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Locomotor exploratory activity in blind and normal guinea pigs
Physiology and Behavior, Vol. 13, pp. 701-702. Brain Research Publications Inc., 1974. Printed in the U.S.A.
BRIEF COMMUNICATION Locomotor Exploratory Activity in Blind and Normal Guinea Pigs' MICHAEL PATRICK O ' H A R A 2 AND ROBERT S. DYER 3
Department o f Psychology, Towson State College, Baltimore, Maryland 21204
(Received l 0 April 1974) O'HARA, M. P. AND R. S. DYER. Locomotor exploratory activity in blind and normal guinea pigs. PHYSIOL. BEHAV. 13(5) 701-702, 1974. - Blind and normal guinea pigs were observed in the closed field for 10 rain a day on 5 consecutive days. The blind were more active than normals, but the groups did not differ with respect to two measures of activity pattern: entries into center squares and direction reversals. Locomotion
Activity
Blindness
RECENT studies have suggested that visual input is important in arousal, as measured by l o c o m o to r activity, in rats [5], monkeys [4] and cats [3]. Other studies have shown that blindness facilitates two way avoidance learning in guinea pigs, and that the mechanism of facilitation is closely related to an increase in lo c o m o t o r activity [ 1 ]. The present experiment was designed to determine whether the increased l o co m o t o r activity observed in the shuttlebox in blind guinea pigs resulted from peculiarities of the avoidance task, or whether the increase was of a more general nature. In addition to comparing overall differences in activity between blind and normal guinea pigs in the closed field, the present experiment attempts to determine if the pattern of exploration used by the two groups is different.
lighted by four 25 W translucent white light bulbs, each mounted in a 12 in. aluminum reflector attached to the aluminum screened lid of the apparatus. Each reflector was mounted between the center of the lid and the top corner of the wall. The 48 x 48 x 1/4 in. plywood floor was ruled into 12 in. squares by black lines 1/8 in. wide. The interior of the field was sealed in urethane to allow easy cleaning. Squares of the field were assigned numbers 1 thru 16 (these numbers did not appear on the field), beginning with 1 (the square in which all animals were released) in a clockwise manner around the perimeter and continuing into the center, 13 thru 16.
Surgery All 20 animals were given a subcutaneous injection of 0.1 mg atropine sulfate followed 20 min later by an intraperitoneal injection of 37 mg/kg sodium pentobarbital (Nembutal). Optic enucleation of 10 guinea pigs was accomplished by section of the extraocular muscles and optic nerve with subsequent removal of the globe. After hemostasis was achieved the eyelids were sutured shut. Trials began three days after surgery.
METHOD
Animals Twenty experimentally naive male pigmented, shorthaired guinea pigs were obtained from Marland Breeding Farms, Wayne, New Jersey, weighing 2 5 0 - 3 0 0 g and were housed individually with access to free food and water (water contained 1% trisulfa) in the home cage. Animals were randomly assigned to either the blind or normal group (n = 10).
Procedure All animals were released in Square 1 facing the center of the field, and were given a 10 min trial every 24 hr on 5 consecutive days. The following measures were manually recorded and totaled for each 2 min interval: entries (E), the placing of both front paws in a square; center activity
Apparatus The animals were tested in a 4 x 4 ft closed field with 1/2 x 24 in. plywood walls painted flat black. The field was
1The research was supported by a grant from the Towson State College faculty research committee to RSD. 2Mr. O'Hara's present address is Department of Psychology, University of Georgia, Athens, Georgia 30601. a Reprints may be obtained from R. S. Dyer, Department of Environmental Medicine, School of Hygiene and Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, Maryland 21205. 701
702
O'HARA AND DYER
(C), entry of a Square 13 thru 16; and reversals (R), the reentry of a square with one intervening entry. RESULTS All measures were analyzed by a three factor analysis of variance with repeated measures on two factors (days; intervals); post hoc tests were done using orthogonal comparisons [ 6 ]. The entry activity results are summarized in Fig. 1, which shows that blind guinea pigs are more active than normals. The finding that blind guinea pigs made significantly more entries than normals, F(1,18) = 7.05, p<0.01, supports the hypothesis that blind guinea pigs are more 50.0
37.5
tu
25.0
i
12,5
0
r.~--o NORMAL e---e BLIND I I I I I 12345 INTE~AL ~YI
I I I I I 12345 I~AL DAY2
I I I I I 12345 INSTAL ~Y3
11111 12345 INSTAL ~Y4
I I I I I 12345 I~E~AL ~Y5
FIG. 1. Mean number of square entries for blind and normal guinea pigs during each 2 rain interval across the 5 days.
active than normal animals in a closed field. Significant effects for days, F(4,72) = 4.26, p4.00, dr= 1,72, p<0.05). Blind and normal guinea pigs did not differ significantly in either reversal activity, F(1,18) = 4.32, p>0.05, or center activity, F(1,18) = 3.74, p>0.05.
