Stimulation In Early Life Research Articles

Effectiveness of citicoline in pediatric patients with refractive amblyopia in Surabaya, East Java, Indonesia

Amblyopia is a decrease of visual acuity that cannot be attributed to any structural abnormality of the eye or visual system, causing a partial or complete loss of vision due to inadequate stimulation in early life. Citicoline has been reported to improve visual acuity in amblyopic eyes as adjuvant treatment. This study was aimed to determine the effectiveness of citicoline in pediatric patients with refractive amblyopia in ophthalmology daily practices. This was a retrospective-descriptive study with a time limited sampling method. This study was conducted at Surabaya Eye Clinic, East Java, Indonesia, by reviewing medical records for the period of January 2018 to December 2019. A total of 34 eyes were included in the study with the majority aged five years (41.2%) and six years (35.3%). The severity of amblyopia varied among patients, 21 eyes (61.76%) had mild amblyopia, seven eyes (20.59%) had moderate amblyopia, and two eyes (5.88%) had severe amblyopia. The duration of given therapy also varied, 18 eyes (52.94%) were given 3 months therapy, two eyes were given 4months therapy, 12 eyes were given 6 months therapy, and two eyes were given 8months therapy. Citicoline was found effective in mild and moderate amblyopia and for the duration of 3 and 6 months (p<0.05). In others group who did not showed statistically significant improvement was due to inadequate samples but clinically significant improvement was noted. Citicoline therapy resulted in a clinically and statistically improvement in refractive amblyopia patients.

Parent-child interaction and stimulation in early life can be related to caries in primary dentition? Hypotheses from a life-course approach

Dental caries has common risk factors with impairments in growth, cognitive development and child general health. Identifying socioeconomic contexts and parental behaviors in early life that may be associated with negative outcomes in the child’s future and their causal mechanisms can contribute to planning early interventions. Therefore, the aim of this paper is to propose and discuss possible ways to explain how early childhood stimulation may be associated with future oral health status, based on the life-course theory of chain-of-risk model and accumulation of risk model. Two hypotheses were suggested: (1) each social exposure or parental behavior in the child’s first years of life increase the risk of chronic diseases, such as dental caries in primary dentition, in a simply additive effect; (2) parental factors could negatively influence the establishment of the pattern of child stimulation (child care) or lead to a modification of the established behavior on the risk of dental caries in the child primary dentition. Prevention of dental caries seems to be the most feasible way of solving this serious public health problem. It therefore justifies the importance of identifying exposures in the child’s early life that may lead to the occurrence of chronic diseases in the future. The evidence seem to converge to the idea that child stimulation in early life may be associated with future health problems related to behaviors and care by parents, including caries.

Excessive Sensory Stimulation during Development Alters Neural Plasticity and Vulnerability to Cocaine in Mice.

Early life experiences affect the formation of neuronal networks, which can have a profound impact on brain function and behavior later in life. Previous work has shown that mice exposed to excessive sensory stimulation during development are hyperactive and novelty seeking, and display impaired cognition compared with controls. In this study, we addressed the issue of whether excessive sensory stimulation during development could alter behaviors related to addiction and underlying circuitry in CD-1 mice. We found that the reinforcing properties of cocaine were significantly enhanced in mice exposed to excessive sensory stimulation. Moreover, although these mice displayed hyperactivity that became more pronounced over time, they showed impaired persistence of cocaine-induced locomotor sensitization. These behavioral effects were associated with alterations in glutamatergic transmission in the nucleus accumbens and amygdala. Together, these findings suggest that excessive sensory stimulation in early life significantly alters drug reward and the neural circuits that regulate addiction and attention deficit hyperactivity. These observations highlight the consequences of early life experiences and may have important implications for children growing up in today’s complex technological environment.

FUT2: filling the gap between genes and environment in Behçet's disease?

