Hormonal acceleration of song development illuminates motor control mechanism in canaries

In songbirds, the ontogeny of singing behavior shows strong parallels with human speech learning. As in humans, development of learned vocal behavior requires exposure to an acoustic model of species‐typical vocalizations, and, subsequently, a sensorimotor practice period after which the vocalization is produced in a stereotyped manner. This requires mastering motor instructions driving the vocal organ and the respiratory system. Recently, it was shown that, in the case of canaries (Serinus canaria), the diverse syllables, constituting the song, are generated with air sac pressure patterns with characteristic shapes, remarkably, those belonging to a very specific mathematical family. Here, we treated juvenile canaries with testosterone at the onset of the sensorimotor practice period. This hormone exposure accelerated the development of song into stereotyped adultlike song. After 20 days of testosterone treatment, subsyringeal air sac pressure patterns of song resembled those produced by adults, while those of untreated control birds of the same age did not. Detailed temporal structure and modulation patterns emerged rapidly with testosterone treatment, and all previously identified categories of adult song were observed. This research shows that the known effect of testosterone on the neural circuits gives rise to the stereotyped categories of respiratory motor gestures. Extensive practice of these motor patterns during the sensorimotor phase is not required for their expression. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 943–960, 2010     

Dynamics of crowing development in the domestic Japanese quail (Coturnix coturnix japonica)

Species-specific behaviours gradually emerge, via incomplete patterns, to the final complete adult form. A classical example is birdsong, a learned behaviour ideally suited for studying the neural and molecular substrates of vocal learning. Young songbirds gradually transform primitive unstructured vocalizations (subsong, akin to human babbling) into complex, stereotyped sequences of syllables that constitute adult song. In comparison with birdsong, territorial and mating calls of vocal non-learner species are thought to exhibit little change during development. We revisited this issue using the crowing behaviour of domestic Japanese quail (Coturnix coturnix japonica). Crowing activity was continuously recorded in young males maintained in social isolation from the age of three weeks to four months. We observed developmental changes in crow structure, both the temporal and the spectral levels. Speed and trajectories of these developmental changes exhibited an unexpected high inter-individual variability. Mechanisms used by quails to transform sounds during ontogeny resemble those described in oscines during the sensorimotor phase of song learning. Studies on vocal non-learners could shed light on the specificity and evolution of vocal learning.     

Sex-age stereotyping: Social perceivers as lay adaptationists

Why do perceivers categorize and stereotype others by their biological sex and age? We suggest that perceivers do so because sex and age interactively shape adaptive goals (e.g., mating, parenting) and strategies. And because such goals and strategies pose different fitness-relevant opportunities and threats, social perceivers use others' sex-age as a cue for predicting others' behaviors. This perspective has multiple implications, which we test in a range of U.S. undergraduate and online survey samples. First, we find that perceivers categorize others not by sex and age independently, but by the interaction of their sex and age (i.e., people mentally group others as females and males of specific ages) (Studies 1 and 2). Second, perceivers hold stereotypes of men and women of specific ages as being differentially oriented towards short- and long-term mating as well as parenting goals (e.g., women are stereotyped to be more oriented towards long-term mating goals than men are, but only at younger ages) (Studies 3 and 4). Finally, providing perceivers with direct information about others' adaptive goals can influence the extent to which perceivers apply stereotypes of agency, communion, and competence, and can even override typical sex stereotypes (e.g., men are generally stereotyped to be more agentic than women, but this sex stereotype disappears when both men and women are presented as engaging in short-term mating goals) (Studies 5 and 6). The current findings challenge existing thinking about sex and age stereotyping, and demonstrate the value of an adaptationist approach for thinking about social perception and stereotypes.     

