Nigrotectal projections in the monkey: An autoradiographic study

Angayarkanni, Jayaraman; Batton, Robert R.; Carpenter, Malcolm B.

doi:10.1016/0006-8993(77)91058-7

Cited by 191 publications

(58 citation statements)

References 11 publications

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“…SNr neurons were activated with short and fixed latencies, consistent with their known input to SC in multiple species (e.g., Chevalier et al 1981;Graybiel 1978;Jayaraman et al 1977). Furthermore, locations within the SC resulting in antidromic activation of SNr neurons occurred at multiple depths, suggesting that SNr axons branch extensively along the vertical dimension within the SC.…”

Section: Relationship To Previous Work On the Uncrossed Snr-sc Pathwaysupporting

confidence: 60%

“…A second pathway also arises from neurons of the cerebral cortex and targets the SC through a series of synapses within basal ganglia (BG) nuclei (Hikosaka et al 1993;Parthasarathy et al 1992;Selemon andGoldman-Rakic 1985, 1988;Stanton et al 1988a;Weyand and Gafka 1998). Of the two output nuclei of the BG, oculomotor studies in monkey emphasize the substantia nigra pars reticulata (SNr) (Basso and Liu 2007;Basso and Wurtz 2002;Basso et al 2005;Bayer et al 2002;Glimcher 1999, 2000;Hikosaka and Wurtz 1983a,b,c,d;Sato and Hikosaka 2002) due to its direct projections to the SC (e.g., Jayaraman et al 1977).…”

Section: Introductionmentioning

confidence: 99%

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Substantia Nigra Stimulation Influences Monkey Superior Colliculus Neuronal Activity Bilaterally

Liu¹,

Basso²

2008

Journal of Neurophysiology

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Liu P, Basso MA. Substantia nigra stimulation influences monkey superior colliculus neuronal activity bilaterally. J Neurophysiol 100: 1098 -1112, 2008. First published June 25, 2008 doi:10.1152/jn.01043.2007. The inhibitory drive arising from the basal ganglia is thought to prevent the occurrence of orienting movements of the eyes, head, and body in monkeys and other mammals. The direct projection from the substantia nigra pars reticulata (SNr) to the superior colliculus (SC) mediates the inhibition. Since the original experiments in the SNr of monkeys the buildup or prelude neuron has been a focus of SC research. However, whether the SNr influences buildup neurons in SC is unknown. Furthermore, a contralateral SNr-SC pathway is evident in many species but remains unexplored in the alert monkey. Here we introduced electrical stimulation of one or both SNr nuclei while recording from SC buildup neurons. Stimulation of the SNr reduced the discharge rate of SC buildup neurons bilaterally. This result is consistent with activation of an inhibitory drive from SNr to SC. The time course of the influence of ipsilateral SNr on the activity of most SC neurons was longer (ϳ73 ms) than the influence of the contralateral SNr (ϳ34 ms). We also found that the variability of saccade onset time and saccade direction was altered with electrical stimulation of the SNr. Taken together our results show that electrical stimulation activates the inhibitory output of the SNr that in turn, reduces the activity of SC buildup neurons in both hemispheres. However, rather than acting as a gate for saccade initiation, the results suggest that the influence of SNr inhibition on visually guided saccades is more subtle, shaping the balance of excitation and inhibition across the SC.

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Section: Relationship To Previous Work On the Uncrossed Snr-sc Pathwaysupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Substantia Nigra Stimulation Influences Monkey Superior Colliculus Neuronal Activity Bilaterally

Liu¹,

Basso²

2008

Journal of Neurophysiology

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“…Some neurons in the SNr send outputs to target areas bilaterally, although the contralateral projection is much sparser than the ipsilateral one (Hopkins and Niessen, 1976;Jayaraman et al, 1977;Huerta et al, 1991). For the nigrothalamic projections, some SNr neurons project bilaterally to the lateral part of the mediodorsal and the adjacent paracentral intralaminar nuclei (Russchen et al, 1987).…”

Section: Discussionmentioning

confidence: 99%

Eye movements in monkeys with local dopamine depletion in the caudate nucleus. I. Deficits in spontaneous saccades

et al. 1995

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The basal ganglia contribute to the suppression and initiation of saccadic eye movements through the inhibitory connection from the substantia nigra pars reticulata (SNr) to the superior colliculus. This mechanism consists of serial and parallel connections, which are mostly inhibitory and GABAergic. Dopamine is known to exert powerful modulatory effects on the basal ganglia function, but its nature and mechanism are still unclear, especially in relation to voluntary behavior. The purpose of this series of investigation was to study the role of dopamine in the control of saccadic eye movements. We examined, in the monkey, whether and how the deficiency of the nigrostriatal dopaminergic innervation affects saccadic eye movements. The present article is focused on spontaneous saccades that the monkey made with no incentive to obtain reward; the next paper will describe task-specific saccades. Using an osmotic minipump we infused 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine (MPTP) unilaterally into the head-body junction of the caudate nucleus of monkeys where presaccadic neurons were clustered. Tyrosine hydroxylase activity, visualized using an immunohistochemical method, decreased locally around the injection site with some effects extending into the ipsilateral putamen and locally in the ipsilateral substantia nigra. Changes of eye movements started to appear 3–5 d after starting the infusion. Spontaneous saccades became less frequent. The area scanned by the saccades became narrower and shifted to the hemifield ipsilateral to the infusion site. The saccade amplitudes and peak velocities decreased; durations were prolonged. These effects were more prominent for saccades directed toward the side contralateral to the infusion site. These monkeys showed no obvious skeletomotor symptoms. These results suggest that the local deprivation of the dopaminergic innervation in the caudate nucleus facilitates neuronal activity of the SNr leading to suppression of saccadic eye movements.

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“…They speculated that such neurons project either to fixation neurons in the rostral SC, or to interneurons in more caudal areas that contain the saccade neurons. There are also indirect connections from DLPFC to the SC, via the basal ganglia and the Substantia Nigra pars reticulara (SNr) (Hikosaka et al 2006;Hikosaka et al 1993;Jayaraman et al 1977). Since SNr neurons are tonically active and are GABAergic, it is generally thought that SNr delivers a constant inhibition to saccade neurons to help maintain fixation.…”

Section: Dlpfcmentioning

confidence: 99%

A competitive integration model of exogenous and endogenous eye movements

2010

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We present a model of the eye movement system in which the programming of an eye movement is the result of the competitive integration of information in the superior colliculi (SC). This brain area receives input from occipital cortex, the frontal eye fields, and the dorsolateral prefrontal cortex, on the basis of which it computes the location of the next saccadic target. Two critical assumptions in the model are that cortical inputs are not only excitatory, but can also inhibit saccades to specific locations, and that the SC continue to influence the trajectory of a saccade while it is being executed. With these assumptions, we account for many neurophysiological and behavioral findings from eye movement research. Interactions within the saccade map are shown to account for effects of distractors on saccadic reaction time (SRT) and saccade trajectory, including the global effect and oculomotor capture. In addition, the model accounts for express saccades, the gap effect, saccadic reaction times for antisaccades, and recorded responses from neurons in the SC and frontal eye fields in these tasks.

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Nigrotectal projections in the monkey: An autoradiographic study

Cited by 191 publications

References 11 publications

Substantia Nigra Stimulation Influences Monkey Superior Colliculus Neuronal Activity Bilaterally

Substantia Nigra Stimulation Influences Monkey Superior Colliculus Neuronal Activity Bilaterally

Eye movements in monkeys with local dopamine depletion in the caudate nucleus. I. Deficits in spontaneous saccades

A competitive integration model of exogenous and endogenous eye movements

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