There is evidence from neuropsychological and psychophysical measurements that conscious sensory information is processed in discrete time segments. The segmentation process may be described as neuronal activity at a frequency of 40 Hz. Stimulus-induced neuronal activities of this frequency are found in the middle latency range of the auditory evoked potential . First, we have studied the effects of different general anesthetics on MLAEP and auditory evoked 40-Hz activity. Second, we investigated MLAEP and explicit and implicit memory for information presented (...) during cardiac anesthesia. In the awake patients peak latencies of the MLAEP were in the normal range. An auditory evoked 40-Hz activity was present 20–100 ms poststimulus. Under nonspecific anesthetics MLAEP and the 40-Hz activity were suppressed, and under receptor-specific agents MLAEP and the 40-Hz activity were partly preserved. None of the cardiac patients had conscious explicit recall of the intraoperative events, whereas some patients showed unconscious implicit memory for an intraoperative tape message. The implicit memory could be related to midlatency auditory evoked potentials. No implicit memory was detectable when MLAEP and the primary cortical processing of the auditory stimuli and 40-Hz activity were blocked. Implicit memory could be detected in more than 50% of the cases when MLAEP, a 30-Hz activity, and the primary cortical stimulus processing were preserved. In conclusion, our observations support the view that a high frequency oscillatory mechanisms, recorded as a grouped neuronal activity in the MLAEP, may be part of a basic neuronal program for conscious sensory information processing. (shrink)

For centuries psychologists have been trying to explain how a man or an animal could perceive space. They have thought of space as having three dimensions and the difficulty was how an observer could see the third dimension. For depth, as Bishop Berkeley asserted at the outset of the New Theory of Vision (1709), “is a line endwise to the eye which projects only one point in the fund of the eye.” Space was its dimensions. It was empty save for (...) a collection of objects or bodies. For an observer, the objects were in different directions at various distances and the question was how these distances could be detected. For two hundred and fifty years we have tried to answer this question and failed. The explanations have been controversial, contradictory, and confused. (shrink)

_One summary of the great Kant's view, to the extent that it can be summed up, is_ _that he takes determinism to be a kind of fact, and indeterminism to be another kind_ _of fact, and our freedom to be a fact too -- but takes this situation to have nothing to_ _do with the kind of compatibility of determinism and freedom proclaimed by such_ _Compatibilists as Hobbes and Hume. Thus Kant does not make freedom consistent_ _with determinism by taking (...) up a definition of freedom as voluntariness -- at bottom,_ _being able to do what you want. This he dismisses as a wretched subterfuge,_ _quibbling about words. Rather, the freedom he seeks to make consistent with_ _determinism does indeed seem to be the freedom of the Incompatibilists --_ _origination. Is he then an Incompatibilist? Well, against that, it can be said he does_ _not allow the existence of origination in what can be called the world we know, as_ _Incompatibilists certainly do._. (shrink)

The basic principles of scientific research from the great French physiologist whose contributions in the 19th century included the discovery of vasomotor nerves; nature of curare and other poisons in human body; more.