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On the Electroencephalogram in the Unilateral Optic Enucleated Chick
ON THE ELECTROENCEPHALOGRAM IN THE UNILATERAL OPTIC ENUCLEATED CHICK M. TARAO AND T. OOKAWA Department of Physiology, Gifu University School of Medicine Gifu, Japan (Received for publication June 30, 1969)
As could be seen in Figure 1A, it was found that slow waves similar to those of sleep still occurred in a state of opening of eye. When an observer approached the bird, they were replaced by low-voltage fast waves or "the arousal pattern". This observation may correspond to the first stage of sleep, which was classified by Ookawa and Gotoh (1965) on the intact adult chicken. Namely, in the "alertresting" state with its eyes opened, bursts of 6 to 12 cycles per second with 200 to 300 microvolts appeared in the record intersperced with the arousal pattern. Furthermore, it was observed that when the chicken was in the sleeping state, the EEG of the bilateral hemispheres showed the high amplitude slow waves, and that when the bird opened spontaneously his eye, the EEG of the contralateral hemisphere (enucleated site) occurred often the arousal pattern, whereas the EEG of the ipsilateral hemisphere showed still the slow waves (Fig. IB). The present evidences seem sufficiently clearcut to warrent the previous publications reporting the unilateral appearance of low voltage fast waves contralateral to the opening of only one eye in the bird telencephalon (Peters et al., 1965; Ookawa, 1967; Ookawa and Takagi, 1968; Ookawa and Kadono, 1968). This phenomenon that appeared in resting state with one eye open could be readily observed in one eye enucleated birds. However, the bird was so sensitive to the external stimuli, that two hemispheres showed simultaneously the arousal pattern when an observer approached the birds or applied an acoustic
1516
Downloaded from http://ps.oxfordjournals.org/ at University of Hong Kong on May 9, 2015
The unilateral appearance of low voltage fast waves contralateral to the open or attentive eye has been reported in the chicken (Peters, et al., 1965; Ookawa, 1967; Ookawa and Takagi, 1968) and in the Japanese quail (Ookawa and Kadono, 1968). This means that the optic nerve of the bird undergoes complete crossing (Kappers et al., 1960; Cowan et al., 1961). The purpose of the present paper is to explore the effect of the unilateral optic enucleation on the electroencephalogram (EEG) in chicks. Eight male White Leghorn chicks, aged between 13 and 55 days, weighing from 85 to 560 grams were used. The EEG recording techniques have been described fully in an earlier paper (Ookawa and Takagi, 1968). All birds tested were recorded by the electroretinogram (ERG) before the enucleation, and they showed normal form (Ookawa et al., unpublished data). In most birds, the unilateral optic enucleation (left eyeball) was performed on between 4th and 16th day after hatching. Two electrodes for recording of the surface-EEG were symmetrically implanted in the caudal part of the frontal bone. Then, recordings were made under non-anesthetized and unrestrained conditions on 2nd day after the electrode placement. Monopolar recordings were employed with reference electrode placed on the comb. The EEG, the electromyogram (EMG) and the electrocardiogram (ECG) were simultaneously registered either with a 8 channel electroencephalograph (Sanei) or with a 4 channel inkwriter system (Nihon-Koden).
RESEARCH NOTES
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t FIG. 1. Effects of a left eye enucleation on the EEG in a 36-day-old (A) and a 18-day-oId (B) chick, respectively. The recordings were made on 6th day after enucleation in the former, and 4th day in the latter. In figure A, the first and the second bursts with large-amplitude on the EMG were the artifacts due to the movement of the neck, when an observer approached the bird. Each vertical indicates 2(XVV in amplitude. An arrow indicates the artifact induced by movement of the head when the bird was aurally stimulated by the sound. S t i m u l u s t o t h e m , s u c h as flaps, a s s e e n i n The of Birds. Hafner Publ. Co., N e w Telencephalon York
A and B of the Figure 1. In addition, the , , , , appearance of the arousal pattern on two hemispheres could be readily induced by a tactile or auditory stimulus in the bilatera l l y e n u c l e a t e d c h i c k ( O o k a w a , in p r e p -
aration). The neural basis for this regula.
.