Predictive Models to Determine Imagery Strategies Employed by Children to Judge Hand Laterality

A commonly used paradigm to study motor imagery is the hand laterality judgment task. The present study aimed to determine which strategies young children employ to successfully perform this task. Children of 5 to 8 years old (N = 92) judged laterality of back and palm view hand pictures in different rotation angles. Response accuracy and response duration were registered. Response durations of the trials with a correct judgment were fitted to a-priori defined predictive sinusoid models, representing different strategies to successfully perform the hand laterality judgment task. The first model predicted systematic changes in response duration as a function of rotation angle of the displayed hand. The second model predicted that response durations are affected by biomechanical constraints of hand rotation. If observed data could be best described by the first model, this would argue for a mental imagery strategy that does not involve motor processes to solve the task. The second model reflects a motor imagery strategy to solve the task. In line with previous research, we showed an age-related increase in response accuracy and decrease in response duration in children. Observed data for both back and palm view showed that motor imagery strategies were used to perform hand laterality judgments, but that not all the children use these strategies (appropriately) at all times. A direct comparison of response duration patterns across age sheds new light on age-related differences in the strategies employed to solve the task. Importantly, the employment of the motor imagery strategy for successful task performance did not change with age.     

Vestibulo-ocular reflexes in the adult sea lamprey

Vestibulo-ocular reflexes were elicited in isolated preparations of small adult sea lampreys (Petromyzon marinus). Mechanical stimulation of the labyrinths or electrical stimulation of the vestibular nerves produced stereotyped, conjugated eye movements (Table 1) and appropriate electrical activities in individual extraocular muscles (Fig. 1). No inhibition of discharges in motor nerves was observed during stimulation of opposing reflexes. Likewise, nystagmus was never seen during continued stimulation. The primitive eye reflexes of the lamprey probably correspond to the simple excitatory pathways from single ampullae to individual eye muscles of higher vertebrates.     

Giardiasis and other intestinal parasitic infections in a Manitoba residential school for the mentally retarded.

A case of severely symptomatic giardiasis in a school for the mentally retarded prompted an epidemiologic survey of the institution. The rate of parasitic infection in the children were just under 50%. Multiple infections were common and one child harboured five different protozoa. The yield included known pathogens (Giardia lamblia, Metorchis conjunctus and Diphyllobothrium sp.), protozoa of potential pathogenicity (Dientamoeba fragilis) and other protozoa, the significance of which has yet to be determined. The prevalence of G. lamblia in the index ward was significantly higher than in a control ward matched for age and mobility of the children. The epidemiologic data suggested person-to-person transmission of G. lamblia within the institution. Recommendations for the control of protozoal intestinal infections in custodial institutions are presented.     

Three young children with Smith-Magenis syndrome: their distinct, recognisable behavioural phenotype as the most important clinical symptoms

We report on the development and behaviour of three young children with Smith-Magenis syndrome (SMS), del 17p11.2. The behaviour problems and the psychomotor delay in preschool children with SMS are often more striking than the dysmorphic features and can serve as a useful clue to the diagnosis. We compare the behaviour with reported data. The behaviour problems in the three four year olds include very demanding behaviour, severe temper tantrums, hyperactivity, aggressive behaviour, self injurious behaviour, sleeping problems and stereotypic behaviour. Head banging, hand, wrist or finger biting are present. Onychotyllomania is not observed. Insertion of objects in the mouth as well as excessive nose picking is very frequent, although polyembolokoilomania is not present. The so called self hug when excited is present in one child. The behaviour problems and psychomotor delay represent a major management problem for the parents.     

Integration of sensory and motor processing underlying social behaviour in túngara frogs

Social decision making involves the perception and processing of social stimuli, the subsequent evaluation of that information in the context of the individual's internal and external milieus to produce a decision, and then culminates in behavioural output informed by that decision. We examined brain networks in an anuran communication system that relies on acoustic signals to guide simple, stereotyped motor output. We used egr-1 mRNA expression to measure neural activation in male túngara frogs, Physalaemus pustulosus, following exposure to conspecific and heterospecific calls that evoke competitive or aggressive behaviour. We found that acoustically driven activation in auditory brainstem nuclei is transformed into activation related to sensory-motor interactions in the diencephalon, followed by motor-related activation in the telencephalon. Furthermore, under baseline conditions, brain nuclei typically have correlated egr-1 mRNA levels within brain divisions. Hearing conspecific advertisement calls increases correlations between anatomically distant brain divisions; no such effect was observed in response to calls that elicit aggressive behaviour. Neural correlates of social decision making thus take multiple forms: (i) a progressive shift from sensory to motor encoding from lower to higher stages of neural processing and (ii) the emergence of correlated activation patterns among sensory and motor regions in response to behaviourally relevant social cues.     

