Summary
Interstitiospinal neurons were activated by antidromic stimulation of the spinal cord ventromedial funiculus at C1 and C4 in cerebellectomized cats under chlor alose anesthesia. Neurons responding only to C1 were classified as N cells and those responding both to C1 and C4 were classified as D cells, as in previous experiments (Fukushima et al. 1980a). Vestibular branching interstitiospinal and reticulospinal neurons were also identified as in the previous experiments.
Stimulation of the ipsilateral pericruciate cortex evoked firing in 31% of N cells, 41% of D cells and 35% of vestibular branching neurons, while stimulation of the contralateral cortex excited 6% of N cells, 29% of D cells and 14% of vestibular branching neurons. Response latencies ranged from 2 to 15 ms after the effective pulse. By measuring the thresholds of activation of these neurons while changing the depth of the stimulating electrodes, and by mapping the cortical areas, it was shown that the lowest threshold areas were in the frontal eye fields and the anterior sigmoid gyrus near the presylvian sulcus (Area 6). Stimulation of the latter area often evoked neck or shoulder muscle contraction.
Stimulation in the deep layers of the ipsilateral superior colliculus evoked firing in about 20% of interstitiospinal neurons and about 42% of vestibular branching neurons, with typical latencies 2–3 ms after the effective pulse, while stimulation of the contralateral superior colliculus was rarely effective. N cells and D cells responded similarly. Thresholds for activation were high in the intermediate tectal layers and declined as the electrodes entered the underlying tegmentum. This suggests that the superior colliculus is not the main source of synaptic inputs to these neurons. Low threshold points were found above the deep fiber layer when stimulating electrodes were inserted into the pretectum.
Stimulation of the C2 biventer cervicis nerve excited about 8% of N cells, 18% of D cells, and 15% of vestibular branching neurons bilaterally with typical latencies around 10 ms. Similar results were obtained when C2 splenius nerves were stimulated. The fibers responsible for such excitation are probably group II, since stimuli stronger than 1.8 times threshold of the lowest threshold fibers were needed to evoke excitation. Response decrement was often observed when stimuli were repeated at 1/s, while no such decrement was observed at the rate of 1/3 s.
When the convergence of cortical and labyrinthine excitatory inputs was studied, 36% of interstitiospinal neurons received single inputs either from the pericruciate cortex or from the labyrinth, 22% of neurons received convergent excitation from both and the remaining 42% did not respond to either stimulus. Although vestibular branching neurons rarely received labyrinthine inputs, they frequently showed convergence of excitation to stimulation of the frontal cortex, superior colliculus and vestibular nuclei.
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References
Abzug C, Maeda M, Peterson BW, Wilson VJ (1974) Cervical branching of lumbar vestibulospinal axons. J Physiol (Lond) 243: 499–522
Altman J, Carpenter MB (1961) Fiber projections of the superior colliculus in the cat. J Comp Neurol 116: 157–178
Anderson ME (1977) Segmental reflex inputs to motoneurons innervating dorsal neck musculature in the cat. Exp Brain Res 28: 175–187
Bilotto G, Fukushima K, Fuller JH, Peterson BW (1979) Control of neck musculature by tectal efferent pathways. Ann Meeting Soc Neurosci 5: 363
Bizzi E (1968) Discharge of frontal eye field neurons during saccadic and following eye movements in unanesthetized monkeys. Exp Brain Res 6: 69–80
Carpenter MB, Harbison JW, Peter P (1970) Accessory oculomotor nuclei in the monkey. Projections and effects of discrete lesions. J Comp Neurol 140: 131–154
Edwards SB (1977) The commissural projection of the superior colliculus in the cat. J Comp Neurol 173: 23–40
Fukushima K, Pitts NG, Peterson BW (1978) Direct excitation of neck motoneurons by interstitiospinal fibers. Exp Brain Res 33: 565–581
