The human central nervous system relies on dedicated descending pathways to translate volitional cognitive intent into coordinated mechanical action across the body. Among these neural superhighways, the anterior corticospinal tract functions as a specialized conduit dedicated primarily to maintaining postural stability and orienting the axial and proximal skeleton during targeted motor behaviors. Understanding its unique anatomical trajectory, local commissural decussation, and functional integration offers foundational insights into both normal motor execution and the pathophysiology of upper motor neuron pathology.
Anterior Corticospinal Tract
1. Concise Definition
The anterior corticospinal tract (also designated historically as the ventral corticospinal tract or the bundle of Türk) is a descending pyramidal motor pathway originating predominantly from pyramidal neurons within the cerebral cortex that traverses uncrossed through the brainstem before descending within the anterior funiculus of the spinal cord. Unlike its larger counterpart, the lateral corticospinal tract, which decussates at the caudal medulla, fibers of the anterior corticospinal tract descend ipsilaterally and cross the midline primarily at segmental spinal cord levels via the anterior white commissure to innervate axial and proximal limb girdle musculature.
Functioning as an essential component of the ventromedial descending motor system, the anterior corticospinal tract constitutes approximately 10 to 15 percent of all fibers within the corticospinal tract system. It terminates primarily within the medial portions of Rexed laminae VII and VIII, as well as establishing direct and indirect synaptic contacts with alpha and gamma motor neurons in Rexed lamina IX. Through these synaptic networks, the tract plays an indispensable role in maintaining bilateral postural adjustments, modulating trunk equilibrium, and stabilizing the axial frame during complex, multi-joint voluntary movements.
2. Etymology & Linguistic Origin
The anatomical nomenclature of the anterior corticospinal tract is derived from Classical Latin and systematic Neo-Latin anatomical conventions. The prefix anterior stems from the Latin comparative adjective meaning “former,” “before,” or “situated toward the front,” referencing the tract’s spatial localization within the ventral or anterior funiculus of the spinal cord relative to the posterior and lateral funiculi.
The compound adjective corticospinal is a Neo-Latin portmanteau uniting cortex (genitive corticis, meaning “bark,” “rind,” or “outer covering,” denoting the cerebral cortex) with spinalis (derived from spina, meaning “thorn” or “backbone,” denoting the spinal cord). In anatomical taxonomy, compound directional tract names consistently place the site of origin first and the site of termination second, thus indicating an efferent pathway originating in the cerebral cortex and terminating within the spinal cord. Historically, the tract was termed the bundle of Türk (or Türck’s column), in honor of the nineteenth-century Austrian physician Ludwig Türck, who first demonstrated its presence and trajectory using histological degeneration stains.
3. Pronunciation & Grammatical Form
Pronunciation: /ænˈtɪə.ri.ər ˌkɔːr.tɪ.koʊˈspaɪ.nəl trækt/ (American English: [ænˈtɪriər ˌkɔrtɪkoʊˈspaɪnəl trækt]; British English: [ænˈtɪəriə ˌkɔːtɪkəʊˈspaɪnl trækt]).
Grammatical Form: Compound noun phrase. The head noun is tract (countable singular noun), modified by the coordinate adjectives anterior and corticospinal. The plural form is anterior corticospinal tracts, reflecting the presence of bilateral paired structures running symmetrically along either side of the anterior median fissure of the spinal cord.
Common Anatomical Variants: Ventral corticospinal tract (tractus corticospinalis anterior in standard Terminologia Anatomica), direct pyramidal tract, and uncrossed pyramidal tract.
4. Detailed Conceptual Explanation
The anterior corticospinal tract represents a specialized division of the upper motor neuron architecture that bypasses the classic decussation of the pyramids in the lower medulla oblongata. When the broad mass of descending corticofugal fibers passes through the medullary pyramids, roughly 85 to 90 percent cross the midline within the pyramidal decussation to form the dorsolateral motor system (the lateral corticospinal tract). The remaining 10 to 15 percent of fibers do not cross in the caudal brainstem; instead, they continue their descent along the ventral margin of the spinal cord adjacent to the anterior median fissure, nestled inside the anterior funiculus.
