The proposed experiments have two goals: First, to investigate the normal functional organization of motor cortex in adult primates and second, to explore the capacity of motor cortex representations to reorganize following peripheral nerve injury or subsequent to the acquisition of a skilled movement. MI representation pattern will be evaluated by combining intracortical microstimulation mapping with EMG recording techniques and by using extracellular and intracellular tracing techniques. Normal """"""""static"""""""" MI organization pattern: Unlike previous studies that have described the movements evoked by MI stimulation, our studies will demonstrate the representation of functional groups of forelimb muscles in MI by recording EMG activity from each of 16 muscles that are activated from individual cortical sites. Muscle representation will be mapped at 100-200 MI sites using several different current intensities. These data will be used to determine the topological relationship, extent of overlap, and size of representation of each of the 16 muscles. Our preliminary data suggest that some muscles are multiply represented in spatially separate foci that overlap the representation of several other muscles. These foci may represent a pattern of functional grouping that has been described in MI. Intracellular recording/dye injection and anatomical pathway tracing techniques will be used after mapping to examine the connectional relationship between these individual or grouped representations in MI. Dynamic organization: A second goal of these studies is to determine the extent to which the relationship of the motor cortex with the muscles is changed (a) under normal conditions (i.e., is there a continual reshaping of MI representations?), (b) following nerve injury that prevents the normal use of the distal forelimb muscles, (c) following the acquisition of skilled digit movements. Microstimulation mapping will be used to study MI representation patterns at different intervals in normal animals, before and after anterior interosseus nerve section and before and after learning of a precision finger grip task. These experiments will provide important new information concerning the efferent topography of primate motor cortex as well as the flexibility of the relationship between MI cortex and muscles. The results of these studies may suggest new strategies for enhancing functional recovery and suppressing spasticity subsequent to injury of the peripheral and central nervous system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS025074-03
Application #
3410181
Study Section
Neurology B Subcommittee 1 (NEUB)
Project Start
1987-07-01
Project End
1992-06-30
Budget Start
1989-07-01
Budget End
1990-06-30
Support Year
3
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Brown University
Department
Type
Schools of Medicine
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
Milekovic, Tomislav; Sarma, Anish A; Bacher, Daniel et al. (2018) Stable long-term BCI-enabled communication in ALS and locked-in syndrome using LFP signals. J Neurophysiol 120:343-360
Accomando, Alyssa W; Vargas-Irwin, Carlos E; Simmons, James A (2018) Spike Train Similarity Space (SSIMS) Method Detects Effects of Obstacle Proximity and Experience on Temporal Patterning of Bat Biosonar. Front Behav Neurosci 12:13
Rule, Michael E; Vargas-Irwin, Carlos; Donoghue, John P et al. (2018) Phase reorganization leads to transient ?-LFP spatial wave patterns in motor cortex during steady-state movement preparation. J Neurophysiol 119:2212-2228
Rule, Michael E; Vargas-Irwin, Carlos E; Donoghue, John P et al. (2017) Dissociation between sustained single-neuron spiking and transient ?-LFP oscillations in primate motor cortex. J Neurophysiol 117:1524-1543
Aghagolzadeh, Mehdi; Truccolo, Wilson (2016) Inference and Decoding of Motor Cortex Low-Dimensional Dynamics via Latent State-Space Models. IEEE Trans Neural Syst Rehabil Eng 24:272-82
Barrese, James C; Aceros, Juan; Donoghue, John P (2016) Scanning electron microscopy of chronically implanted intracortical microelectrode arrays in non-human primates. J Neural Eng 13:026003
Lu, Yao; Truccolo, Wilson; Wagner, Fabien B et al. (2015) Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex. J Neurophysiol 113:3574-87
Rule, Michael E; Vargas-Irwin, Carlos; Donoghue, John P et al. (2015) Contribution of LFP dynamics to single-neuron spiking variability in motor cortex during movement execution. Front Syst Neurosci 9:89
Vargas-Irwin, Carlos E; Brandman, David M; Zimmermann, Jonas B et al. (2015) Spike train SIMilarity Space (SSIMS): a framework for single neuron and ensemble data analysis. Neural Comput 27:1-31
Vargas-Irwin, Carlos E; Franquemont, Lachlan; Black, Michael J et al. (2015) Linking Objects to Actions: Encoding of Target Object and Grasping Strategy in Primate Ventral Premotor Cortex. J Neurosci 35:10888-97

Showing the most recent 10 out of 66 publications