Order-dependent timing of unimodal and multimodal stimulation affects prenatal auditory learning in bobwhite quail embryos

This study examined the relationship between unimodal and multimodal sensory stimulation and their effects on prenatal auditory learning in bobwhite quail embryos. Embryos exposed to a maternal call in the 24 hr prior to hatching (unimodal condition) significantly preferred this familiar call over an unfamiliar call in postnatal testing, but failed to demonstrate this preference when the maternal call was presented concurrently with non-synchronized patterned light (multimodal condition). To further explore this interference effect, we provided one group of embryos concurrent exposure to a maternal call and patterned light for 12 hr followed by 12 hr exposure to the call alone (multimodal-->unimodal call). This group failed to prefer the familiar call during postnatal testing. In contrast, reversing the order of presentation during prenatal exposure (unimodal call-->multimodal) led a second group of subjects to significantly prefer the familiar call, suggesting that the order-dependent timing of sensory stimulation can significantly impact prenatal auditory learning. Experiment 3 examined the influence of modality versus timing of sensory stimulation on prenatal auditory learning by providing three groups of embryos with exposure to a maternal call during the 12 hr prior to hatching and by varying the duration of visual stimulation. Results indicate that 12 hr unimodal exposure to patterned light does not support prenatal auditory learning when it is followed by 12 hr exposure to multimodal stimulation (light-->multimodal), but can facilitate prenatal auditory learning when it is followed by unimodal exposure to the call alone (light-->call). Results are discussed in terms of intersensory relationships during perinatal development.     

Effects of prenatal visual stimulation on growth and heart rate in bobwhite quail (Colinus virginianus)

This study examined the effects of prenatal visual stimulation on bobwhite quail embryos' growth and heart rate. No differences in growth rate were found between embryos exposed to visual stimulation during the late prenatal period and control embryos. Embryos exposed to visual stimulation throughout incubation maintained lower heart rates in response to visual stimulation than did naïve embryos. In a subsequent experiment, naïve embryos that underwent an egg‐opening procedure exhibited heart rates that were lower than embryos measured in intact eggshells. Embryos in opened eggs maintained lower heart rates than comparison embryos across time; however, a less invasive egg‐opening procedure led to a quicker heart rate recovery than did a more invasive egg‐opening procedure. These findings indicate that prenatal heart rate responses may be mediated by multiple features of the organism's developmental context, including intensity and duration of sensory stimulation. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 315–324, 2006.     

Augmented prenatal auditory stimulation alters postnatal perception,arousal, and survival in bobwhite quail chicks

This study examined whether previously reported effects of altered prenatal sensory experience on subsequent acceleration of intersensory development in precocial birds are mediated by mechanisms sensitive to the overall amount of stimulation provided. Results revealed that bobwhite quail chicks exposed to substantially augmented amounts of prenatal auditory stimulation show altered patterns of species-typical perceptual development. Specifically, chicks continued to respond to maternal auditory cues into later stages of postnatal development and failed to demonstrate responsiveness to maternal visual cues. In addition, embryos exposed to substantially augmented amounts of prenatal auditory stimulation exhibited a higher level of behavioral arousal and higher mortality rates than embryos provided either moderately augmented amounts or no additional amount of prenatal auditory stimulation. These findings suggest that substantially increased amounts of prenatal sensory stimulation can interfere with the emergence of species-typical patterns of postnatal perceptual functioning and lend support to the notion that sensory stimulation that falls within some optimal range maintains or facilitates normal patterns of perceptual development, whereas stimulation beyond the range of the species norm can result in intrasensory and intersensory interference. © 1997 John Wiley & Sons, Inc. Dev Psychobiol 30: 201–212, 1997     

Prenatal exposure to temporal and spatial stimulus properties affects postnatal responsiveness to spatial contiguity in bobwhite quail chicks

Little is known about how experiential factors guide and organize the development of intersensory perception. This study manipulated the amount of late prenatal and early postnatal experience with the temporal synchrony and spatial contiguity of audio-visual stimulation available to bobwhite quail embryos and hatchlings to explore this question. Results revealed that only embryos exposed to temporally synchronous and spatially contiguous audio-visual stimulation prior to hatching subsequently preferred spatially contiguous audio-visual maternal information following hatching, despite being denied postnatal visual experience. In contrast, embryos that did not receive exposure to both temporal synchrony and spatial contiguity (and were also denied postnatal visual experience) failed to show a preference for the spatial contiguity of maternal auditory and visual information following hatching. These results suggest that prenatal exposure to the amodal properties of temporal synchrony and spatial contiguity facilitate chicks' emerging sensitivity to the spatial contiguity of audio-visual information in the period following hatching.     

