Professional Education


  • Doctor of Philosophy, University of Pittsburgh (2017)
  • Bachelor of Science, St Marys University Of San Antonio (2011)

Lab Affiliations


All Publications


  • Artifact-free recordings in human bidirectional brain-computer interfaces JOURNAL OF NEURAL ENGINEERING Weiss, J. M., Flesher, S. N., Franklin, R., Collinger, J. L., Gaunt, R. A. 2019; 16 (1): 016002

    Abstract

    Intracortical microstimulation has shown promise as a means of evoking somatosensory percepts as part of a bidirectional brain-computer interface (BCI). However, microstimulation generates large electrical artifacts that dominate the recordings necessary for BCI control. These artifacts must be eliminated from the signal in real-time to allow for uninterrupted BCI decoding.We present a simple, robust modification to an existing clinical BCI system to allow for simultaneous recording and stimulation using a combination of signal blanking and digital filtering, without needing to explicitly account for varying parameters such as electrode locations or amplitudes. We validated our artifact rejection scheme by recording from microelectrodes in primary motor cortex (M1) while stimulating in somatosensory cortex of a person with a spinal cord injury.M1 recordings were digitally blanked using a sample-and-hold circuit triggered just prior to stimulus onset and a first-order 750 Hz high-pass Butterworth filter was used to reduce distortion of the remaining artifact. This scheme enabled spike detection in M1 to resume as soon as 740 µs after each stimulus pulse. We demonstrated the effectiveness of the complete bidirectional BCI system by comparing functional performance during a 5 degree of freedom robotic arm control task, with and without stimulation. When stimulation was delivered without this artifact rejection scheme, the number of objects the subject was able to move across a table in 2 min under BCI control declined significantly compared to trials without stimulation (p  <  0.01). When artifact rejection was implemented, performance was no different than in trials that did not include stimulation (p  =  0.621).The proposed technique uses simple changes in filtering and digital signal blanking with FDA-cleared hardware and enables artifact-free recordings during bidirectional BCI control.

    View details for DOI 10.1088/1741-2552/aae748

    View details for Web of Science ID 000450311900002

    View details for PubMedID 30444217

  • Implicit Grasp Force Representation in Human Motor Cortical Recordings FRONTIERS IN NEUROSCIENCE Downey, J. E., Weiss, J. M., Flesher, S. N., Thumser, Z. C., Marasco, P. D., Boninger, M. L., Gaunt, R. A., Collinger, J. L. 2018; 12
  • Intracortical microstimulation of human somatosensory cortex SCIENCE TRANSLATIONAL MEDICINE Flesher, S. N., Collinger, J. L., Foldes, S. T., Weiss, J. M., Downey, J. E., Tyler-Kabara, E. C., Bensmaia, S. J., Schwartz, A. B., Boninger, M. L., Gaunt, R. A. 2016; 8 (361): 361ra141

    Abstract

    Intracortical microstimulation of the somatosensory cortex offers the potential for creating a sensory neuroprosthesis to restore tactile sensation. Whereas animal studies have suggested that both cutaneous and proprioceptive percepts can be evoked using this approach, the perceptual quality of the stimuli cannot be measured in these experiments. We show that microstimulation within the hand area of the somatosensory cortex of a person with long-term spinal cord injury evokes tactile sensations perceived as originating from locations on the hand and that cortical stimulation sites are organized according to expected somatotopic principles. Many of these percepts exhibit naturalistic characteristics (including feelings of pressure), can be evoked at low stimulation amplitudes, and remain stable for months. Further, modulating the stimulus amplitude grades the perceptual intensity of the stimuli, suggesting that intracortical microstimulation could be used to convey information about the contact location and pressure necessary to perform dexterous hand movements associated with object manipulation.

    View details for DOI 10.1126/scitranslmed.aaf8083

    View details for Web of Science ID 000389442300006

    View details for PubMedID 27738096