Early Deprivation Research Articles

Histological and immunohistochemical study of the effect of early maternal deprivation on the hippocampus and dentate gyrus of male albino rat offspring at adulthood: The role of vitamin B12 supplementation after weaning

Histological and immunohistochemical study of the effect of early maternal deprivation on the hippocampus and dentate gyrus of male albino rat offspring at adulthood: The role of vitamin B12 supplementation after weaning

Adolescent social isolation induces distinct changes in the medial and lateral OFC-BLA synapse and social and emotional alterations in adult mice.

Early-life social isolation is associated with social and emotional problems in adulthood. However, neural mechanisms underlying how social deprivation impairs social and emotional development are poorly understood. Recently, the orbitofrontal cortex (OFC) and basolateral amygdala (BLA) have been highlighted as key nodes for social and emotional functions. Hence, we hypothesize that early social deprivation disrupts the information processing in the OFC-BLA pathway and leads to social and emotional dysfunction. Here, we examined the effects of adolescent social isolation on the OFC-BLA synaptic transmission by optogenetic and whole-cell patch-clamp methods in adult mice. Adolescent social isolation decreased social preference and increased passive stress-coping behaviour in adulthood. Then, we examined excitatory synaptic transmissions to BLA from medial or lateral subregions of the OFC (mOFC or lOFC). Notably, adolescent social isolation decreased the AMPA/NMDA ratio in the mOFC-BLA synapse in adulthood, while the ratio was increased in the lOFC-BLA synapse. Furthermore, we optogenetically manipulated the mOFC-BLA or lOFC-BLA transmission in behaving mice and examined the effects on social and stress-coping behaviours. Optogenetic manipulation of the mOFC-BLA transmission altered social behaviour without affecting passive stress-coping behaviour, while optogenetic manipulation of the lOFC-BLA transmission altered passive stress-coping behaviour without affecting social behaviour. Our results suggest that adolescent social isolation induces distinct postsynaptic changes in the mOFC-BLA and lOFC-BLA synapses, and these changes may separately contribute to abnormalities in social and emotional development.

Spatial Memory and Blindness: The Role of Visual Loss on the Exploration and Memorization of Spatialized Sounds.

Spatial memory relies on encoding, storing, and retrieval of knowledge about objects’ positions in their surrounding environment. Blind people have to rely on sensory modalities other than vision to memorize items that are spatially displaced, however, to date, very little is known about the influence of early visual deprivation on a person’s ability to remember and process sound locations. To fill this gap, we tested sighted and congenitally blind adults and adolescents in an audio-spatial memory task inspired by the classical card game “Memory.” In this research, subjects (blind, n = 12; sighted, n = 12) had to find pairs among sounds (i.e., animal calls) displaced on an audio-tactile device composed of loudspeakers covered by tactile sensors. To accomplish this task, participants had to remember the spatialized sounds’ position and develop a proper mental spatial representation of their locations. The test was divided into two experimental conditions of increasing difficulty dependent on the number of sounds to be remembered (8 vs. 24). Results showed that sighted participants outperformed blind participants in both conditions. Findings were discussed considering the crucial role of visual experience in properly manipulating auditory spatial representations, particularly in relation to the ability to explore complex acoustic configurations.

Perks of blindness: Enhanced verbal memory span in blind over sighted adults

Blind individuals commonly use verbal encoding (i.e. text-to-speech) and memory-based strategies (i.e. serial recall) for situations in which sighted individuals use vision (i.e. finding items). These strategies may serve to train cognitive systems responsible for maintaining and manipulating verbal information. To test this hypothesis, we investigate whether early visual deprivation is linked to improved verbal short-term and working memory abilities, and thus might illustrate experience-dependent plasticity in memory systems. We also test whether the sensory modality for encoding information influences performance. Our data show that blind adults recalled more items on a verbal short-term memory span task than sighted participants. Furthermore, blind individuals performed equally well on auditory forward and backward conditions despite the fact that recalling items in reverse order is more difficult for the general population. However, the benefits of recalling items in reverse order did not extend to the tactile domain, specifically, a braille version of the short-term memory digit span task in blind individuals. Furthermore, we observed no differences between blind and sighted individuals on a more demanding auditory n-back task evaluating more complex working memory processes. We conclude that the memory benefits associated with blindness might be restricted to auditory-verbal short-term memory and likely reflect strategy use and practice.

