Prenatal and early sucking influences on dietary preference in newborn, weaning, and young adult cats

Early experiences are of potential importance in shaping long-term behavior. This study examined the relative influence of prenatal and/or early postnatal experience of chemosensory stimuli on subsequent olfactory and dietary preferences of cats as newborns, at 9-10 weeks, and at 6 months. Cats were exposed to vanillin or 4-ethylguaiacol via their mother's diet either prenatally, postnatally, perinatally (prenatal and postnatal), or experienced no exposure to the stimuli (control). Newborns were given a two-choice olfactory test between the familiar "odor" and no odor; 9-10 week olds were tested for their preference between two food treats, one flavored with the familiar stimulus and the other unflavored; at 6 months, cats were given a choice of two bowls of food, one flavored with the familiar stimulus and the other unflavored. At all ages, cats preferred the familiar, and avoided the unfamiliar, stimulus. Perinatal exposure exerted the strongest influence on preference. Prenatal exposure influenced preference at all ages and postnatal exposure exerted a stronger effect as the cat aged. We conclude that long-term chemosensory and dietary preferences of cats are influenced by prenatal and early (nursing) postnatal experience, supporting a natural and biologically relevant mechanism for the safe transmission of diet from mother to young.

Long-term retention of kinship recognition established during infancy in the domestic dog

The ability of the domestic dog to recognise its kin, and to retain this information once acquired, was studied in this paper. Dogs were examined for their ability to recognise their siblings, offspring to recognise their mother, and mothers to recognise their offspring, using a series of two choice tests. The results revealed that, at 4-5.5 weeks of age, pups can recognise their siblings and their mother, and mothers can recognise their offspring. The preference of pups at this age appears to be strongest for their mother. Olfactory cues are sufficient for this recognition to take place. At approximately 2 years of age, and having been separated from their offspring from 8-12 weeks after their birth, mothers were able to recognise their now adult offspring and these adult offspring could recognise their mothers. Siblings could only recognise one another if they had been living with a sibling (not the test animal). Dogs living on their own were unable to recognise their siblings. Thus dogs can recognise their kin, retaining this information for a period of two years in the case of mother-offspring. It is suggested that mother-offspring and siblings are recognised by different mechanisms.

The psychosocial impact of orthognathic surgery: a systematic review

The aim of this study was to review the reported psychosocial benefits of orthognathic surgery. A systematic review of the literature was conducted using MEDLINE (1966 to December 2000), Web of Science (1981 to December 2000), and reference sections of identified articles. We also hand searched key orthodontic, oral surgery, and psychology journals. No language limitations were imposed. Randomized controlled trials, other controlled clinical trials, prospective studies (with or without controls), and retrospective studies (with or without controls) were considered for inclusion. Two reviewers extracted the data and independently assessed the quality of the studies. In all, 29 studies, including a number of prospective and retrospective studies, were identified as relevant. The results of the review indicated that orthognathic patients experience psychosocial benefits as a result of orthognathic surgery, including improved self-confidence, body and facial image, and social adjustment. However, there were wide variations in the study designs and a lack of uniformity in measuring the psychosocial constructs. This made it difficult to quantify the extent and the duration of the psychosocial benefits.

Prevalence of behaviour problems reported by owners of dogs purchased from an animal rescue shelter

This study examined the prevalence of behaviour problems exhibited by dogs within 4 weeks of acquisition from a rescue shelter in Northern Ireland. One thousand five hundred and forty-seven people who had purchased a dog from a rescue shelter in Northern Ireland were sent a postal questionnaire designed to collect information on the behaviours exhibited by their dog within the first month of acquisition. Five hundred and fifty-six people responded to the survey, representing a response rate of 37%. The majority of respondents (68.3%) reported that their dog exhibited a behaviour problem, the most common being fearfulness. Most of those respondents (89.7%) who returned their dog to the shelter did so because the animal exhibited behaviour that they considered undesirable. Male dogs showed more unacceptable behaviours than females, specifically inter-male aggression, sexual problems and straying tendencies. More stray dogs displayed undesirable behaviour than unwanteds, specifically straying tendencies. Puppies were less likely to exhibit unacceptable behaviours than juveniles or adults, particularly fearfulness, sexual problems and straying tendencies. More juvenile dogs showed excessive activity and excessive barking than puppies or adults. More adult dogs displayed aggression towards other dogs than juveniles or puppies. Findings indicate that dogs purchased from rescue shelters do exhibit behaviour problems that may lead to their return. The number of dogs admitted or returned to rescue shelters with behaviour problems may be reduced by raising public awareness regarding the value of behaviour therapy and introducing behaviour therapy schemes to rescue shelters.