Characteristics of the conditioned motor reactions of unrestrained elasmobranches and teleosts

In elasmobranch (Scyllium canicula, Galleus canis) and teleost (Migull capitocum) fishes it is possible to form motor food-searching conditioned reflexes to discrimination of light and darkness. Some differences were revealed in ecological and conditioned motor behavioural activities in higher and lower sharks. Elasmobranch and teleost fishes exhibit significant differences in ecological, feeding and conditioned reflex behaviour. Nervous activity in elasmobranchs is characterized by lower and primitive organization as compared to that in teleosts.     

An ultrastructural study of adhesive junctions in reaggregates of unincubated chick embryos.

Cell suspensions obtained by the dissociation of unincubated chick embryo blastoderms were allowed to reaggregate on a gyratory shaker for 24-48 hours. The reaggregates which form during this period consist of an inner phase of tightly packed cohesive cells surrounded by an external phase of loosely packed cells. This sorted out arrangement achieves its definitive form between 24 and 48 hours of rotation culture. It was determined that the external phase consists of primitive ectoderm and that the internal phase consists of primitive endoderm. Both 24- and 48-hour reaggregates were examined in the electron microscope and observations were directed to areas of close membrane apposition between cells. In 48-hour reaggregates, primitive endoderm cells were joined by many specialized junctions (desmosomes). The formation of desmosomes in reaggregates of dissociated unincubated chick embryo cells was correlated with the sorting out process.     

Intermuscular coordination in a sprint push-off.

This study was designed to investigate the patterns of intermuscular coordination during a sprinting event. In previous research it was found that despite the indeterminacy problem of movement control, movements like vertical jumping, speed skating and cycling are performed in a stereotyped manner. It was hypothesized that this might be due to constraints associated with the transformation of joint rotations into the desired translation. The objective of the present study was to determine the extent to which the intermuscular coordination patterns during other movements also are performed in a stereotyped manner and, if that is true, whether this can be understood on the basis of such constraints. Seven elite sprint runners were instructed to execute an explosive sprinting dash. Ground reaction forces and cinematographic data were recorded for the second stance phase of the sprint. Simultaneously, electromyographic activity of nine leg muscles was recorded telemetrically. Linked-segment modeling was used to obtain net joint moments and net joint powers. Different athletes appeared to perform the sprint in a stereotyped manner. The muscle coordination pattern is characterized by a proximo to distal sequence in timing of the monoarticular muscles. When compared to the sequential pattern found in jumping, the biarticular hamstrings and rectus femoris muscles behave differently; in the sprint a more pronounced reciprocal activity between these muscles exists. The resulting movement pattern is characterized by a sequence of upper leg extension and plantar flexion. The observed sequence in timing of muscle activation patterns is aimed at solving the problems associated with the earlier identified geometrical and anatomical constraint. However, the coordination pattern cannot be fully understood on the basis of these constraints. A specific constraint is identified with respect to the direction of the ground reaction force, which explains the pronounced reciprocal activity of the biarticular hamstring and rectus femoris muscles. The intermuscular coordination pattern in the sprint can be seen as a compromise between the specific requirement of the sprint and the advantageous effect of a proximo to distal sequence as found previously for jumping.     

