A psychoengineering paradigm for the neurocognitive mechanisms of biofeedback and neurofeedback.

We believe that the missing keystone to design effective and efficient biofeedback and neurofeedback protocols is a comprehensive model of the mechanisms of feedback learning. In this manuscript we review the learning models in behavioral, developmental and cognitive psychology, and derive a synthetic model of the psychological perspective on biofeedback. We afterwards review the neural correlates of feedback learning mechanisms, and present a general neuroscience model of biofeedback. We subsequently show how biomedical engineering principles can be applied to design efficient feedback protocols. We finally present an integrative psychoengineering model of the feedback learning processes, and provide new guidelines for the efficient design of biofeedback and neurofeedback protocols. We identify five key properties, (1) perceptibility=can the subject perceive the biosignal?, (2) autonomy=can the subject regulate by himself?, (3) mastery=degree of control over the biosignal, (4) motivation=rewards system of the biofeedback, and (5) learnability=possibility of learning. We conclude with guidelines for the investigation and promotion of these properties in biofeedback protocols.

Short wavelength-automated perimetry compared with standard achromatic perimetry in autosomal dominant optic atrophy.

BACKGROUND: Autosomal dominant optic atrophy (ADOA, Kjer-type) is a heterogeneous, non-inflammatory degeneration of retinal ganglion cells. The diagnosis of ADOA can be challenging owing to its insidious onset and large variability in phenotypic expression, both within and between individual pedigrees. The earliest literature reports relatively mild centrocaecal scatomas to white targets in ADOA, but extensive and dense peripheral field loss to coloured targets, especially blue, with Bjerrum perimetry. The phrase "inverted peripheral visual fields to coloured targets" has been used to describe this phenomenon. METHODS: Humphrey standard achromatic perimetry (SAP) and short wavelength-automated perimetry (SWAP) were carried out on five patients with ADOA. RESULTS: Regardless of wide variations in patient age, visual acuity, disc appearance and colour vision, the SWAP mean deviation (MD) was between 10 and 20 times more depressed than the SAP MD. The actual differences ranged from 9.38 to 13.78 dB. CONCLUSIONS: These data are consistent with the original reports suggesting that, early in this disease process, the blue-target deficits are typically peripheral and that this difference between SAP and SWAP perimetry may be a robust indicator of ADOA in both early and late stages of this disease.

A quick and efficient system for antibiotic-free expression of heterologous genes in tobacco roots.

Requirement for antibiotic-resistance selection markers and difficulty in identifying transgenes with the highest expression levels remain the major obstacles for rapid production of recombinant proteins in plants. An alternative approach to producing transgenic plants free of antibiotic-resistance markers is the phenotypic-based selection with root-proliferation genes (rol genes) of Agrobacterium rhizogenes. By using Agrobacterium tumefaciens harboring the pRYG transformation vector with a cluster of rol genes linked to a heterologous gene of interest, we have developed a rapid transformation tool using hairy root formation as a selection marker. The expression of beta-glucuronidase in newly induced transgenic tobacco roots could be detected as early as 12 days after inoculation. Higher levels of transgene expression in the roots correlated positively with the rates of root elongation on hormone-free medium and thus could be used for positive selection. When tobacco plants were transformed with pRYG harboring the expression cassette for secreted alkaline phosphatase (SEAP), the release of SEAP from roots of the fully regenerated transgenic plants could be quantified at rates as high as 28 microg/g root dry weight per day.

Rhizosecretion of recombinant proteins from plant hairy roots.

Rhizosecretion of a target protein in the hydroponic medium provides an alternative manufacturing platform that simplifies the downstream purification procedure and increases protein yield. In order to increase the production rates of rhizosecreted proteins, we have exploited the ability of Agrobacterium rhizogenes to induce the formation of large amounts of root tissue on transgenic tobacco plants engineered to secrete a model recombinant protein, human secreted alkaline phosphatase (SEAP). The secretion of SEAP from hairy roots induced on the stems of transgenic tobacco plants was 5-7 times higher than that from adventitious transgenic roots.