To identify new susceptibility loci for Behçet's disease (BD), we performed a genome-wide association study (GWAS) using DNA pooling. Two replicate pools of 292 Iranian BD cases and of 294 age- and sex-matched controls were allelotyped in quadruplicate on the Affymetrix Genome-Wide Human SNP Array 6.0. Of the 51 top markers, 47 were technically validated through individually genotyping. Replication of validated single nucleotide polymorphisms (SNPs) was performed in an independent Iranian dataset (684 cases and 532 controls). In addition to the well-established HLA-B locus, rs7528842 in a gene desert on chromosome 1p21.2, and rs632111 at the 3'UTR of FUT2 were associated in both the discovery and replication datasets (individually and in combination). However, only the FUT2 SNP was associated in a previous GWAS for BD in Turkish people. Fine-mapping of FUT2 in the full Iranian dataset showed additional associations in five coding SNPs (2.97E-06<pcombined<1.34E-04), including the rs601338 nonsense (W143X) variant which, in Caucasians, determines the secretion of the H antigen (precursor of the ABO blood group antigens) in body fluids and on the intestinal mucosa. Meta-analysis with the published Turkish GWAS data strengthened the FUT2 associations (4.78E-09<pmeta<1.66E-07). This study suggests for the first time a putative link between a specific gene and environment in the aetiopathogenesis of BD. The non-secretor phenotype affects mucosal glycosylation, which may explain its known association with dysbiosis and altered susceptibility to infections. A different antigenic stimulation in early life and consequent increased propensity for autoimmunity and inflammation may contribute to BD development.

Neonatal tactile stimulation alleviates the negative effects of neonatal isolation on novel object recognition, sociability and neuroendocrine levels in male adult mandarin voles (Microtus mandarinus)

Neonatal isolation results in long-lasting negative alterations to the brain and behavior. Some of these changes include effects on non-spatial learning and memory, sociability and neuroendocrine levels. Theoretically, neonatal tactile stimulation should reverse the impacts of neonatal isolation; however, this remains unknown for changes relating to learning, memory, sociability and hormones in social animals. Using socially monogamous mandarin voles (Microtus mandarinus), the long-lasting effects of these early manipulations on anxiety-like behavior, novel object recognition, sociability, and neuroendocrine levels were investigated. Compared with neonatal-isolated males, males subjected to the same manipulation but accompanied with tactile stimulation had heavier body weights across PND4-18 and displayed significantly less anxiety-like behavior in an open field test. In addition, tactile stimulation increased the preference index for novel object recognition reduced by neonatal isolation. Compared with control males, neonatal-isolated males engaged in less body contact with unfamiliar same-sex individuals and this effect was reversed by neonatal tactile stimulation. Tactile stimulation enhanced aggressive behavior in neonatal-isolated males and increased the levels of AVP and OT in the paraventricular nucleus (PVN) which were decreased by neonatal isolation. This early manipulation also reduced serum CORT levels that were significantly up-regulated by neonatal isolation in both neonatal and adult offspring. These results indicate that adequate tactile stimulation in early life plays an important role in the prevention of behavioral disturbances induced by neonatal isolation, possibly through the alteration of central OT, AVP and the serum corticosterone levels.

La estimulación neonatal por un ambiente nuevo mejora la producción de huevos en gallinas ponedoras

El desarrollo de las respuestas comportamentales y endocrinas al estrés agudo está fuertemente influenciado por el entorno postnatal temprano. Estos efectos ambientales &#x0D; persisten a lo largo de la vida, generando diferencias individuales estables en la temerosidad. &#x0D; La estimulación temprana, como la exposición a un ambiente nuevo, disminuye la reactividad comportamental. También se demostró en investigaciones previas que una estimulación &#x0D; temprana en la vida, tal como una exposición neonatal al ambiente nuevo, redujo la reactividad comportamental. El objetivo de este estudio fue evaluar si una estimulación temprana aumenta la producción de huevos en gallinas adultas. Pollitos de gallinas ponedoras de un día de edad se expusieron a un laberinto en T (método A) o una prueba basada en la latencia para picotear un objeto (método B), posteriormente se trasladaron a una granja avícola hasta &#x0D; la edad adulta. Se designó a un grupo de gallinas como control, las cuales no se estimularon por ninguno de los métodos anteriormente nombrados. Durante 25 semanas se registró la postura semanal de huevos, el peso individual de los huevos y el consumo de alimento semanal en las gallinas ponedoras criadas bajo condiciones de granja. Se observó un aumento en el número de huevos en las gallinas estimuladas por el método A (5,22 ± 0,06, p &lt; 0,01) y por el método B (5,33 ± 0,08, p &lt; 0,001) comparadas a los controles no estimulados (4,78 ± 0,24). &#x0D; Del mismo modo, el índice de conversión alimenticia también fue mayor para las gallinas estimuladas por el método A (0,356 ± 0,042, p &lt; 0,05) y el método B (0,363 ± 0,053, p &lt; 0,01) respecto al grupo control (0,330 ± 0,085). Estos resultados indican que la estimulación temprana puede ayudar a mejorar la adaptación de gallinas ponedoras a las condiciones de cría intensiva en las granjas avícolas industriales.&#x0D; Palabras clave: pollito, estimulación temprana, producción de huevos, gallinas ponedoras, estrés.

