The objective of this project is to understand what and how movement features are encoded in ensembles of interacting motor cortical neurons. Although previous electrophysiological research has focused on encoding in single motor cortical neurons, very little work has examined whether spatial-temporal patterns of activity emerging from ensembles of interacting neurons encode features of movement planning and execution. To test this hypothesis, high-density electrode arrays will be chronically implanted in primary motor cortex (MI) and dorsal premotor cortex (PMd) from which 100s of single units will be simultaneously recorded while monkeys perform complex visuo-motor tasks with the arm. A continuous random-tracking task and a step random-tracking task are ideally suited to investigate neural encoding because they uncouple the statistical dependencies among many of the relevant motor variables, more thoroughly sample the movement space, and reduce non-stationarities. Forward and reverse correlation, information-theoretic, and decoding methods will be used to analyze the encoding problem as well the information mapping between the two cortical areas.
Two specific aims are proposed in this project. First, kinematic and kinetic tuning properties of motor cortical ensembles will be investigated and compared to single neuron tuning functions under different behavioral contexts. The stability of these tuning functions will be examined by applying different external loads to the arm, varying the behavioral mode (freely moving vs. isometric), or changing the posture of the forearm. Second, it will determined whether spatio-temporal patterns within motor cortical ensembles can be elicited by altering the temporal dynamics and predictability of the movement. This work is significant because it will elucidate how groups of interacting cortical neurons control and coordinate complex movements and will provide an important step in understanding how neuronal ensembles in other cortical areas represent other high-level functioning. In addition, this work has direct relevance towards the development of a neuro-motor prosthesis by which paralyzed patients may be able to control external devices by activating their cortex.
| Tele?czuk, Bartosz; Dehghani, Nima; Le Van Quyen, Michel et al. (2017) Local field potentials primarily reflect inhibitory neuron activity in human and monkey cortex. Sci Rep 7:40211 |
| Balasubramanian, Karthikeyan; Vaidya, Mukta; Southerland, Joshua et al. (2017) Changes in cortical network connectivity with long-term brain-machine interface exposure after chronic amputation. Nat Commun 8:1796 |
| Kai Qian; Dos Anjos, Luiz Antonio; Balasubramanian, Karthikeyan et al. (2017) Using monkey hand exoskeleton to explore finger passive joint movement response in primary motor cortex. Conf Proc IEEE Eng Med Biol Soc 2017:3624-3627 |
| Takahashi, Kazutaka; Best, Matthew D; Huh, Noah et al. (2017) Encoding of Both Reaching and Grasping Kinematics in Dorsal and Ventral Premotor Cortices. J Neurosci 37:1733-1746 |
| Best, Matthew D; Suminski, Aaron J; Takahashi, Kazutaka et al. (2017) Spatio-Temporal Patterning in Primary Motor Cortex at Movement Onset. Cereb Cortex 27:1491-1500 |
| Dehghani, Nima; Peyrache, Adrien; Telenczuk, Bartosz et al. (2016) Dynamic Balance of Excitation and Inhibition in Human and Monkey Neocortex. Sci Rep 6:23176 |
| Best, Matthew D; Takahashi, Kazutaka; Suminski, Aaron J et al. (2016) Comparing offline decoding performance in physiologically defined neuronal classes. J Neural Eng 13:026004 |
| Tobaa, Adil A; Best, Matthew D; Balasubramanian, Karthikeyan et al. (2016) Properties of primary motor cortical local field potentials in the leg and trunk representations during arm movements. Conf Proc IEEE Eng Med Biol Soc 2016:1636-1639 |
| Le Van Quyen, Michel; Muller 2nd, Lyle E; Telenczuk, Bartosz et al. (2016) High-frequency oscillations in human and monkey neocortex during the wake-sleep cycle. Proc Natl Acad Sci U S A 113:9363-8 |
| Best, Matthew D; Nakamura, Yuki; Kijak, Nicoletta A et al. (2015) Semiautomatic marker tracking of tongue positions captured by videofluoroscopy during primate feeding. Conf Proc IEEE Eng Med Biol Soc 2015:5347-50 |
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