Habituation in fetuses of diabetic mothers

Fetuses of diabetic mothers exhibit maturational delays in their behaviour and disturbances in behavioural and intellectual functioning in childhood. This suggests an effect of maternal diabetes on the central nervous system of the fetus. The habituation technique enables the functioning of the higher central nervous system to be examined. A normal habituation pattern reflects an intact central nervous system. Previous studies have found abnormalities in the fetal central nervous system are reflected in habituation performance. This paper examined the habituation ability of fetuses of diabetic mothers and of non-diabetic mothers. The fetuses were tested at 28, 32 and 36 weeks of gestation. After 2 min of fetal inactivity a series of vibroacoustic stimuli were presented to the fetus. This continued until no response was observed on five consecutive stimulus presentations. The number of stimulus presentations to habituate at each gestational age was recorded. The results reveal that there was a highly significant main effect of group (F(1,47)=19.65, P<0.001). Fetuses of diabetic pregnancies took longer to habituate. There was a significant effect of gestational age (F(2,94)=44.67, P<0.0001). In both groups the number of trials to habituate decreased with advancing gestation. There was no relationship between random blood glucose levels and habituation performance. The results demonstrate that maternal diabetes affects higher aspects of central nervous system functioning in the fetus.

The discrimination of dog odours by humans

The domestic dog is able to identify both individual conspecifics, i.e. other dogs, and individual interspecifics, e.g. humans, by smell. Whilst humans can recognise individual members of their own species using olfactory information, it is unknown whether they can identify members of any other species in this manner. We examined the ability of humans to identify individual dogs by smell. Twenty-six dog owners were required to smell two blankets, one impregnated with the odour of their own dog, the other impregnated with the odour of an unfamiliar dog. Participants were required to indicate which of the odours smelt the strongest, which smelt the most pleasant, and which of the odours belonged to their own dog. Most of the participants (88.5%) were able to recognise the odour of their own dog. They showed no significant bias, however, in responding which of the odours they thought smelt the strongest or most pleasant. The results indicate that dogs produce odours that are individually distinctive to their owners, and highlight the fact that humans can recognise members of another species using olfactory cues--an ability presumably acquired without conscious effort.

Effects of replicating primary-reflex movements on specific reading difficulties in children: a randomised, double-blind, controlled trial

BACKGROUND

Children with specific reading difficulties have problems that extend beyond the range of underlying language-related deficits (eg, they have difficulties with balance and motor control). We investigated the role of persistent primary reflexes (which are closely linked in the earliest months of life to the balance system) in disrupting the development of reading skills.

METHODS

We assessed the efficacy of an intervention programme based on replicating the movements generated by the primary-reflex system during fetal and neonatal life. A randomised, individually matched, double-blind, placebo-controlled design was used and children (aged 8-11 years) with persistent primary reflexes and a poor standard of reading were enrolled into one of three treatment groups: experimental (children were given a specific movement sequence); placebo-control (children were given non-specific movements); and control (no movements).

FINDINGS

From an initial sample of 98 children, 60 children, 20 in each group were matched on age, sex, verbal intelligence quotient (IQ), reading ability, and persistent asymmetrical tonic neck reflex. For asymmetrical tonic neck-reflex levels there was a significant (group by time) interaction (p<0.001). The experimental group showed a significant decrease in the level of persistent reflex over the course of the study (mean change -1.8 [95% CI -2.4 to -1.2], p<0.001), whereas the changes in the placebo-control and control groups were not significant (-0.2 [-0.9 to 0.6] and -0.4 [-0.9 to 0.2]).

INTERPRETATION

This study provides further evidence of a link between reading difficulties and control of movement in children. In particular, our study highlights how the educational functioning of children may be linked to interference from an early neurodevelopmental system (the primary-reflex system). A new approach to the treatment of children with reading difficulties is proposed involving assessment of underlying neurological functioning, and appropriate remediation.

