Biomedical subjects

M A Vince

Publications and source records attributed to M A Vince.

At least 19 recordsLinked to original sources

PubMed1988

Responses of neonates to parents' and others' voices.

Infants stimulated with 8-s recordings of speech and voices reading numbers showed a discrimination between their own mothers' and alien voices. In general, the infants' heart rates rose more in response to their mothers' than to an alien voice. However, infants tested less than 24 h after birth responded with significant heart rate deceleration to the mother's spontaneous speech and to the mother reading numbers. Response to the father's voice was also deceleration but to all alien voices was acceleration. Older infants' responses also tended to be acceleratory to most stimuli. Results support the suggestion that sounds which are repeatedly experienced before birth (especially the mother's voice) become familiar to the fetus so that the neonate responds selectively by orienting to them during the first few hours after birth.

Arousal↗

PubMed1985

Maternal vocalisations and other sounds in the fetal lamb's sound environment.

In a first experiment a miniaturised radio hydrophone was implanted inside the amniotic sac in three pregnant ewes and recordings were made from 3 weeks before the lambs were born until they had emerged; these recordings showed that the sound of the mother's voice was slightly louder when picked up by the hydrophone inside the amniotic sac than when picked up by a microphone beside her flank and that sounds recorded during labour included long and loud low frequency sounds associated with contractions, and an increase, compared with before labour, in the incidence of sounds produced by the maternal cardiovascular system and by breathing. Over the last 3 weeks of gestation the attenuation of sounds from outside the mother decreased at frequencies between 500 and 4000 Hz, but not below or above those frequencies. In a second experiment the bleats of 23 pregnant ewes were recorded; their lambs were taken at birth and tested with the sound of either their own mother's bleats, or with bleats from an alien ewe. Heart rate changes which occurred during playback of maternal and alien bleats differed significantly, but only on the occasion when each lamb heard its first bleat, postnatally.

Animals↗

PubMed1984

The synchronisation of hatching in quail embryos: aspects of development affected by a retarding stimulus.

One hundred twenty-eight quail embryos were tested in 33 groups. In each group one egg was stimulated with sounds at a rate known to delay hatching (0.9 clicks/second). In groups of bobwhite quail, stimulation began three days or two days before hatching, and three days before hatching in groups of Japanese quail. All eggs were incubated separately and respiration was monitored to indicate 1) the onset of lung ventilation, 2) the time when the egg began to click, and 3) the hatching time. In one set of bobwhite quail heart rate was also monitored. Stimulated bobwhite quail hatched later than controls, but only when stimulated from three days before hatching. In the Japanese quail fewer embryos were retarded. In retarded bobwhites the duration of breathing, but not the duration of clicking, was lengthened. Respiration rates in stimulated bobwhites were higher throughout stimulation than those of controls. One factor contributing to this increase appeared to be the pacing of breathing in stimulated embryos: breathing tended to stabilise at the level of the stimulation rate. The heart rate of stimulated embryos was higher than that of controls, significantly so around the time of the onset of breathing. In bobwhite, but not in Japanese quail, the increase in respiration rate was found to be associated with retardation and not with stimulation alone; it did not occur in those embryos which were stimulated but not retarded.

Acoustic Stimulation↗

PubMed1983

Changes in plasma iodohormone concentrations during the day before hatching in Gallus domesticus.

Plasma concentrations of thyroxine (T4) and triiodothyronine (T3) were measured at the onset of breathing, clicking and hatching in unstimulated chick embryos. There was a progressive increase in plasma T3 concentration from the onset of breathing (482 hr of incubation) to hatching (496 hr). Plasma T4 concentration did not change significantly between the start of breathing and clicking (494 hr) but decreased between the onset of clicking and hatching. Embryos stimulated with artificial clicks hatched 19 hr before their unstimulated counterparts but their plasma concentrations of T3 and T4 did not differ at hatching from those of unstimulated embryos; however, the plasma T3 concentration, but not T4, at hatching was higher than in unstimulated embryos incubated for a similar length of time, i.e. to the onset of breathing.

Acoustic Stimulation↗

PubMed1980

The fetal sound environment of sheep.

Hydrophones implanted inside the intact amniotic sac recorded sounds available to fetal lambs. Unlike recordings made from outside the intact amnion in human subjects, sounds produced at levels similar to normal conversation from outside the ewe were picked up without masking by maternal cardiovascular sounds. Noises from inside the mother were intermittent and linked to her activity.

Amnion↗

PubMed1980

Effects of thyroxine on prehatching developmental rate and behavior in the chick.

Development of chick embryos was studied following injection of thyroxine or the goitrogen thiourea and compared with that in control saline-injected eggs. The three stages recorded (onset of beak clapping, clicking, and hatching movements) all occurred late in embryos treated with thiourea on the 16th day of incubation. Thyroxine-treated eggs hatched significantly early only when incubated in groups in contact. This suggests that an acceleration effect of thyroxine reported in previous work may have represented an unreliable effect of thyroxine coupled with the synchronizing effect of contact with other eggs. Changes in hatching times following hormone injection are compared with these associated with effects of clicks, which are known to regulate developmental rate and to play a part in the synchronization of hatching.

Animals↗

PubMed1980

Sound stimulation available to the sheep foetus.

Work on the uterine sound environment has been carried out by implanting a hydrophone on the neck of the foetus in two pregnant ewes a few weeks before term. Stimulation with sounds of known amplitude and the use of calibrated microphones and a frequency analyser enabled us to assess (1) the amount of attenuation of sounds of different frequency when they had passed through the maternal tissues and amniotic fluid to become available to the foetus, (2) the absolute level of sound entering the amnion from within the mother and (3) the recognizability of external sound such as speech, when recorded from within the uterus. One puzzling feature of the results has been our inability to hear those sounds which are commonly believed to constitute a predominant stimulus for the foetus: those produced by the maternal cardiovascular system.

