Neurotoxicology and Teratology, Vol 19, No 5, pp 383-389,1997 Copyright 1997 Elsevier Science Inc Printed in the USA All rights reserved 0892.0362/97 $17.00 + OO PII SOS92-0362(97)00064-O Alcohol Exposure During Development Social Recognition and Social Communication in Rats SANDRA J KELLY Department of Psychology, Received AND TUAN Alters D TRAN University of South Carolina, Columbia, SC 29208 16 August 1996; Accepted 11 May 1997 KELLY, S J AND T D TRAN Alcohol exposure during development alters social recognition and social communication in rats NEUROTOXICOL TERATOL 19(5) 383-389,1997.-The present study examined the effects of postnatal alcohol exposure via gastric intubation on social communication of diet preference and social recognition Rats were placed in one of three treatment groups All treatments occurred from postnatal day (PD) through 10 and Experiments and were conducted when the rats reached 60 and 100 days of age, respectively Alcohol-exposed pups received a 3.0 g/kg dose of ethanol in milk solution that was delivered by insertion of PE-10 tubing down the esophagus daily from PD through 10 Intubated control animals underwent intubation without ethanol or milk Nontreated control pups were weighed daily In Experiment 1, a nonexperimental rat was initially given access to lab chow mixed with a spice and then housed with an experimental rat for 30 The experimental rat was subsequently given access to two diets-one that the nonexperimental rat had consumed and a novel diet It was found that the alcohol-exposed females consumed a greater percent of the communicated diet than the control females In Experiment 2, the experimental rats were first exposed to a juvenile for and then exposed to the same juvenile after a delay of 30 or 90 Investigation time was recorded in both sessions and a reduction of investigation time in the second session is an indicator of social recognition memory Alcohol-exposed rats of both sexes had poorer memory of a juvenile than both control groups after a 90.min delay Together, these data indicate that basic components of social behavior may be altered by alcohol exposure during development Postnatal ethanol exposure Fetal Alcohol Syndrome Gastric intubation Social communication o 1997 Elsevier Science Inc Social behavior THE central nervous system deficits that are central to Fetal Alcohol Syndrome (FAS) can be manifested as changes in cognition, emotionality, and behavior (29,30,32) Social behavior is vital for adaptation to the environment and deficits in social behavior can hinder one’s performance in many facets of life including work and school Adolescents and adults with FAS continue to be markedly impaired on socialization skills such as failure to consider consequences of one’s own actions and lack of reciprocal friendships, as measured by the Vineland Adaptive Behavior Scale (31), even when there are no longer deficits in I.Q (31) Indeed, deficits in social behavior in children with FAS are much greater than those seen in children matched for I.Q without FAS (33) Although social behavior in animals is not as complex as in humans, considerable knowledge has been gained through in- vestigations of effects of alcohol exposure during development on components of social behavior in rats Rats exposed to alcohol during the prenatal period show reductions in the number of ultrasonic vocalizations when isolated from their mothers (24), and rats exposed to alcohol during either the prenatal or postnatal period take longer to attach to a nipple compared to controls (1,26) Males typically show higher levels of play than females (21), but this sexually dimorphic effeet is reversed when rats are given alcohol prenatally (22) Furthermore, juvenile rats prenatally (2) or postnatally (38) exposed to alcohol show an increase in the latency to retrieve rat pups Adult female rats prenatally exposed to alcohol also exhibit less pup-induced maternal behavior (2) Male adult rats normally strongly prefer receptive females to other males; prenatal alcohol exposure attenuates this preference differ- Requests for reprints should be addressed to Sandra J Kelly, Department Fax: (803) 777-9558; E-mail: Social recognition kelly@garnet.cla.sc.edu 383 of Psychology, University of South Carolina, Columbia; SC 29208 KELLY 384 ence (7) Finally, although adult males normally interact more frequently than adult females, this effect is reversed in rats that have been exposed to alcohol during the early postnatal period (19) To continue the characterization of the changes in the different components of social behavior induced by