Fukushima K, Hirai N, Rapoport S (1979a) Direct excitation of neck flexor motoneurons by the interstitiospinal tract. Brain Res 160: 358–362
Fukushima K, Pitts NG, Peterson BW (1979b) Interstitiospinal action on forelimb, hindlimb, and back motoneurons. Exp Brain Res 37: 605–608
Fukushima K, Murakami S, Matsushima J, Kato M (1980a) Vestibular responses and branching of interstitiospinal neurons. Exp Brain Res 40: 131–145
Fukushima K, Murakami S, Ohno M, Kato M (1980b) Properties of interstitiospinal neurons in the cat. Proc Int Union Physiol Sci 24: 421
Fukushima K, Murakami S, Ohno M, Kato M (1980c) Properties of mesencephalic reticulospinal neurons in the cat. Exp Brain Res 41: 75–78
Guitton D, Mandl G (1978) Frontal ‘oculomotor’ area in alert cat. II. Unit discharges associated with eye movements and neck muscle activity. Brain Res 149: 313–327
Hassler R, Hess WR (1954) Experimentelle und anatomische Befunde über die Drehbewegungen und ihre nervösen Apparate. Arch Psychiatr Nervenkr 192: 488–526
Hyde JE, Toczek S (1962) Functional relation of interstitial nucleus to rotatory movements evoked from zona incerta stimulation. J Neurophysiol 25: 455–466
King WM, Precht W, Dieringer N (1980) Synaptic organization of frontal eye field and vestibular afférents to interstitial nucleus of Cajal in the cat. J Neurophysiol 43: 912–928
Künzle H, Akert K (1977) Efferent connections of cortical area 8 (frontal eye field) in Macaca fascicularis. A reinvestigation using the autoradiographic technique. J Comp Neurol 173: 147–164
Mabuchi M, Kusama T (1970) Mesodiencephalic projections to the inferior olive and the vestibular and perihypoglossal nuclei. Brain Res 17: 133–136
Markham CH (1968) Midbrain and contralateral labyrinth influences on brain stem vestibular neurons in the cat. Brain Res 9: 312–333
Markham CH, Precht W, Shimazu H (1966) Effect of stimulation of interstitial nucleus of Cajal on vestibular unit activity in the cat. J Neurophysiol 29: 493–507
Morimoto M, Kanaseki T (1980) Descending projections of the pretectum in the cat. Neurosci Lett [Suppl] 4: 66
Nieoullon A, Rispal-Padel L (1976) Somatotopic localization in cat motor cortex. Brain Res 105: 405–422
Nyberg-Hansen R (1966) Functional organization of descending supraspinal fibre systems to the spinal cord. Anatomical observations and physiological correlations. Ergeb Anat Entwicklungsgesch 39: 1–48
Schlag J, Schlag-Rey M (1970) Induction of oculomotor responses by electrical stimulation of the prefrontal cortex in the cat. Brain Res 22: 1–13
Schwindt PC, Precht W, Richter A (1974) Monosynaptic excitatory and inhibitory pathway from medial midbrain nuclei to trochlear motoneurons. Exp Brain Res 20: 223–238
Shimazu H, Precht W (1965) Tonic and kinetic responses of cat's vestibular neurons to horizontal angular acceleration. J Neurophysiol 28: 991–1013
Szentágothai J (1943) Die zentrale Innervation der Augenbewegungen. Arch Psychiatr Nervenkr 116: 721–760
Szentágothai J, Rajkovitz K (1958) Der Hirnnervenanteil der Pyramidenbahn und der prämotorische Apparat motorischer Hirnnervenkerne. Arch Psychiatr Nervenkr 197: 335–354
Thomas RC, Wilson VJ (1965) Precise localization of Renshaw cells with a new marking technique. Nature 206: 211–213
Woolsey CN (1958) Organization of somatic sensory and motor areas of the cerebral cortex. In: Harlow HF, Woolsey CN (eds) Biological and biochemical basis of behavior. The University of Wisconsin Press, Madison, pp 63–81
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Supported in part by a Grant-in-Aid for Scientific Research (No. 477063) from The Ministry of Education, Science, and Culture of Japan
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Fukushima, K., Ohno, M., Murakami, S. et al. Effects of stimulation of frontal cortex, superior colliculus, and neck muscle afferents on interstitiospinal neurons in the cat. Exp Brain Res 44, 143–153 (1981). https://doi.org/10.1007/BF00237335
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DOI: https://doi.org/10.1007/BF00237335