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Schedule dependence of schedule induced polydipsia and lever pressing
Physiology and Behavior, Vol. 10, pp. 965-966. Brain Research Publications Inc., 1973. Printed in the U.S.A.
BRIEF COMMUNICATION Schedule Dependence of Schedule Induced Polydipsia and Lever Pressing I M. J. W A Y N E R A N D I, G R E E N B E R G
Brain Research Laboratory, Syracuse University, 601 University Avenue, Syracuse, New York 13210
(Received 8 D e c e m b e r 1972)
WAYNER, M. J. AND I. GREENBERG. Schedule dependence of schedule induced polydipsia and leverpressing. PHYSIOL. BEHAV. 10(5) 965-966, 1973.--Two male hooded rats maintained at 80% of initial body weight were tested for schedule induced polydipsia at fixed time (FT) intervals of 1.0, 2.0, 3.0, 4.0 and 5.0 min. A total of 180 45 mg pellets were delivered during the test session. Each animal was tested five times at each FT interval. Total number of licks, lever presses and water consumption increased as the FT interval was increased to a maximum at 4.0 min and then decreased at 5.0 min. Although delivery of the food pellet was not contingent upon pressing the lever, lever pressing occurred and followed the same time related function as licking and water consumption. Results were interpreted in terms of increased motor activity attributed to intermittent food delivery. Schedule induced polydipsia Drinking Polydipsia
Adjunctive behavior
Motor arousal
Fixed time schedule
Procedure
WHEN animals such as the rat are subjected to i n t e r m i t t e n t schedules of r e i n f o r c e m e n t at reduced b o d y weight and are given the o p p o r t u n i t y to drink during the test session intense and persistent post f o o d pellet drinking occurs readily in most of the animals. Research o n this p h e n o m e non, which is usually referred to as schedule induced polydipsia, has been reviewed t h o r o u g h l y on several occasions [1, '2, 3, 4 ] . T h e fact that the effect is schedule d e p e n d e n t within limits [2] has not been c o n f i r m e d and the time d e p e n d e n c y relation w h e n lever pressing is not a required contingency has not been d e m o n s t r a t e d . The purpose o f the present e x p e r i m e n t was to confirm the time d e p e n d e n c y of schedule induced polydipsia and to d e m o n strate that lever pressing is not required. The data confirm earlier results and d e m o n s t r a t e in a d d i t i o n that lever pressing can occur adjunctively and be time d e p e n d e n t under the same conditions,
Animals were reduced to 80% of their initial weight by restriciting their daily ration of food. Animals were tested daily. The test chamber consisted of a standard LVE 1469 m e d i u m size test cage and matching sound attenuating cubicle with a lever and pellet dispensing mechanism. A stainless steel ball point drinking spout was m o u n t e d in the center o f the back wall o f tile test cage, 4.0 cm above the grid floor, and p r o t r u d e d 1,5 cm into the cage. The drinking spout was attached to a graduated e u d i o m e t e r t u b e for measuring water c o n s u m p t i o n . A standard f o o d cup was m o u n t e d in the adjacent wall as close as possible to the back wall and 1.0 cm above the floor. The lever was m o u n t e d in the same wall as the f o o d cup, 3.0 cm above the floor and 2.5 cm f r o m the front of the cage. Licks were recorded by means o f a contact resistance sensitive licko m e t e r on a cumulative recorder. Water was c o n t i n u o u s l y available in the living cage. Daily water c o n s u m p t i o n was recorded. Animals were placed in the test chamber at approximately the same time each night. The test cage was c o n t i n u o u s l y illuminated by an overhead light and extraneous sounds were masked by c o n t i n u o u s white noise. The
METHOD
Animals T w o male h o o d e d rats, 360 g in weight, were selected from our c o l o n y and placed in individual living cages.
