2008 — 2012 |
Bosworth, Rain G Dobkins, Karen R (co-PI) [⬀] |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Effects of Biological Maturation and Visual Experience On Human Visual Developmen @ University of California San Diego
[unreadable] Description (provided by applicant): The degree to which visual development is governed by "nature" vs. "nurture" has been a long-standing topic in vision research. Although much has been learned from animal studies in the last 50 years, relatively little is known about the factors influencing visual development in humans. The current proposal investigates whether factors related to visual experience ("nurture") vs. preprogrammed biological maturation ("nature"), or both, are important in shaping visual development. To this end, we propose visual psychophysical studies with four different subject populations that tease apart these factors. (A) Fullterm Infants and (B) Healthy Preterm Infants. If early visual experience is the dominant force in visual development, preterm infants should show the same developmental trajectories as fullterm infants when plotted in terms of postnatal age (i.e. age since birth). By contrast, if biological maturation is more influential, preterm infants should match fullterm babies when plotted in postconceptional age (i.e., age since conception). (C) Monozygotic vs. Dizygotic Twins. While both twin types share the same environment and parents, they differ in the degree of shared genetic makeup. We apply a biometrical twin model that can identify the proportion of "phenotypic" variance in visual performance that can be accounted for by shared environment versus genes. (D) Infants and Children with Early Abnormal Visual Input. Comparisons made between this group (cataract, strabismus, and anisometropia) and healthy controls will address the vulnerability of various aspects of visual processing to abnormal visual experience early in development. Three aims address different levels of visual processing: 1) Subcortical Pathway Processing: We ask if the three main retinogeniculate pathways, Magnocellular (M), Parvocellular (P) and Koniocellular (K), are equally or differentially affected by visual experience, by obtaining contrast sensitivities for luminance, red/green and blue/yellow stimuli, thought to be mediated by these pathways, respectively. 2) Subcortical Input to Cortical Motion Processing: We will obtain an estimate of the extent of P vs. M subcortical pathway input to motion processing using a "Motion/Detection" threshold ratio paradigm that measures the relative effects of chromatic (P pathway) vs. luminance (M pathway) contrast on motion processing. Previous results from our laboratory suggest that the relative P vs. M input to motion decreases with age, and here we will ask whether this re-weighting process is influenced more by visual experience or biological maturation. 3) Cortical Motion Processing: We will assess global motion processing, which is believed to be a higher-level cortical function. Unlike many previous studies, our global motion stimuli will be scaled to detectability for each subject, such that differences observed across ages/subject groups can be more definitively interpreted. The results of these projects, which will reveal what aspects of visual development are more vs. less amenable to effects of visual experience, may have important implications for treating children with congenital eye disorders. PUBLIC HEALTH RELEVANCE The degree to which visual development is governed by "nature" (i.e., pre-programmed biological maturation) vs. "nurture" (i.e., visual experience) has been a long-standing topic in vision research. The current proposal investigates this question by conducting infant visual psychophysical studies in subject populations that bear relevance: preterm infants, twin infants and infants born with congenital eye disorders. The results of these studies, which we hope will reveal what aspects of visual development are more vs. less amenable to effects of visual experience, may have important implications for treating children with visual disorders. [unreadable] [unreadable] [unreadable]
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2014 — 2017 |
Bosworth, Rain Dobkins, Karen (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
The Effects of Deafness and Visual Language Experience On Visual Perception From Infancy to Adulthood @ University of California-San Diego
Deaf individuals must rely more than hearing individuals on visual information to understand what is happening in the world around them. As a result, the brains of deaf people typically reorganize to help them make better use of the available visual information. The questions addressed by this research project are whether and how greater reliance on visual information actually changes visual experiences. The project also investigates how differences between hearing and deaf people's visual processing develop across infancy, childhood, and adulthood.
There is evidence that aspects of vision are altered or enhanced in deaf people, providing evidence for plasticity of the human brain to compensate for the absence of sound. Yet, very little is known about how these alterations emerge during development. This project investigates the consequences of altered early sensory experience during development, measuring perceptual sensitivity to motion, form, faces, and objects. Deaf people may have altered processing of these aspects of vision for two reasons. First, lack of auditory input compels deaf people to rely more on their intact visual modality, and, second, many deaf people use a visual language (American Sign Language, ASL), which may enhance certain aspects of visual processing that convey critical linguistic information. To tease apart effects of deafness versus ASL language experience, the studies will compare visual sensitivity in Deaf and Hearing individuals who are either Signers or Nonsigners. Also, effects of deafness could occur during an early critical period rather than due to accumulated altered sensory experiences across the lifespan. To address this possibility, the project will also involve studying a group of "Hearing Restored" children who received cochlear implants around 12-18 months, following a period of auditory deprivation starting at birth. Results from these studies will reveal how sensory systems adjust to altered input and elucidate mechanisms of brain plasticity, which may have widespread implications for deaf and blind individuals, as well as for those who lose their hearing or sight later in life.
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0.915 |
2015 — 2018 |
Bosworth, Rain G Dobkins, Karen R (co-PI) [⬀] |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Impact of Deafness and Language Experience On Visual Development @ University of California San Diego
? DESCRIPTION (provided by applicant): While many studies have shown that vision is altered and/or enhanced in deaf people, it is not known how this develops. The current proposal is the first to study visual development in deaf people from infancy to adulthood, as well as in hearing restored (HR) children who received cochlear implants (CIs) by 18 months, a cohort that is increasingly on the rise. In Aim 1, we measure different visual abilities (including motion, form, face and object perception) in deaf and hearing infants (6 - 10 months), children (6 - 10 years) and adults, using comparable stimuli/paradigms across ages. Many deaf people use a visual language, American Sign Language (ASL), and thus to tease apart whether altered vision in deaf signers is due to deafness or to experience with ASL, we test a third control group of hearing signers, who were born to deaf signing parents and have roughly the same ASL experience as deaf people who also learned ASL early. In infants, we test these same three analogous groups (sign-exposed deaf infants, non-sign-exposed hearing infants, and sign-exposed hearing infants), as well as an additional control group, i.e., non-sign-exposed deaf infants. To test the effects of ASL further, we ask whether the degree of altered vision correlates with receptive ASL proficiency, as measured with standardized ASL tests. By understanding the developmental trajectory of altered vision due to deafness vs. ASL, we hope to elucidate mechanisms of developmental plasticity. Aim 2 asks whether there is an early critical period for the effects of deafness on visual perception, by investigating whether altered vision persists in HR children. We also measure receptive spoken language proficiency in HR children, which allows us to ask by when in development must auditory input be restored for auditory and speech processing to develop normally. This aim also addresses a growing concern in the CI field that altered early vision in deaf people may hinder the efficacy of the CI. Here, the idea is that if deafness leads to functional reallocation of auditory cortex for visual processing, this might prevent the auditory cortex from being properly stimulated by CIs. If this is true, we expect to find that HR individuals with the most altered vision will show the worse proficiency in receptive spoken language. The current proposal will be the first to test this maladaptive hypothesis early in development, and the results should have implications for optimizing best long-term language outcomes in CI children.
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