Biomedical subjects

William Marslen-Wilson

Publications and source records attributed to William Marslen-Wilson.

4 recordsLinked to original sources

PubMed2006

Locating the initial stages of speech-sound processing in human temporal cortex.

It is commonly assumed that, in the cochlea and the brainstem, the auditory system processes speech sounds without differentiating them from any other sounds. At some stage, however, it must treat speech sounds and nonspeech sounds differently, since we perceive them as different. The purpose of this study was to delimit the first location in the auditory pathway that makes this distinction using functional MRI, by identifying regions that are differentially sensitive to the internal structure of speech sounds as opposed to closely matched control sounds. We analyzed data from nine right-handed volunteers who were scanned while listening to natural and synthetic vowels, or to nonspeech stimuli matched to the vowel sounds in terms of their long-term energy and both their spectral and temporal profiles. The vowels produced more activation than nonspeech sounds in a bilateral region of the superior temporal sulcus, lateral and inferior to regions of auditory cortex that were activated by both vowels and nonspeech stimuli. The results suggest that the perception of vowel sounds is compatible with a hierarchical model of primate auditory processing in which early cortical stages of processing respond indiscriminately to speech and nonspeech sounds, and only higher regions, beyond anatomically defined auditory cortex, show selectivity for speech sounds.

Adult↗

PubMed2005

New evidence for morphological errors in deep dyslexia.

Morphological errors in reading aloud (e.g., sexist-->sexy) are a central feature of the symptom-complex known as deep dyslexia, and have historically been viewed as evidence that representations at some level of the reading system are morphologically structured. However, it has been proposed (Funnell, 1987) that morphological errors in deep dyslexia are not morphological in nature but are actually a type of visual error that arises when a target word that cannot be read aloud (by virtue of its low imageability and/or frequency) is modified to form a visually similar word that can be read aloud (by virtue of its higher imageability and/or frequency). In the work reported here, the deep dyslexic patient DE read aloud lists of genuinely suffixed words (e.g., killer), pseudosuffixed words (e.g., corner), and words with non-morphological embeddings (e.g., cornea). Results revealed that the morphological status of a word had a significant influence on the production of stem errors (i.e., errors that include the stem or pseudostem of the target): genuinely suffixed words yielded more stem errors than pseudosuffixed words or words with non-morphological embeddings. This effect of morphological status could not be attributed to the relative levels of target and stem imageability and/or frequency. We argue that this pattern of data indicates that apparent morphological errors in deep dyslexic reading are genuinely morphological, and discuss the implications of these errors for theories of deep dyslexia.

Dyslexia↗

PubMed2005

Temporal and frontal systems in speech comprehension: an fMRI study of past tense processing.

A prominent issue in cognitive neuroscience is whether language function is instantiated in the brain as a single undifferentiated process, or whether regions of relative specialisation can be demonstrated. The contrast between regular and irregular English verb inflection has been pivotal to this debate. Behavioural dissociations related to different lesion sites in brain-damaged patients suggest that processing regular and irregular past tenses involves different neural systems. Using event-related fMRI in a group of unimpaired young adults, we contrast processing of spoken regular and irregular past tense forms in a same-different judgement task, shown in earlier research with patients to engage left hemisphere language systems. An extensive fronto-temporal network, linking anterior cingulate (ACC), left inferior frontal cortex (LIFC) and bilateral superior temporal gyrus (STG), was preferentially activated for regularly inflected forms. Access to meaning from speech is supported by temporal cortex, but additional processing is required for forms that end in regular inflections, which differentially engage LIFC processes that support morpho-phonological segmentation and grammatical analysis.

Adolescent↗

PubMed2005

Dissociating neuro-cognitive component processes: voxel-based correlational methodology.

Relating behavioural deficits to lesion site has long been an important tool for localising the brain bases of cognitive function. Voxel-based methods, based on statistical analyses of structural brain images, allow a major step forward in the effectiveness of this approach. These methods provide a fine-grained assessment of damaged tissue by assigning a continuous value to each voxel over the entire brain. This information, correlated with continuous behavioural data reflecting specific aspects of cognition, offers new opportunities for identifying the neural organisation underlying cognitive function. The research reported here demonstrates the ability of this correlational methodology to differentiate between the neuro-cognitive components involved in word recognition and lexical decision, providing an important new tool for directly linking brain areas to specific aspects of psychological performance.

Acoustic Stimulation↗