Quantitative comparison of corticospinal tracts arising from different cortical areas in humans

Usuda, Noboru; Sugawara, Sho K.; Fukuyama, Hidetoshi; Nakazawa, Kimitaka; Amemiya, Kiyomi; Nishimura, Yukio

doi:10.1016/j.neures.2022.06.008

Cited by 11 publications

(15 citation statements)

References 124 publications

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“…Recent tractography data have suggested potential direct connections between premotor areas including PMV and SMA and even lower cervical segments. However, these should be considered with caution due to reduced spatial resolution at the spinal levels (Usuda et al, 2022). Finally, studies in stroke patients have related the extent of damage to CSTs originating from premotor areas to deficits and recovery processes (Ito et al, 2022; Newton et al, 2006; Schulz et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Association between activity in the ventral premotor cortex and spinal cord activation during force generation—A combined cortico‐spinal fMRI study

Braaß,

Feldheim,

Chu

et al. 2023

Human Brain Mapping

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Force generation is a crucial element of dexterity and a highly relevant skill of the human motor system. How cerebral and spinal components interact and how spinal activation is associated with the activity in the cerebral primary motor and premotor areas is poorly understood. Here, we conducted combined cortico‐spinal functional magnetic resonance imaging during a simple visually guided isometric force generation task in 20 healthy young subjects. Activation was localized in the right cervical spinal cord and left primary motor and premotor areas. The main finding is that spinal activation was negatively correlated with ventral premotor cortex activation. Spinal activation was furthermore significantly correlated with primary motor cortex activation, while increasing target forces led to an increase in the amount of activation. These data indicate that human premotor areas such as the ventral premotor cortex might be functionally connected to the lower cervical spinal cord contributing to distal upper limb functions, a finding that extends our understanding of human motor function beyond the animal literature.

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Section: Introductionmentioning

confidence: 99%

Association between activity in the ventral premotor cortex and spinal cord activation during force generation—A combined cortico‐spinal fMRI study

Braaß,

Feldheim,

Chu

et al. 2023

Human Brain Mapping

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“…The functional loss of limb control in individuals with SCI or stroke can be caused by the interruption of corticospinal pathways originating from the motor cortex, although the neural circuits located above and below the lesion remain functional. A substantial portion of corticospinal pathways are derived from M1 ( Toyoshima and Sakai, 1982 ; He et al, 1993 ; Usuda et al, 2022 ). Numerous studies have shown that the neural activity in M1 represents the level of muscle activity ( Fetz and Cheney, 1980 ; Cheney et al, 1985 ; Buys et al, 1986 ; Lemon et al, 1986 ), joint torque ( Evarts, 1968 ; Kakei et al, 1999 ), and force ( Cheney and Fetz, 1980 ; Sergio and Kalaska, 2003 ).…”

Section: Discussionmentioning

confidence: 99%

Corticospinal interface to restore voluntary control of joint torque in a paralyzed forearm following spinal cord injury in non-human primates

Obara

Kaneshige²,

Suzuki³

et al. 2023

Front. Neurosci.

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The corticospinal tract plays a major role in the control of voluntary limb movements, and its damage impedes voluntary limb control. We investigated the feasibility of closed-loop brain-controlled subdural spinal stimulation through a corticospinal interface for the modulation of wrist torque in the paralyzed forearm of monkeys with spinal cord injury at C4/C5. Subdural spinal stimulation of the preserved cervical enlargement activated multiple muscles on the paralyzed forearm and wrist torque in the range from flexion to ulnar-flexion. The magnitude of the evoked torque could be modulated by changing current intensity. We then employed the corticospinal interface designed to detect the firing rate of an arbitrarily selected “linked neuron” in the forearm territory of the primary motor cortex (M1) and convert it in real time to activity-contingent electrical stimulation of a spinal site caudal to the lesion. Linked neurons showed task-related activity that modulated the magnitude of the evoked torque and the activation of multiple muscles depending on the required torque. Unlinked neurons, which were independent of spinal stimulation and located in the vicinity of the linked neurons, exhibited task-related or -unrelated activity. Thus, monkeys were able to modulate the wrist torque of the paralyzed forearm by modulating the firing rate of M1 neurons including unlinked and linked neurons via the corticospinal interface. These results suggest that the corticospinal interface can replace the function of the corticospinal tract after spinal cord injury.

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“…This study has suggested the existence of descending influences onto the proprio-spinal system not only for M1 but also for PMV (52). Tractography data have recently argued – despite critical limitations in the spatial resolution – for the existence of direct connections between premotor areas including PMV and SMA and even lower cervical segments (53).…”

Section: Discussionmentioning

confidence: 99%

“…Evidence suggesting proprio-spinal inter-neurons as important inhibitory target networks for top-down PMV influence in humans comes from a recent spatial facilitation study combining TMS and peripheral nerve stimulation on the upper limb (52). Finally, the absence of retrograde cortical degeneration in PMV in patients after spinal cord injury and absent motor responses after PMV electrical stimulation have argued against direct mono-synaptic connections between PMV and the spinal cord (53). Therefore, we speculate that poly-synaptic trajectories originating from PMV with long-range excitatory pathways converging onto inhibitory spinal networks which modulate spinal motor neurons, are most likely to transmit the cortico-spinal influence from PMV during force generation.…”

Section: Discussionmentioning

confidence: 99%

“…Recent tractography data have suggested potential direct connections between premotor areas including PMV and SMA and even lower cervical segments. However, these should be considered with caution due to reduced spatial resolution at the spinal levels (53). Finally, studies in stroke patients have related the extent of damage to CSTs originating from premotor areas to deficits and recovery processes (54)(55)(56).…”

Section: Introductionmentioning

confidence: 99%

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Ventral premotor cortex influences spinal cord activation during force generation

Braaß

Feldheim

Chu

et al. 2023

Preprint

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Force generation is a crucial element of dexterity and a highly relevant skill of the human motor system. How cerebral and spinal components interact and how spinal activation is influenced by cerebral primary motor and premotor areas is poorly understood. Here we conducted combined cortico-spinal functional MRI during a simple visually guided isometric force generation task in a group of 20 healthy young subjects. Activation was localized in the ipsilateral cervical spinal cord and contralateral primary motor and premotor areas. The main finding is that spinal activation was influenced by ventral premotor cortex activation. Spinal activation was furthermore significantly correlated with primary motor cortex activation while increasing target forces led to an increase in the amount of activation. These data indicate that human premotor areas such as the ventral premotor cortex might be functionally connected to the lower cervical spinal cord contributing to distal upper limb functions, a finding which extends our understanding about human motor function beyond the animal literature.

show abstract

Quantitative comparison of corticospinal tracts arising from different cortical areas in humans

Cited by 11 publications

References 124 publications

Association between activity in the ventral premotor cortex and spinal cord activation during force generation—A combined cortico‐spinal fMRI study

Association between activity in the ventral premotor cortex and spinal cord activation during force generation—A combined cortico‐spinal fMRI study

Corticospinal interface to restore voluntary control of joint torque in a paralyzed forearm following spinal cord injury in non-human primates

Ventral premotor cortex influences spinal cord activation during force generation

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