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Your search keyword '"Bensmaia, Sliman"' showing total 11 results
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11 results on '"Bensmaia, Sliman"'

4. Decoding hand kinematics from population responses in sensorimotor cortex during grasping.

Author

Okorokova, Elizaveta V, Goodman, James M, Hatsopoulos, Nicholas G, and Bensmaia, Sliman J

Subjects
SENSORIMOTOR cortex, SUPERIOR colliculus, KINEMATICS, MOTOR cortex, SOMATOSENSORY cortex, DEGREES of freedom, BRAINWASHING
Abstract

Objective. The hand—a complex effector comprising dozens of degrees of freedom of movement—endows us with the ability to flexibly, precisely, and effortlessly interact with objects. The neural signals associated with dexterous hand movements in primary motor cortex (M1) and somatosensory cortex (SC) have received comparatively less attention than have those associated with proximal upper limb control. Approach. To fill this gap, we trained two monkeys to grasp objects varying in size and shape while tracking their hand postures and recording single-unit activity from M1 and SC. We then decoded their hand kinematics across tens of joints from population activity in these areas. Main results. We found that we could accurately decode kinematics with a small number of neural signals and that different cortical fields carry different amounts of information about hand kinematics. In particular, neural signals in rostral M1 led to better performance than did signals in caudal M1, whereas Brodmann's area 3a outperformed areas 1 and 2 in SC. Moreover, decoding performance was higher for joint angles than joint angular velocities, in contrast to what has been found with proximal limb decoders. Significance. We conclude that cortical signals can be used for dexterous hand control in brain machine interface applications and that postural representations in SC may be exploited via intracortical stimulation to close the sensorimotor loop. [ABSTRACT FROM AUTHOR]

Published
2020
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7. Sensory adaptation to electrical stimulation of the somatosensory nerves

Author

UCL - SST/ICTM/INMA - Pôle en ingénierie mathématique, Graczyk, Emily L, Delhaye, Benoit, Schiefer, Matthew A, Bensmaia, Sliman J, Tyler, Dustin J, UCL - SST/ICTM/INMA - Pôle en ingénierie mathématique, Graczyk, Emily L, Delhaye, Benoit, Schiefer, Matthew A, Bensmaia, Sliman J, and Tyler, Dustin J

Abstract

Objective. Sensory systems adapt their sensitivity to ambient stimulation levels to improve their responsiveness to changes in stimulation. The sense of touch is also subject to adaptation, as evidenced by the desensitization produced by prolonged vibratory stimulation of the skin. Electrical stimulation of nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial touch is also subject to adaptation, despite the fact that the peripheral mechanotransducers are bypassed. Approach. Using well-established psychophysical paradigms, we characterize the time course and magnitude of sensory adaptation caused by extended electrical stimulation of the residual somatosensory nerves in three human amputees implanted with cuff electrodes. Main results. We find that electrical stimulation of the nerve also induces perceptual adaptation that recovers after cessation of the stimulus. The time course and magnitude of electrically-induced adaptation are equivalent to their mechanically-induced counterparts. Significance. We conclude that, in natural touch, the process of mechanotransduction is not required for adaptation, and artificial touch naturally experiences adaptation-induced adjustments of the dynamic range of sensations. Further, as it does for native hands, adaptation confers to bionic hands enhanced sensitivity to changes in stimulation and thus a more natural sensory experience.

Published
2018

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