, . „
,
,
> PP- 1358-1401.
Ookawa, T., 1967. Electroencephalographic study of
^
c h i c k e n t e l e n c e p h a l o n i n wakefulness-sleeP
anesthesia. Acta Scholae Med. 76-85.
and
in Gifu, 15:
Ookawa, T., and H. Kadono, 1968. Electroencephalo
§ r a m of
the
J a P a n e s * q uail (.Cotumix cotumix
iaponica) during non-anesthetized and anesthet-
tory mechanism may chiefly depend on endogenous events, such as on the reticu-
^ perio(Js P o u h r y s d 6 ? ; 3 2 ^ 3 2 5 ookawa, T., and J. Gotoh, 1965. Electroencephalo-
lar formation.
gram of the chicken recorded from the skull under various conditions. J. Comp. Neur. 124: 1-14. Ookawa, T., and K. Takagi, 1968. Electroencephalograms of free behavioral chicks at various developmental ages. Jap. J. Physiol. 18: 87-99. Peters, J. J., A. Vonderahe and D. Schmid, 1965. Onset of cerebral electrical activity associated with behavioral sleep and attention in the developing chick. J. Exp. Zool. 160: 255-262.
REFERENCES Cowan, W. M., L. Adamson and T. P. S. Powell, 1961. An experimental study of the avian visual system. J. Anat. 95: 545-563. Kappers, C. U. A., G. C. Huber and E. C. Crosby, 1960. The Comparative Anatomy of The Nervous System of Vertebrates, Including Man. Vol. 3,
NOVEMBER 6-10, 1970. FIRST AMERICAN INSTITUTE OF BIOLOGICAL SCIENCES NATIONAL BIOLOGICAL CONGRESS, COBO HALL, DETROIT, MICHIGAN. SEPTEMBER 6-12, 1970. FOURTEENTH WORLD'S POULTRY CONGRESS, MADRID, SPAIN.
Downloaded from http://ps.oxfordjournals.org/ at University of Hong Kong on May 9, 2015
I* \
As could be seen in Figure 1A, it was found that slow waves similar to those of sleep still occurred in a state of opening of eye. When an observer approached the bird, they were replaced by low-voltage fast waves or "the arousal pattern". This observation may correspond to the first stage of sleep, which was classified by Ookawa and Gotoh (1965) on the intact adult chicken. Namely, in the "alertresting" state with its eyes opened, bursts of 6 to 12 cycles per second with 200 to 300 microvolts appeared in the record intersperced with the arousal pattern. Furthermore, it was observed that when the chicken was in the sleeping state, the EEG of the bilateral hemispheres showed the high amplitude slow waves, and that when the bird opened spontaneously his eye, the EEG of the contralateral hemisphere (enucleated site) occurred often the arousal pattern, whereas the EEG of the ipsilateral hemisphere showed still the slow waves (Fig. IB). The present evidences seem sufficiently clearcut to warrent the previous publications reporting the unilateral appearance of low voltage fast waves contralateral to the opening of only one eye in the bird telencephalon (Peters et al., 1965; Ookawa, 1967; Ookawa and Takagi, 1968; Ookawa and Kadono, 1968). This phenomenon that appeared in resting state with one eye open could be readily observed in one eye enucleated birds. However, the bird was so sensitive to the external stimuli, that two hemispheres showed simultaneously the arousal pattern when an observer approached the birds or applied an acoustic
1516
Downloaded from http://ps.oxfordjournals.org/ at University of Hong Kong on May 9, 2015
The unilateral appearance of low voltage fast waves contralateral to the open or attentive eye has been reported in the chicken (Peters, et al., 1965; Ookawa, 1967; Ookawa and Takagi, 1968) and in the Japanese quail (Ookawa and Kadono, 1968). This means that the optic nerve of the bird undergoes complete crossing (Kappers et al., 1960; Cowan et al., 1961). The purpose of the present paper is to explore the effect of the unilateral optic enucleation on the electroencephalogram (EEG) in chicks. Eight male White Leghorn chicks, aged between 13 and 55 days, weighing from 85 to 560 grams were used. The EEG recording techniques have been described fully in an earlier paper (Ookawa and Takagi, 1968). All birds tested were recorded by the electroretinogram (ERG) before the enucleation, and they showed normal form (Ookawa et al., unpublished data). In most birds, the unilateral optic enucleation (left eyeball) was performed on between 4th and 16th day after hatching. Two electrodes for recording of the surface-EEG were symmetrically implanted in the caudal part of the frontal bone. Then, recordings were made under non-anesthetized and unrestrained conditions on 2nd day after the electrode placement. Monopolar recordings were employed with reference electrode placed on the comb. The EEG, the electromyogram (EMG) and the electrocardiogram (ECG) were simultaneously registered either with a 8 channel electroencephalograph (Sanei) or with a 4 channel inkwriter system (Nihon-Koden).
