Modified prenatal sensory stimulation influences postnatal behavioral and perceptual responsiveness in bobwhite quail chicks (Colinus virginianus)

Asynchronous bimodal stimulation during prenatal development elicits higher levels of behavioral and physiological arousal in precocial avian embryos than does unimodal sensory stimulation. To investigate whether the increased arousal associated with prenatal bimodal stimulation has enduring effects into postnatal development, bobwhite quail (Colinus virginianus) embryos received no supplemental stimulation, unimodal auditory stimulation, or bimodal (audiovisual) stimulation prior to hatching. Embryos exposed to concurrent bimodal stimulation demonstrated greater levels of behavioral activity and failed to use maternal visual cues to successfully direct species-specific perceptual preferences following hatching. These results provide initial evidence that asynchronous bimodal sensory stimulation during prenatal development can have enduring effects on early postnatal behavioral arousal and perceptual responsiveness and suggest that developmental limitations on prenatal sensory stimulation play an important role in the emergence of species-typical behavior.     

Early visual experience affects postnatal auditory responsiveness in bobwhite quail (Colinus virginianus)

Results from 6 experiments suggest perinatal visual experience interferes with postnatal auditory responsiveness in bobwhite quail (Colinus virginianus). Light- or dark-reared control chicks responded similarly to bobwhite maternal Calls A or B following hatching. Light-reared chicks that experienced 10 min/hr of Call A or B from hatching until testing preferred the familiar call at Days 2-4, but dark-reared chicks preferred the familiar call at all ages. Increased amounts of exposure to maternal calls during postnatal Days 1-2 led to auditory responsiveness deficits in light-reared chicks. Similarly, embryos exposed to 10 min/hr of prenatal visual cues required 48 hr of postnatal Call A or B exposure to demonstrate auditory discrimination. These findings highlight the linkages between developing auditory and visual systems during infancy.     

Modification of prenatal auditory experience alters postnatal auditory preferences of bobwhite quail chicks.

This study assessed the effects of altered prenatal auditory experience on bobwhite quail chicks' (Colinus virginianus) species-specific preference for the bobwhite maternal call. Results revealed that when the repetition rate of the embryonic vocalizations normally present in the prenatal environment was altered, the species-typical auditory preference of hatchlings for the maternal call was also altered. Specifically, embryos exposed to embryonic vocalizations with a faster repetition rate than normal subsequently preferred a bobwhite maternal call with a faster repetition rate over one with its normal repetition rate. Bobwhite embryos thus appear able to abstract features of their prenatal auditory environment to other auditory events in the postnatal period. This demonstration of prenatal perceptual learning is in keeping with other recent studies from behavioural embryology, which have also demonstrated that prenatal perceptual experience can influence later responses to species-typical stimulation.     

Amount of prenatal visual stimulation alters incubation times and postnatal preferences in leopard geckos (Eublepharis macularius)

The authors exposed gecko (Eublepharis macularius) embryos to patterned visual stimulation beginning at either 1 week or 2 weeks prior to hatching. Embryos exposed to the substantially augmented amount of prenatal visual stimulation hatched significantly earlier than the embryos either exposed to the moderately augmented prenatal visual stimulation or not exposed to any prenatal visual stimulation (p < .01). Hatchling mass was not affected. Embryos exposed to substantially augmented visual stimulation demonstrated a postnatal preference for patterned light in a simultaneous choice test at 24 hr of age (p < .01). Control embryos demonstrated a preference for normal light conditions (p < .01), whereas experimental embryos exposed to lesser amounts of prenatal visual stimulation did not show a preference for either stimulus. At 1 week of age, geckos in all conditions failed to exhibit a preference for either stimulus.     

Modification of prenatal auditory experience alters postnatal auditory preferences of bobwhite quail chicks

This study assessed the effects of altered prenatal auditory experience on bobwhite quail chicks' (Colinus virginianus) species-specific preference for the bobwhite maternal call. Results revealed that when the repetition rate of the embryonic vocalizations normally present in the prenatal environment was altered, the species-typical auditory preference of hatchlings for the maternal call was also altered. Specifically, embryos exposed to embryonic vocalizations with a faster repetition rate than normal subsequently preferred a bobwhite maternal call with a faster repetition rate over one with its normal repetition rate. Bobwhite embryos thus appear able to abstract features of their prenatal auditory environment to other auditory events in the postnatal period. This demonstration of prenatal perceptual learning is in keeping with other recent studies from behavioural embryology, which have also demonstrated that prenatal perceptual experience can influence later responses to species-typical stimulation.     

