Biology Reference
In-Depth Information
signals. The amputated nerves are surgically reconnected to residual muscles
that they reinnervate. Therefore, patients can send volitional orders to move
the phantom limb via the nerves that now are stimulating the residual mus-
cles, whose EMG activity is recorded by a surface electrode array and
redirected to control artificial prostheses with several degrees of freedom,
and that can also be processed by pattern recognition (
Kuiken et al.,
2009
). Moreover, these amputees were even able to perceive tactile sensa-
tions of the missing limb when touched on the reinnervated skin areas
(
Sensinger, Schultz, & Kuiken, 2009
).
Further advances under testing rely on directly interfacing the severed
nerves that subserved the amputated limb with multipolar electrodes that
may record motor commands and stimulate sensory feedback, thus
reestablishing a bidirectional link between the nervous system and the pros-
thesis in a physiological manner. Recent investigations have reported that a
cybernetic prosthesis can be commanded by interfacing peripheral nerves
with intraneural electrodes. Several LIFEs were implanted in the median
and ulnar nerves of chronic amputees, allowing to perform three distinct
hand movements under voluntary control, and providing sensory feedback
from the hand prosthesis that allowed perceptions of joint position and
object recognition (
Dhillon, Lawrence, Hutchinson, & Horch, 2004;
Dhillon et al., 2005; Horch, Meek, Taylor, & Hutchinson, 2011; Micera
et al., 2011; Rossini et al., 2010
). Still limited but promising experiences
support the view that intraneural interfaces may also allow a refined link with
external teleoperated robotic devices (
Warwick et al., 2003
).
5. CONCLUSION
The possibility of interfacing and controlling artificial machines with
biological signals has a long history of multidisciplinary research. The rapid
growth of knowledge and applications in the fields of neural regeneration
and neuroprosthesis has prompted to identify new areas for converging
research, which are evolving in recent years. They include, among others,
enhancement of axonal regeneration and injury healing by electrical mod-
ulation, development of hybrid neural interfaces combining artificial and
biological elements, investigation of patterned neural activity in regulating
dysfunctional neuronal circuits, and promoting neural plasticity for improv-
ing rehabilitation (
Andrews, 2009; Aravamudhan & Bellamkonda, 2011;
Grill et al., 2001
).