The relationship between obesity and seasonal variation in body weight among elementary school children in Tokyo

Typical patterns of seasonal variation in body weight among Japanese children involve increases during the fall and/or winter and decreases during the summer. However, atypical variations, namely, increases in weight during the summer, have been reported for obese children. The present study examines whether weight gain during the summer (i.e., July through September) is a possible cause of obesity. We examined seasonal changes in weight for 446 elementary school children in Tokyo in six waves between 1972 and 2004. Weight was measured monthly for 6 years in each child and was evaluated by means of time-series analysis. Overall, significant seasonal variations in weight were found in 86% of the children, most of which were typical (i.e., decreases during the summer and increases during the fall, winter, and/or early spring). On the other hand, weight gain in the summer was observed exclusively among obese children. Children whose weight increased during the summer holiday spent most of their time comfortably indoors because of air conditioners, which became popular in 1970s. A possible explanation of the observed weight gain during the summer seems to be changes in life style associated with the use of air conditioning, concomitant with insufficient physical exercise and excessive consumption of food and drink, which could disturb the rhythms of seasonal weight changes and lead to obesity.     

Routine ultrasonography in utero and subsequent handedness and neurological development.

OBJECTIVE--To examine any associations between routine ultrasonography in utero and subsequent brain development as indicated by non-right handedness at primary school age and neurological development during childhood. DESIGN--Follow up of 8 and 9 year old children of women who took part in two randomised, controlled trials of routine ultrasonography during pregnancy. SETTING--Clinics of 60 general practitioners in Norway during 1979-81. Maternal and child health centres. SUBJECTS--2161 (89%) of 2428 eligible singletons were followed up, partly through a questionnaire to their parents and partly through information from health centres. MAIN OUTCOME MEASURES--The dominant hand of the child was assessed by 10 questions. Deficits in attention, motor control, and perception were evaluated by five questions. Impaired neurological development during the first year of life was assessed by an abbreviated version of the Denver developmental screening test. RESULTS--The odds of non-right handedness were higher among children who had been screened in utero than among control children (odds ratio 1.32; 95% confidence interval 1.02 to 1.71). No clear differences were found between the groups with regard to deficits in attention, motor control, and perception or neurological development during the first year of life. CONCLUSION--Our data suggest a possible association between routine ultrasonography in utero and subsequent non-right handedness, whereas no association with impaired neurological development was found. As the question on non-right handedness was one of six initial hypotheses, the observed results may be due to chance. None the less, the results suggest that the hypothesis may have some merit and should be tested in future studies.     

Individual responses to methylphenidate and caffeine in children with minimal brain dysfunction.

Eight children with minimal brain dysfunction were studied for their individual responses to two stimulant medications--methylphenidate hydrochloride and caffeine citrate. Four types of behavioural responses were observed in the double-blind crossover experiment: four children responded favourably to both psychostimulants, one responded to methylphenidate alone and two responded to the placebo. The behaviour of one child deteriorated while he was taking methylphenidate and caffeine. In general, methylphenidate was superior to caffeine in diminishing hyperactive and aggressive behaviour. It is apparent that such stimulant medication exerts its therapeutic effects in these two areas primarily and would therefore be useful as one aspect of a complete treatment program for children with this syndrome.     

Anthropometric Characteristics,Physical Fitness and Motor Coordination of 9 to 11 Year Old Children Participating in a Wide Range of Sports

ObjectivesThe aim of this study was to investigate to what extent 9 to 11 year old children participating in a specific sport already exhibit a specific anthropometric, physical fitness and motor coordination profile, in line with the requirements of that particular sport. In addition, the profiles in children with a different training volume were compared and possible differences in training hours per week between children from a low, moderate, and high level of physical fitness and motor coordination were investigated.DiscussionThe study showed that in general, children at a young age do not exhibit sport-specific characteristics, except in children with a high training volume. It is possible that on the one hand, children have not spent enough time yet in their sport to develop sport-specific qualities. On the other hand, it could be possible that they do not take individual qualities into account when choosing a sport.     