This research was supported by NSF Grant GB-18414X and NIMH Grant 15473 and Training Grant MH-06969. 965
966
WAYNI!R ANI) ~;RFENBI~RG
a u t o m a t i c delivery of the 45 mg Noyes food pellet was accomplished by means of standard LVE test e q u i p m e n t . The i m p e n d i n g delivery of the f o o d pellet was preceded by turning on all six stimulus lights in the test c h a m b e r for two sec. At the end of the t w o sec period the lights were turned off and the pellet was delivered. Pellets were delivered according to a p r e d e t e r m i n e d fixed time ( F T ) interval for each test session. Five different FT intervals were tested: 1.0, 2.0, 3.0, 4.0, and 5.0 rain. A total of 180 pellets were delivered during each test session. Animals were tested on successive nights, 5 d e t e r m i n a t i o n s at each FT in a n o n s y s t e m a t i c order. The only e x c e p t i o n occurred following the FT of 5 rain, which required a total test session length of 900 rain to c o m p l e t e , when the animal was given an additional 24 hr before it was tested again. The lever was not c o n n e c t e d electrically to the pellet dispenser. T o t a l n u m b e r of licks, lever presses, and water consumed in ml for each test session were recorded.
18o
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--• -O
HOH LICKS LEVERPRESSES
160 "i
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i
140 -i
3O
~oo 4
25
. 20 60
]
40
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o ~. . . .
I-
IO
20
L 10
,
T
T.
3.0
40
.
.
.
IS
!
r
~
0
sO
FIXED TIME MIN
R ES U LTS As the results for b o t h animals were very similar the data were c o m b i n e d and are summarized in Fig. 1 where the m e a n total fluid c o n s u m e d in ml, lever presses, and licks for b o t h animals are presented as a f u n c t i o n of the five different FT intervals: 1.0, 2.0, 3.0, 4.0, and 5.0 rain. Each point is based u p o n the mean of five d e t e r m i n a t i o n s at each FT for each animal. As e x p e c t e d water c o n s u m p t i o n tended to be closely associated with licking and b o t h displayed the same time d e p e n d e n t o p t i m u m or peak at a FT interval of 4.0 rain. As delivery of the pellet was not contingent u p o n depression of the lever, the schedule related lever pressing with the same m a x i m u m at a FT of 4.0 rain is very interesting. A l t h o u g h the total n u m b e r of lever presses is very small, the t i m e d e p e n d e n c y is obvious. The schedule induced polydipsia was p r o n o u n c e d and copious a m o u n t s of water were c o n s u m e d by b o t h animals, a mean of t 22 ml at a FT of 4.0 rain. DISCUSSION These data confirm the results of an earlier study [2]
FIG. 1. Combined data from two animals. Mean total number of licks, lever presses, and water consumed in ml as a function of the different FT intervals. Each point based upon 5 determinations for each FT for each animal.
which d e m o n s t r a t e d that schedule induced polydipsia was also schedule dependent. In addition these results indicate that the adjunctive lever pressing which occurred might be a measure of increased m o t o r activity associated with the delivery of the pellet. Under these conditions drinking and lever pressing are b o t h adjunctive and tend to support an earlier hypothesis that the i n t e r m i t t e n c e in the delivery of food results in an increase in the excitability of m o t o r pathways [4] which produces an increase in m o t o r activity and readiness to respond. Therefore, schedule induced polydipsia is primarily an e n h a n c e m e n t of the m o t o r p h e n o m e n o n of licking and the fluid consumed is a normal consequence of this act.
REFERENCES
1. 2.
Falk, J. L. Studies on schedule-induced polydipsia. In: Thirst in the Regulation o f Body Water, edited by M. J. Wayner. Oxford: Pergamon Press, 1964, pp. 95-116. Falk, J. L. Conditions producing psychogenic polydipsia in animals. Ann. N. Y. Acad. Sci. 157: 569-593, 1969.
3. 4.
Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6:577 588, 1971. Wayner, M. J. Motor control functions of the laterat hypothalamus and adjunctive behavior. Physiol. Behav. 5: 1319 1325, 1970.