Effects of prenatal sensory stimulation on heart rate and behavioral measures of arousal in bobwhite quail embryos

Although a number of studies have demonstrated the effects of altered prenatal experience on subsequent behavioral development, how these effects are achieved remains a topic of enduring interest. The present study examined the immediate effects of unimodal and multimodal prenatal sensory stimulation on physiological and behavioral arousal in bobwhite quail embryos. Embryos were videotaped and their heart rate was monitored during a 4-min exposure period to (a) no supplemental sensory stimulation, (b) unimodal auditory stimulation, (c) unimodal visual stimulation, (d) two sources of concurrent auditory stimulation, or (e) concurrent auditory/visual stimulation. Results indicated that quail embryos' overall activity levels and heart rate can be significantly affected by the type of prenatal sensory stimulation provided during the period prior to hatching. In particular, multimodal stimulation increased both behavioral activity levels and heart rate compared to controls. Across the unimodal and intramodal groups, however, behavioral and physiological measures revealed different patterns of activity in response to supplemental sensory stimulation, highlighting the value of using multiple levels of analysis in exploring arousal mechanisms involved in prenatal perceptual responsiveness.     

Effects of maternal breathing rate, psychiatric status, and cortisol on fetal heart rate

Women's experiences during pregnancy are predictive of variation in neurobehavioral profiles in their children. Few studies have assessed these relationships during the prenatal period. In 113 women in the 36^th –38^th gestational week (mean age 26.3 ± 5.4 years), electrocardiogram, blood pressure, respiration, salivary cortisol, and fetal heart rate (HR) were measured during baseline, a psychological challenge (Stroop color–word matching task), and a standardized paced breathing protocol. Subjects underwent the Structured Clinical Interview for DSM‐IV prior to testing and were grouped as: depressed, co–morbid for depression and anxiety, anxiety disorder only, and control. There was a significant main effect of maternal diagnostic group on fetal HR only during the Stroop task: fetuses of women in the co–morbid group had a greater HR increase compared to controls (p < .05). Overall, fetuses showed robust increases in HR during paced breathing (p < .0001), and there was no significant difference by maternal diagnosis. For both tasks, changes in fetal HR were independent of women's concurrent cardiorespiratory activity. Finally, although cortisol was higher in the co‐morbid group (p < .05), across all participants, there was a trend for maternal baseline cortisol to be positively associated with average fetal HR (p = .06). These findings indicate that variation in fetal HR reactivity—an index of emerging regulatory capacities—is likely influenced by multiple acute and chronic factors associated with women's psychobiology. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 53:221–233, 2011.     

Biased embryos: Prenatal experience alters the postnatal malleability of auditory preferences in bobwhite quail

Many precocial birds show a robust preference for the maternal call of their own species before and after hatching. This differential responsiveness to species-specific auditory stimuli by embryos and neonates has been the subject of study for more than four decades, but much remains unknown about the dynamics of this ability. Gottlieb [Gottlieb [1971]. Development of species identification in birds: An enquiry into the prenatal determinants of perception. Chicago/London: University of Chicago Press.] demonstrated that prenatal exposure to embryonic vocalizations serves to canalize the formation of species-specific preferences in ducklings. Apart from this, little is known about the features of the developmental system that serve to canalize such species-typical preferences, on the one hand, and generate novel behavioral phenotypes, on the other. In the current study, we show that briefly exposing bobwhite quail embryos to a heterospecific Japanese quail (JQ) maternal call significantly enhanced their acquisition of a preference for that call when chicks were provided with subsequent postnatal exposure to the same call. This was true whether postnatal exposure involved playback of the maternal call contingent upon chick contact vocalizations or yoked, non-contingent exposure to the call. Chicks that received both passive prenatal and contingent postnatal exposure to the JQ maternal call redirected their species-typical auditory preference, showing a significant preference for JQ call over the call of their own species. In contrast, chicks receiving only prenatal or only postnatal exposure to the JQ call did not show this redirection of their auditory preference. Our results indicate that prenatal sensory stimulation can significantly bias postnatal responsiveness to social stimuli, thereby altering the course of early learning and memory.     