alcohol exposure during development, this study focused on two social behaviors The first type of social behavior, social communication of diet preference, requires the animal to process social cues while its performance is motivated by nonsocial demands A rat is fed an unusual food and then allowed to interact with an experimental rat for a brief period of time The experimental rat is then allowed to choose between two types of food mixes-one of which the other rat had consumed and one of which is novel The experimental rat shows a preference for the food that had been consumed by the other rat (16) This preference does not occur by mere exposure to the odor of the diet: the preference is only formed when the exposure to the diet odor occurs in the presence of another awake rat (14,lS) To examine any general alterations in responsivity to odor and taste cues, this experiment also examined taste aversion learning The second type of social behavior examined is social recognition memory This task involves briefly exposing an adult rat to a juvenile, removing the juvenile from the testing environment for a stipulated period of time, and reexposing the adult to the same juvenile (34) The adult rat has formed a social memory for the juvenile if the amount of investigation is reduced in the second exposure compared to the first exposure Reductions in investigation time not occur when a different juvenile is presented in the second exposure, suggesting that the recognition memory is specific for the individual juvenile and that the reduction in investigation time when the same juvenile is used is not the result of habituation to the situation Social recognition memory is sexually dimorphic with respect to both the behavior (4) and the neural bases (4,s) Given that alcohol exposure during the early postnatal period affects active social interactions, another sexually dimorphic social behavior it seemed probable that this behavior would show effects as well The animal model of FAS used in this study entails gastric intubation during the early postnatal period, in a manner similar to Serbus et al (28) The postnatal period was chosen because, during this period, the brain undergoes a period of rapid growth (12) and thus, may be particularly vulnerable to the effects of alcohol (36) This period is equivalent to the latter portion of the second trimester and all of the third trimester in humans with respect to brain growth (3) Traditionally, investigations of postnatal alcohol effects have relied on an artificial rearing procedure: however, this procedure results in a very artificial social experience early in life and seemed likely to alter social behaviors by itself In contrast, gastric intubations allow the pup to receive maternal care and milk and to have contact with its siblings Thus, the decision was made to use gastric intubations rather than artificial rearing to minimize effects of administration procedures while investigating the effect of alcohol exposure during development on social communication and social recognition in rats METHOD Subjects Fifty-seven Long-Evans rats were used as experimental subjects and were housed in the animal colony in the Department of Psychology at the University of South Carolina Food AND TRAN and water was available ad lib and lighting was maintained on a 12:12 h 1ight:dark cycle with the light phase beginning at 0700 h All testing was conducted during the second half of the light phase Experimental animals were bred in the colony at the University of South Carolina Parent animals were Long-Evans female breeders (90 days of age) and were housed with male breeders overnight Vaginal smears were collected the following morning and positive samples indicated gestational day of pregnancy Offspring from eight litters were randomly assigned to one of three treatment groups on PD There were never more than two rats from the same litter in each group and each litter had pups from all three treatment groups Litters were culled to 10 pups Treatment groups consisted of an ethanol-intubated (EI) intubated-control (IC), and a nontreated-control (NC) group Subject numbers are shown in Table From PD through PD 10, animals in the EI group were weighed and then intubated with g/kg of ethanol in a volume of 0.0278 ml/g of milk formula (37) followed by 0.0278 ml/g of milk formula alone h later The second feeding of milk was done to compensate for any weight loss resulting from alcohol intoxication Intubations were implemented using clear PE-IO tubing connected to a shorter section of PE-SO tubing that was attached to a 26-gauge