Dissociation between neonatal novelty-induced preferential maternal care and enhancement in cognitive, social, and emotional functions

Early life stimulation is known to produce long-lasting changes in the brain and behavior. One such early stimulation method is the neonatal novelty exposure procedure which allows the isolation of the novelty effect from several prominent confounding factors inherent to the neonatal handling procedure. In two previous studies, we found long-lasting novelty effects on different sets of functional measures without accompanying preferential maternal care, even when the observation was made immediately after the novelty manipulation, a time when such preferential care is most likely to be expressed. Here, within a single cohort of Long-Evans male rats, we demonstrate that novelty exposure leads to enhancements across several functional domains, including increased disinhibition to novelty, enhanced spatial and social memory, and reduced aggression, again without the accompaniment of preferential maternal care. These findings extend novelty exposure effects to aggression and replicate previously known novelty exposure effects on spatial and social memory with extension to new developmental stages. Most importantly, these findings do not support the hypothesis that preferential maternal care towards novelty-exposed pups mediates the observed novelty effects. We discuss the possibility that the effects of neonatal novelty exposure are mediated via repeated activation of the hypothalamic–pituitary–adrenal (HPA) axis that serves to inoculate pups for future exposures to novelty and novelty-induced HPA activation and that maternal influence is likely to be expressed via its modulatory role—the mother sets the individual-family specific behavioral and hormonal context to allow the same early life experience to have a family-specific effect.

Environmental factors associated with childhood-onset type 1 diabetes mellitus: an exploration of the hygiene and overload hypotheses.

To assess the relationship between selected maternal and infant characteristics and risk of type 1 diabetes mellitus, specifically characteristics identified from birth records that may pertain to the hygiene or overload hypotheses. Population-based case-control study. Washington State from 1987 to 2005. All children younger than 19 years hospitalized for type 1 diabetes (International Classification of Diseases, Ninth Revision codes 250.x1 and 250.x3) identified (n=1852) from hospital discharge data and linked with their birth certificates. Controls (n=7408) were randomly selected from birth records, frequency matched on year of birth. Maternal factors included age, race, educational attainment, marital status, use of Medicaid insurance, body mass index, prepregnancy weight, prior births, timing and adequacy of prenatal care, and cesarean delivery. Infant factors included birth weight, size for gestational age, and gestational age. The main outcome was first hospitalization for type 1 diabetes mellitus; adjusted odds ratios were estimated for the association of selected maternal and infant characteristics with type 1 diabetes. Consistent with the hygiene hypothesis, type 1 diabetes was negatively associated with having older siblings (for >or=3 siblings, odds ratio [OR], 0.56; 95% confidence interval [CI], 0.45-0.70) and with indicators of lower economic status or care access, such as an unmarried mother (OR, 0.79; 95% CI, 0.69-0.91), inadequate prenatal care (OR, 0.53; 95% CI, 0.40-0.71), or Medicaid insurance (OR, 0.67; 95% CI, 0.58-0.77). Related to the overload hypothesis, maternal body mass index of 30 or higher (OR, 1.29; 95% CI, 1.01-1.64) was associated with increased risk of diabetes. Environmental factors related to decreased antigenic stimulation in early life and maternal obesity may be associated with type 1 diabetes.

Characterization of the behavioural dose-response of NMDA in 3xTg-AD mice at different stages of the disease and its modulation by early-life stimulation

Characterization of the behavioural dose-response of NMDA in 3xTg-AD mice at different stages of the disease and its modulation by early-life stimulation

Neonatal tactile stimulation reverses the effect of neonatal isolation on open-field and anxiety-like behavior, and pain sensitivity in male and female adult Sprague–Dawley rats