Acoustic Stimulation↗

PubMed1979

Effects of accelerating stimulation on different indices of development in Japanese quail embryos.

Effects of continuous accelerating stimulation on the timing, duration and rate of occurrence of different indices of development in Japanese quail embryos were examined. Indices used were: the onset of breathing and hatching, also pipping, clicking, vocalisation, membrane penetration, yolk sac withdrawal and lung aeration. Results showed that embryos stimulated by clicks began breathing about nine hours in advance of unstimulated controls and hatched about 23 hours in advance. All other indices occurred early in comparison with controls but not all occurred at the same accelerated rate and some having begun early, proceeded at the same rate as controls then were completed rapidly just before hatching. Developmental problems are discussed in the light of these results and it is suggested that continuous accelerating stimulation affects development in two main stages.

Animals↗

PubMed1979

Postnatal effects of prenatal sound stimulation in the guinea pig.

Pregnant guinea pigs were stimulated with a natural sound alien to their species. Postnatally the response of their young to this sound was compared with that of unstimulated controls. All young were tested with a series of the alien sounds followed by series of guinea pig calls. Heart rate changes showed that prenatally stimulated young responded less to the alien sounds than did controls, whereas both groups responded equally to guinea pig calls. Response of controls diminished during daily test sessions and over the five test days and comparison with an older control group showed that this was due to repetition of the stimulus. It is suggested that the response of prenatally stimulated animals had waned before birth.

Animal Communication↗

PubMed1979

Heart rate response to egg rotation in the domestic fowl embryo.

1. In eggs turned about 12 times daily, around the long axis of the egg and through about 180 degrees, significant increases in heart rate occurred during turning on the 15th and 17th, although not on the 16th, d of incubation. 2. On and after the 18th d heart rate increases were more marked and occurred both during and after turning. 3. When a single group of embryos was turned every day for the last 4 d of incubation there were significant increases in heart rate on the last 3 d: this repeated retesting had no effect on the response to turning.

Animals↗

PubMed1977

Heart rate response to light in the embryo of the Japanese quail (Coturnix coturnix).

The effects of exposure to light were investigated during and shortly after the period of light stimulation. A particular objective was to evaluated any responses to the type of illumination conditions generally used for observation of avian embryos. Twenty 16-day Japanese quail embryos were illuminated for 15 minutes each during a total recording period of 55 minutes. Heart rate, respiration rate and an approximate measure of activity were recorded. Mean heart rate was found to be higher during stimulation than before and did not return to the prestimulation level during the recording period after stimulation ceased. The lack of an immediate heart rate response to the onset of stimulation separates the effects of light from those of touch, rotation, odours, tastes and maternal calls. The possibility that light may act to stimulate accelerated development is discussed.

Animals↗

PubMed1977

Taste sensitivity in the embryo of the domestic fowl.

Two experiments were carried out to investigate the sense of taste in embryos of the domestic fowl. In the first, four taste substances; NaCl, HCl, glucose and SOA were diluted with distilled water and the response was compared with that to distilled water alone. No significant effects of taste were found. In the second experiment five taste substances: HCl, fructose, NaCl, KCl and quinine were diluted with fluids normally imbibed by the embryo: amniotic and/or allantoic fluid taken from other eggs. These solutions and also distilled water were compared with egg-fluid alone. A highly significant effect of the five solutions was found showing that the taste system becomes functional before the time of hatching. Distilled water produced on an unexpectedly large response in the embryo; possible reasons for this are discussed.

Animals↗

PubMed1976

Sensitivity to odours in the embryo of the domestic fowl.

Sensitivity to odours in the embryo of the domestic fowl was investigated on the day before hatching. Embryos were tested with four odorants: dichloroethane, cineole, amyl acetate and formic acid. Three odorants (dichloroethane, formic acid and cineole) produced an increase in the heart rate and a rise in the rates of beak-clapping and the first two increased the amount of head-shaking. Odorants had little effect on other types of activity. The response to amyl acetate varied between experiments. Blocking the nostrils with wax abolished the response. Some implications of these results are discussed briefly.

Acetates↗

PubMed1976

Behaviour and aeration of the respiratory system in the domestic fowl embryo.

1. The monitoring of developmental stage and under-water dissection were used to examine the initial aeration of the respiratory system in domestic fowl embryos. 2. A virtually complete absence of free air within the chorioallantois was found before the beak had begun to make 'beak-clapping' movements, even when the membranes were already draped over its tip. 3. During the 'beak-clapping' stage, but before the membranes were pierced and before respiratory movements had begun, many embryos were found to contain free bubbles of air within the trachea and air sacs. 4. All embryos in which the respiratory system was aerated were found also to have froth in the crop or other parts of the digestive system. 5. Air was found in both the respiratory and digestive systems of all embryos examined after membrane penetration by the beak. 6. When air was injected into the chorioallantois before the stage of initial aeration it was recovered 5 min later from both the respiratory and digestive systems in under-water dissections. 7. It is suggested that lung ventilation takes place in the avian embryo in three distinct stages: the major air-ways become aerated, then respiratory movements begin and lastly the tertiary bronchi are slowly aerated. It is suggested also that movements involved in the imbibing of fluids play a part in aeration before the membranes are pierced.

Air↗

PubMed1975