needle The end of the tube was dipped in corn oil and the tubing was inserted down the animal’s esophagus until it had reached the stomach IC rats underwent similar intubation procedures as the El group, but did not receive the alcohol or the milk and animals in the NC group were weighed and did not receive either the intubations or alcohol The intubation process took after which the pup was returned to its dam Blood alcohol concentrations (BACs) were taken on PD 6, 90 after the end of the first intubation Blood samples were taken from both EI and IC rats The tip of the animal’s tail was severed with a fine blade, and 10 p_l of blood was drawn into a capillary tube The blood was then placed in 190 ~1 of 0.52 N perchloric acid and neutralized with 200 ~1 of 0.30 M potassium carbonate Samples were centrifuged (Beckman Microfuge E) on high for 15 and were refrigerated (4°C) All samples and ethanol-containing standards were assayed for alcohol content using an enzymatic procedure (13) On PD IO all pups were paw-marked with permanent ink for later identification (17) All pups were weaned on PD 21 and housed in same-sex pairs until the time of behavioral testing, which was at 60 and 100 days of age All behavioral testing was conducted blind to the treatment group Experiment I: Sociul Communication Aversion Leurning und Taste The social communication test was a modification of the test by Galef and Stein (15) The testing for both social communication and taste aversion utilized two diet pairs-either cinnamon and cocoa or anise and marjoram The diets were made by mixing g of marjoram, g of cocoa, g of cinnamon, or g of anise with 100 g of powdered rat chow The spices were McCormick brand and powdered Within a test, the diet pairs and the diet to be communicated or to be followed by LiCl were counterbalanced across groups and sexes In the taste aversion testing the experimental rat was tested with the diet pair that had not been used in the social communication test for that particular rat Large and small hanging cages used in the tests were 24.0 W X 67.5 L X lY.0 H cm and 24 W X 19.5 L X 19.0 H cm respectively ALCOHOL AND SOCIAL BEHAVIOR 385 Until the time of testing, the experimental rats were housed in same-sex pairs in plastic cages with free access to food and water On postnatal day 60, the experimental rat was moved into one side of a large hanging wire cage divided into two equal halves by wire mesh The experimental rat was given free access to water rat pellets, and two bowls of plain powdered rat chow The bowls were 3.5 cm deep, cm in diameter, and bolted to the floor On the other side, an unfamiliar, nonexperimental rat of the same sex and approximately the same weight was housed and given free access to water only For two consecutive pretest days, the nonexperimental rat was removed from the partitioned cage after 23 h of food deprivation to a small hanging wire cage, given free access to powdered rat chow in a small bowl for h, and then returned to its half of the partitioned cage On the third day, which was the test day, the nonexperimental rat was given access to 2.5 g of a flavored diet that was to be communicated for h after 23 h of food deprivation The rat was then returned to the same side of the partitioned cage as the experimental rat for 30 and then removed from the partitioned cage entirely After the 30 of interaction with the nonexperimental rat, the experimental rat was given access to 25 g of the communicated diet and 2.5 g of the other member of the diet pair (e.g., cinnamon vs cocoa or marjoram vs anise) in two small bowls The regular rat pellets were removed from the cage After 24 h, the amount of each diet consumed was determined The experimental rats were returned to their prior housing conditions in same-sex pairs On postnatal day 67, the experimental rat was placed into a small wire cage with two empty bowls in it The rat had free access to water but had access to plain powdered rat chow in the bowls for only h after 23 h of food deprivation Then, after a further 23 h of food deprivation, the rat was given access to a flavored diet for h The rat was then injected with 2% (w/v) solution of LiCl in a volume of 1% body weight Twenty-four hours later the rat was given access to 25 g of the flavored diet paired with LiCl and 25 g of the other member of the diet pair The amount of each diet consumed over 24 h was measured The experimental rats were returned to their regular housing conditions Experiment estrus There were test days, which were not necessarily consecutive, and each test day consisted of two sessions of