It is well known that early life events induce long-lasting psychophysiological and psychobiological influences in later life. In rodent studies, environmental enrichment after weaning prevents the adulthood behavioral and emotional disturbances in response to early adversities. We compared the behavioral effect of neonatal isolation (NI) with the effect of NI accompanied by tactile stimulation (NTS) to determine whether NTS could reverse or prevent the effects of NI on the adulthood behavioral and emotional responses to environmental stimuli. In addition, we also examined the sex difference of the NTS effect. Measurements of body weights, an open-field locomotor test, an elevated plus maze test, a hot-plate test, and a contextual fear-conditioning test were performed on postnatal day 60. As compared with rats subjected to NI, rats subjected to NTS showed significantly higher activity and exploration in the open-field locomotor test, lower anxiety-like behavior in the elevated plus maze test, and significantly prolonged latencies in the hot-plate test, and this effect was equal among males and females. In the contextual fear-conditioning test, whereas NTS significantly reduced the enhanced freezing time due to NI in females, no significant difference in the freezing time between NI and NTS was found in males. These findings indicate that adequate tactile stimulation in early life plays an important role in the prevention of disturbances in the behavioral and emotional responses to environmental stimuli in adulthood induced by early adverse experiences.

Neonatal handling increases fear and aggression in lactating rats

Neonatal handling reduces fear in male and cycling female rats, but increases maternal aggressive behavior against intruders to the nest area. Present study aimed to analyze the effects of neonatal handling on the maternal aggressive behavior and the activity in the open field with a predator of lactating rats on the 8th and the 18th postpartum days (periods of high and low aggressiveness). As pups, animals were divided into two groups: nonhandled (no neonatal manipulation) and handled (handling for 1 min during the first 10 days after delivery). As adults, females of both groups were impregnated and tested against a male intruder for aggressive behavior and in the open field with a cat inside a wire-meshed cage. Results showed that on the 8th day frequency of aggressive behaviors of handled females was higher than that of the nonhandled ones, but on the 18th day, no significant difference was detected. Surprisingly, in the open field test, handled females showed decreased locomotion and increased freezing on the 8th day compared to the nonhandled ones. The opposite relationship between increased aggressiveness with reduced fear is observed in the nonhandled control females in early and late lactation periods. However, neonatal handling abolishes this relationship. Apparently, the increased aggressiveness in neonatal handled lactating females does not depend on a decrease in fear. Our findings support the hypothesis that long lasting effects of early life stimulation is a dynamic function depending on the behavioral system and the period of life analyzed. Moreover, they caution the relationship between aggressive behavior and fear.

Developmentally stable sex-dependent modulation of turning asymmetry by neonatal novelty exposure

In rats, early life stimulation can enhance learning and memory and induce parallel changes in brain asymmetry. Despite persistent interest in human brain asymmetry, relatively little is known in animal models about developmental stability of early-experience effects on asymmetry and how early-experience may affect males and females differently in asymmetry measures across developmental stages. We exposed male and female neonatal rats to a novel cage for 3 min per day during the first 3 weeks of life and measured spontaneous turning behavior at juvenility (7 weeks of age) and adulthood (7 months of age). We found that (1) the effects of such neonatal novelty exposure on turning bias are developmentally stable, and (2) neonatal novelty exposure differentially modulates turning bias in males and females. We briefly discuss implications of these findings in terms of the role of brain asymmetry in modulating cognitive and emotional development.

Effects of neonatal handling on the behavior and prolactin stress response in male and female rats at various ages and estrous cycle phases of females

Neonatal handling induces behavioral and hormonal changes, characterized by reduced fear in novel environments, and lesser elevation and faster return to basal levels of plasma corticosterone, prolactin and adrenaline, in response to stressors in adulthood. The present study aimed to analyze the effects of neonatal handling from Days 1 to 10 postnatal on prolactin response to ether stress in male and female rats at three life periods: neonatal, peripubertal and adulthood. Moreover, adult females were tested in two different phases of the estrous cycle, i.e., diestrus and estrus. In another set of experiments, the behavior of peripubertal and adult males and females in estrus and diestrus was analyzed in the elevated plus maze test. Pups were either handled for 1 min (handled group) or left undisturbed (nonhandled group) during the first 10 days after delivery. In adults, in the handled females in diestrus, stress induced a lesser increase in plasma prolactin compared with nonhandled ones, as in males. However, in estrus, handled females showed no difference in the prolactin response to stress. In the elevated plus maze, handled females in diestrus, but not in estrus, showed higher locomotor activity compared with nonhandled ones. Peripubertal male and female rats handled during the neonatal period showed no difference in behavior in the elevated plus maze compared with nonhandled animals. Early-life stimulation can induce long-lasting behavioral and stress-related hormonal changes, but they are not stable throughout life and phases of the estrous cycle.