DISCUSSION The finding that blind guinea pigs made significantly more entries than normals is compatible with results found by others with rats [2,5]. It further suggests that the increases in spontaneous crossings observed by Dyer [ 1 ] in the shuttle box were not necessarily induced by the requirements of the task, but may have been increases in general locomotor activity produced directly by blindness. Thus, the possibility that the facilitated avoidance performance of blind guinea pigs is a spurious result of hyperactivity cannot be ruled out. The finding that blind guinea pigs do not differ from normats in total number of reversals or center entries is in accord with results found by Klein and Brown [5] who showed that blind rats alternated spontaneously at the same rate as controls. This suggests that blindness may not disrupt a general trend to vary locomotor exploratory activity.
REFERENCES 1. Dyer, R.S. Influences of the visual system upon two-way avoidance learning in the guinea pig. J. comp. physiol. Psychol. 76: 434-440, 1971. 2. Glickman, S. E. Effects of peripheral blindness on exploratory behavior in rats. Can. J. Psychol. 12: 45-51, 1958. 3. Isaac, W. S. and W.G. Reed. The effect of sensory stimulation on the activity of cats. J. comp. physiol. Psychol. 54: 677-678, 1961.
4. Isaac, W. and R. Troelstrup. Opposite effect of illumination and d-amphetamine upon activity in the squirrel monkey (Saimiri) and owl monkey (Aotes). Psychopharmacologia 15: 260-264, 1969. 5. Klein, D. R. and T. S. Brown. Exploratory behavior and spontaneous alternation in blind and anosmic rats. J. comp. physiol. Psychol. 68: 107-118, 1969. 6. Winer, B. J. Statistical Principles in Experimental Design. New York: McGraw-Hill, 1971.
BRIEF COMMUNICATION Locomotor Exploratory Activity in Blind and Normal Guinea Pigs' MICHAEL PATRICK O ' H A R A 2 AND ROBERT S. DYER 3
Department o f Psychology, Towson State College, Baltimore, Maryland 21204
(Received l 0 April 1974) O'HARA, M. P. AND R. S. DYER. Locomotor exploratory activity in blind and normal guinea pigs. PHYSIOL. BEHAV. 13(5) 701-702, 1974. - Blind and normal guinea pigs were observed in the closed field for 10 rain a day on 5 consecutive days. The blind were more active than normals, but the groups did not differ with respect to two measures of activity pattern: entries into center squares and direction reversals. Locomotion
Activity
Blindness
RECENT studies have suggested that visual input is important in arousal, as measured by l o c o m o to r activity, in rats [5], monkeys [4] and cats [3]. Other studies have shown that blindness facilitates two way avoidance learning in guinea pigs, and that the mechanism of facilitation is closely related to an increase in lo c o m o t o r activity [ 1 ]. The present experiment was designed to determine whether the increased l o co m o t o r activity observed in the shuttlebox in blind guinea pigs resulted from peculiarities of the avoidance task, or whether the increase was of a more general nature. In addition to comparing overall differences in activity between blind and normal guinea pigs in the closed field, the present experiment attempts to determine if the pattern of exploration used by the two groups is different.
lighted by four 25 W translucent white light bulbs, each mounted in a 12 in. aluminum reflector attached to the aluminum screened lid of the apparatus. Each reflector was mounted between the center of the lid and the top corner of the wall. The 48 x 48 x 1/4 in. plywood floor was ruled into 12 in. squares by black lines 1/8 in. wide. The interior of the field was sealed in urethane to allow easy cleaning. Squares of the field were assigned numbers 1 thru 16 (these numbers did not appear on the field), beginning with 1 (the square in which all animals were released) in a clockwise manner around the perimeter and continuing into the center, 13 thru 16.