BRIEF COMMUNICATION Schedule Dependence of Schedule Induced Polydipsia and Lever Pressing I M. J. W A Y N E R A N D I, G R E E N B E R G
Brain Research Laboratory, Syracuse University, 601 University Avenue, Syracuse, New York 13210
(Received 8 D e c e m b e r 1972)
WAYNER, M. J. AND I. GREENBERG. Schedule dependence of schedule induced polydipsia and leverpressing. PHYSIOL. BEHAV. 10(5) 965-966, 1973.--Two male hooded rats maintained at 80% of initial body weight were tested for schedule induced polydipsia at fixed time (FT) intervals of 1.0, 2.0, 3.0, 4.0 and 5.0 min. A total of 180 45 mg pellets were delivered during the test session. Each animal was tested five times at each FT interval. Total number of licks, lever presses and water consumption increased as the FT interval was increased to a maximum at 4.0 min and then decreased at 5.0 min. Although delivery of the food pellet was not contingent upon pressing the lever, lever pressing occurred and followed the same time related function as licking and water consumption. Results were interpreted in terms of increased motor activity attributed to intermittent food delivery. Schedule induced polydipsia Drinking Polydipsia
Adjunctive behavior
Motor arousal
Fixed time schedule
Procedure
WHEN animals such as the rat are subjected to i n t e r m i t t e n t schedules of r e i n f o r c e m e n t at reduced b o d y weight and are given the o p p o r t u n i t y to drink during the test session intense and persistent post f o o d pellet drinking occurs readily in most of the animals. Research o n this p h e n o m e non, which is usually referred to as schedule induced polydipsia, has been reviewed t h o r o u g h l y on several occasions [1, '2, 3, 4 ] . T h e fact that the effect is schedule d e p e n d e n t within limits [2] has not been c o n f i r m e d and the time d e p e n d e n c y relation w h e n lever pressing is not a required contingency has not been d e m o n s t r a t e d . The purpose o f the present e x p e r i m e n t was to confirm the time d e p e n d e n c y of schedule induced polydipsia and to d e m o n strate that lever pressing is not required. The data confirm earlier results and d e m o n s t r a t e in a d d i t i o n that lever pressing can occur adjunctively and be time d e p e n d e n t under the same conditions,
Animals were reduced to 80% of their initial weight by restriciting their daily ration of food. Animals were tested daily. The test chamber consisted of a standard LVE 1469 m e d i u m size test cage and matching sound attenuating cubicle with a lever and pellet dispensing mechanism. A stainless steel ball point drinking spout was m o u n t e d in the center o f the back wall o f tile test cage, 4.0 cm above the grid floor, and p r o t r u d e d 1,5 cm into the cage. The drinking spout was attached to a graduated e u d i o m e t e r t u b e for measuring water c o n s u m p t i o n . A standard f o o d cup was m o u n t e d in the adjacent wall as close as possible to the back wall and 1.0 cm above the floor. The lever was m o u n t e d in the same wall as the f o o d cup, 3.0 cm above the floor and 2.5 cm f r o m the front of the cage. Licks were recorded by means o f a contact resistance sensitive licko m e t e r on a cumulative recorder. Water was c o n t i n u o u s l y available in the living cage. Daily water c o n s u m p t i o n was recorded. Animals were placed in the test chamber at approximately the same time each night. The test cage was c o n t i n u o u s l y illuminated by an overhead light and extraneous sounds were masked by c o n t i n u o u s white noise. The
METHOD
Animals T w o male h o o d e d rats, 360 g in weight, were selected from our c o l o n y and placed in individual living cages.
