Spike Processing on an Embedded Multi-task Computer: Image Reconstruction

There is an emerging philosophy, called Neuro-informatics, contained in the Artificial Intelligence field, that aims to emulate how living beings do tasks such as taking a decision based on the interpretation of an image by emulating spiking neurons into VLSI designs and, therefore, trying to re-create the human brain at its highest level. Address-Event-Representation (AER) is a communication protocol that has embedded part of the processing. It is intended to transfer spikes between bioinspired chips. An AER based system may consist of a hierarchical structure with several chips that transmit spikes among them in real-time, while performing some processing. There are several AER tools to help to develop and test AER based systems. These tools require the use of a computer to allow the higher level processing of the event information, reaching very high bandwidth at the AER communication level. We propose the use of an embedded platform based on a multi-task operating system to allow both, the AER communication and processing without the requirement of either a laptop or a computer. In this paper, we present and study the performance of a new philosophy of a frame-grabber AER tool based on a multi-task environment. This embedded platform is based on the Intel XScale processor which is governed by an embedded GNU/Linux system. We have connected and programmed it for processing Address-Event information from a spiking generator.Ministerio de Educación y Ciencia TEC2006-11730-C03-0

A Global Workspace perspective on mental disorders

Recent developments in Global Workspace theory suggest that human consciousness can suffer interpenetrating dysfunctions of mutual and reciprocal interaction with embedding environments which will have early onset and often insidiously staged developmental progression, possibly according to a cancer model. A simple rate distortion argument implies that, if an external information source is pathogenic, then sufficient exposure to it is sure to write a sufficiently accurate image of it on mind and body in a punctuated manner so as to initiate or promote simililarly progressively punctuated developmental disorder. There can, thus, be no simple, reductionist brain chemical 'bug in the program' whose 'fix' can fully correct the problem. On the contrary, the growth of an individual over the life course, and the inevitable contact with a toxic physical, social, or cultural environment, can be expected to initiate developmental problems which will become more intrusive over time, most obviously according to some damage accumulation model, but likely according to far more subtle, highly punctuated, schemes analogous to tumorigenesis. The key intervention, at the population level, is clearly to limit such exposures, a question of proper environmental sanitation, in a large sense, a matter of social justice which has long been understood to be determined almost entirely by the interactions of cultural trajectory, group power relations, and economic structure, with public policy. Intervention at the individual level appears limited to triggering or extending periods of remission, as is the case with most cancers

Region Adjacency Graph Approach for Acral Melanocytic Lesion Segmentation

Malignant melanoma is among the fastest increasing malignancies in many countries. Due to its propensity to metastasize and lack of effective therapies for most patients with advanced disease, early detection of melanoma is a clinical imperative. In non-Caucasian populations, melanomas are frequently located in acral volar areas and their dermoscopic appearance differs from the non-acral ones. Although lesion segmentation is a natural preliminary step towards its further analysis, so far virtually no acral skin lesion segmentation method has been proposed. Our goal was to develop an effective segmentation algorithm dedicated for acral lesions

The modularity of processing and perception in the visual brain

Practical and theoretical approaches were applied to try to unravel the relationship of the anatomical processing sites to the relative timing of processing and perception. Psychophysical, imaging and theoretical studies led to the overall conclusion that simultaneously presented attributes that are perceived at the same time are processed at the same site, and ones that are perceived at different times are processed at different sites. This is referred to as to the theory of perceptual sites. Functional magnetic resonance imaging (fMRI) experiments charted the organisation of the human colour centre (the V4-complex), and found it to be more complex than previously believed. It has two subdivisions, V4 and V4α, of which V4 is retinotopically organised, while V4α is not. The extent and organisation of the colour centre revealed in this study may account for the variability and severity of the syndrome of achromatopsia (acquired cortical colour blindness). Application of an independent components analysis (ICA) to fMRI data showed that these two subdivisions are coactive and can be isolated together from the remaining brain activity. It was further shown that, because cortical areas enjoy substantial autonomy, they differ in their activation time courses, such that ICA can dissect the brain computationally into its functional units, creating what we call chronoarchitectonic maps. The above evidence, when viewed in context of previous experimental and clinical studies, leads us to propose the following: First, that the activity in different visual areas reaches conscious perceptual endpoints at different times; leading to the supposition that consciousness is not unitary but consists of many microconsciousnesses. Second, that since activity at each processing site can become perceptually explicit, there is no terminal perceptual stage in the visual brain; leading to the conclusion that activity at each site of the visual brain can be integrated with activity at any other site, and to the theory of multistage integration

Entering the blackboard jungle: canonical dysfunction in conscious machines

The central paradigm of Artificial Intelligence is rapidly shifting toward biological models for both robotic devices and systems performing such critical tasks as network management and process control. Here we apply recent mathematical analysis of the necessary conditions for consciousness in humans in an attempt to gain some understanding of the likely canonical failure modes inherent to a broad class of global workspace/blackboard machines designed to emulate biological functions. Similar problems are likely to confront other possible architectures, although their mathematical description may be far less straightforward