Development of Visual Memory Capacity Following Early-Onset and Extended Blindness

It is unknown whether visual memory capacity can develop if onset of pattern vision is delayed for several years following birth. We had an opportunity to address this question through our work with an unusual population of 12 congenitally blind individuals ranging in age from 8 to 22 years. After providing them with sight surgery, we longitudinally evaluated their visual memory capacity using an image-memorization task. Our findings revealed poor visual memory capacity soon after surgery but significant improvement in subsequent months. Although there may be limits to this improvement, performance 1 year after surgery was found to be comparable with that of control participants with matched visual acuity. These findings provide evidence for plasticity of visual memory mechanisms into late childhood but do not rule out vulnerability to early deprivation. Our computational simulations suggest that a potential mechanism to account for changes in memory performance may be progressive representational elaboration in image encoding.

Grey Matter Hypertrophy and Atrophy in Early-Blind Adolescents: A Surface-Based Morphometric Study.

Objective This study is aimed at exploring the regional changes in brain cortical morphology (thickness, volume, and surface area) in the early-blind adolescents (EBAs) by using the surface-based morphometric (SBM) method. Methods High-resolution structural T1-weighted images (T1WI) of 23 early-blind adolescents (EBAs) and 21 age- and gender-matched normal-sighted controls (NSCs) were acquired. Structural indices, including cortical thickness (CT), cortical volume (CV), and surface area (SA), were analyzed by using FreeSurfer software, and the correlations between structural indices and the blindness duration were computed by Pearson correlation analysis. Results Compared to controls, EBAs had significantly reduced CV and SA mainly in the primary visual cortex (V1) and decreased CV in the left vision-related cortices (r-MFC). There were no regions that EBAs had a significantly larger CV or SA than NSCs. EBAs had significantly increased CT in the V1 and strongly involved the visual cortex (right lateral occipital gyrus, LOG.R) and the left superior temporal gyrus (STG.L), while it had decreased CT in the left superior parietal lobule (SPL.L) and the right lingual gyrus (LING.R). Additionally, no correlation was found between cortical morphometric measures and clinical variables in the EBA group. Conclusions SBM is a useful method for detecting human brain structural abnormalities in blindness. The results showed that these structural abnormalities in the visual cortex and visual-related areas outside the occipital cortex in the EBAs not only may be influenced by neurodevelopment, degeneration, plasticity, and so on but also involved the interaction of these factors after the early visual deprivation.

Structural and Functional Network-Level Reorganization in the Coding of Auditory Motion Directions and Sound Source Locations in the Absence of Vision.

hMT+/V5 is a region in the middle occipitotemporal cortex that responds preferentially to visual motion in sighted people. In cases of early visual deprivation, hMT+/V5 enhances its response to moving sounds. Whether hMT+/V5 contains information about motion directions and whether the functional enhancement observed in the blind is motion specific, or also involves sound source location, remains unsolved. Moreover, the impact of this cross-modal reorganization of hMT+/V5 on the regions typically supporting auditory motion processing, like the human planum temporale (hPT), remains equivocal. We used a combined functional and diffusion-weighted MRI approach and individual in-ear recordings to study the impact of early blindness on the brain networks supporting spatial hearing in male and female humans. Whole-brain univariate analysis revealed that the anterior portion of hMT+/V5 responded to moving sounds in sighted and blind people, while the posterior portion was selective to moving sounds only in blind participants. Multivariate decoding analysis revealed that the presence of motion direction and sound position information was higher in hMT+/V5 and lower in hPT in the blind group. While both groups showed axis-of-motion organization in hMT+/V5 and hPT, this organization was reduced in the hPT of blind people. Diffusion-weighted MRI revealed that the strength of hMT+/V5-hPT connectivity did not differ between groups, whereas the microstructure of the connections was altered by blindness. Our results suggest that the axis-of-motion organization of hMT+/V5 does not depend on visual experience, but that congenital blindness alters the response properties of occipitotemporal networks supporting spatial hearing in the sighted.SIGNIFICANCE STATEMENT Spatial hearing helps living organisms navigate their environment. This is certainly even more true in people born blind. How does blindness affect the brain network supporting auditory motion and sound source location? Our results show that the presence of motion direction and sound position information was higher in hMT+/V5 and lower in human planum temporale in blind relative to sighted people; and that this functional reorganization is accompanied by microstructural (but not macrostructural) alterations in their connections. These findings suggest that blindness alters cross-modal responses between connected areas that share the same computational goals.

