RANKIN , James

The existence of spatially localized solutions in neural networks is an important topic in neuroscience as these solutions are considered to characterize working (short-term) memory. We work with an unbounded neural network represented by the neural field equation with smooth firing rate function and a wizard hat spatial connectivity. Noting...

The existence of spatially localized solutions in neural networks is an important topic in neuroscience as these solutions are considered to characterize work- ing (short-term) memory. We work with an unbounded neural network represented by the neural field equation with smooth firing rate function and a wizard hat spatial connectivity. Noting...

We analyse radially symmetric localized bump solutions of an integro-differential neural field equation posed in Euclidean and hyperbolic geometry. The connectivity function and the nonlinear firing rate function are chosen such that radial spatial dynamics can be considered. Using integral transforms, we derive a partial differential equation...

The phenomenon of perceptual multistability in which alternate interpretations of a fixed stimulus are perceived intermittently is an active area of research and the underlying mechanisms that gate perception are little understood. Numerical tools from bifurcation analysis are applied to the study of a competition model posed as a feature-only...

Animals exploit antagonistic interactions for sensory processing and these can cause oscillations between competing states. Ambiguous sensory inputs yield such perceptual multi-stability. Despite numerous empirical studies using binocular rivalry or plaid pattern motion, the driving mechanisms behind the spontaneous transitions between...

A computational study into the motion perception dynamics of a multistable psychophysics stimulus is presented. A diagonally drifting grating viewed through a square aperture is perceived as moving in the actual grating direction or in line with the aperture edges (horizontally or vertically). The different percepts are the product of interplay...

The phenomenon of perceptual multistability in which alternate interpretations of a fixed stimulus are perceived intermittently is an active area of research and the underlying mechanisms that gate perception are little understood. Numerical tools from bifurcation analysis are applied to the study of a competition model posed as a feature-only...

The phenomenon of perceptual multistability in which alternate interpretations of a fixed stimulus are perceived intermittently is an active area of research and the underlying mechanisms that gate perception are little understood. Numerical tools from bifurcation analysis are applied to the study of a competition model posed as a feature-only...

We studied the temporal dynamics of perceptual switches that are known to occur during prolonged presentations of a multi-stable visual motion stimulus using a neural fields, population-level representation of cortical activity in the middle temporal (MT) visual area. The so-called 'barber pole'' stimulus is considered with an aperture...

A computational study into the motion perception dynamics of a multistable psychophysics stimulus is presented. A diagonally drifting grating viewed through a square aperture is can be perceived as moving in the actual grating direction or in line with the aperture edges (horizontally or vertically). The different percepts are the product of...

We used an obliquely oriented moving luminance grating within a square aperture as a stimulus. We probed how the aperture problem (determining direction of a contour within an aperture) is solved following onset. It is perceived to move in horizontally (H), diagonally (D) or vertically (V), shifting perception during extended presentation. The...

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We use a mathematical model to investigate the early temporal dynamics of motion integration with a multistable input. A drifting grating stimulus is considered with an aperture configuration that supports horizontal (H), diagonal (D) or vertical (V) perceived directions for the same input. A shift in perceptual dominance from D to either H/V...

When an obliquely moving sine wave grating is presented inside a square aperture, observers are faced with a conflict of local motion signals resulting from the "aperture problem". Motion signals along the grating contours on average have a diagonal direction (D) while those near the horizontal (H) and vertical (V) edges lie along these...

In sensory systems, a range of computational rules are presumed to be implemented by neuronal subpopulations with di erent tuning functions. For instance, in primate cortical area MT, di erent classes of direction-selective cells have been identi ed and related either to motion integration, segmentation or transparency. Still, how such di erent...

We study localised activity patterns in neural field equations posed on the Euclidean plane; such models are commonly used to describe the coarse-grained activity of large ensembles of cortical neurons in a spatially continuous way. We employ matrix-free Newton-Krylov solvers and perform numerical continuation of localised patterns directly on...

In sensory systems, different computational rules are postulated to be implemented by different neuronal subpopulations, each one being characterised by a particular tuning function. For instance, in primate cortical area MT, different classes of direction-selective cells have been identified and related to either motion integration,...

We study localised activity patterns in neural field equations posed on the Euclidean plane; such models are commonly used to describe the coarse-grained activity of large ensembles of cortical neurons in a spatially continuous way. We employ matrix-free Newton-Krylov solvers and perform numerical continuation of localised patterns directly on...

A ring network model under neural fields formalism with a structured input is studied. Bifurcation analysis is applied to understand the behaviour of the network model under different connectivity regimes and input conditions. The parameter regimes over which the localised input bumps could be preserved, combined or selected are used to...