Biomedical subjects

Jacqueline Liederman

Publications and source records attributed to Jacqueline Liederman.

5 recordsLinked to original sources

PubMed2005

A temporally dynamic context effect that disrupts voice onset time discrimination of rapidly successive stimuli.

Across three experiments, voice onset time discrimination along a/ba/-/pa/ continuum was found to be influenced by the order of presentation of rapidly successive stimuli. Specifically, discrimination was disrupted when a relatively unambiguous /pa/ syllable was presented before, rather than after, a more ambiguous /pa/ or/ba/ syllable. In Experiments 1 and 2, for between-category discrimination, this order effect was significant at interstimulus intervals (ISIs) below 250 msec, but not at 250 or 1,000 msec. In Experiments 2 and 3, the order effect was also significant for within-category discrimination at ISIs below 250 msec. In addition, in Experiment 3 this order effect was not diminished by provision of performance feedback across eight testing sessions. These findings reveal a particular vulnerability of phonological processing in response to rapidly successive stimuli and may have implications for mathematical and neural models of speech processing of normal and impaired populations.

Adult↗

PubMed2004

Spatiotemporal continuity implicated in the binding of features and object identity.

This study continues the work of Anes et al. (in preparation) in which manipulation of features incidental to an object elicited robust effects in a dynamic object recognition paradigm. In the current series, the spatiotemporal continuity of identity and feature presentation is increasingly distorted between experiments in an attempt to disrupt a process Triesman (1996) calls "binding" of an object's identity and features. Across three experiments, increasing disruption of spatiotemporal continuity significantly diminished the effect of features on object identification, evidence that spatiotemporal continuity is, in part, responsible for binding features to an object.

Adult↗

PubMed2003

The role of motion direction selective extrastriate regions in reading: a transcranial magnetic stimulation study.

Why reading ability is correlated with motion processing ability is perplexing. Activity in motion direction processing regions (Area V5/MT+) was perturbed by means of repetitive transcranial magnetic stimulation (rTMS) to examine its effect on reading. A functional probe (significant shortening of the motion aftereffect) was used to identify Area V5/MT+. Right-handed participants (8 m, 8 f) received three 7.5 min blocks of rTMS, after which two phonological and one orthographic reading tasks were administered. Application of rTMS to Area V5/MT+ (as compared to a non-rTMS baseline) significantly decreased performance only during non-word naming. The pattern of naming errors and the absence of deficits on the second phonological task were not consistent with a role for Area V5/MT+ in phonological decoding. Instead, its role in reading may be limited to image stabilization and/or letter localization.

Adult↗

PubMed2002

Greater plasticity in lower-level than higher-level visual motion processing in a passive perceptual learning task.

Simple exposure is sufficient to sensitize the human visual system to a particular direction of motion, but the underlying mechanisms of this process are unclear. Here, in a passive perceptual learning task, we found that exposure to task-irrelevant motion improved sensitivity to the local motion directions within the stimulus, which are processed at low levels of the visual system. In contrast, task-irrelevant motion had no effect on sensitivity to the global motion direction, which is processed at higher levels. The improvement persisted for at least several months. These results indicate that when attentional influence is limited, lower-level motion processing is more receptive to long-term modification than higher-level motion processing in the visual cortex.

Adult↗

PubMedDate not supplied

Male vulnerability to reading disability is not likely to be a myth: a call for new data.

Whether boys are more vulnerable than girls to reading disabilities (RD) is controversial. We review studies that were designed to minimize ascertainment bias in the selection of individuals with RD. These include population-based studies that identified children with RD by objective, unbiased methods and studies that examined the gender ratios among the affected relatives of those diagnosed with RD. We conclude that even when ascertainment biases are minimized, there is still a significant preponderance of boys with RD, although the gender ratio of the affected relatives of those with RD manifests the weakest male bias. Furthermore, we demonstrate that potentially confounding factors such as attentional or neurological problems, race, IQ, and severity of RD cannot account for the observed gender bias. We end with a clarion call to future researchers to (a) consider analyzing gender differences by means of more than one definition of RD, (b) compare gender ratios when boys and girls are ranked against the performance of their own gender as opposed to an average across genders, and (c) report group differences in variability and effect sizes of obtained gender ratios.

Attention↗