A simple method for testing odor detection and discrimination in chicks

A simple procedure for testing newly hatched chicks' responses to olfactory stimuli is described. Chicks that were hand held under a heatlamp became inactive and closed their eyes (as if asleep) within 2 min. Sleeping chicks displayed overt behavioral responses to an odorized q-tip (head shaking, beak clapping) that were not observed in awake chicks. Sleeping latencies were shorter for 1-day-old chicks that had been food deprived prior to testing than for chicks that had ad lib access to food and water. When airborne odors were presented by squeezing a soft plastic odor bottle near the beak, sleeping chicks' reactions to mint were of a greater magnitude than their responses to lavender or orange scents. Nonetheless, all three odors elicited more pronounced behavioral responses than did the water control stimulus. This method allows rapid testing of individual chicks for odor detection and discrimination.

Developmental aspects of kin recognition

The ability to recognise kin requires the individual to possess a variety of abilities. Individuals must produce a cue which indicates relatedness, they must process this cue to determine relatedness and then must act on this cue. Research has concentrated on the first and final stage of this process, i.e., the cues of kinship and kin correlated behaviour. Little attention has been paid to how individuals process cues to determine relatedness. This paper discusses how individuals 'recognise' kin, the exhibition of kin correlated behaviour and considers the role of the MHC in these processes. Two broad theories have emerged to explain how individuals recognise their kin: either a recognition gene(s) or some experiential mechanism. In mammals there is no evidence to suggest that recognition (the processing of the cue) is under genetic control but rather is the result of experience, learning about related individuals during development. Moreover studies on kin recognition in the domestic dog suggest that all kin are not recognised by the same process but different classes of kin, parents, siblings may well be recognised using different means. Studies of kin correlated behaviour suggest that the behaviour exhibited towards kin by Mongolian gerbils is mediated by the environment. Factors of environmental familiarity, sex and developmental age all affect the response of individuals to kin and non-kin. In these situations the ability to recognise kin does not change but the exhibition of kin correlated behaviour changes according to environmental conditions. These studies indicate that kin recognition may not be the 'unified' process previously thought and thus any explanations of the proximate and ultimate causation of kin recognition need to encompass this complexity. The question remains of whether the MHC is complex enough to do so.

Prevalence of disease in dogs purchased from an animal rescue shelter

The prevalence of diseases suffered by dogs within two weeks of their acquisition from a rescue shelter in Northern Ireland was investigated. A postal questionnaire was completed by 556 people who had purchased a dog from the Ulster Society for the Prevention of Cruelty to Animals (USPCA) to provide information on the diseases suffered by their dog. The majority of the dogs (53.7 per cent) had an ailment the most common being coughing and diarrhoea. Of the respondents who returned their dog to the USPCA, 92 per cent did so because the animal was unhealthy. Stray dogs were more likely to have an ailment than unwanted dogs, specifically coughing, and/or skin problems. More puppies suffered from parvovirus, vomiting, and/or diarrhoea than did juveniles or adults. Adult dogs were more likely to have a cough than juveniles or puppies. There was no association between the sex of the dogs and their ailments.

Lateralised behaviour in first trimester human foetuses

Behavioural lateralisation is a common feature of everyday behaviour, most familiar in the exhibition of handedness. Despite differing theories about the origins of laterality, little is known about their ontogenesis. This study observed the left and right arm movements of 72 foetuses at 10 weeks of gestational age, the first age at which lateralised behaviour may be observed. There was a highly significant preference for foetuses to move their right arm more than their left arm, 85% exhibiting more right arm than left arm movements. There was no difference in the amount of movements exhibited with the preferred arm, whether it be right or left. Laterality of behaviour at such an early gestational age (probably as early as it is possible for it to be observed) is unlikely to be under brain control but is probably of more muscular or spinal determination. The possibility that early differential motor behaviour may contribute to subsequent laterality of behaviour and asymmetrical brain growth, must be considered.

