In this paper I argue for the cognitive impenetrability of perception by undermining the argument from reentrant pathways. To do that I will adduce psychological and neuropsychological evidence showing that (a) early vision processing is not affected by our knowledge about specific objects and events, and (b) that the role of the descending pathways is to enable the early-vision processing modules to participate in higher-level visual or cognitive functions. My thesis is that a part of observation, which I (...) will call perception, is bottom-up and theory neutral. As such, perception could play the role of common ground on which a naturalized epistemology can be built and relativism avoided. (shrink)
The search for neural correlates of consciousness (or NCCs) is arguably the cornerstone in the recent resurgence of the science of consciousness. The search poses many difficult empirical problems, but it seems to be tractable in principle, and some ingenious studies in recent years have led to considerable progress. A number of proposals have been put forward concerning the nature and location of neural correlates of consciousness. A few of these include.
Theories of binding have recently come into the focus of the consciousness debate. In this review, we discuss the potential relevance of temporal binding mechanisms for sensory awareness. Specifically, we suggest that neural synchrony with a precision in the millisecond range may be crucial for conscious processing, and may be involved in arousal, perceptual integration, attentional selection and working memory. Recent evidence from both animal and human studies demonstrates that specific changes in neuronal synchrony occur during all of these (...) processes and that they are distinguished by the emergence of fast oscillations with frequencies in the gamma-range. (shrink)
Neural correlates exist for a basic component of logical formulae, PREDICATE(x). Vision and audition research in primates and humans shows two independent neuralpathways; one locates objects in body-centered space, the other attributes properties, such as colour, to objects. In vision these are the dorsal and ventral pathways. In audition, similarly separable “where” and “what” pathways exist. PREDICATE(x) is a schematic representation of the brain's integration of the two processes of delivery by the senses of (...) the location of an arbitrary referent object, mapped in parietal cortex, and analysis of the properties of the referent by perceptual subsystems. The brain computes actions using a few “deictic” variables pointing to objects. Parallels exist between such nonlinguistic variables and linguistic deictic devices. Indexicality and reference have linguistic and nonlinguistic (e.g., visual) versions, sharing the concept of attention. The individual variables of logical formulae are interpreted as corresponding to these mental variables. In computing action, the deictic variables are linked with “semantic” information about the objects, corresponding to logical predicates. Mental scene descriptions are necessary for practical tasks of primates, and preexist language phylogenetically. The type of scene descriptions used by nonhuman primates would be reused for more complex cognitive, ultimately linguistic, purposes. The provision by the brain's sensory/perceptual systems of about four variables for temporary assignment to objects, and the separate processes of perceptual categorization of the objects so identified, constitute a pre-adaptive platform on which an early system for the linguistic description of scenes developed. Key Words: argument; attention; deictic; dorsal; logic; neural; object; predicate; reference; ventral. (shrink)
This is a brief and accessible English summary of the "Self-model Theory of Subjectivity" (SMT), which is only available as German book in this archive. It introduces two new theoretical entities, the "phenomenal self-model" (PSM) and the "phenomenal model of the intentionality-relation" PMIR. A representationalist analysis of the phenomenal first-person persepctive is offered. This is a revised version, including two pictures.
This paper discusses the content of agency awareness. It contrast three elements in content: what the goal is, how it is to be reached, and who is having the goal/performing the action ? Marc Jeannerod's claim that goal representations are self-other neutral is discussed. If goal representations are essentially sharable, then we do not understand other people by projecting a piece of internal knowledge on to them, as often assumed. The problem which our brain has to solve is the converse (...) problem : determining who the agent is, once a goal is identified. This view has interesting consequences on the theory of mentalization. One can plausibly speculate that observing action, with an additional simulatory component for action memory, form major building blocks in understanding other minds. Metarepresenting, in this perspective, would depend on additional executive capacities for maintaining distinct the inferences from diverse simulated contexts of action. (shrink)
At the start of the 20th century the question of whether life could be explained in purely me- chanical terms was as hotly debated as the mind-body problem is today. Two factions opposed each other: Biological mechanists claimed that the properties characteristic of living organisms could be ex- plained mechanistically, in the way the behavior of a clock can be explained by the properties and the arrangement of its cogs, springs, and weights. Substantial vitalists, on the other hand, maintained that (...) the explanation envisaged by the mechanists was impossible and that one had to postulate a special nonphysical substance in order to explain life. (shrink)
The detection and categorization of animate motions is a crucial task underlying social interaction and perceptual decision making. Neural representations of perceived animate objects are partially located in the primate cortical region STS, which is a region that receives convergent input from intermediate-level form and motion representations. Populations of STS cells exist which are selectively responsive to specific animated motion sequences, such as walkers. It is still unclear how and to what extent form and motion information contribute to the (...) generation of such representations and what kind of mechanisms are involved in the learning processes. The article develops a cortical model architecture for the unsupervised learning of animated motion sequence representations. We demonstrate how the model automatically selects significant motion patterns as well as meaningful static form prototypes characterized by a high degree of articulation. Such key poses are selectively reinforced during learning through a cross talk between the motion and form processing streams. Furthermore, we show how sequence-selective representations are learned in STS by fusing static form and motion input from the segregated bottom-up driving input streams. Cells in STS, in turn, feed their activities recurrently to their input sites along top-down signal pathways. We show how such learned feedback connections enable predictions about future input as anticipation generated by sequence-selective STS cells. Network simulations demonstrate the computational capacity of the proposed model by reproducing several experimental findings from neurosciences and by accounting for recent behavioral data. (shrink)
Consciousness has many elements, from sensory experiences such as vision and bodily sensation, to nonsensory aspects such as memory and thought. All are presented as experiences of a single subject, and all seem to be contained within a unified field of experience. This unity raises many questions: How do diverse systems in the brain co-operate to produce a unified experience? Are there conditions under which this unity breaks down? Is conscious experience really unified at all? Such questions are addressed in (...) this thought-provoking book. (shrink)