each Prior to each session, the experimental adult rat was placed in a cage containing fresh bedding For each test day, the experimental rat was exposed to a novel juvenile rat (2130 days old) for in the first session and then returned to its home cage The same juvenile was used in the second session following an interval of 90 on test day and 30 on test day On the third test day, a novel juvenile was used in the second session, which occurred after a 30-min interval The third test day was done as a control test, which would detect any group differences in habituation or reactivity to the juvenile in the second session that might confound the measurement of recognition memory Investigation time (in seconds), which included both sniffing and grooming, was recorded using an S&K Event Recorder (NEC model 100) in all sessions Statistical Analyses Because the appropriate comparisons were known at the time of the design of the experiment, analyses of variance (ANOVA) followed by planned orthogonal comparisons were conducted on the behavioral data (20,39) Within each sex, the IC and NC groups were compared and if these groups did not differ from each other, then the EI group was compared to the two control groups A comparison between sexes was also conducted For the BAC data, a t-test comparing the sexes in the EI group was conducted The planned comparisons were orthogonal to each other and, because orthogonality controls for repeated tests, significance was assumed at the 0.05 level for all analyses (21) Two repeated measures ANOVAs were conducted on the body weight data from PD through 10 and then on the body weight data on PD 10, PD 21, PD 30, and PD 60 F,,,,, tests were used to compare the variances between the sexes in the behavioral tests All error bars and error terms are SEMs RESULTS Physical Parameters The body weights of the groups on PDs 10,21, and 60 and blood alcohol concentrations are depicted in Table For both of the ANOVAs conducted on the body weight data, there were no effects of or interactions with group, indicating that none of the treatments had an effect on body weight There were significant interactions of sex and day in the body weights from PD through 10, F(8, 400) = 6.79, p < 0.001, and from PD 10 through PD 60, F(3, 153) = 268.51, p < 0.001, such that 2: Social Recognition Social recognition testing was a modification of that done by Sawyer et al (27) and began when the animals reached 100 days of age Animals were tested during the latter half of the day portion of the light cycle (1400-1700 h) Females were tested only during diestrus, a stage in which hormonal levels are relatively stable: daily vaginal smears verified the stage of TABLE PHYSICAL PARAMETERS AND SUBJECT NUMBERS (MEANS Body Weights Treatment Group Ethanol-intubated Intubated-control Sex female PDlO PD2 I SEMs) at PD6U BACs (mgidl) 21.9 0.7 50.1 1.2 228.5 k 5.2 267 -c 35 male 10 24.3 1.1 57.1 2.2 357.0 7.7 242 -t 27 female 11 22.1 t 0.7 52.1 t 1.4 221.9 + 3.4 26.0 ? 1.1 60.3 2.1 362.0 8.7 10 22.9 0.8 53.9 i- 1.7 252.9 9.1 25.5 1.1 58.8 2.4 357.9 k 7.4 male Nontreated-control Subject Number AND female male 386 KELLY TRAN Males Females Ethanollntubated AND SZ ii?l +++ NontreatedControl IntubatedControl FIG Mean percentage SEM of communicated food consumed by ethanolintubated, intubated-control, and nontreated-control rats EI females consumed significantly more communicated food than both IC and NC females the difference in weight between the sexes became greater as they became older There were no significant differences between the sexes with respect to blood alcohol concentrations between group and sex, F(2, 52) = 4,61, p < 0.05, in total amount of food consumed Female EI rats consumed significantly less than the total amount consumed by the NC or IC female rats, F(l, 52) = 10.34, p < 0.01, which did not differ from each other (see Table 2) There were no differences among the male rats with respect to total amount of food consumed (see Table 2) There was an overall sex difference in total amount consumed such that males consumed more food than females, F(l, 52) = 48.62, p < 0.001 An F,,,,, test indicated that the variance of the female data did not differ from the variance of the male data All of the groups showed aversion to the diet paired with the LiCl injection; however, there were no main effects of nor interactions with groups with respect to the degree of aversion (as measured as percent of total amount consumed of the paired diet) (see Table 2) In general, females showed greater aversion than males, F(l, 52) = 10.78, p < 0.01 There were no