Abstract
We evoked both ear and eye movements in area 8b, the rostral area of frontal cortex, in two monkeys. In some sites it was possible to evoke only ear movements or only eye movements; in other locations we evoked both ear and eye movements by varying the intensity of electrical stimulation. The electrically evoked ear movements were forward, or backward, or oblique (upward-forward; upward-backward). In two penetrations the ear movements were bilateral, in the other penetrations they were contralateral. Ipsilateral ear movements were not observed. The evoked eye movements were mainly fixed-vector saccades, contralateral and with an upward orientation of about 45°. If we considered only the sites where the threshold was equal to or lower than 50 μA, the stimulation of this area evoked mainly ear movements. In addition we recorded the electrical activity of 195 neurons. Of these neurons: 74% (145/195) discharged before ear movements (ear cells); 20% (40/195) discharged before ear and eye movements (ear-eye cells); 5% (10/195) discharged only before eye movements (eye cells). Ninety-one percent (132/145) of ear cells presented a preferred direction; 90% (36/40) of ear-eye cells presented a preferred direction for ear movements, and 15% (6/40) presented a preferred direction for eye movements. Eighty-five percent (34/40) of cells did not present a preferred direction for visually guided saccades and were active when the monkey made saccades toward the unlit targets (checking saccades). Our results show that a field of area 8b is related to ear movements and to eye-ear movements. The findings that it is possible to obtain both ear and eye movements with low-intensity currents and that there are cells firing for the two types of movements suggest that area 8b may be involved in the orientation and coordination of both ear and eye. This area might be considered a rostral extension of supplementary eye field (SEF) or a different region. However, based on its distinct functional characteristics and connectivity, it is probably better regarded as a separate field. Regardless, the combination of 8b and SEF may constitute a cortical center for orienting processes.
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References
Bizzi E, Kalil RE, Tagliasco V (1971) Eye-head coordination in monkeys. Evidence for centrally patterned organization. Science 173:452–454
Bon L, Lucchetti C (1990) Neurons signalling the maintenance of attentive fixation in frontal area 6ab of macaque monkey. Exp Brain Res 82:231–233
Bon L, Lucchetti C (1992) The dorsomedial frontal cortex of the macaca monkey: fixation and saccade-related activity. Exp Brain Res 89:571–580
Brodmann K (1905) Beiträge zur histologischen Lokalisation der Grosshirnrinde: die Rindenfelder der niederen Affen. J Psychol Neurol 4:177–226
Bruce CJ, Goldberg ME (1985) Primate frontal eye fields. I. Single neurons discharging before saccades. J Neurophysiol 53:603–635
Burman D, Bruce CJ, Russo GS (1988) Pinna movements elicited by microstimulation in the prefrontal cortex of monkeys. Soc Neurosci Abstr 208:4
Camarda R, Luppino G, Matelli M, Rizzolatti G (1991) Cortical connections of two different eye fields in the dorsomedial frontal cortex of the macaque monkey. Soc Neurosci Abstr 185:14
Hyde JE, and Toczek S (1962) Functional relation of interstitial nucleus to rotatory movements evoked from zona incerta stimulation. J Neurophysiol 25:455–466
Judge SJ, Richmond BJ, Chu FC (1980) Implantation of magnetic search coil for measurement of eye position: an improved method. Vision Res 20:535–538
Levinsohn G (1909) Über die Beziehungen der Grosshirnrinde beim Affen zu den Bewegungen des Auges. Graefes Arch Ophthalmol 71:313–378
Mitz AR, Godschalk M (1989) Eye-movement representation in the frontal lobe of rhesus monkeys. Neurosci Lett 106:157–162
Mott FW, Schaefer EA (1890) On associated eye-movements produced by cortical faradization of the monkey's brain. Brain 13:165–173
Parthasarathy HB, Schall JD, Graybiel AM (1992) Distributed but convergent ordering of corticostriatal projections: analysis of the frontal eye field and supplementary eye field in the macaca monkey. J Neurosci 12:4468–4488
Peck CK (1990) Neuronal activity related to head and eye movements in cat superior colliculus. J Physiol (Lond) 421:79–104
Remmel RS (1984) An inexpensive eye movement monitor using the sciera coil technique. IEEE Trans Biomed Eng 31 (4): 388–390
Roucoux A, Guitton D, Crommelinck M (1980) Stimulation of the superior colliculus in the alert cat. II. Eye and head movements evoked when the head is unrestrained. Exp Brain Res 39:75–85
Russo GS, Bruce CJ (1993) Effect of eye position within the orbit on electrically elicited saccadic eye movement: a comparison of the Macaque monkey's frontal and supplementary eye fields. J Neurophysiol 69:800–818
Russo GS, Bruce CJ (1994) Frontal eye field activity aurally guided saccades. J Neurophysiol 71:1250–1253
Schall JD (1991) Neuronal activity related to visual guided saccadic eye movements in the supplementary motor area of Rhesus monkeys. J Neurophysiol 66:530–558
Schlag J, Schlag-Rey M (1987) Evidence for a supplementary eye field. J Neurophysiol 57:179–200
Schlag J, Schlag-Rey M, Pigarev I (1992) Supplementary eye field influence of eye position on neural signals of fixation. Exp Brain Res 90:302–306
Tanji J, Taniguchi K, Saga T (1980) Supplementary motor area: neuronal response to motor instruction. J Neurophysiol 43:60–68
Van der Steen J, Russell IS, James GO (1986) Effects of unilateral frontal eye-field lesions on eye-head coordination in monkey. J Neurophysiol 55:696–713
Vogt O, Vogt C (1919) Ergebnisse unserer Hirnforschung. J Psychol Neurol (Leipzig) 25:277–462
Von Bonin G, Bailey P (1947) The neocortex of Macaca mulatta. University of Illinois Press, Urbana
Walker AE (1940) A cytoarchitectural study of frontal area of the Macaque monkey. J Comp Neurol 73:59–86
Zangermaister WM, Stark L (1982) Gaze latency: variable interactions of head and eye latency. Exp Neurol 75:389–406
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Bon, L., Lucchetti, C. Ear and eye representation in the frontal cortex, area 8b, of the macaque monkey: an electrophysiological study. Exp Brain Res 102, 259–271 (1994). https://doi.org/10.1007/BF00227513
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DOI: https://doi.org/10.1007/BF00227513