The somata that give rise to the anterior corticospinal tract are predominantly giant pyramidal cells (Betz cells) and large pyramidal neurons residing within cortical layer V of the primary motor cortex (Brodmann area 4), the premotor cortex (Brodmann area 6), and the supplementary motor area (SMA). A smaller fraction of fibers originates within the primary somatosensory cortex (Brodmann areas 3, 1, and 2) and the parietal operculum, providing sensory modulation and feedback gating directly onto the spinal interneuronal apparatus. The axons emerge from these diverse cortical regions, coalesce in the corona radiata, and traverse the posterior limb of the internal capsule in close proximity to the genu, where somatotopically organized motor fibers are situated.
From the internal capsule, the fibers traverse the central intermediate three-fifths of the crus cerebri (cerebral peduncles) within the midbrain, pass through the longitudinal pontine bundles of the basis pontis, and descend through the ventral medullary pyramids. Upon reaching the spinal cord, the anterior corticospinal tract extends caudally, gradually diminishing in diameter as it progresses. While the tract is most prominent within the cervical and upper thoracic segments of the spinal cord, anatomical tract-tracing studies demonstrate that an attenuated contingent of fibers frequently extends into lower thoracic and occasionally lumbar segments.
The functional execution of the anterior corticospinal tract is defined by its terminal trajectory. Unlike the lateral corticospinal tract, which decussates once in the brainstem and projects predominantly unilaterally onto the distal musculature of the contralateral hand or foot, the anterior corticospinal tract descends ipsilaterally until reaching the specific spinal level of its target. Here, the axons sweep across the anterior white commissure to synapse primarily on the contralateral side, though a significant proportion bifurcates to innervate medial motor nuclei bilaterally. This bilateral arborization makes the anterior tract uniquely suited to govern midline motor behaviors, such as the maintenance of an upright spinal column, bilateral respiratory stabilization during exertion, and synchronized bilateral head movements.
5. Historical Development
The systematic investigation of the descending motor pathways commenced in the nineteenth century with the advent of histological staining methods and experimental lesion studies. In the early 1850s, Ludwig Türck (1810–1868), an Austrian neurologist working in Vienna, used secondary Wallerian degeneration techniques to trace damaged nerve fibers following brain lesions. Türck documented that while the bulk of degenerating fibers crossed to the opposite side of the spinal cord at the level of the medullary pyramids, a distinct anterior bundle failed to cross, descending directly along the ventral margin of the anterior median fissure. Consequently, this pathway was widely commemorated in early neuroanatomy texts as “Türck’s column” or the “bundle of Türck.”
Toward the late nineteenth and early twentieth centuries, pioneering neurohistologists, including Camillo Golgi and Santiago Ramón y Cajal, applied silver-impregnation and Golgi stains to map the microcircuitry of the spinal cord. Ramón y Cajal demonstrated that the fibers of the ventral pyramidal tract did not terminate indiscriminately; rather, they systematically crossed through the anterior white commissure before terminating within the intermediate zone and anterior horn of the gray matter, thereby confirming that the tract was functionally decussating at a segmental level rather than remaining entirely uncrossed.
During the mid-twentieth century, neurophysiologists such as Derek Denny-Brown and later Hans Kuypers significantly revised the conceptual understanding of descending motor control. Kuypers formulated the seminal classification dividing descending motor systems into a “lateral system” (comprising the lateral corticospinal and rubrospinal tracts) and a “medial system” (incorporating the anterior corticospinal, reticulospinal, and vestibulospinal tracts). Kuypers’ anatomical tract-tracing experiments in primates clarified that the anterior corticospinal tract functions not as an isolated motor conduit, but as part of an integrated ventromedial network specifically tuned for trunk equilibrium, bilateral postural stabilization, and the synergistic positioning of proximal limb segments.
6. Theoretical Foundations
The structural and functional architecture of the anterior corticospinal tract is grounded in the theoretical framework of hierarchical and parallel motor processing. According to classic motor control theory, the central nervous system coordinates movement across distinct motor functional domains: manipulative distal control and supportive proximal/axial stability. The anterior corticospinal tract exemplifies the cortical contribution to the ventromedial postural control system, functioning in tight synchronization with subcortical pathways.
Under the Dual Systems Framework formulated by Kuypers and elaborated by modern motor systems neuroscientists, descending motor tracts are broadly segregated based on terminal topography and motor role:
- The Ventromedial Group: Comprising the anterior corticospinal tract, tectospinal (colliculospinal) tract, reticulospinal tract, and lateral and medial vestibulospinal tracts. These pathways terminate predominantly in the medial motor column of the spinal anterior horn, which contains motor neuron pools supplying axial, paraspinal, and proximal girdle muscles. Their primary operational goal is the regulation of posture, balance, and whole-body orienting reflexes.