Topologic Reorganization of White Matter Connectivity Networks in Early-Blind Adolescents.

Blindness studies are important models for the comprehension of human brain development and reorganization, after visual deprivation early in life. To investigate the global and local topologic alterations and to identify specific reorganized neural patterns in early-blind adolescents (EBAs), we applied diffusion tensor tractography and graph theory to establish and analyze the white matter connectivity networks in 21 EBAs and 22 age- and sex-matched normal-sighted controls (NSCs). The network profiles were compared between the groups using a linear regression model, and the associations between clinical variables and network profiles were analyzed. Graph theory analysis revealed “small-world” attributes in the structural connection networks of both EBA and NSC cohorts. The EBA cohort exhibited significant lower network density and global and local efficiency, as well as significantly elevated shortest path length, compared to the NSC group. The network efficiencies were markedly reduced in the EBA cohort, with the largest alterations in the default-mode, visual, and limbic areas. Moreover, decreased regional efficiency and increased nodal path length in some visual and default-mode areas were strongly associated with the period of blindness in EBA cohort, suggesting that the function of these areas would gradually weaken in the early-blind brains. Additionally, the differences in hub distribution between the two groups were mainly within the occipital and frontal areas, suggesting that neural reorganization occurred in these brain regions after early visual deprivation during adolescence. This study revealed that the EBA brain structural network undergoes both convergent and divergent topologic reorganizations to circumvent early visual deprivation. Our research will add to the growing knowledge of underlying neural mechanisms that govern brain reorganization and development, under conditions of early visual deprivation.

Number Stroop Effects in Arabic Digits and ASL Number Signs: The Impact of Age and Setting of Language Acquisition

ABSTRACT Multiple studies have reported mathematics underachievement for students who are deaf, but the onset, scope, and causes of this phenomenon remain understudied. Early language deprivation might be one factor influencing the acquisition of numbers. In this study, we investigated a basic and fundamental mathematical skill, automatic magnitude processing, in two formats (Arabic digits and American Sign Language number signs) and the influence of age of first language exposure on both formats by using two versions of the Number Stroop Test. We compared the performance of individuals born deaf who experienced early language deprivation to that of individuals born deaf who experienced sign language in early life and hearing second language learners of ASL. In both formats of magnitude representation, late first language learners demonstrated overall slower reaction times. They were also less accurate on incongruent trials but performed no differently from early signers and second language learners on other trials. When magnitude was represented by Arabic digits, late first language learners exhibited robust Number Stroop Effects, suggesting automatic magnitude processing, but they also demonstrated a large speed difference between size and number judgments not observed in the other groups. In a task with ASL number signs, the Number Stroop Effect was not found in any group, suggesting that magnitude representation might be format-specific, in line with the results from several other languages. Late first language learners also demonstrate unusual patterns of slower reaction time for neutral rather than incongruent stimuli. Together, the results show that early language deprivation affects the ability to automatically judge quantities expressed both linguistically and by Arabic digits, but that it can be acquired later in life when language is available. Contrary to previous studies that find differences in speed of number processing between deaf and hearing participants, we find that when language is acquired early in life, deaf signers perform identically to hearing participants.