effects of Social Communication and Taste Aversion ANOVA indicated that there was a significant interaction of group and sex, F(2,52) = 3.50, p < 0.05, on the amount of communicated food consumed as a percent of total amount consumed Among females, EI rats consumed more communicated food than the NC and IC female rats, F(l, 52) = 9.23, p < 0.01, which did not differ from each other (see Fig 1) There were no differences among male groups or any overall sex difference in percent of communicated food consumed (see Fig 1) There were no differences among groups with respect to total amount of food consumed by their paired nonexperimental rat However, there was a significant interaction TABLE FOOD CONSUMED IN SOCIAL COMMUNICATION PERCENT OF FOOD CONSUMED THAT WAS TASTE AVERSION TASK (MEANS Treatment Food Consumed Communicated* Group Ethanol-intubated Intubated-control Nontreated-control *These graphed as TThese in the taste female male female male female male 12.2 19.5 13.5 18.8 15.0 17.8 % + t + 1.1 I.6 1.1 1.1 1.3 1.2 TASK (IN GRAMS) PAIRED WITH LICL AND SEMs) Food Consumed Novel* 3.2 12.6 10.4 12.4 10.3 13.3 t 0.9 t 1.1 t 1.5 i 2.3 I!I 1.4 + 1.4 AND IN Percent Consumedt 21.3 30.5 24.3 32.3 24.8 37.7 t -t + t + i- 2.6 6.2 5.2 7.3 6.2 6.6 data are the raw data from the social communication task and are percents in Fig data are the percent of total food consumed that was paired with LiCl aversion task ALCOHOL AND SOCIAL BEHAVIOR 387 or interactions with group with respect to total amount of food consumed prior to injection of LiCl and the total amount of food consumed after the injection of LiCl There was an overall sex difference in both total amount measures such that males consumed more food than females, F(l, 52) = 55.12, p < 0.001; F(l, 52) = 43.45,~ < 0.001 There was no difference in variance between the sexes, as indicated by an F,,, test Social Recognition An examination of investigation times for the first session only collapsed across the test days revealed that males spent more time investigating a novel juvenile than females, F(1,52) = 51.18, p < 0.001 The means (in seconds) and SEMs for the first session investigation times for males and females were 93.5 ? 4.8 and 40.2 2.4 There were no main effects of or interactions with group To examine whether there was social recognition of juveniles during the second session of testing, proportional scores were obtained by dividing the second session score by the first session score A proportional score of 1.0 indicates that an animal has no memory for the previously encountered juvenile and proportional scores less than 1.0 indicate that a memory of the juvenile was retained An ANOVA indicated that there was a trend towards a significant effect of group on day of testing (90-min interval, same juvenile in each session), F(2, 52) = 2.72, p = 0.07 Planned comparisons indicated that EI rats showed greater proportional scores than the combined control animals, F(1, 52) = 5.90, p < 0.05, which did not differ from each other (see Fig 2) Day (30-min interval, same juvenile in each session) analyses revealed no significant differences in proportional scores among groups Day (30-min interval, different juvenile in each session) analyses revealed no significant differences in proportional scores among groups There were no interactions of sex and group on any of the test days There were no main effects of sex on proportional scores on test days and but males DAY Ethanollntubated showed greater proportional scores than females on test day 2, F(l, 52) = 8.01, p < 0.01 There were no differences between the sexes in the variance in the proportional scores on any of the test days, as indicated by an F,,,,, test DISCUSSION Alcohol exposure during the early postnatal period causes an enhanced responsiveness to social communication of diet preference in females This result was not expected In hindsight, it might have been predicted from the prior finding that alcohol-exposed females show an increase in frequency of active social interactions (19); it may be that the increased frequency of active social interactions translates into increased responsiveness to social cues However, it should be noted that untreated males have a greater frequency of active social interactions than untreated females (19) yet there were no differences in responsiveness in social communication between the sexes Thus, it is not a simple translation of increased frequency to increased responsiveness Furthermore, the taste aversion learning was the same among groups so the increase in responsiveness to social communication cannot be a