Chemosensory learning in the chicken embryo

Prenatal chemosensory learning has been demonstrated in mammals, fish, amphibians, and insects, but not birds, although there is evidence of the avian's ability to learn auditory stimuli before hatching. This paper examines how exposure to a chemosensory stimulus (strawberry) prior to hatching affects subsequent chemosensory preferences of newly hatched chicks. The chicks' preferences were assessed at 2 days after hatching using an "olfactory" preference test (strawberry-smelling shavings versus water-coated shavings) and at 4 days after hatching using a "gustatory" preference test (strawberry-flavoured water versus unflavoured water). Chicken embryos were exposed to strawberry from Day 15 to Day 20 of incubation by either presenting the odour in the air around the egg, rubbing it onto the shell, or injecting it into the air space. With no exposure to strawberry before hatching, strawberry was highly aversive to chicks after hatching. However, following exposure to strawberry before hatching, chicks expressed a greater preference for (or weaker aversion to) the strawberry stimulus. Chicks exposed to strawberry before hatching drank more strawberry-flavoured water and spent more time in a strawberry-scented area than chicks having no exposure before hatching. This change in preference was specific to the stimulus experienced before hatching and was present in the absence of any posthatching exposure to the stimulus. The results demonstrate that a chick's chemosensory preferences are changed as a result of experience with a stimulus before hatching and are suggestive of learning. The results, similar to those obtained in other animal groups, indicate the universality of "prenatal" chemosensory learning in the animal kingdom. A possible role of embryonic chemosensory learning for recognition is discussed.

Fetal memory: does it exist? What does it do?

Whether fetal memory exists has attracted interest for many thousands of years. The following review draws on recent experimental evidence to consider two questions: does the fetus have a memory? And, if so, what function(s) does it serve? Evidence from fetal learning paradigms of classical conditioning, habituation and exposure learning reveal that the fetus does have a memory. By comparison little attention has been paid to the possible function of memory. Possible functions discussed are: practice, recognition of and attachment to the mother, promotion of breastfeeding, and language acquisition. It is concluded that the fetus does possess a memory but that more attention to the functions of fetal memory will guide future studies of fetal memory abilities.

Development of fetal hearing

Previous research has revealed that the human fetus responds to sound, but to date there has been little systematic investigation of the development of fetal hearing. The development of fetal behavioural responsiveness to pure tone auditory stimuli (100 Hz, 250 Hz, 500 Hz, 1000 Hz, and 3000 Hz) was examined from 19 to 35 weeks of gestational age. Stimuli were presented by a loudspeaker placed on the maternal abdomen and the fetus's response, a movement, recorded by ultrasound. The fetus responded first to the 500 Hz tone, where the first response was observed at 19 weeks of gestational age. The range of frequencies responded to expanded first downwards to lower frequencies, 100 Hz and 250 Hz, and then upwards to higher frequencies, 1000 Hz and 3000 Hz. At 27 weeks of gestational age, 96% of fetuses responded to the 250 Hz and 500 Hz tones but none responded to the 1000 Hz and 3000 Hz tones. Responsiveness to 1000 Hz and 3000 Hz tones was observed in all fetuses at 33 and 35 weeks of gestational age, respectively. For all frequencies there was a large decrease (20-30 dB) in the intensity level required to elicit a response as the fetus matured. The observed pattern of behavioural responsiveness reflects underlying maturation of the auditory system. The sensitivity of the fetus to sounds in the low frequency range may promote language acquisition and result in increased susceptibility to auditory system damage arising from exposure to intense low frequency sounds.

Frequency discrimination by the fetus

The ability to discriminate between acoustic signals of different frequencies is fundamental to the interpretation of auditory information and the development of language perception and production. The fact that the human fetus responds to sounds of different frequencies raises the question of whether the fetus is able to discriminate between them? To investigate whether the fetus has the ability to discriminate between different pure tone acoustic stimuli and different speech sounds the following study used an habituation paradigm and examined whether the fetus could discriminate between two pure tone acoustic stimuli, 250 Hz and 500 Hz, or two speech sounds, [ba] and [bi], at 27 and 35 weeks of gestational age. The results indicated that the fetus is capable of discriminating between the different sounds, i.e. 250 Hz and 500 Hz and [ba] and [bi] at 35 weeks of gestational age but less able at 27 weeks of gestational age. The implications of this for the development of the auditory system are discussed.

