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P Mathews

Publications and source records attributed to P Mathews.

21 records · Page 2Linked to original sources

The phonology-morphosyntax interface: affixed words in agrammatism.

In three experiments with nondysarthric agrammatics, we explored the association between phonology and morphosyntax. (1) Contrasting phonological and nonphonological factors on inflectional-affix production of English verbs across three tasks in eight agrammatics, longer stem-syllabic length and stem-final-CC status resulted in poorer affix-production. (2) Studying verb inflections in six agrammatic Spanish-speakers, affix-length and affix-stress correlated with poorer repetition, as did low affix frequency. (3) Four English-speaking agrammatics read aloud and repeated derived words varying in syllable-length and stem-stress reassignment; both contributed independently to word-production difficulty. Phonological complexity of affixes and stems appears to reduce resources for morphological processing in nondysarthric agrammatics.

Aphasia, Broca↗

Normal brain development in PS1 hypomorphic mice with markedly reduced gamma-secretase cleavage of betaAPP.

Presenilin 1-null mice die at birth from brain and skeletal developmental deformities due to disrupted Notch signaling. Presenilin 1-null mice also have severely reduced gamma-secretase cleavage of betaAPP. The assumption has been that facilitation of Notch signaling and betaAPP processing by presenilin 1 are analogous functions. Here we describe a presenilin 1-targetted mouse model that expresses extremely low levels ( approximately 1% of normal) of mutant PS1-M146L. Homozygous mice have significantly reduced viability due to a Notch-like phenotype. The animals that survive have severe axial skeletal deformities and markedly diminished gamma-secretase activity and accumulation of betaAPP-C100, but no obvious abnormalities in brain development. These results suggest that, in mice, a marked reduction of PS1-facilitated gamma-secretase activity is not detrimental to normal brain development.

Amyloid Precursor Protein Secretases↗