This research was supported by NSF Grant GB-18414X and NIMH Grant 15473 and Training Grant MH-06969. 965
966
WAYNI!R ANI) ~;RFENBI~RG
a u t o m a t i c delivery of the 45 mg Noyes food pellet was accomplished by means of standard LVE test e q u i p m e n t . The i m p e n d i n g delivery of the f o o d pellet was preceded by turning on all six stimulus lights in the test c h a m b e r for two sec. At the end of the t w o sec period the lights were turned off and the pellet was delivered. Pellets were delivered according to a p r e d e t e r m i n e d fixed time ( F T ) interval for each test session. Five different FT intervals were tested: 1.0, 2.0, 3.0, 4.0, and 5.0 rain. A total of 180 pellets were delivered during each test session. Animals were tested on successive nights, 5 d e t e r m i n a t i o n s at each FT in a n o n s y s t e m a t i c order. The only e x c e p t i o n occurred following the FT of 5 rain, which required a total test session length of 900 rain to c o m p l e t e , when the animal was given an additional 24 hr before it was tested again. The lever was not c o n n e c t e d electrically to the pellet dispenser. T o t a l n u m b e r of licks, lever presses, and water consumed in ml for each test session were recorded.
18o
]
--• -O
HOH LICKS LEVERPRESSES
160 "i
-
4e
i
140 -i
3O
~oo 4
25
. 20 60
]
40
d
i
j
o ~. . . .
I-
IO
20
L 10
,
T
T.
3.0
40
.
.
.
IS
!
r
~
0
sO
FIXED TIME MIN
R ES U LTS As the results for b o t h animals were very similar the data were c o m b i n e d and are summarized in Fig. 1 where the m e a n total fluid c o n s u m e d in ml, lever presses, and licks for b o t h animals are presented as a f u n c t i o n of the five different FT intervals: 1.0, 2.0, 3.0, 4.0, and 5.0 rain. Each point is based u p o n the mean of five d e t e r m i n a t i o n s at each FT for each animal. As e x p e c t e d water c o n s u m p t i o n tended to be closely associated with licking and b o t h displayed the same time d e p e n d e n t o p t i m u m or peak at a FT interval of 4.0 rain. As delivery of the pellet was not contingent u p o n depression of the lever, the schedule related lever pressing with the same m a x i m u m at a FT of 4.0 rain is very interesting. A l t h o u g h the total n u m b e r of lever presses is very small, the t i m e d e p e n d e n c y is obvious. The schedule induced polydipsia was p r o n o u n c e d and copious a m o u n t s of water were c o n s u m e d by b o t h animals, a mean of t 22 ml at a FT of 4.0 rain. DISCUSSION These data confirm the results of an earlier study [2]
FIG. 1. Combined data from two animals. Mean total number of licks, lever presses, and water consumed in ml as a function of the different FT intervals. Each point based upon 5 determinations for each FT for each animal.
which d e m o n s t r a t e d that schedule induced polydipsia was also schedule dependent. In addition these results indicate that the adjunctive lever pressing which occurred might be a measure of increased m o t o r activity associated with the delivery of the pellet. Under these conditions drinking and lever pressing are b o t h adjunctive and tend to support an earlier hypothesis that the i n t e r m i t t e n c e in the delivery of food results in an increase in the excitability of m o t o r pathways [4] which produces an increase in m o t o r activity and readiness to respond. Therefore, schedule induced polydipsia is primarily an e n h a n c e m e n t of the m o t o r p h e n o m e n o n of licking and the fluid consumed is a normal consequence of this act.
REFERENCES
1. 2.
Falk, J. L. Studies on schedule-induced polydipsia. In: Thirst in the Regulation o f Body Water, edited by M. J. Wayner. Oxford: Pergamon Press, 1964, pp. 95-116. Falk, J. L. Conditions producing psychogenic polydipsia in animals. Ann. N. Y. Acad. Sci. 157: 569-593, 1969.
3. 4.
Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6:577 588, 1971. Wayner, M. J. Motor control functions of the laterat hypothalamus and adjunctive behavior. Physiol. Behav. 5: 1319 1325, 1970.