Fetal eye movements

Since 1981, when eye movements of the human fetus were first reported, the study of fetal eye movements has increased, mainly focusing on the ontogenesis of eye movements and as one parameter of behavioral states. Using real-time ultrasound, fetal eye movements can be clearly observed from 14 weeks of gestational age. Fetal eye movements may be described in terms of their pattern, frequency and incidence of periods containing eye movements and no eye movements. Furthermore, the relationship of eye movements to other behaviors may be used to give information on the integration of central nervous system function. A picture of normal fetal eye movements can be constructed and used to detect abnormalities in eye movements which can indicate underlying abnormalities of the central nervous system. This paper concludes that, although in its early stages, the study of fetal eye movements holds promise for a greater understanding of brain development and the assessment of the condition of the fetus.

In utero release from a single transient hypoxic episode: a positive reinforcer?

In this experiment, fetal rats, Rattus norvegicus, were subjected to a single transient hypoxic episode before an injection of orange essence or isotonic saline through the uterine and amniotic membranes into the amniotic fluid within 5 s of the release from hypoxia. Other animals experienced either orange essence or isotonic saline alone following no hypoxic episode. At 120 days after birth, adult rats were given a two-choice preference test between orange and water. Only those animals who experienced the orange following release from hypoxia showed a preference for the orange. These results suggest that the acquired preference is not a result of simple exposure but is suggestive of a role for reoxygenation as a positive reinforcer.

Abnormal fetal behaviour in first trimester spontaneous abortion

The behaviour of 5 fetuses at 10 weeks of gestational age that later underwent a spontaneous abortion during the first trimester of pregnancy was compared to similar aged normal fetuses (n = 116). Marked abnormalities of behaviour were noted in three of the pregnancies that spontaneously aborted. These behavioural abnormalities were not identified in any of the pregnancies which continued to term. We conclude that fetal behaviour, which reflects the neural integrity of the individual, and thus fetal well-being, can be used during the first trimester to give an indication as to the viability of the on-going pregnancy.

Embryonic olfactory learning in frogs

We examined the effect of embryonic olfactory experiences on behaviour after hatching in two species of anuran amphibians, Rana temporaria and Rana sylvatica. Odorants (orange and citral) injected into the egg were "learned" by the embryo and subsequently preferred by tadpoles after hatching. The observed preferences were specific to the odours experienced prior to hatching, and tadpoles discriminated between the odour experienced as embryos and a novel odour. The acquired preference was maintained after metamorphosis for those individuals that exhibited a preference as tadpoles. Preferences of tadpoles were also influenced "naturally" by odours present in the water surrounding the developing embryos. The experimentally induced olfactory preferences did not appear to influence the exhibition of sibling recognition abilities. The study represents the first demonstration of "embryonic" learning in amphibians, and the functions and importance of early olfactory learning for amphibians are discussed.

Habituation in normal and Down's syndrome fetuses

The ability of ten normal and two Down's syndrome fetuses to habituate to a repeated auditory stimulus was assessed. The normal fetuses were assessed on two separate occasions during the final trimester of pregnancy. The number of trials to habituate and latency to respond were recorded. The results demonstrated that all normal fetuses exhibited a decrement in response to repeated presentations of the stimulus, a 250-Hz sine wave. This was the result of habituation and not fatigue since fetuses recovered responding upon presentation of a new (500 Hz) stimulus and habituated faster on re-presentation of the original stimulus. The performance of fetuses remained stable over the two testing periods. The response of the Down's syndrome fetuses was different to that of normal fetuses rarely overlapping indices of habituation exhibited by normal fetuses. The study concludes that habituation may be a powerful tool to examine the behavioural and sensory development of the fetus and may be of use in the antenatal assessment of the existence and severity of neural abnormality.

Trisomy 18: behavioral and structural abnormalities. An ultrasonographic case study

A behavioral and structural analysis using ultrasound of a fetus suffering from Edwards syndrome is described. A number of structural anomalies were observed: the classic hand deformity, extended legs, diamond-shaped head, open mouth and a severe cardiac abnormality. A number of distinctive behavior patterns were observed: vertical eye movements, longitudinal rotation of the trunk, rotation of hands, tremor of extremities and pulsatile body movements, which are not usually seen in the normal fetus. The use of behavioral indicators in the diagnosis of abnormalities is discussed. We conclude that the analysis of behavior may make a significant contribution to the ultrasonographic diagnosis of handicap.