simple increased responsiveness to odor cues A number of hypotheses can be made about the increased responsiveness to social communication in alcohol-exposed females One hypothesis is that the alcohol exposure alters the nervous system such that the females are hyperresponsive to all social cues; however, there is at least one social behavior, namely maternal responsiveness as measured by retrieval of pups, in which alcohol exposure appears to result in less responsiveness (2,38) It may be that the increase in responsiveness is restricted to social cues from other adults or is a general hyperresponsiveness to all stressful situations that manifests itself differently in maternal and adult-adult social interactions This last explanation might also account for the overall decrease DAY IntubatedControl DAY NontreatedControl FIG Mean proportional scores k SEM of adult rats across the days of testing EI rats had significantly higher proportional scores than both IC and NC groups during the first test day (90-min interval, same juvenile in both sessions) No differences were found among groups for the second (30-min interval, same juvenile in both sessions) and third (30-min interval, different juvenile in the two sessions) test day 388 KELLY in food consumption seen in the alcohol-exposed females Another hypothesis is that the motivational aspects of the social communication scenario, namely motivation to learn about food sources and the motivation to respond to social cues is different in the alcohol-exposed female rats However, there is some evidence suggesting that alcohol exposure reduces food motivation (6.23) and the alcohol-exposed females in the present study consumed a smaller overall amount of food, at least during the social communication study These findings make it unlikely that an increased motivation for food is the cause of an increase in responsiveness A final explanation of the effect of alcohol exposure on social communication is that this effect occurs because this form of social learning, which requires the animal to be able to form a preference for a diet because of its odor being in the presence of a live conspecific, is quite complex and possibly too demanding for the alcohol-exposed females (14-16) Interestingly, although the finding of no alcohol-induced changes in adult acquisition of taste aversion is consistent with others (6.25), it has been found that retention of taste aversion is impaired in alcohol-exposed animals (6) This suggests that there is some alcohol-induced alteration in the ability to form associations that is fairly subtle It may be that the sheer complexity of the social communication task reveals effects of alcohol exposure during development and that the effect is not specific to social stimuli Social recognition of previously encountered juveniles by adult rats treated with alcohol was impaired relative to control rats Importantly, there were no differences among groups with respect to time spent investigating the juvenile in the first session or responding to a different juvenile in the second session These latter findings suggest that the higher proportional scores in the alcohol-exposed rats of both sexes after a 90.min interval reflect a deficit in social recognition memory and not a difference in initial investigation of the juvenile rat or differences in reactivity to the juvenile rat in the second session In this and other (4) studies, females spend less time investigating the juvenile in the first session than males, suggesting that this is a sexually dimorphic behavior Indeed, in females social recognition appears to be mediated by estrogen Ovariectomized females display decreased ability to form social memories, but estradiol treatment in these animals reverses this effect (18) In contrast, social recognition in males is likely to be influenced by androgens and vasopressin Both peripheral and central injections of vasopressin enhance social recognition in males (9,lO) The interaction between androgens and vasopressin is such that castration does not reduce investigations during the second exposure period (27) but vasopressin antagonists no longer have any effect on the memory for the juvenile rat (5) The vasopressinergic neurons originating in the bed nucleus of the stria terminalis projecting to the lateral septum appear to mediate social recognition in males and not in females (5) Because of the above findings, it is possible that whereas alcohol exposure during development produces deficits in AND TRAN social recognition in both sexes the neural bases for these changes differs in