Neuronal coding of information coming from external and internal environments and transducted by sensory receptors constitutes a basic biophysical problem. After the coding phase, such information orients organism responses, shaping complex behavioural patterns. The characteristics of both neurons (interneurons with re-entering connections, latency times, filter bandwidth with respect to input signals, logic operations on multiple convergent signals) and neuron nets (reverberating nets, feedback/feed-forward connections, oscillations due to endogenous activity patterns) are important for coding mechanisms. Neuronal coding is implied also in the higher phases of information processing linked to consciousness, when neuronal activity patterns are related to perceptual mental representations.

This book provides a most complete overview of physiological and psychophysical properties of perceptual systems in man and animals. The information processing chains are described step-by-step from the stimuli of the respective environments, via the perceptual neuronal coding networks to conscious sensations and behaviour.Articles by W G K Backhaus, A G Clark, B Hiley, A Iznak, M Kavaliers, B Kramer, A Michelsen, C Neumeyer, G A Orban, T Radil, D G Stavenga, M Stengl, U Thurm, R L DeValois, R Wehner, J S Werner, W Wiltschko, and related short articles.

Vol. 3.

For a few decades, the puzzle of consciousness, which for centuries was analysed by philosophers, has been finding a wide interest in the scientific field, where previously it was not entitled to be a member. It has become one of the most-debated problems in the cognitive sciences. The anatomical bases, neurophysiological correlates and elementary mechanisms underlying complex processes arising with consciousness have been compared with the psychological (perceptive, cognitive, volitive, emotional) aspects of conscious expressions, in normal and pathological conditions. Various theories, which attempt to fit systematically and coherently neural and psychological data, have been debated, proving the emergence of the phenomenon of consciousness.

Perception is the first step in the whole of the cognitive processes (attention, learning, memory, categorization, imagery, intuition, inference, comprehension, thought, judgement, expression) which culminate in the reasoning activity and to which emotions make a contribution. The production of perception representations is correlated with the perception events. Such perception representations occur by means of the contribution of two kinds of factors: sensory signals which reproduce the spatio-temporal characteristics of the receptor modifications, and interpretation of the intrinsic ambiguity of such signals by means of unconscious inferences. Various interactions intervene between bottom-up signals from peripheral receptors and top-down signals from higher centres.

The light sense is conceivably the key sense in both the animal and the plant kingdom. Vision research, undoubtedly a fast-growing field, is providing impressive results — thanks to modern theoretical and methodological advances. The approach of biophysics and neuroscience seems to be of great benefit and, for this reason, the present book gives an outline of recent acquisitions and updated advanced methods concerning this approach. Visual mechanisms and processes are analysed at several (molecular, cellular, integrative, computational and cognitive) levels by different methodologies (from molecular biology to computation) applied to different living models (from protists to humans, via invertebrates and lower vertebrates).