Dynamic Amodal Completion Through the Magic Wand Illusion

In the Magic Wand effect, an overlying figure of the same color as its background is revealed by the motion of a wand behind it. The occluding figure is inferred by integration of the occluding edge information over time. The overlying figure is perceived by modal completion, while the wand and the background underneath are perceived by amodal completion. This illusion is compared with its predecessor from nearly two centuries ago, the Plateau Anorthoscopic Illusion, in which an object is recognizable when moved behind a slit

Comprehensive analysis of the retinal cell contributions to the human ERG

Purpose. Standard electroretinogram (ERG) protocols are largely designed to isolate the responses of the rod and cone retinal pathways, including the use of adapting backgrounds to suppress unwanted off-pathway responses. Here, we record spectral ERGs in the low-to-high mesopic sensitivity range in the absence of any adapting background in order to assess interactions between the pathways. Methods. We have developed a comprehensive neuroanalytic model of the component structure of the ERG driven by knowledge of the underlying retinal physiology, to enhance its power as a critical diagnostic tool for a broad range of both retinal and systemic dysfunctions. The ERG is conceptualized as a highly diagnostic signal of the retinal subsystems, each consisting of: an a-wave (photoreceptor extracellular current flow), a b-wave (transient bipolar cells), an inner retinal photopic negative response (PhNR; ganglion cells), and a melanopsin response (intrinsic ganglion-cell light response). This model is applied to an array of full-field spectral ERGs over a range of colors and intensities. Results and Conclusion. Most of these response components are driven by both the rod and cone photoreceptor types, thus constituting about a dozen distinct components of the ERG, differentiated according to post-stimulus time of expression and the light level. At every light level, rod-driven components are typically slower than cone-driven components, equated for quantum catch. This neuroanalytic approach has been applied to a variety of spectral ERG datasets to account for as much as 95% of the variance of the ERG

The Emergent Aspect Dualism View of Quantum Physics: A New Ontology to Resolve the Complementarity Conundrum

To resolve the conceptual problem of the conflict between quantal and relativistic formulations of Quantum Physics, this paper proposes a new conceptual ontology, Emergent Aspect Dualism, that reconceptualizes the foundations of the field. Emergent Aspect Dualism is a philosophical approach that starts from the assumption is that the primary “material” of the universe is energy, which can be manifested as kinetic energy, potential energy or matter. The flow of such energy throughout the universe is described by the continuous Schrödinger Equation, but in order to account for the hierarchy of levels of organization reality, we need to invoke the concept of emergence, under which the operative principles of each level of organization of this energy are entirely dissociated from those of the levels below it, and, crucially, the functional emergence of the properties of the conscious mind that are dualistically dissociated from the underlying biochemical principles of brain organization. Rather than assigning probabilities to the quantal realm, Emergent Aspect Dualism treats probability as an operational concept that can be held only by a conscious mind, a philosophical category that incorporates the properties of a) the superposition of states and b) the collapse of this superposition once an observation is made

The Fundamental Nature of Time

The nature of time is intimately bound up with the nature of energy propagation, which has a long history of its philosophical understanding. Here I propose a new post-Einsteinian view of the nature of time, conceptualized as the outcome of the pure unidimensional rate of change of a process through the infinitesimal operator of differential equations. In this view, time is a local property that is generated by every individual process in the Universe rather than a fundamental dimension in which processes operate. The rate of change has an inherent “arrow of time” that does not depend on the ensemble properties of multiple processes, such as the laws of entropy, but is inherent to the function of each process, by virtue of its genesis in the Big Bang. The conventional view of time may be approximated either by aggregating the operations of large ensembles of diverse processes, or by choosing a process (such as the Atomic Clock) that has demonstrably stable temporal properties. For processes that are sufficiently nonlinear, their iterative progression may in principle lead to solutions describable as fractals, for which the integral derivation of the time variable would fractionate into a form of fractal time

The Role of the Visual Arts in Enhancing the Learning Process

With all the wealth of scientific activities, there remains a certain stigma associated with careers in science, as a result of the inevitable concentration on narrow specializations that are inaccessible to general understanding. Enhancement of the process of scientific learning remains a challenge, particularly in the school setting. While direct explanation seems the best approach to expedite learning any specific subject, it is well known that the ability to deeply absorb facts and concepts is greatly enhanced by placing them in a broader context of relevance to the issues of everyday life and to the larger goals of improvement of the quality of life and advancement to a more evolved society as a whole. If the sciences can be associated with areas of artistic endeavor, they may be viewed as more accessible and favorable topics of study. There is consequently an urgent need for research in the relationship between learning and experience in the arts because both art education and scientific literacy remain at an inadequate level even in economically advanced countries. The focus of this review is the concept that inspiration is an integral aspect of the artistic experience, both for the artist and for the viewer of the artwork. As an integrative response, inspiration involves not only higher cortical circuitry but its integration with the deep brain structures such as limbic system and medial frontal structures, which are understood to mediate the experience of emotions, motivational rewards, and the appreciation of the esthetic values of the impinging stimuli. In this sense, inspiration can turn almost any occupation in life into an avocation, a source of satisfaction in achieving life goals. Conversely, when inspiration is lacking, the motivation to learn, adapt, and prosper is impeded. Thus, inspiration may be viewed as a potent aspect of human experience in linking art and science

Consequences of traumatic brain injury for human vergence dynamics

Purpose: Traumatic brain injury involving loss of consciousness has focal effects in the human brainstem, suggesting that it may have particular consequences for eye movement control. This hypothesis was investigated by measurements of vergence eye movement parameters. Methods: Disparity vergence eye movements were measured for a population of 123 normally sighted individuals, 26 of whom had suffered diffuse traumatic brain injury (dTBI) in the past, while the remainder served as controls. Vergence tracking responses were measured to sinusoidal disparity modulation of a random-dot field. Disparity vergence step responses were characterized in terms of their dynamic parameters separately for the convergence and divergence directions. Results: The control group showed notable differences between convergence and divergence dynamics. The dTBI group showed significantly abnormal vergence behavior on many of the dynamic parameters. Conclusion: The results support the hypothesis that occult injury to the oculomotor control system is a common residual outcome of dTBI

Traversing the Highwire from Pop to Optical

A visual neuroscientist comments on the art of Roy Lichtenstein, as viewed in a recent exhibition at the San Francisco Museum of Modern Ar

Relative contributions of sustained and transient pathways to human stereoprocessing

AbstractIt has been proposed [Hubel & Livingstone (1987) Journal of Neuroscience, 7, 3378–3415] that stereopsis is mediated solely by magnocellular pathway in primates. This hypothesis was evaluated for humans in psychophysical experiments with dynamic random-noise stimuli, based on the sustained/transient relationship of behavior mediated by the two divisions of the LGN [Merigan & Maunsell (1993) Annual Review of Neuroscience, 16, 369–402]. The stereoscopic limits show that stereoscopic system is more sensitive to sustained random-dot stimuli than to transient ones. Quantitative modeling of the result implied a weak role for magnocellular input, suggests that human stereopsis is more strongly influenced by parvocellular input through the LGN