Behavior of neurons in the abducens nucleus of the alert cat—I. Motoneurons

Delgado‐García, José M.; Pozo, Francisco del; Baker, R.

doi:10.1016/0306-4522(86)90072-2

Cited by 258 publications

(87 citation statements)

References 46 publications

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“…In monkey, one study (17) reported standard deviations of motoneuron discharge rate ranging from 3.7 to 13.5 with a mean of 6.4 when expressed as a percentage of mean interval, and similar values are reported by others (5,16). Similar studies in cat (18)(19)(20) found that variability increased in proportion to the duration of the fixation and that the firing rate during repeated fixation at the same eye position was affected significantly by the direction of the preceding saccade and by the animal's level of alertness. Variability in the discharge of neurons in motor and parietal areas of the primate cortex was measured during a period that included an arm movement, but no attempt was made to analyze variability in the neuronal discharge associated with the actual movement (21).…”

Section: Discussionsupporting

confidence: 71%

“…We know of no previous attempts to measure the reliability of motor command signals generated by individual neurons during a saccadic eye movement. The reliability of the discharge of oculomotor motoneurons in cat and monkey has been examined during the fixation period between saccades (5,(16)(17)(18)(19)(20). In monkey, one study (17) reported standard deviations of motoneuron discharge rate ranging from 3.7 to 13.5 with a mean of 6.4 when expressed as a percentage of mean interval, and similar values are reported by others (5,16).…”

Section: Discussionmentioning

confidence: 99%

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Reliability of oculomotor command signals carried by individual neurons

Jiang

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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The responses of sensory neurons to repeated presentations of identical stimuli can be highly reproducible. Little is known about the reliability of the motor command signals carried by individual premotor neurons. We measured the variability in the interspike intervals of the high-frequency, saccade-related bursts generated by neurons in the pontine reticular formation. During movements having similar amplitudes and velocity profiles, the interspike intervals of the high-frequency component of the bursts are very similar. The low variability in interspike intervals cannot be attributed to a burst mode characterized by fixed interspike times. Different, but repeatable, burst patterns are observed when movements having approximately the same amplitude but different velocity profiles occur. These findings suggest that the discharge of a single pontine cell is strongly correlated with the activity of other pontine burst cells. Both the high temporal precision of the saccade-related bursts and the correlated activity of pontine burst cells reduce variability in the signals sent to the motoneuron pools and, thereby, contribute to the accuracy and precision of saccadic eye movements.monkey ͉ saccade ͉ pons

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Reliability of oculomotor command signals carried by individual neurons

Jiang

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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“…High kt value units were generally weak, low kt value units were generally powerful, and the possible relation between kt value and motoneuron K value (the change in motoneuron firing as alert animals fixated targets in 1°increments) (Keller, 1981;Delgado-Garcia et al, 1986;Fuchs et al, 1988) will be considered in the Discussion.…”

Section: Abstract: Extraocular; Eye Movement; Abducens; Motoneuron; mentioning

confidence: 99%

Extraocular Motor Unit and Whole-Muscle Responses in the Lateral Rectus Muscle of the Squirrel Monkey

Goldberg¹,

Meredith²,

Shall

1998

J. Neurosci.

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Because primate studies provide data for the current experimental models of the human oculomotor system, we investigated the relationship of lateral rectus muscle motoneuron firing to muscle unit contractile characteristics in the squirrel monkey. Also examined was the correlation of whole-muscle contractile force with the degree of evoked eye displacement. A force transducer was used to record lateral rectus whole-muscle or muscle unit contraction in response to abducens whole-nerve stimulation or stimulation of single abducens motoneurons or axons. Horizontal eye displacement was recorded using a magnetic search coil.(1) Motor units could be categorized based on contraction speed (fusion frequency) and fatigue. (2) The kt value (change in motoneuronal firing necessary to increase motor unit force by 1.0 mg) of the units correlated with maximum tetanic tension. (3) There was some tendency for maximum tetanic tension of this unit population to separate into three groups. (4) At a constant frequency of 100 Hz, 95% of the motor units demonstrated significantly different force levels dependent on immediately previous stimulation history (hysteresis). (5) A mean force change of 0.32 gm/° and a mean frequency change of 4.7 Hz/° of eye displacement were observed in response to whole-nerve stimulation.These quantitative data provide the first contractile measures of primate extraocular motor units. Models of eye movement dynamics may need to consider the nonlinear transformations observed between stimulation rate and muscle tension as well as the probability that as few as two to three motor units can deviate the eye 1°.

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“…All abducens neurons recorded in mammals fire in the form of pulse step (Fuchs and Luschei, 1970;Schiller, 1970;Delgado-Garcia et al, 1986;Stahl and Simpson, 1995), whereas abducens neurons recorded in birds discharge sustained firing and/or several bursts. The present study revealed that sustained firing in abducens cells originates from the OKNrelated nLM/nBOR, whereas bursting activity originates from the saccade-related raphe complex.…”

Section: Discussionmentioning

confidence: 99%

“…In particular, horizontal eye movements are mainly actuated by the lateral and medial rectus muscles, which are innervated by motoneurons in the abducens nucleus and the contralateral oculomotor nucleus. These neurons in mammals discharge in a phasictonic pattern around the saccade (Fuchs and Luschei, 1970;Robinson, 1970;Schiller, 1970;Delgado-Garcia et al, 1986;Stahl and Simpson, 1995). The phasic and tonic signals originate from several midbrain and brainstem structures including the paramedian pontine reticular formation (Fuchs et al, 1985;Fukushima et al, 1992;Moschovakis et al, 1996;Moschovakis, 1997;Sparks, 2002).…”

Section: Introductionmentioning

confidence: 99%

Neuronal Circuitry and Discharge Patterns Controlling Eye Movements in the Pigeon

Yang

Wang³

2008

J. Neurosci.

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Horizontal eye movements in humans and other vertebrates are actuated by the lateral and medial rectus muscles that are innervated by the abducens and oculomotor nuclei. Here we show by single-cell recording in the pigeon that there exist three types of abducens neurons in terms of discharge patterns, which generate the shift and/or oscillation components of a horizontal saccadic eye movement. Shiftrelated neurons discharged sustained firing around saccadic shift, oscillation-related neurons produced several bursts accompanying saccadic oscillations, and saccade-related neurons discharged both sustained firing and several bursts perisaccadically. Oscillation-and saccade-related neurons were each divided into two groups according to their firing behaviors during nasotemporal saccades: bursting activity began before (leading) or after (lagging) the onset of saccades. Abducens neurons in the lagging group but not those in the leading group were activated by antidromic stimulation of the contralateral oculomotor nucleus. Blockade of the nucleus lentiformis mesencephali and the nucleus of the basal optic root, both of which are involved in optokinetic nystagmus, abolished sustained firing in abducens neurons and shift component of saccades, whereas blockade of the saccade-related raphe complex eliminated bursting activity in abducens neurons and oscillation component of saccades. The present study revealed oculomotor circuitry in the pigeon, in which the optokinetic nuclei and the raphe complex send differential signals to abducens neurons to generate three types of discharge patterns, and thereby initiate the shift and oscillation components of a horizontal saccade.

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Behavior of neurons in the abducens nucleus of the alert cat—I. Motoneurons

Cited by 258 publications

References 46 publications

Reliability of oculomotor command signals carried by individual neurons

Reliability of oculomotor command signals carried by individual neurons

Extraocular Motor Unit and Whole-Muscle Responses in the Lateral Rectus Muscle of the Squirrel Monkey

Neuronal Circuitry and Discharge Patterns Controlling Eye Movements in the Pigeon

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