Effects of emotions on heart rate asymmetry

Heart rate asymmetry (HRA) is an index that accounts for an uneven contribution of decelerations and accelerations to the heart rate variability (HRV). Clinical studies indicated that HRA measures have additive clinical value over the more frequently used HRV indexes. Despite the abundance of studies on psychological influences on HRV, little is known whether psychological factors influence HRA. Based on previous research regarding HRA and stress, we expected that negative emotions compared to positive emotions would decrease the contribution of decelerations to HRV. Thirty female participants watched three clips that produced negative emotions, positive emotions, and neutral affect. Besides electrocardiogram, we measured several physiological and behavioral responses to ascertain the affective impact of the clips. Using the RR interval time series, we calculated HRV and HRA indexes. We found that HRA differentiated between positive emotions and negative emotions reactivity. Positive emotions produced a higher number of decelerations in short‐term variability to the total short‐term variability (C1_d) compared to negative emotions. Moreover, C1_d correlated with subjective ratings of affect. In sum, the results of this study indicated that HRA is sensitive to psychological influences. HRA indexes are likely to contribute to a more nuanced physiological differentiation between emotions.     

Influence of long-term beta receptor stimulation with prenalterol on intrinsic heart rate in rats

Summary Previous studies have shown that the intrinsic heart rate (IHR) may undergo changes, e.g., decrease after long-term endurance training. The mechanism for this adaptation is not known. In this study, rats were subjected to long-term oral treatment with the beta receptor stimulating drug prenalterol. During the treatment period heart rates at rest and during submaximal exercise were measured. Heart rate after 30 min rest and also 2 min after exercise was higher in the treated animals, due to the beta stimulation. The treated rats had a significantly lower heart rate increase during exercise than untreated controls, consistent with a partial beta-blocking effect of the drug in states with a high endogenous sympathetic activity. Therefore, the animals were not trained but only exposed to the increased stimulation of cardiac beta receptors accomplished by the drug while at rest. After 25 weeks, prenalterol was withdrawn and the IHR was measured in situ after a denervation procedure. The treatment with prenalterol had not altered the IHR. Our previous results from training studies indicate that a heart rate increase above a certain level or the stimulation of cardiac beta receptors are not the main stimuli for a lower setting of the IHR as seen after endurance training. In this study chronic beta receptor stimulation with prenalterol did not influence the IHR, which supports that hypothesis.     

The influence of prenatal tactile and vestibular stimulation on auditory and visual responsiveness in bobwhite quail: A matter of timing

The fact that the sensory systems do not become functional at the same time during prenatal development raises the question of how experience in a given modality can influence functioning in other sensory modalities. The present study exposed groups of bobwhite quail embryos to augmented tactile and vestibular stimulation at times that either coincided with or followed the period of onset of function in the later-developing auditory and visual modalities. Differences in the timing of augmented prenatal stimulation led to different patterns of subsequent auditory and visual responsiveness following hatching. No effect on normal visual responsiveness to species-typical maternal cues was found when exposure to tactile and vestibular stimulation coincided with the emergence of visual function (Days 14-19), but when exposure took place after the onset of visual functioning (Days 17-22), chicks displayed enhanced responsiveness to the same maternal visual cues. When augmented tactile and vestibular stimulation coincided with the onset of auditory function (Days 9-14), embryos subsequently failed to learn a species-typical maternal call prior to hatching. However, when given exposure to the same type and amount of augmented stimulation following the onset of auditory function (Days 14-19), embryos did learn the maternal call. These findings demonstrate that augmented stimulation to earlier-emerging sensory modalities can either facilitate or interfere with perceptual responsiveness in later-developing modalities, depending on when that stimulation takes place.     

