Effects of Selective Attention on Brainstem Auditory Evoked Potential Amplitude and Latency


Book Description

Previous investigations have demonstrated that shifting attention across modalities produces changes in neural responding to auditory stimuli at the level of the cortex. More recent studies have presented evidence that alterations in the focus of attention produce opposite changes in responding in the auditory periphery. Few studies, however, have examined the influence of attention on neural signaling at the level of the brainstem. The present study sought to compare the changes in the neural representation of an auditory stimulus at the level of the brainstem across two balanced attending conditions: one engaging visual attention and the other engaging auditory attention. Brainstem auditory evoked potentials (BAEPs) were measured while the participants counted short, infrequent oddball click trains (auditory attending) and while counting targeted instances of Gabor gradient phase shifts (visual attending). BAEPs were employed because they allow the observation of neural responding to auditory stimuli specifically at the level of the brainstem, a region which has seen little investigation in the realm of attention. Our results suggest that across attending conditions, absolute and peak-to-peak amplitudes were significantly different in early and late portions of the waveform.










The Effect of Attention on Auditory Evoked Potentials


Book Description

Click-evoked potentials were recorded from unanesthetized cats with electrodes chronically implanted in the auditory cortex, cochlear nucleus, and round window. The clicks (irrelevant stimuli) were presented continuously as background before, during, and after the presentation of a visual discrimination task (relevant stimuli) which attempted to alter the attentive state of the animals. The mean peak-to-peak amplitudes of averaged click-evoked responses from six adult female cats were significantly smaller during attention to the visual discrimination stimuli when compared with the pre-discrimination and control periods. This relationship was present at all electrode placements for five experimental animals with middle ear muscles cut as well as one control animal with middle ear muscles intact. The results suggest that during attention, a central inhibitory mechanism, independent of middle ear muscles, modifies click-evoked responses possibly via the olivo-cochlear bundle which terminates on the hair cells in the cochlea. (Author).







Human Evoked Potentials


Book Description

From August 25 - 28, 1978 a conference on averaged evoked po tentials was held at Konstanz, West Germany. Research on human evoked potentials has progressed rapidly in the past decade, and a series of international conferences have served to maintain com munication between active workers in the field. Among the organiza tions that have a tradition of supporting such mUlti-national com munication are the North Atlantic Treaty Organization Scientific Affairs Division, the u.s. Office of Naval Research and the German Research Society (Deutsche Forschungsgemeinschaft). We have been fortunate to have the support of all three. In the early stages of planning, a committee was formed composed of Professors Rudolph Cohen (Konstanz), Otto Creutzfeldt (Goettingen), John Desmedt (Brussels), A.M. Halliday (London), Anthony Remond (Paris) and Herbert Vaughan (New York). A call for papers was circulated as widely as possible, and this committee carried out the difficult task of selecting a limited number of participants from a large number of excellent abstracts. At the same time Professor Cohen of the University of Konstanz was generous enough to shoulder the task of playing host to the conference. His thoughtful arrangements contributed enormously to the comfort of the participants. He and his colleagues also engi neered an ideal ambience for sharing of ideas and observations, while the University of Konstanz generously provided audio-visual support.




Evoked Potentials


Book Description

The past decade has seen great progress in the measurement of evoked potentials in man; a steady increase in our understanding of their charac teristics, their origins and their usefulness; and a growing application in the field of clinical diagnosis. The topic is a truly multidisciplinary one. Important research contributions have been made by workers of many different backgrounds and clinical applications span the specialities. This book represents a revised and updated version of the work originally presented at the international evoked potential symposium held in Nottingham 4-6 1978. The Nottingham Symposium provided a forum for a state-of-the-art discussion amongst workers from many different disciplines and from many different countries. For each major topic in the field an expert review set the scene for discussion of current research presentations. This format is retained in the book: the chapters in Part A provide the context in which the research presented in Part B is set. The task of selecting material for this book, from the wealth of interesting work presented at the Symposium, was undertaken by a selection committee of distinguished authors who were the chairmen for the specialized sessions. To Dr F. W. Campbell, Professor S. J. Crews, Mr W. P. R. Gibson, Professor G. F. A. Harding, Dr D. A. Jeffreys, Dr D. G. Small, Professor H. Spekreijse, Dr A. Starr, Dr A. R. D. Thornton and Professor L. H. van der Tweel, I record my thanks.