Etude de l'influence des facteurs visuels sur les comportements sexuels et agressifs de Mollienesia (Poecilia) velifera (Pisces,Poeciliidae)

One of the most striking features of cave fishes is their pronounced ocular regression. They are, however, perfectly adapted since they multiply and display the behaviour patterns which are biologically important in their surroundings. It is therefore of interest to study the relative role of visual factors in the corresponding behaviour patterns in related epigean species.Other authors have previously demonstrated the dominant role of chemical stimuli in the releasing of sexual behaviour patterns in M. sphenops, of which some forms are cavernicolous. In M. velifera and M. latipinna, on the contrary, visual factors seem more important. The releasers of the aggressive behaviour patterns of these three species seem to be predominantly visual. In the present study, the importance of visual factors has been verified experimentally in M. velifera by comparing the observed behavioural differences in experimentally blinded individuals and normal controls.The results of the pre-experimental phase show that there is no difference between these two groups before blinding, neither in the frequency of the patterns, nor in their numerical values.The results of the first experimental phase confirm the importance of visual releasers in the sexual behaviour patterns of M. velifera. Thus, sexual approaches, mouth—abdomen contacts and copulation attempts are totally absent in blinded pairs. Sexual motivation however is still present since the gonopodal flexions are equally frequent in both groups. On the other hand, it seems that aggressive behaviour patterns are maintained in blinded individuals but only when the partners are very close to each other or when an actual contact has taken place.The comparison of pairs in which only one of the partners is blinded (second experimental phase), as well as results of the first phase, suggest that experimental blinding does not cause hormonal changes liable to influence the observed patterns. In addition to this, the role of the ♀ in courtship has been specified. When a ♀ individual is intact and receptive, it will initiate courtship when it is placed in the company of an inactive blinded partner.     

Stereotypies,aggression and the feeding schedules of tethered sows

Thirty tethered sows were observed for 5 min every half-hour for 9 h spanning the two feeding periods. Activity, consisting largely of food searching behaviour and drinking, was largely restricted to two 2-h periods following each feed. Three categories of stereotyped behaviour were observed and these were closely tied to the feeding periods. Short-duration bouts of rubbing, head-waving and bar-biting occurred during food delivery, while long-duration bouts of highly stereotyped and idiosyncratic sequences of rubbing and drinking were shown by older sows immediately after feeding. Vaccuum chewing tended to occur slightly later. I suggest that frustration of feeding motivation rather than under-stimulation underlies stereotypies in pigs, and that the different forms may represent stereotype of the appetitive and consummatory phases. Aggression was rare and was not closely related to the feeding periods or to stereotypies.     

Motor programs for abdominal positioning in crayfish

Summary Using chronically implanted suction electrodes (Fig. 2), records were obtained from the tonic abdominal flexor motor neurons of crayfish while they were undergoing various self-generated movements (Fig. 3). The main behavior examined in this study was one of abdominal extension (Fig. 1), a response which could be evoked repeatedly. Other stereotyped movements were also observed. Each class of behavior we examined has been evoked previously in dissected preparations by stimulating command interneurons, allowing comparison of selfgenerated and electrically evoked motor patterns.During abdominal extension, the flexor inhibitor neuron was observed to fire in a characteristic way (Fig. 4 left, Fig. 5) that was not materially altered even if the associated movements were prevented by rigid restraint (Fig. 4 right). These self-generated motor programs resembled those obtained from command fiber stimulation, both in detail and reproducibility, suggesting that the normal means of executing such stereotyped behavior in these animals is via selected command interneurons.Central reciprocity between the tonic flexor motor neurons and the flexor inhibitor was observed routinely in self-generated programs (Figs. 3, 6, 7), as was seen in dissected animals under command fiber control. The incidence of failure of reciprocity, however, appears to be more common in natural programs than in those evoked by direct stimulation of command interneurons.This work was supported by NIH Grant NS-05423-07 (JLL). Support for one of us (A. C. E.) was obtained in part from NIH Training Grant 2T01 GM-00836-08. We gratefully acknowledge the technical assistance of Mr. Gregg Holmes, and note also the interest and valuable discussions offered by Dr. Lon Wilkens, Mr. George Wolfe and Mr. Terry Page.