Maternal cigarette-smoking during pregnancy disrupts rhythms in fetal heart rate

OBJECTIVE: To examine the effects of maternal cigarette smoking during pregnancy on the developing infant's autonomic regulation before the possible effects of parturition and neonatal withdrawal could alter outcome measures. METHODS: Heart rate variability (HRV) was assessed for 10 min during late gestation for 21 cigarette-exposed (CE) and 22 nonexposed (NE) fetuses. RESULTS: HRV was significantly lower in fetuses whose mothers smoked cigarettes during pregnancy. Spectrum analysis of that variability showed temporally organized rhythms at a frequency similar to rhythms previously found in fetal cyclic motility (approximately .3 cycles per min). Lower powered rhythms--associated with poorer development--at the first, second, and dominant rhythms, as well as lower overall power of the power spectrum, were found for CE fetuses. Pearson correlations showed significant negative correlations between the amount of maternal cigarette smoking during the first trimester of pregnancy and measures of fetal HRV and power of spectral peaks. CONCLUSIONS: Results show that CE fetuses have lower HRV and disrupted temporal organization of autonomic regulation before effects of parturition, postnatal adaptation, and possible nicotine withdrawal contributes to differences in infant neurobehavioral function.     

Cortical thickness,resting state heart rate,and heart rate variability in female adolescents

Resting state heart rate variability (HRV) is a psychophysiological marker that has gained increasing research interest, in particular in developmental neuroscience. HRV has been shown to be associated with mental and physical health, beyond simple measures of heart rate (HR) and shows inter‐ and intraindividual variance across aging. Recently, three studies reported on a positive correlation between resting state HRV and cortical thickness in selected regions of interest (ROIs) in adult samples. Structural thickness, HRV, and HR change during the sensitive period of adolescence. Previously, no study has addressed the structural concomitants of resting HR and HRV in adolescents. Cortical thickness (3‐T MRI), HR, and HRV were recorded in 20 healthy, female adolescents (mean age: 15.92 years; SD = 1.06; range: 14–17). In line with existing research in adults, cortical thickness in a number of ROIs was associated with resting state HRV but not HR. The comparison of regression analyses using the Bayes factor revealed evidence for a correlation between HRV and cortical thickness of the bilateral rostral anterior cingulate cortex. However, unlike in adults, greater cortical thickness was associated with reduced HRV in female adolescents. Analyses on HR showed no superior model fit. Results suggest that greater HRV might be beneficial for cortical development during adolescence (cortical thinning). On the other hand, cortical development might determine changes in autonomic nervous system function in adolescents. Future studies are needed to replicate these findings in larger samples including boys and to test these hypotheses in longitudinal designs.     

Contextual determinants of auditory learning in bobwhite quail embryos and hatchlings.

This study examined the ability of bobwhite quail embryos and hatchlings to learn an individual bobwhite maternal call. Results revealed that embryos could learn an individual maternal call and remember that call for at least 24 hr following exposure. In contrast, hatchlings reared socially in groups of same-age chicks during postnatal exposure to a maternal call did not demonstrate a preference for that familiar call at 24 hr following exposure. However, individual auditory recognition was exhibited by hatchlings reared in social isolation, suggesting that the perceptual and social complexity of the postnatal situation can disrupt or interfere with early auditory learning. Additional support for this view was the finding that embryos exposed to unusually early visual stimulation during prenatal exposure to a maternal call also failed to prefer that familiar maternal call in subsequent choice tests. The idea that early auditory learning capacity is determined more by context and experience rather than the organism's specific age or stage of development is discussed.     

