enable, e.g., senses of movement, position, effort. We aim to examine the effect of proprioceptive feedback on cortical motor processes and output using navigated transcranial magnetic stimulation (nTMS) combined with electroencephalography (EEG) and new groundbreaking multi-locus TMS (mTMS). For the first time, mTMS enables noninvasive stimulation of nearby cortical regions even with sub-ms intervals using electrical targeting and a priori tractography guided TMS targeting. Thus, we can investigate directly their causal functional interactions, and base it also on their structural white matter connectivity.
Our two primary aims:
(1) Proprioceptive mapping: to establish cortical proprioceptive representations of the fingers at sub-millimeter resolution using our neuroimaging compatible proprioceptive stimulators in 3T- and 7T-functional magnetic resonance imaging (fMRI). These finger specific cortical loci will be used as targets in TMS causal mapping (see below).
(2) Causal mapping: to examine whether the human cortex embodies a closed causally effective proprioceptive–motor loop between anatomically wired hand areas in the primary somatosensory and motor cortices. First, we expect the conditioning stimulation of the postcentral proprioceptive target to modulate the nearby wired precentral motor output to the target muscles. Secondly, we expect this conditioning effect to be further modulated to proprioceptive feedback arriving to the cortex shortly after stimulation of proprioceptors in the periphery.
This ambitious project is a great opportunity for groundbreaking discoveries in human motor neuroscience. The project will undoubtedly provide insights into functional anatomy of sensorimotor cortices and interplay between proprioceptive afference and motor efference, i.e., causal body-brain interactions. This new evidence is important to better understand the basic mechanisms of cortical sensorimotor integration and various motor disorders, but also for developing brain-computer interfaces.
Our two primary aims:
(1) Proprioceptive mapping: to establish cortical proprioceptive representations of the fingers at sub-millimeter resolution using our neuroimaging compatible proprioceptive stimulators in 3T- and 7T-functional magnetic resonance imaging (fMRI). These finger specific cortical loci will be used as targets in TMS causal mapping (see below).
(2) Causal mapping: to examine whether the human cortex embodies a closed causally effective proprioceptive–motor loop between anatomically wired hand areas in the primary somatosensory and motor cortices. First, we expect the conditioning stimulation of the postcentral proprioceptive target to modulate the nearby wired precentral motor output to the target muscles. Secondly, we expect this conditioning effect to be further modulated to proprioceptive feedback arriving to the cortex shortly after stimulation of proprioceptors in the periphery.
This ambitious project is a great opportunity for groundbreaking discoveries in human motor neuroscience. The project will undoubtedly provide insights into functional anatomy of sensorimotor cortices and interplay between proprioceptive afference and motor efference, i.e., causal body-brain interactions. This new evidence is important to better understand the basic mechanisms of cortical sensorimotor integration and various motor disorders, but also for developing brain-computer interfaces.