- The Dorsolateral Group: Comprising the lateral corticospinal tract and the rubrospinal tract, which terminate in the lateral motor column and intermediate gray matter, providing direct, fractionated control of distal extremities (such as intrinsic hand muscles) essential for fine, skilled manipulation.
From a biomechanical and cybernetic perspective, fine motor manipulation performed by distal effectors cannot occur without a stable biomechanical foundation. The anterior corticospinal tract provides real-time cortical anticipation and feedforward postural adjustments (known as anticipatory postural adjustments or APAs). When a human subject prepares to rapidly elevate an arm or manipulate a tool, the premotor cortex generates motor commands that traverse the anterior corticospinal pathway milliseconds prior to the movement itself, stabilizing the contralateral and ipsilateral core musculature against impending gravitational and inertial destabilization.
7. Key Components, Types & Dimensions
The anatomical and functional identity of the anterior corticospinal tract can be broken down into specific operational components, path dimensions, and structural properties:
- Cortical Somata of Origin: Large pyramidal projection neurons in layer V of the primary motor cortex (M1, Brodmann area 4), premotor cortex (PMA, Brodmann area 6), and supplementary motor area (SMA). A distinct sensory contingent arises from the primary somatosensory cortex (S1, Brodmann areas 3a and 3b).
- Internal Capsule Trajectory: Fibers traverse the posterior limb of the internal capsule (PLIC), positioned immediately posterior to the corticobulbar fibers running through the genu.
- Brainstem Descent: The fibers travel uninterrupted through the intermediate zone of the crus cerebri in the ventral midbrain, scatter through the pontine nuclei within the basis pontis, and reassemble within the medullary pyramids.
- Pyramidal Integrity: At the caudal border of the medulla, the fibers of the anterior corticospinal tract distinctly resist decussation, continuing down the ventral side of the neuraxis.
- Spinal Cord Localization: The tract runs adjacent to the anterior median fissure within the anterior funiculus, medial to the anterolateral system and ventral to the anterior gray horn.
- Segmental Decussation via Anterior White Commissure: At their target spinal cord levels, the vast majority of fibers cross through the anterior white commissure to the contralateral side; a subset bifurcates or remains ipsilateral to establish bilateral control.
- Spinal Terminations: Synapses terminate on interneurons in medial Rexed laminae VII and VIII, as well as establishing monosynaptic inputs onto motor neurons in medial lamina IX supplying paraspinal, abdominal, pelvic, and neck muscles.
- Longitudinal Extent and Dimensions: The tract is quantitatively largest in the cervical segments, where it controls neck and pectoral girdle muscles, gradually attenuates in the thoracic cord, and usually disappears completely before reaching the lower lumbar or sacral segments.
8. Examples & Illustrative Cases
The unique anatomical profile of the anterior corticospinal tract manifests clearly in several concrete physiological and clinical scenarios:
Anticipatory Postural Stabilization: Consider a healthy individual who is instructed to quickly push or pull a heavy resistance lever with their right hand. Electromyographic (EMG) studies demonstrate that the erector spinae, rectus abdominis, and contralateral thoracic trunk muscles become active approximately 50 to 100 milliseconds before the biceps or anterior deltoid muscles contract. This feedforward activation is driven partly by the premotor cortex via the anterior corticospinal tract, which braces the spine to prevent the reactionary forces of the limb movement from knocking the subject off balance.
Clinical Case Illustration: Unilateral Motor Cortex Infarction: An adult patient suffers an ischemic stroke resulting in the complete destruction of the right primary motor cortex. The clinical examination demonstrates dense hemiplegia and spasticity in the contralateral left hand and foot (loss of the lateral corticospinal tract). However, upon examining the patient’s trunk musculature and respiration, voluntary activation of the abdominal muscles, diaphragm, and paraspinal stabilizers remains remarkably preserved on both sides. This preservation occurs because the anterior corticospinal tracts descend with significant bilateral terminal innervation, allowing the intact left motor cortex to provide bilateral compensatory drive to the midline trunk musculature.