Modification of Social Memory, Hypothalamic-Pituitary-Adrenal Axis, and Brain Asymmetry by Neonatal Novelty Exposure

Although corticosterone (a stress hormone) is known to influence social behavior and memory processes, little has been explored concerning its modulatory role in social recognition. In rats, social recognition memory for conspecifics typically lasts <2 hr when evaluated using a habituation paradigm. Using neonatal novelty exposure, a brief and transient early life stimulation method known to produce long-lasting changes in the hypothalamic-pituitary-adrenal axis, we found that social recognition memory was prolonged to at least 24 hr during adulthood. This prolonged social memory was paralleled by a reduction in the basal blood concentration of corticosterone. The same neonatal stimulation also resulted in a functional asymmetry expressed as a greater right-turn preference in a novel environment. Rats that preferred to turn right showed better social recognition memory. These inter-related changes in basal blood corticosterone concentration, turning asymmetry, and social recognition memory suggest that stress hormones and brain asymmetry are likely candidates for modulating social memory. Furthermore, given that neonatal stimulation has been shown to improve learning and memory performance primarily under aversive learning situations, the neonatal novelty exposure-induced enhancement in social recognition broadens the impact of early life stimulation to include the social domain.

Neonatal novelty exposure modulates hippocampal volumetric asymmetry in the rat.

Early life environmental manipulations have been shown to affect hippocampal-dependent learning, hippocampal volume and cerebral lateralization. In this study, we investigated the effects of neonatal stimulation on hippocampal volumetric asymmetry. Long-Evans hooded rats were exposed to a novel non-home environment 3 min daily for the first 3 weeks of life. Histological measures of the left and right hippocampus were made at 8 months of age. We found that neonatal novelty exposure resulted in a long-lasting change in hippocampal volumetric asymmetry. Specifically, this brief and transient early life stimulation increased the right hippocampal volumetric dominance at mid-adulthood.

Neonatal exposure to a novel environment enhances the effects of corticosterone on neuronal excitability and plasticity in adult hippocampus

Electrophysiological studies have shown that activation of glucocorticoids receptors (GRs) influences neuronal excitability and activity dependent synaptic plasticity. In developmental studies, early life stimulation such as neonatal handling results in an up-regulation of glucocorticoid-receptor (GR) binding in the hippocampus that persists into adulthood. It is, therefore, hypothesized that early environment-induced changes in receptor sensitivity to corticosterone (CORT) might have functional effects on adult neuronal excitability and synaptic plasticity. To test this hypothesis, we exposed rats daily from post-natal days 1–21 to a non-home environment for 3 min. When the animals became adults, we studied the effects of glucocorticoid hormone corticosterone (CORT) on population spike (PS) amplitude and long-term potentiation of population spikes (PS-LTP) in vitro in the hippocampal CA1 region following activation of the Schaffer collateral fibers. Bath application of CORT reduced PS amplitude and subsequent induction of PS-LTP. This inhibitory effect of CORT was significantly greater in the slices from the novelty exposed rats (Novel) than the control rats that remained in their home cage (Home). Inhibition of population spike amplitude during CORT perfusion was 28.0±5.3% of baseline in Novel slices, and 9.1±4.4% in Home slices. CORT pre-exposure (20 min) also inhibited the subsequent induction of PS-LTP in Novel slices by 57.7±17.7% and by 7.5±12.1% in Home slices. These results provide electrophysiological evidence that neonatal novelty exposure results in functional increases in receptor sensitivity to CORT that enhances the inhibitory effects of CORT on field CA1 neuronal excitability and plasticity.

Do early-life events permanently alter behavioral and hormonal responses to stressors?