the two sexes Female rats exposed to alcohol during the postnatal period have been shown to have lower levels of estrogen than controls (3X), and this change may mediate the deficit in social recognition memory Similarly, males exposed to alcohol during the prenatal period show lower levels of testosterone (8.35) in adulthood and these lower levels may alter the function of the testosteronedependent vasopressin fibers known to be involved in social recognition in males An interesting follow-up study would be to examine the vasopressin system in males exposed to alcohol during development The model utilizing intubations of alcohol during the early postnatal period worked well The mortality was low and there were no weight differences among the groups These findings are similar to those of others (28) Serbus et al (28) did not find any weight differences among their groups even though they did not use a second supplementary intubation 01 milk in the alcohol group However, they used a different strain of rat and lower levels of alcohol exposure than the current study The advantages of the use of the intubation procedure rather than artificial rearing to administer alcohol during the early postnatal period is that the pups still have both olfactory and tactile contact with the dam and siblings and feed mostly on the dam’s milk rather than a synthetic formula The contact with the dam and sibling is particularly important if one is interested in social behaviors The main disadvantage of the intubation procedure is that the pups are handled during a period when handling has been shown to alter a number of behaviors [see, e.g., (1 l)] However the intubated control group controls for these handling effects and care is taken to ensure that the animals have less than of handling per intuhation It should also be noted that altered pup-dam interactions may occur due to the changed behavior in the alcohol-exposed pups and this may contribute to the differences in social behavior In conclusion two forms of social behavior-social recognition of juveniles and responsiveness to social communicationhave been shown to be altered by alcohol exposure during the early postnatal period The alcohol-induced alterations are sexually dimorphic in one instance and the changes in social recognition in the two sexes quite possibly have different neural and hormonal bases Given the sexually dimorphic nature of social hchavior in general it may be prudent to investigate alcoholinduced alterations in social behavior in the two sexes scparately Nevertheless these present data contribute to the growing body of literature suggesting that alcohol exposure during development has severe and varied effects on social behavior ACKNOW’LFDGEMFN IS We thank Frank Beylotte and Rebecca O’Neill for their technical assistance This research was supported by a Venture Fund Grant from the University of South Carolina REFERENCES Barron S.; Kelly S J.; Riley E P.: Neonatal alcohol exposure alters suckling behavior in neonatal rat pups Pharmacol Biochcm Behav 39:423-427; 1991 Barton, S.: Riley, E P.: Pup-induced maternal behavior in adult and juvenile rats exposed to alcohol prenatally Alcohol Clin Exp Res 9:360-365: 1985 Bayer, S A.: Altman, J.; Russo, R J.; Zhang, X.: Timetables of neurogenesis in the human brain based on experimentally dctermined patterns in the rat Neurotoxicology 14:83-144: 1993 does not involve BluthC R M.: Dantzer, R.: Social recognition vasopressinergic neurotransmission in female rats Brain Res 535:301-304: 1990 J.; Dantzer R.: Androgen-dependent Bluthe, R M.: Schoenen vasopressinergic neurons are involved in social recognition in rats Brain Res Sl9:150-157: 1990 Clausing, P.; Ferguson, S A.; Holson, R R.: Richard R A.: Paule M G.: Prenatal ethanol exposure in rats: Long-lasting effects on Icarning Neurotoxicol Teratol 17545%552: 1995 ALCOHOL AND SOCIAL BEHAVIOR I Dahlgren, I L.; Matuszczyk, I V.; Hard, E.: Sexual orientation in male rats prenatally exposed to ethanol Neurotoxicol Teratol 13:267-269; 1991 Dahlgren, I L.; Eriksson, C J P.; Gustafsson, B.; Harthon, C.: Hard, E.; Larsson, K.: Effects of chronic and acute ethanol treatment during prenatal and early postnatal ages on testosterone levels and sexual behaviors in rats Pharmacol Biochem Behav 33:867-873; 1989 Dantzer, R.; Bluthe, R M.; Koob, G F.; Le Moal, M.: Modulation of social memory in male rats by neurohypophyseal peptides Psychopharmacology (Berlin) 91:363-368; 1987 10 Dantzer, R.; Koob, G.F.; Bluthe, R.M.; Le Meal, M.: Septal vasopressin modulates social memory in male rats Brain Res 457: 143-147; 