Real-Time Performance of a Tactile Neuroprosthesis on Awake Behaving Rats

Öztürk, Sevgi; Devecioğlu, İsmail; Beygi, M H Miran; Atasoy, Ahmet; Mutlu, Senol; Ozkan, Mehmed; Güçlü, Burak

doi:10.1109/tnsre.2019.2910320

Cited by 17 publications

(5 citation statements)

References 39 publications

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“…Implantable neural interfaces offer a method for external electronic devices to be connected to the central nervous system (CNS) in order to stimulate or record neurological signals, such as action potentials or multi-unit extracellular potentials, with the additional benefit of high spatial and temporal resolution. This interface forms a link for direct communication with the CNS through which the complex activities of neurons can be decoded to control active prosthetic devices or to stimulate one or more neural circuits to restore or enhance physiological functions [1].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

et al. 2019

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One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from the material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. Here, we report on the fabrication and initial electrochemical characterization of a nearly monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe. The probe consists of a single 5 mm-long shank with 16 electrode sites. An ~8 µm-thick p-type 3C-SiC epilayer was grown on a silicon-on-insulator (SOI) wafer, which was followed by a ~2 µm-thick epilayer of heavily n-type (n+) 3C-SiC in order to form conductive traces and the electrode sites. Diodes formed between the p and n+ layers provided substrate isolation between the channels. A thin layer of amorphous silicon carbide (a-SiC) was deposited via plasma-enhanced chemical vapor deposition (PECVD) to insulate the surface of the probe from the external environment. Forming the probes on a SOI wafer supported the ease of probe removal from the handle wafer by simple immersion in HF, thus aiding in the manufacturability of the probes. Free-standing probes and planar single-ended test microelectrodes were fabricated from the same 3C-SiC epiwafers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed on test microelectrodes with an area of 491 µm2 in phosphate buffered saline (PBS) solution. The measurements showed an impedance magnitude of 165 kΩ ± 14.7 kΩ (mean ± standard deviation) at 1 kHz, anodic charge storage capacity (CSC) of 15.4 ± 1.46 mC/cm2, and a cathodic CSC of 15.2 ± 1.03 mC/cm2. Current-voltage tests were conducted to characterize the p-n diode, n-p-n junction isolation, and leakage currents. The turn-on voltage was determined to be on the order of ~1.4 V and the leakage current was less than 8 μArms. This all-SiC neural probe realizes nearly monolithic integration of device components to provide a likely neurocompatible INI that should mitigate long-term reliability issues associated with chronic implantation.

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Section: Introductionmentioning

confidence: 99%

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

et al. 2019

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“…To our knowledge, three behavioral paradigms have been described in the literature for assessing ICMS in the primary somatosensory cortex of rodents ( Koivuniemi A. et al, 2011 ; Öztürk et al, 2019 ; Urdaneta et al, 2021 ; Lycke et al, 2023 ). These behavioral tasks use either a freely moving passive avoidance psychophysical detection task, a freely moving active avoidance conditioning paradigm, or a head-fixed go/no-go task.…”

Section: Introductionmentioning

confidence: 99%

“…These behavioral tasks use either a freely moving passive avoidance psychophysical detection task, a freely moving active avoidance conditioning paradigm, or a head-fixed go/no-go task. All were successful at detecting thresholds for up to 33 weeks with 70–95% accuracy; however, all three paradigms involve water deprivation for up to 36 h prior to behavioral testing ( Koivuniemi A. et al, 2011 ; Öztürk et al, 2019 ) which can produce stress ( Vasilev et al, 2021 ) and confound chronic assessments. Alternative behavioral paradigms that use food-restriction have been described for the testing of auditory thresholds.…”

Section: Introductionmentioning

confidence: 99%

Behavioral paradigm for the evaluation of stimulation-evoked somatosensory perception thresholds in rats

Smith

Cheon

et al. 2023

Front. Neurosci.

