The human brain is organized so that specific areas of the sensorimotor cortex control or gather information from specific body parts (e.g. the limbs) (S. Dall’Orso, T. Hamstreet, S. Muceli, The “little person” in our brain who helps to direct our movements, Frontiers for Young Minds, 10:750301, 2023). In the adult brain, areas related to contralateral upper or lower limbs have a strong functional connectivity, as well as areas related to ipsilateral limbs. In INFANTPATTERNS, we analyzed functional magnetic resonance data from 400 infants born in the period corresponding to the third trimester of pregnancy. Data were collected within an ERC synergy project (319456) granted to the secondment institution (King’s College London). We found that a crude spatial organization is already present in the preterm infant somatosensory cortex and matures over the perinatal period to became similar to the organization in the adult brain (S. Dall’Orso, T. Arichi, S. P. Fitzgibbon, A. D. Edwards, E. Burdet, S. Muceli, Development of functional organization within the sensorimotor network across the perinatal period, Human Brain Mapping, 43(7): 2249-2261, 2022). Kinematic analysis of general movements of preterm infants revealed a correlation between movements from the same limb in contralateral body sides and ipsilateral upper and lower limbs.
Movement results from forces acting upon body joints. Forces are produced by muscle activation, that in turns depends on the spinal and cortical input muscles receive. Muscle activity can be recorded with high-density grids of electrodes (T. Hamstreet, S. Muceli, The pop and color of our electrified muscles, Frontiers for Young Minds, 10:742590, 2022), that allow to estimate the input muscles receive through an ad hoc signal processing method known as decomposition.
In the project, we also developed a smart biocompatible sensor for the detection of grasping force in neonates (D. Lo Presti, S. Dall’Orso, S. Muceli, T. Arichi, S. Neumane, A. Lukens, R. Sabbadini, C. Massaroni, M. A. Caponero, E. Schena, D. Formica, E. Burdet, An fMRI compatible smart device for measuring palmar grasping actions in newborns, Sensors, 20(21): 6040, 2020).
It emerged from our literature review (I. Campanini, A. Merlo, C. Disselhorst-Klug, L. Mesin, S. Muceli, R. Merletti, Fundamental concepts of bipolar and high-density surface EMG understanding and teaching for clinical, occupational and sport applications: origin, detection, and main errors, Sensors, 22(11): 4150, 2022) that when muscles have small cross-sectional areas, as in the case of children and infants, miniaturized electrodes with good electrical contact with the skin should be used. Therefore, we developed novel high-density miniaturized electrodes, that because of their mechanical flexibility and constituent material properties are highly compliant with the shape of the skin overlying small muscles. Finally, we advanced decomposition algorithms (M. Shirzadi, H. R. Marateb, K. C. McGill, S. Muceli, M. A. Mañanas, D. Farina, An accurate and real-time method for resolving superimposed action potentials in multiunit recordings, IEEE Trans Biomed Eng, 70(1): 378-389, 2023). EMG recordings will be performed in infants as possible in future.
