TY - JOUR
T1 - The functional consequences of chronic, physiologically effective intracortical microstimulation
AU - Parker, Rebecca A.
AU - Davis, Tyler S.
AU - House, Paul A.
AU - Normann, Richard A.
AU - Greger, Bradley
PY - 2011
Y1 - 2011
N2 - Many studies have demonstrated the ability of chronically implanted multielectrode arrays (MEAs) to extract information from the motor cortex of both humans and nonhuman primates. Similarly, many studies have shown the ability of intracortical microstimulation to impart information to the brain via a single or a few electrodes acutely implanted in sensory cortex of nonhuman primates, but relatively few microstimulation studies characterizing chronically implanted MEAs have been performed. Additionally, device and tissue damage have been reported at the levels of microstimulation used in these studies. Whether the damage resulting from microstimulation impairs the ability of MEAs to chronically produce physiological effects, however, has not been directly tested. In this study, we examined the functional consequences of multiple months of periodic microstimulation via chronically implanted MEAs at levels capable of evoking physiological responses, that is, electromyogram (EMG) activity. The functionality of the MEA and neural tissue was determined by measuring impedances, the ability of microstimulation to evoke EMG responses, and the recording of action potentials. We found that impedances and the number of recorded action potentials followed the previously reported trend of decreasing over time in both animals that received microstimulation and those which did not receive microstimulation. Despite these trends, the ability to evoke EMG responses and record action potentials was retained throughout the study. The results of this study suggest that intracortical microstimulation via MEAs did not cause functional failure, suggesting that MEA-based microstimulation is ready to transition into subchronic (< 30. days) human trials to determine whether complex spatiotemporal sensory percepts can be evoked by patterned microstimulation.
AB - Many studies have demonstrated the ability of chronically implanted multielectrode arrays (MEAs) to extract information from the motor cortex of both humans and nonhuman primates. Similarly, many studies have shown the ability of intracortical microstimulation to impart information to the brain via a single or a few electrodes acutely implanted in sensory cortex of nonhuman primates, but relatively few microstimulation studies characterizing chronically implanted MEAs have been performed. Additionally, device and tissue damage have been reported at the levels of microstimulation used in these studies. Whether the damage resulting from microstimulation impairs the ability of MEAs to chronically produce physiological effects, however, has not been directly tested. In this study, we examined the functional consequences of multiple months of periodic microstimulation via chronically implanted MEAs at levels capable of evoking physiological responses, that is, electromyogram (EMG) activity. The functionality of the MEA and neural tissue was determined by measuring impedances, the ability of microstimulation to evoke EMG responses, and the recording of action potentials. We found that impedances and the number of recorded action potentials followed the previously reported trend of decreasing over time in both animals that received microstimulation and those which did not receive microstimulation. Despite these trends, the ability to evoke EMG responses and record action potentials was retained throughout the study. The results of this study suggest that intracortical microstimulation via MEAs did not cause functional failure, suggesting that MEA-based microstimulation is ready to transition into subchronic (< 30. days) human trials to determine whether complex spatiotemporal sensory percepts can be evoked by patterned microstimulation.
KW - Electromyogram
KW - Feline
KW - Impedance
KW - Micro-electrode array
KW - Microstimulation
KW - Motor cortex
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UR - http://www.scopus.com/inward/citedby.url?scp=79960755672&partnerID=8YFLogxK
U2 - 10.1016/B978-0-444-53815-4.00010-8
DO - 10.1016/B978-0-444-53815-4.00010-8
M3 - Article
C2 - 21867801
AN - SCOPUS:79960755672
SN - 0079-6123
VL - 194
SP - 145
EP - 165
JO - Progress in Brain Research
JF - Progress in Brain Research
ER -