Species-specific auditory preference of bobwhite quail chicks (Colinus virginianus) is altered by social interaction with siblings

This study examined whether reinstating specific aspects of the normally occurring postnatal setting (ongoing social interaction with siblings during rearing and/or testing) would influence bobwhite quail chicks' attraction to their species-typical maternal call. Results revealed that incubator-reared chicks exhibit a strong preference for the species-typical bobwhite maternal call over a group of same-aged siblings in simultaneous choice tests at 24 hr and 48 hr after hatching, but only if the birds are kept in relative social isolation. No preference for the maternal call was found at 24 hr or at 48 hr if chicks were reared in a group of same-aged chicks from hatching and tested to the maternal call vs. siblings or the maternal call paired with a live adult bobwhite hen vs. siblings. These results raise doubts about the appropriateness of the usual methods of isolation rearing in the study of species-typical perceptual preferences and underscore the importance of considering features of the natural social context in the analysis of early perceptual and social behavior.     

Intersensory redundancy educates selective attention in bobwhite quail embryos

We assessed whether exposure to amodal properties in bimodal stimulation (e.g. rhythm, rate, duration) could educate attention to amodal properties in subsequent unimodal stimulation during prenatal development. Bobwhite quail embryos were exposed to an individual bobwhite maternal call under several experimental and control conditions during the day prior to hatching. Experimental groups received redundant auditory and visual exposure to the temporal features of an individual maternal call followed by unimodal auditory exposure to the same call immediately or after a 2-hr or 4-hr delay. Control groups received (1) the same exposure but in the reverse sequence (unimodal --> redundant bimodal), (2) asynchronous bimodal --> unimodal, (3) only unimodal exposure, or (4) only bimodal exposure. All experimental groups showed a significant preference for the familiar maternal call over a novel maternal call when tested 2 days after hatching, whereas none of the control groups showed a significant preference for the familiar call. These results indicate that intersensory redundancy can direct attention to amodal properties in bimodal stimulation and educate attention to the same amodal properties in subsequent unimodal stimulation where no intersensory redundancy is available.     

Intersensory redundancy facilitates prenatal perceptual learning in bobwhite quail (Colinus virginianus) embryos.

Information presented redundantly and in temporal synchrony across sensory modalities (intersensory redundancy) selectively recruits attention and facilitates perceptual learning in human infants. This comparative study examined whether intersensory redundancy also facilitates perceptual learning prenatally. The authors assessed quail (Colinus virginianus) embryos' ability to learn a maternal call when it was (a) unimodal, (b) concurrent but asynchronous with patterned light, or (c) redundant and synchronous with patterned light. Chicks' preference for the familiar over a novel maternal call was assessed 24 hr following hatching. Chicks receiving redundant, synchronous stimulation as embryos learned the call 4 times faster than those who received unimodal exposure. Chicks who received asynchronous bimodal stimulation showed no evidence of learning. These results provide the first evidence that embryos are sensitive to redundant, bimodal information and that it can facilitate learning during the prenatal period.     

Development of species identification in ducklings: III. Maturational rectification of perceptual deficit caused by auditory deprivation.

Mute ducklings, devocalized as embryos and maintained in auditory isolation, manifest a selective high-frequency perceptual deficit vis-à-vis the maternal call of their species at 24 hr after hatching. Since it takes a rather specific auditory experiential input to rectify this high-frequency insensitivity at 24 hr, it was predicted that, in the absence of auditory experience, devocal-isolated ducklings would fail to show sufficient endogenously mediated improvement to bring them up to the level of perceptual competence of vocal-communal ducklings at any age. This hypothesis proved wrong in that the proportion of devocalized ducklings showing a preference for the normal maternal call over the greater than 825-Hz attenuated one became equivalent to the vocal ducklings at 48 hr after hatching, as did their ability to discriminate the normal maternal call from greater than 1,800-Hz attenuated maternal call. At 65 hr, however, the devocalized ducklings' performance deteriorated back to the level observed at 24 hr. Embryonic exposure to the (sibling) contact-contentment call prevents the perceptual deficit at 24 hr and the deterioration at 65 hr.     

0 + 1 > 1: How adding noninformative sound improves performance on a visual task

It is well known that the nervous system combines information from different cues within and across sensory modalities to improve performance on perceptual tasks. In this article, we present results showing that in a visual motion-detection task, concurrent auditory motion stimuli improve accuracy even when they do not provide any useful information for the task. When participants judged which of two stimulus intervals contained visual coherent motion, the addition of identical moving sounds to both intervals improved accuracy. However, this enhancement occurred only with sounds that moved in the same direction as the visual motion. Therefore, it appears that the observed benefit of auditory stimulation is due to auditory-visual interactions at a sensory level. Thus, auditory and visual motion-processing pathways interact at a sensory-representation level in addition to the level at which perceptual estimates are combined.     