Vascular Lesion: Anterior Spinal Artery Occlusion: In anterior spinal artery syndrome, ischemia occurs in the anterior two-thirds of the spinal cord, sparing the posterior columns. Both the anterior corticospinal tracts and the lateral corticospinal tracts are infarcted bilaterally. As a result, the patient experiences immediate complete flaccid paralysis below the level of the lesion, losing not only fine distal limb manipulation but also total control of the axial frame, inability to sit upright unsupported, and profound bilateral trunk paralysis.
9. Measurement & Assessment
Assessing the anatomical integrity and functional performance of the anterior corticospinal tract requires a combination of neuroimaging, neurophysiological profiling, and specialized clinical neurological examinations:
Diffusion Tensor Imaging (DTI) and Tractography: Advanced magnetic resonance imaging (MRI) utilizing diffusion tensor imaging allows neuroscientists and neurosurgeons to track the three-dimensional trajectory of the corticospinal pathways in vivo. By analyzing the directional diffusion of water molecules along myelinated axons, probabilistic tractography can resolve the anterior corticospinal tract as a discrete bundle descending within the anterior funiculus of the cervical spinal cord, separating it computationally from the more prominent lateral corticospinal tract.
Transcranial Magnetic Stimulation (TMS): Corticospinal excitability to axial muscles can be measured using single-pulse and paired-pulse TMS applied over the motor cortex midline. By placing surface electromyographic (EMG) recording electrodes on the paraspinal or abdominal muscles bilaterally, clinicians evoke motor evoked potentials (MEPs). TMS protocols routinely show that unilateral cortical stimulation produces bilateral MEPs in axial muscles with nearly identical latencies, serving as direct electrophysiological proof of the bilateral projection patterns mediated by the anterior corticospinal and reticulospinal systems.
Clinical Bedside Assessment of Axial Motor Function: Neurologists assess the integrity of axial motor pathways through specialized physical maneuvers:
- Beevor’s Sign: The patient is asked to perform a partial sit-up from a supine position. If specific thoracic segments of the anterior horn or descending tracts are compromised, the umbilicus deviates toward the preserved, functioning abdominal musculature.
- Trunk Impairment Scale (TIS): A validated clinical tool assessing static sitting balance, dynamic sitting balance, and trunk coordination in post-stroke or spinal cord injury populations, reflecting the functional state of ventromedial descending pathways.
- Cervical Rotation and Stabilization: Testing voluntary resistance against lateral, anterior, and posterior cervical displacement evaluates the corticospinal control of sternocleidomastoid, trapezius, and deep cervical flexor/extensor muscle groups.
10. Applications & Practical Significance
The clinical and operational significance of the anterior corticospinal tract spans multiple domains of medicine, neurorehabilitation, and athletic performance:
Neurorehabilitation Post-Stroke: Following an ischemic or hemorrhagic stroke that disrupts the lateral corticospinal tract, hemiparetic patients frequently exhibit profound distal deficits (such as an inability to execute fractionated finger movements). Neurorehabilitation strategies capitalize on the anterior corticospinal tract’s bilateral architecture. Therapists engage patients in trunk-targeted dynamic balance exercises, core stability regimens, and whole-body postural training. Because the undamaged hemisphere projects bilaterally via anterior corticospinal fibers, targeted axial training can substantially improve sitting balance, ambulation safety, and foundational stability, providing a physical anchor that facilitates distal limb rehabilitation.
Spinal Cord Injury (SCI) Recovery: In incomplete spinal cord injuries (e.g., Central Cord Syndrome or Brown-Séquard Syndrome), the anterior funiculus may be selectively spared or damaged depending on the mechanical vector of injury. Sparing of the anterior funiculi preserves the anterior corticospinal tracts and reticulospinal fibers, which strongly correlates with a patient’s ultimate ability to regain independent standing and non-wheelchair ambulation, even when fine distal dexterity remains permanently impaired.
Neurosurgical Planning: During neurosurgical procedures involving the ventral cervical spinal cord, such as the resection of ventral meningiomas, schwannomas, or anterior corpectomy for cervical myelopathy, neurosurgeons monitor motor evoked potentials specifically to protect the anterior funiculus. Maintaining the integrity of the anterior corticospinal tract is critical to prevent post-operative axial instability, dropped head syndrome, and severe postural dyscontrol.