咖啡摄入前后心率变异性的对比研究

目的研究中等剂量咖啡摄入对青年受试者心率变异性的影响,明确咖啡对心脏自主神经活性的作用。方法无咖啡因摄入习惯的16名健康青年受试者(身高167 cm±7.2 cm、体重61.3 kg±6.3kg、年龄24.9岁±2.8岁)参与本项研究,在摄入含6 mg/kg咖啡因的咖啡饮品后,于8:40~10:45应用动态心电图记录仪(Holter)进行咖啡摄入前后心电信号的采集及心率(heart rate,HR)和心率变异性指标的分析。心率变异性指标包括R-R间期标准差(SDNN)、相邻R-R间期差值的均方根值(r MSSD)、相邻的R-R间期之差大于50 ms的心搏数占总心搏数的百分比(PNN50)、标化低频(normalized low frequency power,LFnorm)、标化高频(normalized high frequency power,HFnorm)、低频功率(low frequency,LF)与高频功率(high frequency,HF)的比值(LF/HF)。结果饮用咖啡后,心率、心率变异性指标均发生改变且具有统计学意义,HR、LFnorm和LF/HF分别降低了7.5%、17%和35%。r MSSD、PNN50和HFnorm分别提高了82%、80%和58%。其中HR及LF/HF随着时间的变化趋势最明显。HRV参数在饮用咖啡前后的差值ΔLF与ΔHF,ΔLF与ΔLF/HF均显著相关,相关系数为-0.980和0.903。结论中等剂量咖啡可引起心率变异性的改变和心率的降低,抑制交感神经活性,提高副交感神经活性。     

Instructed heart rate control in a high heart rate population

Forty college students were selected from a large number of introductory psychology students on the basis of high heart rate during an initial screening session. Subjects were then contacted and participated in two additional sessions during which heart rate, respiration rate, and skin conductance measures were obtained. Each session consisted of a baseline period followed by five trial periods during which subjects attempted to control their heart rate or performed a visual tracking task. Subjects were randomly assigned to one of four groups. One group served as a control and monitored a visual feedback display driven by their own heart rate but received no instructions to decrease their heart rate. In contrast, the three heart rate control groups were instructed to decrease heart rate during the trial periods by utilizing a relaxation procedure, proportional biofeedback, or proportional biofeedback plus criterion information. No group differences were present during the baseline periods. During feedback trials, however, all the training groups differed from the control in heart rate but did not differ from each other. It is suggested that feedback displays may not facilitate heart rate reduction beyond the level achieved by instructing subjects to use a general relaxation procedure.     

Differences in pulse rate and heart rate and effects on the calculation of heart rate reactivity during periods of mental stress

Heart rate and reactivity from pulse and ECG were compared over rest and mental arithmetic periods of 2-min duration each for 32 males and 50 females. Data from the two sources of heart rate were not significantly different during the rest period but did differ significantly during periods of heart rate acceleration and deceleration. Sex effects were also noted, with females having consistently higher heart rates from both sources of measurement. Calculation of heart rate reactivity via five procedures based upon the wider literature revealed significant differences between data from different sources of heart rate. Implications for assessment of heart rate reactivity to laboratory stressors are discussed, with suggestions for future research.     

Comparison of heart rate response and heart rate recovery after step test among smoker and non-smoker athletes

BackgroundExercise performance depend on the ability of the cardiovascular system to respond to a wide range of metabolic demands and physical exertion.ObjectivesTo investigate the habitual smoking effects in heart rate response and heart rate recovery after step test in athletes.MethodsSeventy-eight physically healthy active athletes (45 non-smokers and 33 smokers) aging 27±8 years old, participated in this study. All participants completed the International Physical Activity Questionnaire and performed the six-minute step test. Cardiovascular parameters such (resting heart rate, peak heart rate, heart rate at 1 min after testing, heart rate recovery, recovery time, blood pressure at rest, and post-testing blood pressure) were recorded.ResultsSmoker-athletes had higher resting heart rate (76 ± 9bpm vs. 72 ± 10bpm, p<0.05), maximum heart rate (154 ± 18bpm vs. 147 ± 17bpm, p<0.05) and recovery time (7min 25sec ± 6min 31sec vs. 4min 21sec ± 4min 30sec, p<0.05) than non-smoker athletes. Scores from the IPAQ were approximately the same (M=7927 ± 10303, M= 6380 ± 4539, p<0.05).ConclusionSmoking was found to affect athletes'' cardiovascular fitness. The change of the athletes'' heart rate recovery and recovery time contributes to the adaptation of cardiovascular function in training requirements.