The Effects of Prenatal Alcohol Exposure on Behavior: Rodent and Primate Studies

The use of alcohol by women during pregnancy is a continuing problem. In this review the behavioral effects of prenatal alcohol from animal models are described and related to studies of children and adults with FASD. Studies with monkeys and rodents show that prenatal alcohol exposure adversely affects neonatal orienting, attention and motor maturity, as well as activity level, executive function, response inhibition, and sensory processing later in life. The primate moderate dose behavioral findings fill an important gap between human correlational data and rodent mechanistic research. These animal findings are directly translatable to human findings. Moreover, primate studies that manipulated prenatal alcohol exposure and prenatal stress independently show that prenatal stress exacerbates prenatal alcohol-induced behavioral impairments, underscoring the need to consider stress-induced effects in fetal alcohol research. Studies in rodents and primates show long-term effects of prenatal and developmental alcohol exposure on dopamine system functioning, which could underpin the behavioral effects.     

Development of species identification in ducklings: II. Experimental prevention of perceptual deficit caused by embryonic auditory deprivation.

Devocalized-isolated ducklings are relatively insensitive to the higher frequencies in their species' maternal call 24 hr after hatching. To assess the efficacy of various sounds in preventing this high-frequency perceptual deficit, devocalized-isolated embryos were exposed to one of three calls and tested with normal versus high-frequency attenuated maternal calls 24 hr after hatching. The embryonic vocalization (contact-contentment call) that most closely matched the region of the devocalized ducklings' greatest insensitivity (1,500-2,500 Hz) proved most efficacious in remedying (preventing) the high-frequency perceptual deficit. Exposure to the embryonic alarm-distress call was somewhat effective, whereas exposure to low-frequency white noise was not effective at all. This finding suggests that the normal development of innate behavior is partially dependent upon prior experience as well as upon intrinsic processes of neural maturation. Although normally occurring embryonic auditory experience does not induce the preference for the maternal call in this species, such experience does contribute to the sharpness of the discriminative basis of the preference 24 hr after hatching.     

Prenatal experience and postnatal perceptual preferences: evidence for attentional-bias in bobwhite quail embryos (Colinus virginianus)

Previous studies have indicated that concurrent multimodal sensory stimulation can interfere with prenatal perceptual learning. This study further examined this issue by exposing 3 groups of bobwhite quail embryos (Colinus virginianus) to (a) no supplemental stimulation, (b) a bobwhite maternal call, or (c) a maternal call paired with a pulsating light in the period prior to hatching. Experiments differed in terms of the types of stimuli presented during postnatal preference tests. Embryos receiving no supplemental stimulation showed no preference between stimulus events in all testing conditions. Embryos receiving exposure to the unimodal maternal call preferred the familiar call over an unfamiliar call regardless of the presence or absence of pulsating light during testing. Embryos exposed to the call-light compound preferred the familiar call only when it was paired with the light during testing. These results suggest that concurrent multimodal stimulation does not interfere with prenatal perceptual learning by overwhelming the young organism's limited attentional capacities. Rather, multimodal stimulation biases what information is attended to during exposure and subsequent testing.     

Intermodal enhancement of stimulus localisation in infants born prematurely

The interaction of auditory and visual modalities in the enhancement of orientation was examined in premature and near-term infants by presenting them auditory or visual stimuli or auditory-visual stimulus combinations at various positions in sensory space. In 4.5--15-mo-olds, brisk orienting responses could be elicited to very peripheral stimulus positions but only when the stimulus consisted of a spatially coherent auditory-visual combination (i.e., where a sound and a light occurred at the same point in space). This occurred for all infants, irrespective of age or gestational age at birth. First, the result shows that infants can respond to visual stimuli at eccentric positions, beyond the supposed limits of their effective visual fields as measured by standard perimetry. Second, the result extends earlier studies showing that intersensory integration and stimulus localisation develop relatively normally in prematurely born infants. The auditory-visual enhancement test as used here may have a number of further uses and applications in the clinic and laboratory.     

