Biomedical subjects

M J Wainwright

Publications and source records attributed to M J Wainwright.

4 recordsLinked to original sources

PubMed1999

Visual adaptation as optimal information transmission.

We propose that visual adaptation in orientation, spatial frequency, and motion can be understood from the perspective of optimal information transmission. The essence of the proposal is that neural response properties at the system level should be adjusted to the changing statistics of the input so as to maximize information transmission. We show that this principle accounts for several well-documented psychophysical phenomena, including the tilt aftereffect, change in contrast sensitivity and post-adaptation changes in orientation discrimination. Adaptation can also be considered on a longer time scale, in the context of tailoring response properties to natural scene statistics. From the anisotropic distribution of power in natural scenes, the proposal also predicts differences in the contrast sensitivity function across spatial frequency and orientation, including the oblique effect.

Adaptation, Ocular↗

PubMed1998

Adenovirus-mediated transduction of intestinal cells in vivo.

The intestinal tract has many features that make it an attractive target for therapeutic gene transfer. In this study, replication-defective adenoviral vectors were used to explore parameters that may be important in administering gene therapy vectors to the intestine. After surgically accessing the intestine, an E1-, E3-deleted adenoviral vector encoding beta-galactosidase (beta-Gal) was directly injected into various regions of the small and large intestine of rats and rabbits. Significant transduction of the tissue was observed and histochemical staining was used to identify enterocytes as the primary targets of gene transfer. Expression of beta-Gal did not differ substantially when the virus was administered to the duodenum, ileum, or colon. When the vector was directly administered to segments of the distal ileum containing a Peyer's patch, transgene expression was approximately 10-fold higher than in segments lacking a Peyer's patch. In the Peyer's patches, a high level of expression was localized to epithelial cells, potentially M cells, overlying the lymphoid follicle domes. Transduction of these cells could have application in DNA-mediated oral vaccination. Administration of an adenoviral vector encoding a secreted alkaline phosphatase to the lumen resulted in expression and secretion of this gene product into the circulation. This finding demonstrates the potential of enterocytes to serve as heterotopic sites for the synthesis of heterologous gene products that would be secreted into the lumen of the intestinal tract or into the bloodstream.

Adenoviridae↗

PubMed1996

Response bias correction in the process dissociation procedure: a reevaluation?

A Buchner and E. Erdfelder (this volume) provide a commentary on our analysis of response bias correction in the process dissociation procedure. Unfortunately, this commentary fails to address the substantive issues that were raised in M. J. Wainwright and E. M. Reingold (1996). In the present article, we attempt to clarify some of their misrepresentations and the inconsistency inherent in their position.

Attention↗

PubMedDate not supplied

Response bias correction in the process dissociation procedure: approaches, assumptions, and evaluation.

Buchner, Erdfelder, and Vaterrodt-Plunnecke (1995) advocated an exposition of the process dissociation procedure within the framework of multinomial modeling. Among the misleading aspects of this exposition is its tendency to obscure the overlap between processes. In contrast, clarifying these crucial interactions leads to a general classification of response bias corrections to the process dissociation procedure. This scheme, in which corrective models are classified on the basis of process interactions, clarifies the assumptions underlying previously proposed corrections. As an illustration of the framework, three such corrections are derived. These corrective models are evaluated by applying them to the data reported by Buchner et al. (1995).

Association Learning↗