Publications by authors named "Oliver Braddick"

Purpose: This cross-sectional monocentric study aims to utilize the Early Childhood Attention Battery to investigate early attention patterns in young preterm children and ascertain the extent to which their attentional abilities diverge from those of term peers.

Methods: Inclusion criteria encompassed gestational age < 34 weeks, with assessments conducted between 3 and 5 years 11 months. Exclusion criteria included major brain lesions, significant motor or behavioral disorders, and intellectual functioning with IQ < 70.

View Article and Find Full Text PDF

Dorsal stream cortical networks underpin a cluster of visuomotor, visuospatial, and visual attention functions. Sensitivity to global coherence of motion and static form is considered a signature of visual cortical processing in the dorsal stream (motion) relative to the ventral stream (form). Poorer sensitivity to global motion compared to global static form has been found across a diverse range of neurodevelopmental disorders, suggesting a "dorsal stream vulnerability.

View Article and Find Full Text PDF

Aim: To investigate whether children with perinatal brain injury have impairments in specific components of visual attention, and whether early dietary supplementation can reduce any deficits.

Method: Children participating in the Dolphin neonatal trial of dietary supplementation were tested at age 6 months with the Infant Fixation Shift Attention Test, and at 4 to 5 years with four subtests of the Early Childhood Attention Battery (ECAB) assessing different components of attention (selective, sustained, and executive function), and the Fluid Crystallized Intelligence Index of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). From 59 children originally assigned to trial groups, 33 were available for testing at 4 to 5 years (18 treatment group of whom seven, six, and five showed mild, moderate, or severe neonatal brain injury; 15 controls with one, seven, and seven in the neonatal brain injury categories respectively).

View Article and Find Full Text PDF

Although the contrast sensitivity function (CSF) changes markedly during infancy, there is no consensus regarding whether, how, and why it continues to develop in later childhood. Here, we analyzed previously published data (N = 1928 CSFs), and present new psychophysical findings from 98 children (4.7-14.

View Article and Find Full Text PDF

The developing visual brain is an integrated system, linking analysis of the visual input to visuomotor control, visual cognition, and attention. Major points in human visual development are the presence of rudimentary pathways present at birth which can control fixation behavior, with subsequent development of specific functions. These functions include the emergence of cortical selectivity; the integration of local signals to provide global representations of motion, shape, and space; the development of visuomotor modules for eye movements, manual reaching, and locomotion; and the development of distinct attentional systems.

View Article and Find Full Text PDF

Background: The Early Childhood Attention Battery (ECAB) has been used to assess three different components of attention in preschool children, namely, selective, sustained and attentional control.

Aim: The aim of the study was: I) to adapt the ECAB to the Italian language; II) to collect Italian reference data using the translated version and III) to expand the available reference data using 6-month age intervals.

Study Design: The adaptation of the ECAB to Italian language and the collection of Italian reference data was performed in four phases: translation and identification of the manual and subtests that needed adaptation; interobserver reliability and feasibility of the Italian version; application of the Italian ECAB; statistical analysis.

View Article and Find Full Text PDF

The ability to judge speed is a fundamental aspect of visual motion processing. Speed judgments are generally assumed to depend on signals in motion-sensitive, directionally selective, neurons in areas such as V1 and MT. Speed comparisons might therefore be expected to be most accurate when they use information within a common set of directionally tuned neurons.

View Article and Find Full Text PDF

In the first day of life, infants respond specifically to the crude configuration of a human face. New research finds that this visual sensitivity is present even in the weeks before birth.

View Article and Find Full Text PDF

The visual processing of complex motion is impaired in Alzheimer's disease (AD). However, it is unclear whether these impairments are biased toward the motion stream or part of a general disruption of global visual processing, given some reports of impaired static form processing in AD. Here, for the first time, we directly compared the relative preservation of motion and form systems in AD, mild cognitive impairment, and healthy aging, by measuring coherence thresholds for well-established global rotational motion and static form stimuli known to be of equivalent complexity.

View Article and Find Full Text PDF

Unlabelled: The Fixation Shift Paradigm (FSP) measures infants' ability to shift gaze from a central fixation stimulus to a peripheral target (e.g. Hood & Atkinson, 1993: Infant Behavior and Development, 16(4), 405-422).

View Article and Find Full Text PDF

Research on neural mechanisms of attention has generally instructed subjects to direct attention covertly while maintaining a fixed gaze. This study combined simultaneous eye tracking and electroencephalogram (EEG) to measure neural attention responses during exogenous cueing in overt attention shifts (with saccadic eye movements to a target) and compared these with covert attention shifts (responding manually while maintaining central fixation). EEG analysis of the period preceding the saccade latency showed similar occipital response amplitudes for overt and covert shifts, although response latencies differed.

View Article and Find Full Text PDF

Reduced global motion sensitivity, relative to global static form sensitivity, has been found in children with many neurodevelopmental disorders, leading to the "dorsal stream vulnerability" hypothesis (Braddick et al., 2003). Individual differences in typically developing children's global motion thresholds have been shown to be associated with variations in specific parietal cortical areas (Braddick et al.