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Intracortical microstimulation (ICMS) of the somatosensory cortex via penetrating microelectrode arrays (MEAs) can evoke cutaneous and proprioceptive sensations for restoration of perception in individuals with spinal cord injuries. However, ICMS current amplitudes needed to evoke these sensory percepts tend to change over time following implantation. Animal models have been used to investigate the mechanisms by which these changes occur and aid in the development of new engineering strategies to mitigate such changes. Non-human primates are commonly the animal of choice for investigating ICMS, but ethical concerns exist regarding their use. Rodents are a preferred animal model due to their availability, affordability, and ease of handling, but there are limited choices of behavioral tasks for investigating ICMS. In this study, we investigated the application of an innovative behavioral go/no-go paradigm capable of estimating ICMS-evoked sensory perception thresholds in freely moving rats. We divided animals into two groups, one receiving ICMS and a control group receiving auditory tones. Then, we trained the animals to nose-poke – a well-established behavioral task for rats – following either a suprathreshold ICMS current-controlled pulse train or frequency-controlled auditory tone. Animals received a sugar pellet reward when nose-poking correctly. When nose-poking incorrectly, animals received a mild air puff. After animals became proficient in this task, as defined by accuracy, precision, and other performance metrics, they continued to the next phase for perception threshold detection, where we varied the ICMS amplitude using a modified staircase method. Finally, we used non-linear regression to estimate perception thresholds. Results indicated that our behavioral protocol could estimate ICMS perception thresholds based on ~95% accuracy of rat nose-poke responses to the conditioned stimulus. This behavioral paradigm provides a robust methodology for evaluating stimulation-evoked somatosensory percepts in rats comparable to the evaluation of auditory percepts. In future studies, this validated methodology can be used to study the performance of novel MEA device technologies on ICMS-evoked perception threshold stability using freely moving rats or to investigate information processing principles in neural circuits related to sensory perception discrimination.

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“…To our knowledge, three behavioral paradigms have been described in the literature for assessing ICMS in the primary somatosensory cortex of rodents Öztürk et al, 2019;Urdaneta et al, 2021;Lycke et al, 2023). These behavioral tasks use either a freely moving passive avoidance psychophysical detection task, a freely moving active avoidance conditioning paradigm, or a head-fixed go/no-go task.…”

Section: Introductionmentioning

confidence: 99%

“…These behavioral tasks use either a freely moving passive avoidance psychophysical detection task, a freely moving active avoidance conditioning paradigm, or a head-fixed go/no-go task. All were successful at detecting thresholds for up to 33 weeks with 70-95% accuracy; however, all three paradigms involve water deprivation for up to 36 h prior to behavioral testing Öztürk et al, 2019) which can produce stress (Vasilev et al, 2021) and confound chronic assessments. Alternative behavioral paradigms that use foodrestriction have been described for the testing of auditory thresholds.…”

Section: Introductionmentioning

confidence: 99%

Behavioral Paradigm for the Evaluation of Stimulation-Evoked Somatosensory Perception Thresholds in Rats

Smith

Cheon

et al. 2023

Preprint

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Intracortical microstimulation (ICMS) of the somatosensory cortex via penetrating microelectrode arrays (MEAs) can evoke cutaneous and proprioceptive sensations for restoration of perception in individuals with spinal cord injuries. However, ICMS current amplitudes needed to evoke these sensory percepts tend to change over time following implantation. Animal models have been used to investigate the mechanisms by which these changes occur and aid in the development of new engineering strategies to mitigate such changes. Non-human primates are commonly the animal of choice for investigating ICMS, but ethical concerns exist regarding their use. Rodents are a preferred animal model due to their availability, affordability, and ease of handling, but there are limited choices of behavioral tasks for investigating ICMS. In this study, we investigated the application of an innovative behavioral go/no-go paradigm capable of estimating ICMS-evoked sensory perception thresholds in freely moving rats. We divided animals into two groups, one receiving ICMS and a control group receiving auditory tones. Then, we trained the animals to nose-poke - a well-established behavioral task for rats - following either a suprathreshold ICMS current-controlled pulse train or frequency-controlled auditory tone. Animals received a sugar pellet reward when nose-poking correctly. When nose-poking incorrectly, animals received a mild air puff. After animals became proficient in this task, as defined by accuracy, precision, and other performance metrics, they continued to the next phase for perception threshold detection, where we varied the ICMS amplitude using a modified staircase method. Finally, we used non-linear regression to estimate perception thresholds. Results indicated that our behavioral protocol could estimate ICMS perception thresholds based on ~95% accuracy of rat nose-poke responses to the conditioned stimulus. This behavioral paradigm provides a robust methodology for evaluating stimulation-evoked somatosensory percepts in rats comparable to the evaluation of auditory percepts. In future studies, this validated methodology can be used to study the performance of novel MEA device technologies on ICMS-evoked perception threshold stability using freely moving rats or to investigate information processing principles in neural circuits related to sensory perception discrimination.

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Real-Time Performance of a Tactile Neuroprosthesis on Awake Behaving Rats

Cited by 17 publications

References 39 publications

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

Behavioral paradigm for the evaluation of stimulation-evoked somatosensory perception thresholds in rats

Behavioral Paradigm for the Evaluation of Stimulation-Evoked Somatosensory Perception Thresholds in Rats

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