Learning to recognize letters in the periphery: Effects of repeated exposure, letter frequency, and letter complexity.

Patients with central vision loss must rely on their peripheral vision for reading. Unfortunately, limitations of peripheral vision, such as crowding, pose significant challenges to letter recognition. As a result, there is a need for developing effective training methods for improving crowded letter recognition in the periphery.

Breastfeeding and dietary variety among preterm children aged 1-3 years.

Among infants born at term, breastfeeding is associated with increased dietary variety in childhood. Preterm birth can limit early feeding options while simultaneously increasing risk for negative health outcomes that could benefit from dietary-based preventative measures. We assessed whether breastfeeding is associated with increased dietary variety at 1-3 years amongst children born preterm.

Breastfeeding and Autism Spectrum Disorder in the National Survey of Children's Health.

Background: Breastfeeding is thought to promote healthy cognitive development. A small number of studies have also reported a protective association between breastfeeding and autism spectrum disorder (ASD). The National Survey of Children's Health (2007, 2011), a large nationally representative survey of US children, was examined to determine whether breastfeeding of infants is associated with later development of ASD.

The efficiency of second order orientation coherence detection.

Neurons in early visual cortex respond to both luminance- (1st order) and contrast-modulated (2nd order) local features in the visual field. In later extra-striate areas neurons with larger receptive fields integrate information across the visual field. For example, local luminance-defined features can be integrated into contours and shapes.

The effect of motion on crowding: zooming text.

Crowding is the major sensory factor responsible for the slow reading speeds exhibited in peripheral vision. Past attempts to improve peripheral reading via crowding reduction have generally focused on applying spatial changes to the stimulus and have been largely ineffective. Recent evidence indicates that dynamic approaches have good potential for reducing crowding in peripheral reading.

A two-stage model of orientation integration for Battenberg-modulated micropatterns.

The visual system pools information from local samples to calculate textural properties. We used a novel stimulus to investigate how signals are combined to improve estimates of global orientation. Stimuli were 29 × 29 element arrays of 4 c/deg log Gabors, spaced 1° apart.

Global processing of orientation in amblyopia.

We set out to determine whether extra-striate ventral stream function was compromised in amblyopia and to compare any observed deficit with previous data on comparable dorsal stream function. We devised a multi-element orientation task where orientation coherence sensitivity could be measured in a comparable way to motion coherence. The use of spatial frequency narrowband elements allowed for accurate correction of any upstream contrast sensitivity influence and ensured that the orientation bandwidth of our elements did not covary with the measured coherence.

Orientation coherence sensitivity.

We developed a global orientation coherence task for the assessment of global form processing along similar lines to the global motion coherence task. The task involved judgments of global orientation for an array of limited duration 1-D Gabors, some of which were signal (signal orientation) and some of which were noise (random orientation). We address two issues.

Amblyopic deficits in processing structure-from-motion.

Amblyopic observers exhibit a range of low- and high-level cortical deficits, and there is strong evidence that the extrastriate cortex is selectively affected for signal/noise tasks but not for simple integration tasks. We tested amblyopic and control observers on a structure-from-motion (SFM) task involving signal integration to gauge whether extrastriate processing is compromised at a level where dorsal and ventral information is combined. SFM tasks require integration of local elements to perceive the global structure using motion-defined depth cues.

Healthy aging delays scalp EEG sensitivity to noise in a face discrimination task.

We used a single-trial ERP approach to quantify age-related changes in the time-course of noise sensitivity. A total of 62 healthy adults, aged between 19 and 98, performed a non-speeded discrimination task between two faces. Stimulus information was controlled by parametrically manipulating the phase spectrum of these faces.

Age-related delay in information accrual for faces: evidence from a parametric, single-trial EEG approach.

Background: In this study, we quantified age-related changes in the time-course of face processing by means of an innovative single-trial ERP approach. Unlike analyses used in previous studies, our approach does not rely on peak measurements and can provide a more sensitive measure of processing delays. Young and old adults (mean ages 22 and 70 years) performed a non-speeded discrimination task between two faces.

Time course and robustness of ERP object and face differences.

Conflicting results have been reported about the earliest "true" ERP differences related to face processing, with the bulk of the literature focusing on the signal in the first 200 ms after stimulus onset. Part of the discrepancy might be explained by uncontrolled low-level differences between images used to assess the timing of face processing. In the present experiment, we used a set of faces, houses, and noise textures with identical amplitude spectra to equate energy in each spatial frequency band.

Inverting houses and textures: investigating the characteristics of learned inversion effects.

Faces, more than other objects, are identified more accurately when upright than inverted. This inversion effect may be linked to differences in expertise. Here, we explore how stimulus characteristics and expertise interact to determine the magnitude of inversion effects.

Single-trial EEG dynamics of object and face visual processing.

There has been extensive work using early event-related potentials (ERPs) to study visual object processing. ERP analyses focus traditionally on mean amplitude differences, with the implicit assumption that all of the neuronal activity of interest is evoked by the stimulus in a time-locked manner from trial to trial. However, several recent studies have suggested that visual ERP components might be explained to a large extent by the partial phase resetting of ongoing activity in restricted frequency bands.

Spatial scaling factors explain eccentricity effects on face ERPs.

Event-related potential (ERP) studies consistently have described a strong, face-sensitive response termed the N170. This component is maximal at the fovea and decreases strongly with eccentricity, a result that could suggest a foveal bias in the cortical generators responsible for face processing. Here we demonstrate that scaling stimulus size according to V1 cortical magnification factor can virtually eliminate face-related eccentricity effects, indicating that eccentricity effects on face ERPs are largely due to low-level visual factors rather than high-level cortical specialization for foveal stimuli.