A computational model of the effect of gene misexpression on the development of cortical areas.

Brain function depends on the specialisation of brain areas. In the murine cerebral cortex, the development of these areas depends on the coordinated expression of several genes in precise spatial patterns in the telencephalon during embryogenesis. Manipulating the expression of these genes during development alters the positions and sizes of cortical areas in the adult.

A Boolean model of the gene regulatory network underlying Mammalian cortical area development.

The cerebral cortex is divided into many functionally distinct areas. The emergence of these areas during neural development is dependent on the expression patterns of several genes. Along the anterior-posterior axis, gradients of Fgf8, Emx2, Pax6, Coup-tfi, and Sp8 play a particularly strong role in specifying areal identity.

The influence of restricted orientation rearing on map structure in primary visual cortex.

Visual experience is critical to the development of the structure of the primary visual cortex and, in turn, normal functional vision. The primary visual cortex contains maps of multiple features of the visual input, and these maps are characterised by specific types of geometric relationships. Manipulations of the visual environment during development in animals such as ferrets, cats and monkeys provide an opportunity to probe the rules governing map formation via their effect on these relationships.

Natural scene statistics and the structure of orientation maps in the visual cortex.

Visual activity after eye-opening influences feature map structure in primary visual cortex (V1). For instance, rearing cats in an environment of stripes of one orientation yields an over-representation of that orientation in V1. However, whether such changes also affect the higher-order statistics of orientation maps is unknown.

Analysis of the growth cone turning assay for studying axon guidance.

The "pipette" or "growth cone turning" assay is widely used for studying how axons respond to diffusible guidance cues in their environment. However, little quantitative analysis has been presented of the gradient shapes produced by this assay, or how they depend on parameters of the assay. Here we used confocal microscopy of fluorescent gradients to characterize these shapes in 3 dimensions.

The effect of angioscotomas on map structure in primary visual cortex.

When blood vessels occlude the photoreceptor layer in the retina, they cast shadows onto the photoreceptors, creating angioscotomas (regions of the visual field to which that eye is blind). Remarkably, Adams and Horton (2002) have recently shown that it is sometimes possible to observe representations of these angioscotomas anatomically in the primary visual cortices of squirrel monkeys. However, there is substantial variability in the degree and form of these representations.

Study of optical properties of electropolymerized melanin films by photopyroelectric spectroscopy.

Photopyroelectric (PPE) spectroscopy, in the 350-1,075 nm wavelength range, was used to study the optical properties of electropolymerized melanin films on indium tin oxide (ITO) coated glass. The PPE intensity signal as a function of the wavelength lambda, V (n)(lambda) and its phase F (n)(lambda) were independently measured. Using the PPE signal intensity and the thermal and optical properties of the pyroelectric detector, we were able to calculate the optical absorption coefficient beta of melanin in the solid-state.