Early visual deprivation prompts the use of body-centered frames of reference for auditory localization

Early visual deprivation prompts the use of body-centered frames of reference for auditory localization

Vulnerability of facial attractiveness perception to early and multi-year visual deprivation.

Judgments of facial attractiveness invariably accompany our perception of faces. Even neonates appear to be capable of making such judgments in a manner consistent with adults. This suggests that the processes supporting facial attractiveness require little, if any, visual experience to manifest. Here we investigate the resilience of these processes to several years of early-onset visual deprivation. Specifically, we study whether congenitally blind children treated several years after birth possess the ability to rate facial attractiveness in a manner congruent to normally sighted individuals. The data reveal significant individual variability in the way each newly sighted child perceives attractiveness. This is in marked contrast to data from normally sighted controls who exhibit strong across-subject agreement in facial attractiveness ratings. This variability may be attributable, in part, to atypical facial encoding strategies used by the newly sighted children. Overall, our results suggest that the development of facial attractiveness perception is likely to be vulnerable to early visual deprivation, pointing to the existence of a possible sensitive period early in the developmental trajectory.

Does the Value of FSH Predict Severity of Metabolic Complications in Females with POI?

Premature ovarian insufficiency (POI) is defined as a cessation of ovarian function before the age of 40. Such early deprivation of estrogens in women may be associated with several adverse cardiovascular and metabolic consequences. The aim of this retrospective study was to investigate whether women with POI and a serum follicle-stimulating hormone (FSH) level of 25–40 I/U (Group A) have the same metabolic profile as women with POI and a serum FSH level of >40 I/U (Group B). One hundred twenty-three women were included in the study group (Group A; n = 41; Group B; n = 82). The control group comprised 77 healthy women with regular menstruation. In the age- and BMI-adjusted model, no differences were found between the groups with respect to total cholesterol, high-density lipoproteins, triglycerides, HOMA-IR, glucose, and insulin. The only significant difference was found in terms of low-density lipoprotein cholesterol (LDL-C). The highest serum concentration was found in Group B, the second highest was found in Group A, and the lowest was in the controls. In conclusion, changing the threshold of FSH required to establish a POI diagnosis may have an impact on the level of serum LDL-C.

Autonomic reactivity to social rejection, peer difficulties, and the buffering effects of adolescent friendships following early psychosocial deprivation.

Autonomic nervous system reactivity has been posited to be a mechanism contributing to social and emotional problems among children exposed to early adversity. Leveraging data from the Bucharest Early Intervention Project, a longitudinal randomized controlled trial of foster care versus institutional care of abandoned children in Romania, we assessed whether altered sympathetic reactivity to peer rejection feedback in early adolescence mediated the relation between early institutional rearing and peer problems in later adolescence. We also assessed whether adolescent friendship quality or randomized placement in foster care early in life moderated these associations. Participants include 68 institutionalized children randomized to care as usual, 68 institutionalized children randomized to foster care, and 135 never-institutionalized children. At age 12, participants reported friendship quality with respect to a best friend and completed a social rejection task while electrocardiogram and impedance cardiography were recorded. Sympathetic nervous system reactivity to rejection feedback was assessed using preejection period (PEP). At ages 12 and 16, peer problems were reported by parents. Mediation analysis revealed that less PEP reactivity to social rejection at age 12 partially mediated the association between early institutionalization and greater peer problems at age 16. Further moderated mediation analysis revealed that this indirect effect was evidenced among previously institutionalized youths with low, but not high, quality friendships. We did not observe foster care intervention effects. These findings suggest that altered sympathetic reactivity to social rejection might be a mechanism linking early institutionalization to social difficulties into adolescence, however, positive adolescent friendships may buffer these effects. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Impact of prenatal and childhood adversity\xa0effects around World War II on multimorbidity: results from the KORA-Age study

