Chapter 5 Morphology of single axons of tectospinal and reticulospinal neurons in the upper cervical spinal cord

Shinoda, Yoshikazu; Kakei, Shinji; Muto, Naoko

doi:10.1016/s0079-6123(08)63321-x

Cited by 9 publications

(6 citation statements)

References 30 publications

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“…These reticular neurons projecting to the neck motoneurons are known to be under cortical control (areas 4 and 6) (Alstermark et al 1985;Isa and Sasaki 2002). In addition, single reticulospinal neurons are connected with different groups of neck motoneurons, suggesting the existence of motor primitives in the reticular formation to control neck muscle synergies (Shinoda et al 1996). These characteristics of the reticulo-spinal neurons argue strongly for the involvement of reticulo-spinal activity in the generation of the 10-to 15-Hz neck muscular oscillations.…”

Section: Neural Control Of the Neck Muscles In Humansmentioning

confidence: 99%

“…On the other hand, the animal literature does not support such a dichotomy in the control of superficial and deep neck muscles. For example, single reticulo-spinal neurons are connected with different groups of neck motoneurons (Shinoda et al 1996). In addition, all neck muscles recorded in cats and monkeys can exhibit phasic activity during voluntary and reflex activation (Corneil et al 2001;Keshner et al 1992).…”

Section: Introductionmentioning

confidence: 99%

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Neural Control of Superficial and Deep Neck Muscles in Humans

Blouin

Siegmund²,

Carpenter³

et al. 2007

Journal of Neurophysiology

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Human neck muscles have a complex multi-layered architecture. The role and neural control of these neck muscles were examined in nine seated subjects performing three series of isometric neck muscle contractions: 50-N contractions in eight fixed horizontal directions, 25-N contractions, and 50-N contractions, both with a continuously changing horizontal force direction. Activity in the left sternocleidomastoid, trapezius, levator scapulae, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles was measured with wire electrodes inserted at the C(4)/C(5) level under ultrasound guidance. We hypothesized that deep and superficial neck muscles would function as postural and focal muscles, respectively, and would thus be controlled by different neural signals. To test these hypotheses, electromyographic (EMG) tuning curves and correlations in the temporal and frequency domains were computed. Three main results emerged from these analyses: EMG tuning curves from all muscles exhibited well-defined preferred directions of activation for the 50-N isometric forces, larger contractions (25 vs. 50 N) yielded more focused EMG tuning curves, and agonist neck muscles from all layers received a common neural drive in the range of 10-15 Hz. The current results demonstrate that all neck muscles can exhibit phasic activity during isometric neck muscle contractions. Similar oscillations in the EMG of neck muscles from different layers further suggest that neck motoneurons were activated by common neurons. The reticular formation appears a likely generator of the common drive to the neck motoneurons due to its widespread projections to different groups of neck motoneurons.

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Section: Neural Control Of the Neck Muscles In Humansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Neural Control of Superficial and Deep Neck Muscles in Humans

Blouin

Siegmund²,

Carpenter³

et al. 2007

Journal of Neurophysiology

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“…An intermediate step of this transformation segregates the movement into cardinal components in the pontomedually reticular formation and mesencephalon (owls: Masino and Knudsen 1993;cats: Fukushima 1987;Naito 1994, 1995;Isa and Sasaki 1992a,b;Sasaki et al 1999). The descending spinal systems from these areas contact a specific subpopulation of neck muscle motoneurons (Isa and Sasaki 1992a,b;Iwamoto and Sasaki 1990;Sasaki 1999;Shinoda et al 1996) forming functional neck muscle synergies hard-wired via descending brain stem systems (Shinoda et al 1996;Siegel and Tomaszewski 1983). We suspect these syn- FIG. 14.…”

Section: Head-only Movementsmentioning

confidence: 99%

Neck Muscle Responses to Stimulation of Monkey Superior Colliculus. II. Gaze Shift Initiation and Volitional Head Movements

Corneil

Olivier

Munoz

2002

Journal of Neurophysiology

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We report neck muscle activity and head movements evoked by electrical stimulation of the superior colliculus (SC) in head-unrestrained monkeys. Recording neck electromyography (EMG) circumvents complications arising from the head's inertia and the kinetics of muscle force generation and allows precise assessment of the neuromuscular drive to the head plant. This study served two main purposes. First, we sought to test the predictions made in the companion paper of a parallel drive from the SC onto neck muscles. Low-current, long-duration stimulation evoked both neck EMG responses and head movements either without or prior to gaze shifts, testifying to a SC drive to neck muscles that is independent of gaze-shift initiation. However, gaze-shift initiation was linked to a transient additional EMG response and head acceleration, confirming the presence of a SC drive to neck muscles that is dependent on gaze-shift initiation. We forward a conceptual neural architecture and suggest that this parallel drive provides the oculomotor system with the flexibility to orient the eyes and head independently or together, depending on the behavioral context. Second, we compared the EMG responses evoked by SC stimulation to those that accompanied volitional head movements. We found characteristic features in the underlying pattern of evoked neck EMG that were not observed during volitional head movements in spite of the seemingly natural kinematics of evoked head movements. These features included reciprocal patterning of EMG activity on the agonist and antagonist muscles during stimulation, a poststimulation increase in the activity of antagonist muscles, and synchronously evoked responses on agonist and antagonist muscles regardless of initial horizontal head position. These results demonstrate that the electrically evoked SC drive to the head cannot be considered as a neural replicate of the SC drive during volitional head movements and place important new constraints on the interpretation of electrically evoked head movements.

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“…For example, single cells in the LP project to both the visual cortex and the CPu, and single cells in the substantia nigra (SN) project to both the LP and the CPu, from which it has been proposed that the CPu may be involved in processing visual information required for orienting behavior determined by a somatic motor activity (Takada, 1992). In fact, it has been pointed out that the CPu is well situated to help direct saccadic eye movements (Lin et al, 1984), since the descending inputs from the striatum via the substantia nigra pars reticulata (SNR) terminate in the deep layers of the superior colliculus (SCD; Wilczyniski andNorthcutt, 1977, 1983a,b;Reiner et al, 1980Reiner et al, , 1982Covey et al, 1987;Lugo-Garcia and Kicliter, 1988;Takada, 1992;Westby et al, 1993), an area known to play a role in saccadic eye movements in mammals (Edwards, 1977;McHaffie and Stein, 1982;Stein et al, 1984;Cowie and Robinson, 1994;Paré et al, 1994;Gerlach and Thier, 1995;Peck et al, 1995;Scudder et al, 1996;Shinoda et al, 1996;Tegetmeyer, 1996;Freedman and Sparks, 1997).…”

Section: Thalamic Projections To the Cpumentioning

confidence: 99%