Heart rate response of the rat fetus and neonate to a chemosensory stimulus

Resting heart rate (HR) and HR responses of fetal and neonatal rats are described before and after intraoral infusion of isotonic saline or lemon solution. Stable measurements of resting HR were obtained for fetuses over the last three days of gestation (E19, E20, E21) and pups on the day of birth (P0) and four subsequent postnatal ages (P1, P3, P5, P7). Resting HR decreased significantly on P0 relative to the three prenatal ages and exhibited a linear increase thereafter. Variability in resting HR was pronounced on E21, decreased sharply after birth, and gradually increased through P7. Developmental changes in the HR response of fetuses and pups were evident following infusion of lemon. Fetal HR responses to lemon were characterized by bradycardia, which increased in magnitude through P1, diminished after P1, and eventually changed to tachycardia by P7. Both resting HR and HR responses to chemosensory stimulation point to the immediate perinatal period as a time of quantitative and qualitative change during sensory development.

Handedness in the human fetus

The developmental origins of behavioural asymmetries, in particular handedness, have aroused considerable interest and debate. Until now such behavioural asymmetries have only been reported after birth. Here we report the existence of handedness before birth, expressed in terms of thumb-sucking by the fetus. Ultrasound observations of fetuses from 15 weeks to term revealed a marked bias for sucking the thumb of the right hand. This preference appears to be maintained throughout pregnancy, is unrelated to fetal position in utero but correlates with head position preference in the supine newborn. The findings indicate that handedness is present prior to birth and the implications of this for the development of laterality are discussed.

Diagnosing handicap using the behaviour of the fetus

The study of fetal behaviour may have important implications for the prenatal diagnosis of handicap. Since behaviour reflects the integrity of the fetal neural system the examination of fetal behaviour enables neurological assessment of the fetus. This paper discusses present methods of assessing fetal well-being and their shortfalls and then considers current research using behaviour to identify the compromised fetus. Studies using both spontaneous and elicited fetal behaviour are discussed. The paper concludes that a greater understanding of fetal behaviour promises great advances in the antenatal detection of handicap or fetal compromise and may enable midwives to become more involved in the assessment of fetal well-being.

Foetal learning: implications for psychiatry?

While many of the ideas presented concerning foetal learning and their implications for psychiatry are at present speculative, I would remind people of the words of Carmichael (1954): "a study of adult behaviour without consideration of its origin before birth is as incomplete as . . . the study of adult anatomy without reference to the embryology of the structures considered." It is folly to overlook the foetal period!

The discrimination of human odour by the dog

In reply to a suggestion made by Galton in 1875, the ability of dogs to discriminate between the odour of human twins was investigated. In a matching-to-sample simultaneous discrimination task, dogs were tested on their ability to discriminate odours from twins differing only in genetic relatedness or only in environmental factors, particularly diet, or from twins identical in both genetic relatedness and environmental factors. Dogs could discriminate between the odours from twins who differed only in environmental factors and between the odours of twins who differed only in genetic relatedness. However, they were unable to discriminate between odours produced by infant twins identical in both genetic relatedness and environmental factors. Thus twins may be discriminated by dogs as long as they differ in genetic relatedness or environmental factors. The possible source of discriminable odours is discussed and how the effects of genes and environment are mediated considered.

Catecholamines and aggression in animals

This paper assesses the evidence for the role of catecholamines in the aggressive behaviour of animals. The effects of manipulating dopamine and noradrenaline function, either alone or in combination, are considered with respect to two categories of aggression, predatory and affective. Affective aggression is further subdivided into shock-induced defensive fighting, isolation-induced aggression and irritable aggression. The results indicate that catecholamines may not have a specific role in aggressive behaviour. Rather, they may act more to excite or inhibit general behavioural systems, although certain treatments do have a specific influence on aggressive behaviour. The review also highlights certain problems concerning the psychopharmacology of aggression; different species may make varying responses to the same treatment, whilst treatments exerting a similar pharmacological action may result in diverse behavioural effects.