Early-life stimulation (e.g. brief handling) attenuates the behavioral and neuroendocrine responses to stressors encountered in adulthood, particularly with respect to activation of hypothalamic-pituitary-adrenal (HPA) activity. In contrast, if neonates were subjected to a more severe stressor, such as protracted separation from the dam or exposure to an endotoxin, then the adult response to a stressor was exaggerated. These early-life experiences program HPA functioning, including negative feedback derived from stimulation of hippocampal glucocorticoid receptors, and corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) coexpression in PVN neurons, to modify the response to subsequent stressor experiences. The persistent variations of HPA activity observed in handled/stimulated animals may stem from alterations in dam–pup interactions (e.g. increased arched-back feeding, licking, grooming). In addition genetic makeup is critical in determining stress reactivity. For instance, BALB/cByJ mice are more reactive to stressors than C57BL/6ByJ mice, exhibiting greater HPA hormonal alterations and behavioral disturbances. BALB/cByJ also fail to acquire a spatial learning response in a Morris water-maze paradigm, which has been shown to be correlated with hippocampal cell loss associated with aging. Early-life handling of BALB/cByJ mice prevented these performance deficits and attenuated the hypersecretion of ACTH and corticosterone elicited by stressors. The stressor reactivity may have been related to maternal and genetic factors. When BALB/cByJ mice were raised by a C57BL/6ByJ dam, the excessive stress-elicited HPA activity was reduced, as were the behavioral impairments. However, cross-fostering the more resilient C57BL/6ByJ mice to a BALB/cByJ dam failed to elicit the behavioral disturbances. It is suggested that genetic factors may influence dam–pup interactive styles and may thus proactively influence the response to subsequent stressors among vulnerable animals. In contrast, in relatively hardy animals the early-life manipulations may have less obvious effects.

A factor analysis of the rat's corpus callosum

Previous work from our laboratory (Berrebi et al., Brain Research, 438 (1988) 216–224) demonstrated region-specific sexual dimorphisms in the size of the rat's corpus callosum, which are modifiable by extra stimulation in early life. These differences are assumed to reflect regional corticocortical fibers of passage which are altered differentially by gender and our experimental manipulations. In this paper, we report our findings when the original data are reanalyzed using a newly developed computer program. This program not only reproduced, with very high accuracy, the original means, but also permitted us to examine computer generated callosal width scores via a factor analysis procedure. Such a procedure yields useful information concerning the clustering of callosal fibers and thus contributes significantly to our hypothesis that discrete cortical regions are selectively sensitive to experimental variables. Factor analyses of the callosal variables and brain weight of 155 rats found 7 width factors, and an eighth factor which contained the variables of brain weight, callosal length, and callosal perimeter. Callosal area did not load significantly on any of these factors. The percentile locations of the width factors, starting the anterior (genu) end were: widths 1–5, 6–17, 24–38, 46–57, 62–72, 79–95 and 96–99. Use of these factor scores in analyses of variance revealed that the male callosum is wider than the female's with the differences most pronounced in the genu and the most posterior portion of the splenium. Both age and early handling experience influenced the callosal width factors. The factor analysis as well as other statistical analyses confirmed our prior conclusion that callosal length and perimeter represent one cluster of callosal parameters which are independent of a second cluster centering around the width measures and area.

Handling in infancy, brain laterality and muricide in rats

Rats were handled for the first 20 days of life or were not disturbed. Between 21 and 50 days approximately half of each group was reared in enriched environments while the remainder was group reared in laboratory cages. When adult, four males from each litter received a right neocortical ablation, a left ablation, a sham operation, or no surgery. They were tested for mouse killing between 9–12 months of age. Intact non-handled controls without enrichment experience had a 96% incidence of muricide. Handling and enrichment treatments independently and additively reduced the rate of mouse killing in animals with intact brains. There was no evidence of brain laterality for animals which received no extra stimulation in early life. In contrast, the brains of handled animals were lateralized, with the left lesion group having a higher killing response than the right. Non-lesioned handled rats had approximately the same level of muricide as those with a right hemisphere lesion, leading to the inference that in the intact brain the left hemisphere inhibits the killing response of the right.

Residual vision in humans who have been monocularly deprived of pattern stimulation in early life.

Spatio-temporal sensitivity at and above threshold was investigated in a group of patients who exhibited visual loss secondary to uniocular congenital cataract which was present within the first year of life and later removed. The results fall into two general categories depending upon the severity of the visual loss and in particular upon the nature of the temporal loss. In the group exhibiting less severe amblyopia, contrast sensitivity for high and medium spatial frequencies was attenuated to a similar extent for all temporal frequencies. In the group exhibiting more severe amblyopia no form vision a was present; only temporal perception remained. In these cases a greater loss of flicker threshold sensitivity occurred at higher temporal frequencies. Supra-threshold tests revealed that movement perception was effectively normal in both of these groups. These results demonstrate that stimulus deprivation amblyopia, while different in some respects from anisometropic amblyopia is more similar to that condition than to strabismic amblyopia Previous animal results derived from monocular lid suture in cat and monkey are compared with these findings.