11. Research & Empirical Evidence
Over the past several decades, rigorous empirical investigations have characterized the physiological and structural properties of the anterior corticospinal tract:
Primate Tracing and Lesion Studies: Foundational anatomical experiments conducted by Hans Kuypers (1964, 1981) demonstrated that selective bilateral sectioning of the pyramidal decussation in rhesus monkeys obliterated fine fractionated digit control. However, these animals retained the capacity to maintain an upright posture, climb cage mesh, and sit unsupported, which Kuypers attributed to the intact uncrossed ventral corticospinal projections and their integration with the brainstem medial motor pathways. Subsequent tracer injections (e.g., horseradish peroxidase and anterograde radioactive amino acids) confirmed that the ventral tract terminates extensively in the medial interneuronal zones of the spinal cord (Rexed laminae VII and VIII) with bilateral collateralization.
Human Neuroimaging and DTI Findings: A landmark study by Lindenberg et al. (2010) examined structural integrity of descending motor pathways in chronic stroke patients using diffusion tensor tractography. Their data demonstrated that when the lateral corticospinal tract suffered extensive damage, functional recovery of gait and gross motor coordination depended heavily on the structural preservation and compensatory microstructural reorganization of the anterior corticospinal tract and adjacent cortico-reticulospinal tracts within the undamaged and damaged hemispheres.
Electrophysiological Mapping: Research by Nathan, Smith, and Deacon (1996) on post-mortem human material from patients who underwent anterolateral cordotomies for intractable pain provided precise mapping of the human pyramidal pathways. Their observations validated that the anterior corticospinal tract varies substantially in size among individuals, ranging from entirely absent (with 100% of fibers decussating laterally) to comprising up to 30% of total corticospinal volume, with fibers occasionally descending as far caudally as the upper lumbar segments.
12. Cultural & Cross-Cultural Considerations
In the context of biomedical science and neuroanatomy, cultural and cross-cultural considerations manifest primarily in the evolution of anatomical taxonomy, global standardization of nomenclature, and comparative evolutionary perspectives across diverse primate lineages:
International Anatomical Standardization: For over a century, anatomical terminology was dominated by localized eponyms and national traditions. German and Austrian clinical schools universally referred to the anterior corticospinal tract as the Türck-Bündel (bundle of Türck), whereas British, French, and American schools favored varying descriptors such as the “direct pyramidal tract” or the “uncrossed anterior column.” The establishment of the Federative International Programme on Anatomical Terminologies (FIPAT) and the publication of Terminologia Anatomica (TA2) harmonized global medical education by strictly codifying the structure as tractus corticospinalis anterior, eliminating confusing eponyms and ensuring cross-national educational consistency across global medical curricula.
Comparative Evolutionary Neuroanatomy: From a comparative biological perspective, the anterior corticospinal tract is an evolutionary adaptation primarily expanded in hominoids and higher anthropoid primates. In non-primate quadrupeds (such as rodents, carnivores, and ungulates), the corticospinal system is overwhelmingly dorsolateral, and the anterior corticospinal tract is either completely absent or indistinguishable from adjacent reticulospinal systems. The evolutionary emergence of a prominent anterior corticospinal tract in primates mirrors the development of an erect or semi-erect trunk, bipedal locomotion, and the evolutionary need to decouple axial trunk stabilization from rhythmic quadrupedal stepping cycles.
13. Criticisms, Debates & Limitations
Despite more than a century of investigation, several neuroanatomical controversies and clinical debates persist regarding the anterior corticospinal tract:
Tract Size and Inter-Individual Variability: One of the central debates in human neuroanatomy concerns the immense anatomical variation of the anterior corticospinal tract. Classical textbooks routinely present a standard figure of 10% to 15% for the tract’s relative volume. However, rigorous anatomical cadaveric studies have shown that the tract exhibits extreme anatomical polymorphism. In approximately 2% to 3% of individuals, the anterior tract is completely non-existent (all descending fibers decussate into the lateral columns at the medulla). In contrast, in other rare individuals, up to 30% of pyramidal fibers enter the anterior funiculus. This high degree of anatomical variance complicates standardized prognostication in acute spinal cord trauma.
The Independence vs. Reticulospinal Redundancy Debate: A significant neurophysiological debate questions whether the anterior corticospinal tract acts as a truly independent functional system or merely as an evolutionary adjuvant to the cortico-reticulospinal system. Many neuroscientists argue that voluntary control of axial and proximal muscles is mediated overwhelmingly by the pontine and medullary reticulospinal tracts, which receive heavy bilateral inputs from the premotor cortex. Proponents of this view argue that the anterior corticospinal tract does not possess unique functional topography, but rather serves as a supplementary direct pathway that duplicates reticulospinal motor commands.