RESEARCH NOTES
F ^ ^ ™
]REST|
1517
|°RPEESNT|\ ALERT
ALERT
1 " "^E"CLO"SED" " ]
EEG(RIGHT) *
A
l}{
ISEC
i
iiMM)> **WtoM>
fEEG(LEFT) EYE CLOSED
v g
v
W
EEG(RIGHT)
I EYE OPEN I
W
^
\
EYE^LOSED
/
^
^
~ I
^
^
EYE OPEN
—
I
i TSECT
f
t FIG. 1. Effects of a left eye enucleation on the EEG in a 36-day-old (A) and a 18-day-oId (B) chick, respectively. The recordings were made on 6th day after enucleation in the former, and 4th day in the latter. In figure A, the first and the second bursts with large-amplitude on the EMG were the artifacts due to the movement of the neck, when an observer approached the bird. Each vertical indicates 2(XVV in amplitude. An arrow indicates the artifact induced by movement of the head when the bird was aurally stimulated by the sound. S t i m u l u s t o t h e m , s u c h as flaps, a s s e e n i n The of Birds. Hafner Publ. Co., N e w Telencephalon York
A and B of the Figure 1. In addition, the , , , , appearance of the arousal pattern on two hemispheres could be readily induced by a tactile or auditory stimulus in the bilatera l l y e n u c l e a t e d c h i c k ( O o k a w a , in p r e p -
aration). The neural basis for this regula.
.
, . „
,
,
> PP- 1358-1401.
Ookawa, T., 1967. Electroencephalographic study of
^
c h i c k e n t e l e n c e p h a l o n i n wakefulness-sleeP
anesthesia. Acta Scholae Med. 76-85.
and
in Gifu, 15:
Ookawa, T., and H. Kadono, 1968. Electroencephalo
§ r a m of
the
J a P a n e s * q uail (.Cotumix cotumix
iaponica) during non-anesthetized and anesthet-
tory mechanism may chiefly depend on endogenous events, such as on the reticu-
^ perio(Js P o u h r y s d 6 ? ; 3 2 ^ 3 2 5 ookawa, T., and J. Gotoh, 1965. Electroencephalo-
lar formation.
gram of the chicken recorded from the skull under various conditions. J. Comp. Neur. 124: 1-14. Ookawa, T., and K. Takagi, 1968. Electroencephalograms of free behavioral chicks at various developmental ages. Jap. J. Physiol. 18: 87-99. Peters, J. J., A. Vonderahe and D. Schmid, 1965. Onset of cerebral electrical activity associated with behavioral sleep and attention in the developing chick. J. Exp. Zool. 160: 255-262.
REFERENCES Cowan, W. M., L. Adamson and T. P. S. Powell, 1961. An experimental study of the avian visual system. J. Anat. 95: 545-563. Kappers, C. U. A., G. C. Huber and E. C. Crosby, 1960. The Comparative Anatomy of The Nervous System of Vertebrates, Including Man. Vol. 3,
NOVEMBER 6-10, 1970. FIRST AMERICAN INSTITUTE OF BIOLOGICAL SCIENCES NATIONAL BIOLOGICAL CONGRESS, COBO HALL, DETROIT, MICHIGAN. SEPTEMBER 6-12, 1970. FOURTEENTH WORLD'S POULTRY CONGRESS, MADRID, SPAIN.
Downloaded from http://ps.oxfordjournals.org/ at University of Hong Kong on May 9, 2015
I* \