Showing papers in "Canadian Journal of Psychology\/revue Canadienne De Psychologie in 1978"

Auditory streaming and the building of timbre.

Abstract: In a natural environment, the auditory system must analyse an incoming wave train to determine two things: (a) which series of frequency components arose over time from the same source and should be integrated into a sequential stream, and (b) which set of simultaneous components arose from one source and should be fused into a timbre structure. A set of experiments was performed in which subject judged the stream organization and the timbre of a repeating cycle formed by a pair of more or less synchronous pure tones, B and C, and a preceding pure tone, A, whose frequency was varied in its proximity to that of the upper tone of the BC pair. These experiments demonstrated that fusion and sequential organization of streams are carried out using two sorts of information which compete to determine the best perceptual description of the input. Proximal frequencies between sequential components promotes a sequential organization and the simultaneity of onset of frequency components promotes perceptual fusion.

Brain-stimulation reward after twenty-five years.

Abstract: Brain self-stimulation was first demonstrated when it was observed that a rat returned to the place in an open-field where it received electrical stimulation of the forebrain (Fig. 1). Subsequently, when rats were tested in a Skinner box it was shown that they would press a lever to initiate electrical stimulation of limbic and hypothalamic sites (Olds & Milner, 1954). The brain stimulation apparently had the properties of positive reinforcement or reward, a conclusion subsequently confirmed in experiments in which animals were observed to run along a straight alley, to traverse a complex maze, or to cross a painful shock grid to obtain brain-stimulation reward (Olds, 1958). During the next few years brain self-stimulation was reported in other species (e.g., cat, dog, gerbil, goat, guinea pig, hamster, monkey, rabbit) including the human.

Brain-Stimulation Reward: Current Issues and Future Prospects

Abstract: This commemorative issue began with abrief discussion of the major themes thathave characterized the study of brain-stimulation reward (BSR) over the pasttwenty-five years. This overview, along withthe research papers which follow, clearlyshow that the field continues to be of majorimportance in brain-behaviour research.However, both the astute observer and thedevil's advocate will also see that much ofthis research has led merely to the refine-ment of important questions which relate tothis phenomenon, rather than their resolu-tion. A silver anniversary is an appropriatetime to assess previous developments and toconsider future prospects. If it appears thatanswers will be forthcoming, then every ef-fort must be made to sustain the momen-tum that has characterized the research inthis field in recent years. If, on the otherhand, there are likely to be only further andfurther refinements of issues in the besttraditions of Hesse's Glass Bead Game, thenperhaps this line of research should be sus-pended until we can find a new MagisterLudi to succeed James Olds.In preparing a prospectus on BSR, thereare two basic issues, each with attendantsubordinate issues, which must be con-sidered. They revolve around questionsof structure and function: (1) what arethe neuroanatomical systems subservingbrain-stimulation reward? (2) what func-tions do such systems have in controllingand modifying an animal's behavioural re-pertoire? As indicated in the prologue, re-consideration of the 'structure' question inlight of histochemical neuroanatomy wasresponsible for a resurgence of interest inself-stimulation in recent years. Researchconcerned with 'structure' is still very muchalive and in fact, as suggested below, holdsevery promise of being resolved in the nearfuture. The 'functional' issue has proven tobe more elusive but there are some en-couraging signs that it too may be solved.