Maintained representations of the ipsilateral and contralateral limbs during bimanual control in primary motor cortex

Cross, Kevin P.; Heming, Ethan A; Cook, Douglas J.; Scott, Stephen H.

doi:10.1101/2020.03.30.015842

Cited by 5 publications

(5 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, we examined the dynamics of a network performing a posture perturbation task, where the network had to respond to sensory feedback about the periphery to generate an appropriate motor correction (Cross et al, 2020;Heming et al, 2019;Omrani et al, 2014Omrani et al, , 2016Pruszynski et al, 2014). Sensory input plays an important role for correctly performing the task and thus the hypothesis is that rotational dynamics should be absent in the network.…”

Section: Rnn Exhibit Rotational Dynamics In the Activities And Sensory Feedback Signals During Posture Taskmentioning

confidence: 99%

Rotational dynamics in motor cortex are consistent with a feedback controller

Kalidindi

Cross

Lillicrap

et al. 2021

eLife

Self Cite

View full text Add to dashboard Cite

Recent studies have identified rotational dynamics in motor cortex (MC), which many assume arise from intrinsic connections in MC. However, behavioral and neurophysiological studies suggest that MC behaves like a feedback controller where continuous sensory feedback and interactions with other brain areas contribute substantially to MC processing. We investigated these apparently conflicting theories by building recurrent neural networks that controlled a model arm and received sensory feedback from the limb. Networks were trained to counteract perturbations to the limb and to reach toward spatial targets. Network activities and sensory feedback signals to the network exhibited rotational structure even when the recurrent connections were removed. Furthermore, neural recordings in monkeys performing similar tasks also exhibited rotational structure not only in MC but also in somatosensory cortex. Our results argue that rotational structure may also reflect dynamics throughout the voluntary motor system involved in online control of motor actions.

show abstract

Section: Rnn Exhibit Rotational Dynamics In the Activities And Sensory Feedback Signals During Posture Taskmentioning

confidence: 99%

Rotational dynamics in motor cortex are consistent with a feedback controller

Kalidindi

Cross

Lillicrap

et al. 2021

eLife

Self Cite

View full text Add to dashboard Cite

show abstract

“…Studies highlight that primary motor cortex (M1) is involved with generating flexible muscle responses to sensory feedback. M1 receives rich proprioceptive feedback with responses that start within ~20ms of an applied load (Conrad et al, 1974(Conrad et al, , 1975Wolpaw, 1980;Fromm et al, 1984;Bauswein et al, 1991;Picard and Smith, 1992;Herter et al, 2009;Takei et al, 2018;Heming et al, 2019;Cross et al, 2020Cross et al, , 2021. Importantly, proprioceptive feedback responses in M1 are modulated by several behavioural factors including limb physics (Pruszynski et al, 2011), prior instruction (Evarts and Tanji, 1976;Pruszynski et al, 2014), and task engagement (Omrani et al, 2014) within 50ms of an applied load.…”

Section: Discussionmentioning

confidence: 99%

Proprioceptive and visual feedback responses in macaques exploit goal redundancy

Cross

Guang

Scott

2022

Preprint

Self Cite

View full text Add to dashboard Cite

A common problem in motor control concerns how to generate patterns of muscle activity when there are redundant solutions to attain a behavioural goal. Optimal feedback control is a theory that has guided many behavioural studies exploring how the motor system incorporates task redundancy. This theory predicts that kinematic errors that deviate the limb should not be corrected if one can still attain the behavioural goal. Several studies in humans demonstrate that the motor system can flexibly integrate visual and proprioceptive feedback of the limb with goal redundancy within 90ms and 70ms, respectively. Here we show monkeys (Macaca mulatta) demonstrate similar abilities to exploit goal redundancy. We trained four male monkeys to reach for a goal that was either a narrow square or a wide, spatially redundant rectangle. Monkeys exhibited greater trial-by-trial variability when reaching to the wide goal consistent with exploiting goal redundancy. On random trials we jumped the visual feedback of the hand and found monkeys corrected for the jump when reaching to the narrow goal and largely ignored the jump when reaching for the wide goal. In a separate set of experiments, we applied mechanical loads to the arm and found similar corrective responses based on goal shape. Muscle activity reflecting these different corrective responses were detected for the visual and mechanical perturbations starting at ~90 and ~70ms, respectively. Thus, rapid motor responses in macaques can exploit goal redundancy similar to humans, creating a paradigm to study the neural basis of goal-directed motor action and motor redundancy.

show abstract

“…This raises a major question: how far can this weighted-average model be extended as we consider more DoFs? Several groups have investigated how neurons tuned to multiple behaviors respond to tasks requiring those behaviors (Cross et al, 2020;Diedrichsen et al, 2013;Heming et al, 2019;Jorge et al, 2020;Stavisky et al, 2019Stavisky et al, , 2020Willett et al, 2020). One way to explain this is that the neural activity underlying separate and combined behaviors can be explained by multiple orthogonal subspaces.…”

Section: Discussionmentioning

confidence: 99%

“…For example, primary motor cortex can simultaneously encode information about upper extremities, fingers, and speech, independent of body laterality (Cross et al, 2020;Diedrichsen et al, 2013;Heming et al, 2019;Jorge et al, 2020;Stavisky et al, 2019Stavisky et al, , 2020Willett et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Real-Time Linear Prediction of Simultaneous and Independent Movements of Two Finger Groups Using an Intracortical Brain-Machine Interface

Nason

Mender

Vaskov

et al. 2020

Preprint

View full text Add to dashboard Cite

Modern brain-machine interfaces can return function to people with paralysis, but current hand neural prostheses are unable to reproduce control of individuated finger movements. Here, for the first time, we present a real-time, high-speed, linear brain-machine interface in nonhuman primates that utilizes intracortical neural signals to bridge this gap. We created a novel task that systematically individuates two finger groups, the index finger and the middle-ring-small fingers combined, presenting separate targets for each group. During online brain control, the ReFIT Kalman filter demonstrated the capability of individuating movements of each finger group with high performance, enabling a nonhuman primate to acquire two targets simultaneously at 1.95 targets per second, resulting in an average information throughput of 2.1 bits per second. To understand this result, we performed single unit tuning analyses. Cortical neurons were active for movements of an individual finger group, combined movements of both finger groups, or both. Linear combinations of neural activity representing individual finger group movements predicted the neural activity during combined finger group movements with high accuracy, and vice versa. Hence, a linear model was able to explain how cortical neurons encode information about multiple dimensions of movement simultaneously. Additionally, training ridge regressing decoders with independent component movements was sufficient to predict untrained higher-complexity movements. Our results suggest that linear decoders for brain-machine interfaces may be sufficient to execute high-dimensional tasks with the performance levels required for naturalistic neural prostheses.

show abstract

Maintained representations of the ipsilateral and contralateral limbs during bimanual control in primary motor cortex

Cited by 5 publications

References 74 publications

Rotational dynamics in motor cortex are consistent with a feedback controller

Rotational dynamics in motor cortex are consistent with a feedback controller

Proprioceptive and visual feedback responses in macaques exploit goal redundancy

Real-Time Linear Prediction of Simultaneous and Independent Movements of Two Finger Groups Using an Intracortical Brain-Machine Interface

Contact Info

Product

Resources

About