T Poston | PubMed Health

PubMed1997

The Brain Bench: virtual tools for stereotactic frame neurosurgery.

We present a suite of neurosurgery supporting tools developed around (i) the Virtual Workbench, a productive environment for the control of 3-D data, in which delicate work can be performed for hours on end without strain, and (ii) the Electronic Brain Atlas, integrating the major print brain atlases in day-to-day clinical use. We describe in detail the Brain Bench, a surgical planning system for stereotactic frame neurosurgery. Its objective is to prepare faster plans; have a better and more accurate choice of target points; improve the avoidance of sensitive structures; have fewer sub-optimal frame attachments and speedier, more effective planning and training. If validated by a clinical study now under way, this will improve medical efficacy and reduce costs.

Brain↗

PubMed1978

Nonlinear modeling of multistable perception.

Multistable figures show that the stimulus-percept relation is not a single valued function. We therefore propose a tentative nonlinear model on the hypothesis that the graph of this relation is the equilibrium set of a dynamic system. For simplicity and to obtain testable predictions, we consider a system whose bifurcations are gradient-like and thus generically described by the elementary catastrophes. We motivate this general model, and then show how, in conjunction with the principle of minimal singularity, it implies cusp catastrophe geometry in a specific perceptual example. Indeed, we argue for canonical cusp geometry in this case. The model incorporates naturally certain observed features of multistable perception, such as hysteresis and bias effects. Despite being a continuum model it is naturally compatible with the subjective dichotomy of bistable perception. The model makes testable predictions which may easily be extended to other specific examples of multistable perception.

Humans↗