BackgroundWhile risk factors for age-related diseases may increase multimorbidity (MM), early life deprivation may also accelerate the development of chronic diseases and MM.MethodsThis study explores the prevalence and pattern of MM in 65–71 year-old individuals born before, during, and after World War II in Southern Germany based on two large cross-sectional KORA (Cooperative Health Research in the Region of Augsburg) -Age studies in 2008/9 and 2016. MM was defined as having at least two chronic diseases, and birth periods were classified into five phases: pre-war, early war, late war, famine, and after the famine period. Logistic regression models were used to analyze the effect of the birth phases on MM with adjustment for sociodemographic and lifestyle risk factors. Furthermore, we used agglomerative hierarchical clustering to investigate the co-occurrence of diseases.ResultsParticipants born during the late war phase had the highest prevalence of MM (62.2%) and single chronic diseases compared to participants born during the other phases. Being born in the late war phase was significantly associated with a higher odds of MM (OR = 1.83, 95% CI: 1.15–2.91) after adjustment for sociodemographic and lifestyle factors. In women, the prevalence of joint, gastrointestinal, eye diseases, and anxiety was higher, while heart disease, stroke, and diabetes were more common in men. Moreover, three main chronic disease clusters responsible for the observed associations were identified as: joint and psychosomatic, cardiometabolic and, other internal organ diseases.ConclusionsOur findings imply that adverse early-life exposure may increase the risk of MM in adults aged 65–71 years. Moreover, identified disease clusters are not coincidental and require more investigation.

Invited Session III: Reawakening plasticity in visual cortex: Recovery from the effects of visual deprivation beyond peak plasticity

Visual experience during early postnatal life plays an important role in the development of neural circuits that support normal vision. Conditions that disrupt visual experience can alter the structure and function of neurons to produce a functional impairment, amblyopia, in the affected eye that can last a lifetime. Susceptibility to the neural modifications presumed to underlie amblyopia is confined to the early years of life during the so-called critical period. Up until recently, recovery from the effects of visual deprivation was likewise thought to be possible only early in life; however, research in rodents has demonstrated that under certain conditions recovery can occur at ages beyond the critical period. We have observed a remarkable recovery from the effects of visual deprivation in cats following temporary retinal inactivation with intraocular application of tetrodotoxin, a potent neural anesthetic. Notably, retinal inactivation produces rapid and significant structural and functional recovery at ages beyond what can be achieved with conventional therapy. This talk will present results from our studies on the use of retinal inactivation to resource plasticity capacity and promote recovery from the effects of early visual deprivation.

Marginal men, respectable masculinity and access to HIV services through intimate relationships with female sex workers in Kampala, Uganda

Masculinity influences men's sexual risk-taking behaviour and affects uptake of HIV services. We draw on data from a year-long (2019) ethnographic study focusing on men in relationships with female sex workers (FSW) in Kampala, Uganda to examine how and why two marginalised groups of people may interact to produce positive health behaviours. Data from in-depth interviews, focus group discussions and participant observation were collected and analysed. We discuss three main themes; the first of which focuses on marginalised masculinities and HIV risk. In this theme we show how accounts of men's life trajectories portrayed a remarkably similar pattern of early deprivation of opportunities and how this shaped construction of risky masculinities. The second theme describes men's relationships with FSW and how this facilitated access to HIV services. We discuss how very marginal women (FSWs) help very marginal men adopt more positive health behaviours. We show how threats to masculinities arising from sex work stigma, men's failure to have exclusive sexual rights over their FSW partner, and men's economic disadvantage are negotiated and dealt with to create an enabling environment for men's uptake of HIV services. The final theme focuses on the positive and negative practices of the men after engaging with HIV services. We conclude that the two marginalised groups can mobilise and combine new aspirations to produce positive health behaviours manifested through FSW assisting their male partners to access HIV services. We suggest that this perspective opens up new opportunities for engaging with marginalised groups and tackling the problem of high HIV infection among key populations.

Anxiety and Depression Assessments in a Mouse Model of Congenital Blindness.

