Biomedical subjects

Jenny J Naji

Publications and source records attributed to Jenny J Naji.

3 recordsLinked to original sources

PubMed2006

Pharmaceutical, cellular and genetic therapies for Huntington's disease.

HD (Huntington's disease) is a devastating neurodegenerative disorder caused by a polyglutamine expansion in the gene encoding the huntingtin protein. Presently, there is no known cure for HD and existing symptomatic treatments are limited. However, recent advances have identified multiple pathological mechanisms involved in HD, some of which have now become the focus of therapeutic intervention. In this review, we consider progress made towards developing safe and effective pharmaceutical-, cell- and genetic-based therapies, and discuss the extent to which some of these therapies have been successfully translated into clinical trials. These new prospects offer hope for delaying and possibly halting this debilitating disease.

Animals↗

PubMed2004

Perceiving depth order during pursuit eye movement.

Pursuit eye movements alter retinal motion cues to depth. For instance, the sinusoidal retinal velocity profile produced by a translating, corrugated surface resembles a sinusoidal shear during pursuit. One way to recover the correct spatial phase of the corrugation's profile (i.e. which part is near and which part is far) is to combine estimates of shear with extra-retinal estimates of translation. In support of this hypothesis, we found the corrugation's spatial phase appeared ambiguous when retinal shear was viewed without translation, but unambiguous when translated and viewed with or without a pursuit eye movement. The eyes lagged the sinusoidal translation by a small but persistent amount, raising the possibility that retinal slip could serve as the disambiguating cue in the eye-moving condition. A yoked control was therefore performed in which measured horizontal slip was fed back into a fixated shearing stimulus on a trial-by-trial basis. The results showed that the corrugation's phase was only seen unambiguously during the real eye movement. This supports the idea that extra-retinal estimates of eye velocity can help disambiguate ordinal depth structure within moving retinal images.

Cues↗

PubMed2002

Head-centred motion perception in the ageing visual system.

Stationary objects appear to move in the opposite direction to a pursuit eye movement (Filehne illusion) and moving objects appear slower when pursued (Aubert-Fleischl phenomenon). Both illusions imply that extra-retinal, eye-velocity signals lead to lower estimates of speed than corresponding retinal motion signals. Intriguingly, the velocity (i.e. speed and direction) of the Filehne illusion depends on the age of the observer, especially for brief display durations (Wertheim and Bekkering, 1992). This suggests relative signal size changes as the visual system matures. To test the signal-size hypothesis, we compared the Filehne illusion and Aubert-Fleischl phenomenon in young and old observers using short and long display durations. The trends in the Filehne data were similar to those reported by Wertheim and Bekkering. However, we found no evidence for an effect of age or duration in the Aubert-Fleischl phenomenon. The differences between the two illusions could not be reconciled on the basis of actual eye movements made. The findings suggest a more complicated explanation of the combined influence of age and duration on head-centred motion perception than that described by the signal-size hypothesis.

Adult↗