View Article and Find Full Text PDF

Sensitivity to global visual motion has been proposed as a signature of brain development, related to the dorsal rather than ventral cortical stream. Thresholds for global motion have been found to be elevated more than for global static form in many developmental disorders, leading to the idea of "dorsal stream vulnerability." Here we explore the association of global motion thresholds with individual differences in children's brain development, in a group of typically developing 5- to 12-year-olds.

View Article and Find Full Text PDF

Purpose: While basic visual functions have been described in subjects with congenital achromatopsia (ACHM), little is known about their mid- or high-level cortical visual processing. We compared midlevel cortical visual processing in ACHM subjects (n = 11) and controls (n = 20).

Methods: Abilities to detect global form, global motion, and biological motion embedded in noise were tested across a range of light levels, including scotopic, in which both ACHM subjects and controls must rely on rods.

View Article and Find Full Text PDF

Advances in potential treatments for rod and cone dystrophies have increased the need to understand the contributions of rods and cones to higher-level cortical vision. We measured form, motion and biological motion coherence thresholds and EEG steady-state visual evoked potentials (SSVEP) responses under light conditions ranging from photopic to scotopic. Low light increased thresholds for all three kinds of stimuli; however, global form thresholds were relatively more impaired than those for global motion or biological motion.

View Article and Find Full Text PDF

This study measured changes in switches of attention between 1 and 9 months of age in 67 typically developing infants. Remote eye-tracking (Tobii X120) was used to measure saccadic latencies, related to switches of fixation, as a measure of shifts of attention, from a central stimulus to a peripheral visual target, measured in the Fixation Shift Paradigm. Fixation shifts occur later if the central fixation stimulus stays visible when the peripheral target appears (competition condition), than if the central stimulus disappears as the peripheral target appears (non-competition condition).

View Article and Find Full Text PDF

Global form and motion sensitivity undergo long development in childhood with motion sensitivity rather than form being impaired in a number of childhood disorders and both impaired in adult clinical populations. This suggests extended development and vulnerability of extrastriate cortical areas associated with global processing. However, in some developmental and clinical populations, it remains unclear to what extent impairments might reflect deficits at earlier stages of visual processing, such as reduced visual acuity and contrast sensitivity.

View Article and Find Full Text PDF

Accurate measures of perceptual threshold are difficult to obtain in infants. In a clinical context, the challenges are particularly acute because the methods must yield meaningful results quickly and within a single individual. The present work considers how best to maximize speed, accuracy, and reliability when testing infants behaviorally and suggests some simple principles for improving test efficiency.

View Article and Find Full Text PDF

Background: Neurological impairment is a common sequelae of perinatal brain injury. Plasticity of the developing brain is due to a rich substrate of developing neurones, synaptic elements and extracellular matrix. Interventions supporting this inherent capacity for plasticity may improve the developmental outcome of infants following brain injury.

View Article and Find Full Text PDF

Purpose: To validate a novel, automated test of infant resolution acuity based on remote eye-tracking.

Methods: Infants aged 2 to 12 months were tested binocularly using a new adaptive computerized test of infant vision using eye tracking (ACTIVE), and Keeler infant acuity cards (KIAC). The ACTIVE test ran automatically, using remote eye-tracking to assess whether the infant fixated a black-and-white grating of variable spatial frequency.

View Article and Find Full Text PDF

We discuss hypotheses that link the measurements we can make with infants to inferences about their developing neural mechanisms. First, we examine evidence from the sensitivity to visual stimulus properties seen in infants' responses, using both electrophysiological measures (transient and steady-state recordings of visual evoked potentials/visual event-related potentials) and behavioral measures and compare this with the sensitivity of brain processes, known from data on mammalian neurophysiology and human neuroimaging. The evidence for multiple behavioral systems with different patterns of visual sensitivity is discussed.

View Article and Find Full Text PDF

Some key stages in the development of manual actions have been discussed in this supplement based on the idea of the dorsal cortical stream as the pathway for translating visual information into action control. We argue that visual information, transmitted through specialized visuomotor dorsal-stream modules, is required in the control of manual actions for selecting and attending to the target object of the action, translating visual spatial information into motor programmes and planning a coordinated sequence of actions so as to reach an optimal end-state. In typical development, we illustrate dorsal-stream processing through results on the use of stereoscopic information to guide infants' reaches, and changes in target selection and detailed kinematics of reaches depending on age, object size, and reaching in darkness (when dorsal-stream information rapidly decays).

View Article and Find Full Text PDF

This article introduces a new battery of attention tests for typically developing and atypically developing children with a mental age of 3-6 years. In the light of adult and child studies supporting a model of distinct networks for specific attentional operations, tests in the current battery were selected with the aim of measuring functions of selective attention, sustained attention and attentional control (executive function). Normative data were collected from 154 typically developing children aged 3-6 years and examined using exploratory factor analysis to determine latent constructs underlying test performance.

View Article and Find Full Text PDF