1988 11 Denenberg, V H.: Zarrow, M X.: Effects of handling in infancy upon adult behavior and adrenocortical activity: Suggestions for a neuroendocrine mechanism In: Walcher, D W.; Peters, D L., eds., Early childhood: The development of self-regulatory mechanisms New York: Academic Press; 1971:39-64 12 Dobbing, J.: The later development of the brain and its vulnerability In: Davis, J A.; Dobbing, J., eds Scientific foundation of pediatrics London: William Heinemann Medical Books: 1974: 744-759 13 Dudek, B C.: Abbott, M E.: A biometrical genetic analysis of ethanol response in selectively bred long-sleep and short-sleep mice Behav Genet 14:1-19; 1984 for social 14 Galef, B G., Jr.; Kennett, D J.: Different mechanisms transmission of diet preference in rat pups of different ages Dev Psychobiol 20:209-215; 1987 influence on observer 15 Galef, B G., Jr.; Stein, M.: Demonstrator diet preference: Analyses of critical social interactions and olfactory signals Anim Learn Behav 13:31-38: 1985 S W.: Transfer of information con16 Galef, B G., Jr.; Wigmore, cerning distant foods-A laboratory investigation of the “information-centre” hypothesis Anim Behav 31:748-758; 1983 17 Geller, L M.; Geller, E H.: A simple technique for the permanent marking of newborn albino rats Physiol Rep 18:29-46; 1969 in ovariectomized and estradiol18 Hlifiak, Z.: Social recognition treated female rats Horm Behav 27:159-166; 1993 R J.: Social behavior and the amygdala 19 Kelly S J.; Dillingham, region are altered by perinatal alcohol exposure Neurotoxicol Teratol 16:377-384; 1994 design (2nd ed.): Procedures for the 20 Kirk, R E.: Experimental behavioral sciences Belmont CA: Brooks/Cole Publishing Company: 19X2:96 21 Meaney, M J.; Stewart, J.: Neonatal androgens influence the social play of prepubescent rats Horm Behav 15:197-213; 1981 22 Meyer, L S.; Riley, E P.: Social play in juvenile rats prenatally exposed to alcohol Teratology 34:1-7; 1986 23 Middaugh, L D.; Gentry, G D.: Prenatal ethanol effects on reward efficacy for adult mice are gestation stage specific Neurotoxicol Teratol 14:365-370: 1992 389 24 Ness, J W.; Franchina, J J.: Effects of prenatal alcohol exposure on rat pups’ ability to elicit retrieval behavior from dams Dev Psychobiology 23:85-99; 1990 25 Riley, E P.; Barron, S.; Driscoll, C D.: Chen, J.: Taste aversion learning in preweanling rats exposed to alcohol prenatally Teratology 29:325-331; 1984 26 Rockwood, G A.; Riley, E P.: Nipple attachment behavior in rat pups exposed to alcohol in utero Neurotoxicol Teratol 12:383389; 1990 27 Sawyer, T F.; Hengehold, A K.; Perez W A.: Chemosensory and hormonal mediation of social memory in male rats Behav Neurosci 98:908-913; 1984 28 Serbus, D C.; Young, M W.; Light, K E.: Blood ethanol concentrations following intragastric intubation of neonatal rat pups Neurobehav Toxicol Teratol 8:403-406: 1986 29 Steinhausen, H C.; Gobel, D.; Nestler, V.: Psychopathology in the offspring of alcoholic parents, J Am Acad Child Psychiatry 23:465-471; 1984 30 Streissguth, A P.: The behavioral teratology of alcohol: Performance, behavioral, and intellectual deficits in prenatal exposed children In: West, J R., ed Alcohol and brain development New York: Oxford University Press; 1986:344 31 Streissguth, A P.; Aase, J M.; Clarren, S K.; Randels, S P.; LaDue, R A.; Smith D F.: Fetal alcohol syndrome in adolescents and adults JAMA 265:1961-1967; 1991 32 Streissguth, A P.; Herman, C S.; Smith, D W.: Intelligence, behavior, and dysmorphogenesis in the fetal alcohol syndrome: A report on 20 patients J Pediatr 92:363-367; 1978 33 Thomas, S E.; Kelly, S J.; Mattson, S N.; Riley, E P.: Specific social abilities in children with FAS: A comparison to cognitively matched and normal controls Alcohol Clin Exp Res 20:74A: 1996 34 Thor, D H.; Holloway W R.: Social memory of the male laboratory rat J Comp Physiol Psycho] 96:1OOt%lOO6: 1982 35 Udani, M.; Parker, S.: Gavaler, J.: Van Thiel, D H.: Effects of in utero exposure to alcohol upon male rats Alcohol Clin Exp Res 9:355-359; 1985 36 West, J R.: Fetal alcohol-induced brain damage and the problem of determining temporal vulnerability: A review Alcohol Drug Res 71423-441; 1987 37 West, J R.; Hamre, K M.; Pierce, D R.: Delay in brain growth induced by alcohol in artificially reared rat pups Alcohol 1:8395; 1984 38 Wilson, J H.; Kelly, S J.: Wilson, M A.: Early postnatal alcohol exposure in rats: Maternal behavior and estradiol levels Physiol Behav 59:287-293; 1996 39 Winer, B J.; Brown, D R.; Michels, K M.: Statistical principles in experimental design, 3rd ed New York: McGraw-Hill, Inc.; 1991:146