This interdisciplinary project will use mathematical modelling, in
conjunction with psychophysics (human perception experiments), to better
understand the neural competition underpinning the dynamics of
perception. Ambiguity in fixed sensory stimuli can lead to spontaneous
switches in perception, both in vision, e.g. binocular rivalry, Necker
cube, and audition, e.g. auditory streaming (switches between grouped or
segregated interpretations of tone sequences). A set of common
characteristics (inevitability of perceptual changes, exclusivity
between the competing percepts, and randomness in the percept
durations), generalise across sensory modalities. The neural competition
driving these perceptual switches has been successfully modelled in
small networks of Wilson-Cowan (firing rate) units, each associated with
the different perceptual interpretations. For certain stimuli, where
competition takes place across a continuous feature space (say, visual
orientation, motion direction, or auditory pitch), a continuum model,
such as the neural field equation can be applied. This PhD project will
involve the derivation of perceptual competition models in a dynamical
systems framework, based on plausible neural mechanisms commonly found
in sensory cortex. Modelling hypotheses and predictions will be tested
against experimental data collected in our lab or from collaborators. On
the modelling side, tools from bifurcation analysis including numerical
continuation will be applied to investigate dynamics. The project will
be flexible in terms of the balance between modelling and experiments.
Candidates with quantitative backgrounds (mathematics, physics, and
engineering) and from neuroscience or psychology programmes are
encouraged to apply. Programming experience and/or knowledge of
dynamical systems theory is a plus.
Contact:
j.a.rankin@exeter.ac.uk Informal enquiries welcome.