情绪和时间辨别任务中视听整合与预先准备效应

本研究分别在时间和情绪认知维度上考察预先准备效应对情绪视听整合的影响。时间辨别任务(实验1)发现视觉引导显著慢于听觉引导,并且整合效应量为负值。情绪辨别任务(实验2)发现整合效应量为正值;在负性情绪整合中,听觉引导显著大于视觉引导;在正性情绪整合中,视觉引导显著大于听觉引导。研究表明,情绪视听整合基于情绪认知加工,而时间辨别会抑制整合;此外,跨通道预先准备效应和情绪预先准备效应都与引导通道有关。     

The strong connection between sensory and cognitive performance in old age: not due to sensory acuity reductions operating during cognitive assessment

Cognitive aging research has documented a strong increase in the covariation between sensory and cognitive functioning with advancing age. In part, this finding may reflect sensory acuity reductions operating during cognitive assessment. To examine this possibility, the authors administered cognitive tasks used in prior studies (e.g., Lindenberger & Baltes, 1994) to middle-aged adults under age-simulation conditions of reduced visual acuity, auditory acuity, or both. Visual acuity was lowered through partial occlusion filters, and auditory acuity through headphone-shaped noise protectors. Acuity manipulations reduced visual acuity and auditory acuity in the speech range to values reaching or approximating old-age acuity levels, respectively, but did not lower cognitive performance relative to control conditions. Results speak against assessment-related sensory acuity accounts of the age-related increase in the connection between sensory and cognitive functioning and underscore the need to explore alternative explanations, including a focus on general aspects of brain aging.     

Learning to utilize information presented over two sensory channels

In three separate experiments, Ss were provided with auditory, visual, or simultaneous auditory and visual information in a classification task. Difficulty of classification was manipulated by varying the stimulus exposure duration. Consistent bisensory facilitation effects were noted for later trials, with interference evident on earlier trials. Exposure duration influenced rate and not amount of learning, with bisensory performance being most affected by duration. A transfer paradigm was used in Experiment III, and little if any transfer was noted between unisensory and bisensory stimulus conditions. It was concluded that Ss were extracting the most salient bisensory stimulus components from the auditory and visual modes of information into a unidimensional information configuration.     

Multisensory-mediated auditory localization

Multisensory integration is a powerful mechanism for maximizing sensitivity to sensory events. We examined its effects on auditory localization in healthy human subjects. The specific objective was to test whether the relative intensity and location of a seemingly irrelevant visual stimulus would influence auditory localization in accordance with the inverse effectiveness and spatial rules of multisensory integration that have been developed from neurophysiological studies with animals [Stein and Meredith, 1993 The Merging of the Senses (Cambridge, MA: MIT Press)]. Subjects were asked to localize a sound in one condition in which a neutral visual stimulus was either above threshold (supra-threshold) or at threshold. In both cases the spatial disparity of the visual and auditory stimuli was systematically varied. The results reveal that stimulus salience is a critical factor in determining the effect of a neutral visual cue on auditory localization. Visual bias and, hence, perceptual translocation of the auditory stimulus appeared when the visual stimulus was supra-threshold, regardless of its location. However, this was not the case when the visual stimulus was at threshold. In this case, the influence of the visual cue was apparent only when the two cues were spatially coincident and resulted in an enhancement of stimulus localization. These data suggest that the brain uses multiple strategies to integrate multisensory information.     

Nicotinic acetylcholine receptors in sensory cortex

Acetylcholine release in sensory neocortex contributes to higher-order sensory function, in part by activating nicotinic acetylcholine receptors (nAChRs). Molecular studies have revealed a bewildering array of nAChR subtypes and cellular actions; however, there is some consensus emerging about the major nAChR subtypes and their functions in sensory cortex. This review first describes the systems-level effects of activating nAChRs in visual, somatosensory, and auditory cortex, and then describes, as far as possible, the underlying cellular and synaptic mechanisms. A related goal is to examine if sensory cortex can be considered a model system for cortex in general, because the use of sensory stimuli to activate neural circuits physiologically is helpful for understanding mechanisms of systems-level function and plasticity. A final goal is to highlight the emerging role of nAChRs in developing sensory cortex, and the adverse impact of early nicotine exposure on subsequent sensory-cognitive function.     

Georg von Békésy: visualization of hearing

Georg von Békésy received the Nobel Prize in 1961 for his research on the functioning of the auditory system. In psychoacoustics, Békésy both extended and perfected the lines of research begun by von Helmholtz in the 19th century. First in his native Hungary and later at Harvard, Békésy used novel and imaginative devices and methods to observe and model the functioning of the inner ear. He also explored the nature of sensory inhibition by which the nervous system sharpens sensory transitions.