Previous studies have reported that visual impairment can affect the quality of life leading to mental health disorders. This study aimed to investigate associations between vision impairment, depression and anxiety using a mouse model of congenital blindness. We phenotyped 15 anophthalmic and 17 sighted adult mice in a battery of tests for anxiety and depression-like behaviors: open field test, elevated plus maze, coated test, splash test, and forced swim test. We found that: (1) Anxiety levels of the anophthalmic mice were significantly lower when compared with sighted mice, (2) Anophthalmic mice displayed more exploratory behaviors in a new environment than the sighted one, and (3) Depression levels between those groups were similar. In conclusion, this behavioral study showed that early visual deprivation lowers anxiety levels, associated with heightened exploratory activity, but does not induce depressive symptoms in a mouse model of congenital blindness, underlying several behavioral adaptations.

Does auditory deprivation impairs statistical learning in the auditory modality?

Early sensory deprivation allows assessing the extent of reorganisation of cognitive functions, well beyond sensory processing. As such, it is a good model to explore the links between sensory experience and cognitive functions. One of these functions, statistical learning – the ability to extract and use regularities present in the environment – is suspected to be impaired in prelingually deaf children with a cochlear implant. However, empirical evidence supporting this claim is very scarce and studies have reported contradictory results. This might be because previous studies have tested statistical learning only in the visual modality and did not make clear distinctions between multiple types of statistical regularities. To overcome these problems, we designed a modified serial reaction time task where cochlear implanted children and normal hearing children had to react to auditory sequences that embed multiple statistical regularities, namely transition probabilities of 0th, 1st or 2nd order. We compared the reaction times of the children with the output of a simple computational model that learns transition probabilities. First, 6–12 years old children were able to learn 0th and 1st order transition probabilities but not 2nd order ones. Second, there were no differences between cochlear implanted children and their normal hearing peers. These results indicate that auditory statistical learning is preserved in congenitally deaf children with cochlear implants. This suggests in turn that early auditory deprivation might not be crucially detrimental for the normal development of statistical learning.

New treatment for amblyopia based on rules of synaptic plasticity: a randomized clinical trial.

Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance of input from the eyes to the visual cortex. We tested the hypothesis that asynchronous stimulation of the two eyes might induce synaptic plasticity and rebalance input. Experiments on normal adults showed that repetitive brief exposure of grating stimuli, with the onset of each stimulus delayed by 8.3 ms in one eye, results in a shift in perceptual eye dominance. Clinical studies (Clinical trial registration number: ChiCTR2100049130), using popular 3D movies with similar asynchrony between the two eyes (amblyopic eye stimulated first) to treat anisometropic amblyopia, established that just 10.5 h of conditioning over <3 weeks produced improvement that met criteria for successful treatment. The benefits of asynchronous conditioning accumulate over 20-30 45 min sessions, and are maintained for at least 2 years. Finally, we demonstrate that asynchronous binocular treatment alone is more effective than patching only. This novel treatment is popular with children and is some 50 times more efficient than patching alone.

The influence of early visual deprivation on audio-spatial working memory.

This study investigates how spatial working memory skills, and the processing and retrieval of distal auditory spatial information are influenced by visual experience. We developed an experimental paradigm using an acoustic simulation. The performance of congenitally blind and sighted participants (n = 9 per group) was compared when recalling sequences of spatialised auditory items in the same or reverse order of presentation. Two experimental conditions based on stimuli features were tested: non-semantic and semantic. Blind participants had a shorter memory span in the backward than the forward order of presentation. In contrast, sighted participants did not, revealing that blindness affects spatial information processing with greater executive source involvement. Furthermore, we found that blind subjects performed worse overall than the sighted group and that the semantic information significantly improved the performance, regardless of the experimental group and the sequences' order of presentation. Lack of early visual experience affects the ability to encode the surrounding space. Congenital blindness influences the processing and retrieval of spatial auditory items, suggesting that visual experience plays a pivotal role in calibrating spatial memory abilities using the remaining sensory modalities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).