Surgery All 20 animals were given a subcutaneous injection of 0.1 mg atropine sulfate followed 20 min later by an intraperitoneal injection of 37 mg/kg sodium pentobarbital (Nembutal). Optic enucleation of 10 guinea pigs was accomplished by section of the extraocular muscles and optic nerve with subsequent removal of the globe. After hemostasis was achieved the eyelids were sutured shut. Trials began three days after surgery.
METHOD
Animals Twenty experimentally naive male pigmented, shorthaired guinea pigs were obtained from Marland Breeding Farms, Wayne, New Jersey, weighing 2 5 0 - 3 0 0 g and were housed individually with access to free food and water (water contained 1% trisulfa) in the home cage. Animals were randomly assigned to either the blind or normal group (n = 10).
Procedure All animals were released in Square 1 facing the center of the field, and were given a 10 min trial every 24 hr on 5 consecutive days. The following measures were manually recorded and totaled for each 2 min interval: entries (E), the placing of both front paws in a square; center activity
Apparatus The animals were tested in a 4 x 4 ft closed field with 1/2 x 24 in. plywood walls painted flat black. The field was
1The research was supported by a grant from the Towson State College faculty research committee to RSD. 2Mr. O'Hara's present address is Department of Psychology, University of Georgia, Athens, Georgia 30601. a Reprints may be obtained from R. S. Dyer, Department of Environmental Medicine, School of Hygiene and Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, Maryland 21205. 701
702
O'HARA AND DYER
(C), entry of a Square 13 thru 16; and reversals (R), the reentry of a square with one intervening entry. RESULTS All measures were analyzed by a three factor analysis of variance with repeated measures on two factors (days; intervals); post hoc tests were done using orthogonal comparisons [ 6 ]. The entry activity results are summarized in Fig. 1, which shows that blind guinea pigs are more active than normals. The finding that blind guinea pigs made significantly more entries than normals, F(1,18) = 7.05, p<0.01, supports the hypothesis that blind guinea pigs are more 50.0
37.5
tu
25.0
i
12,5
0
r.~--o NORMAL e---e BLIND I I I I I 12345 INTE~AL ~YI
I I I I I 12345 I~AL DAY2
I I I I I 12345 INSTAL ~Y3
11111 12345 INSTAL ~Y4
I I I I I 12345 I~E~AL ~Y5
FIG. 1. Mean number of square entries for blind and normal guinea pigs during each 2 rain interval across the 5 days.
active than normal animals in a closed field. Significant effects for days, F(4,72) = 4.26, p
DISCUSSION The finding that blind guinea pigs made significantly more entries than normals is compatible with results found by others with rats [2,5]. It further suggests that the increases in spontaneous crossings observed by Dyer [ 1 ] in the shuttle box were not necessarily induced by the requirements of the task, but may have been increases in general locomotor activity produced directly by blindness. Thus, the possibility that the facilitated avoidance performance of blind guinea pigs is a spurious result of hyperactivity cannot be ruled out. The finding that blind guinea pigs do not differ from normats in total number of reversals or center entries is in accord with results found by Klein and Brown [5] who showed that blind rats alternated spontaneously at the same rate as controls. This suggests that blindness may not disrupt a general trend to vary locomotor exploratory activity.
REFERENCES 1. Dyer, R.S. Influences of the visual system upon two-way avoidance learning in the guinea pig. J. comp. physiol. Psychol. 76: 434-440, 1971. 2. Glickman, S. E. Effects of peripheral blindness on exploratory behavior in rats. Can. J. Psychol. 12: 45-51, 1958. 3. Isaac, W. S. and W.G. Reed. The effect of sensory stimulation on the activity of cats. J. comp. physiol. Psychol. 54: 677-678, 1961.
4. Isaac, W. and R. Troelstrup. Opposite effect of illumination and d-amphetamine upon activity in the squirrel monkey (Saimiri) and owl monkey (Aotes). Psychopharmacologia 15: 260-264, 1969. 5. Klein, D. R. and T. S. Brown. Exploratory behavior and spontaneous alternation in blind and anosmic rats. J. comp. physiol. Psychol. 68: 107-118, 1969. 6. Winer, B. J. Statistical Principles in Experimental Design. New York: McGraw-Hill, 1971.