Imaging Resolution Limitations: A contemporary technical limitation lies in diffusion tensor imaging (DTI). Due to the small cross-sectional diameter of the anterior corticospinal tract in the spinal cord, its proximity to bone-tissue interfaces (susceptibility artifacts from vertebral bodies), and cerebrospinal fluid pulsations in the subarachnoid space, tractographic reconstruction of the anterior corticospinal tract frequently suffers from high false-positive and false-negative rates compared to the massive lateral tract.
14. Related Terms & Distinctions
Understanding the anterior corticospinal tract requires distinguishing it clearly from related anatomical tracts and neuroanatomical concepts:
- Lateral Corticospinal Tract (LCST): The largest descending motor tract (comprising 85–90% of corticospinal fibers). Unlike the anterior tract, the LCST decussates fully at the medullary pyramids, descends in the lateral funiculus of the spinal cord, and projects primarily unilaterally to lateral motor nuclei in the anterior horn, controlling distal, skilled, fractionated limb movements (e.g., individual finger manipulation).
- Reticulospinal Tract (RST): A major extrapyramidal descending pathway originating from the reticular formation of the pons and medulla. While both the RST and the anterior corticospinal tract descend in the ventromedial funiculi and terminate on medial motor columns to regulate posture, the RST is driven primarily by subcortical integration centers and central pattern generators rather than direct monosynaptic cortical pyramidal efferents.
- Tectospinal (Colliculospinal) Tract: A descending pathway arising from the superior colliculus of the midbrain. It descends in the anterior funiculus adjacent to the anterior corticospinal tract, but its function is strictly limited to coordinating reflex head, neck, and eye orienting movements in response to sudden visual, acoustic, and somatosensory stimuli.
- Vestibulospinal Tract (VST): Comprising lateral and medial divisions originating in the vestibular nuclei of the rostral medulla and caudal pons. The VST descends uncrossed in the anterior funiculus to innervate antigravity extensor muscles in response to inner ear labyrinthine signals, functioning largely autonomously from direct cortical control.
- Corticobulbar (Corticonuclear) Tract: A sister pyramidal tract originating from the ventrolateral precentral gyrus that innervates the motor nuclei of cranial nerves within the brainstem (controlling facial expression, mastication, phonation, and swallowing), whereas the anterior corticospinal tract continues caudally into the spinal cord.
15. Summary / Key Takeaways
The anterior corticospinal tract is a specialized, descending pyramidal pathway originating within the primary motor and premotor cortices that descends uncrossed through the brainstem and enters the anterior funiculus of the spinal cord. Constituting roughly 10% to 15% of the total corticospinal system, the tract diverges from the classic lateral corticospinal pathway by avoiding decussation in the caudal medulla. Instead, it maintains an ipsilateral ventral descent until reaching segmental spinal levels, where its fibers traverse the anterior white commissure to synapse bilaterally within the medial motor columns of Rexed laminae VII, VIII, and IX.
Functionally integrated within the ventromedial motor network, the anterior corticospinal tract specializes in coordinating axial posture, trunk stabilization, and anticipatory postural adjustments that support coordinated extremity movements. Its bilateral projection architecture provides remarkable clinical resilience, explaining why patients with severe unilateral motor cortex stroke typically retain substantial control over trunk and midline muscle groups. A firm grasp of its anatomy, evolutionary trajectory, and clinical presentation is essential for accurate neurological diagnosis, surgical safety, and contemporary neurorehabilitation design.
References
- Kuypers, H. G. J. M. (1981). Anatomy of the descending pathways. In V. B. Brooks (Ed.), Handbook of Physiology, The Nervous System, Motor Control (pp. 597–666). American Physiological Society. https://doi.org/10.1002/cphy.cp010213
- Lindenberg, R., Renga, V., Zhu, L. L., Nair, D., & Schlaug, G. (2010). Structural integrity of corticospinal and transcallosal tracts predicts motor recovery in chronic stroke. Stroke, 41(2), 281–287. https://doi.org/10.1161/STROKEAHA.109.564765
- Nathan, P. W., Smith, M. C., & Deacon, P. (1996). The corticospinal tracts in man: Course and location of fibres at different levels of the spinal cord. Brain, 119(1), 291–306. https://doi.org/10.1093/brain/119.1.291
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