Behrendt & Young/A unifying model for hallucinations in brain disease: BBS Call for Commentators

Below is a link to the forthcoming BBS target article Hallucinations in schizophrenia, sensory impairment and brain disease: A unifying model by Ralf-Peter Behrendt and Claire Young http://www.bbsonline.org/Preprints/Behrendt-01042003/Referees/ This article has been accepted for publication in Behavioral and Brain Sciences (BBS), an international, interdisciplinary journal providing Open Peer Commentary on important and controversial current research in the biobehavioral and cognitive sciences. Commentators must be BBS Associates or suggested by a BBS Associate. To be considered as a commentator for this article, to suggest other appropriate commentators, or for information about how to become a BBS Associate, please reply by EMAIL within three (3) weeks to: calls(a)bbsonline.org The Calls are sent to 10,000 BBS Associates, so there is no expectation (indeed, it would be calamitous) that each recipient should comment on every occasion! Hence there is no need to reply except if you wish to comment, or to suggest someone to comment. If you are not a BBS Associate, please approach a current BBS Associate (there are currently over 10,000 worldwide) who is familiar with your work to nominate you. All past BBS authors, referees and commentators are eligible to become BBS Associates. An electronic list of current BBS Associates is available at this location to help you select a name: http://www.bbsonline.org/Instructions/assoclist.html (please note that this list is being updated) If no current BBS Associate knows your work, please send us your Curriculum Vitae and BBS will circulate it to appropriate Associates to ask whether they would be prepared to nominate you. (In the meantime, your name, address and email address will be entered into our database as an unaffiliated investigator.) ======================================================================= ** IMPORTANT ** ======================================================================= To help us put together a balanced list of commentators, it would be most helpful if you would send us an indication of the relevant expertise you would bring to bear on the paper, and what aspect of the paper you would anticipate commenting upon. (Please note that we only request expertise information in order to simplify the selection process.) Please DO NOT prepare a commentary until you receive a formal invitation, indicating that it was possible to include your name on the final list, which is constructed so as to balance areas of expertise and frequency of prior commentaries in BBS. To help you decide whether you would be an appropriate commentator for this article, an electronic draft is retrievable at the URL that follows the abstract and keywords below. ======================================================================= ======================================================================= Hallucinations in schizophrenia, sensory impairment and brain disease: A unifying model Ralf-Peter Behrendt and Claire Young ABSTRACT: Based on recent insight into the thalamocortical system and its role in perception and conscious experience, a unified pathophysiological framework for hallucinations in neurological and psychiatric conditions is proposed, which integrates previously unrelated neurobiological and psychological findings. Gamma-frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in networks of thalamocortical circuits, thereby transiently forming assemblies of coherent gamma oscillations under constraints of afferent sensory input and prefrontal attentional mechanisms. If perception is based on synchronisation of intrinsic gamma activity in the thalamocortical system, then sensory input to specific thalamic nuclei may merely play a constraining role. Hallucinations can be regarded as underconstrained perceptions that arise when the impact of sensory input on activation of thalamocortical circuits and synchronisation of thalamocortical gamma activity is reduced. In conditions that are accompanied by hallucinations, factors such as cortical hyperexcitability, cortical attentional mechanisms, hyperarousal, increased noise in specific thalamic nuclei and random sensory input to specific thalamic nuclei may to a varying degree contribute to underconstrained activation of thalamocortical circuits. The reticular thalamic nucleus plays an important role in suppressing random activity of relay cells in specific thalamic nuclei and its dysfunction may be implicated in the biological vulnerability to hallucinations in schizophrenia. Combined with general activation during cholinergic arousal, this leads to excessive disinhibition in specific thalamic nuclei, which may allow cortical attentional mechanisms to recruit thalamic relay cells into resonant assemblies of gamma oscillations regardless of their actual sensory input, thereby producing an underconstrained perceptual experience. KEYWORDS: Charles Bonnet syndrome, gamma oscillations, hallucinations, Lewy-body dementia, perception, schizophrenia, thalamocortical system http://www.bbsonline.org/Preprints/Behrendt-01042003/Referees/ ======================================================================= ======================================================================= *** SUPPLEMENTARY ANNOUNCEMENT *** (1) Call for Book Nominations for BBS Multiple Book Review In the past, Behavioral and Brain Sciences (BBS) had only been able to do 1-2 BBS multiple book treatments per year, because of our limited annual page quota. BBS's new expanded page quota will make it possible for us to increase the number of books we treat per year, so this is an excellent time for BBS Associates and biobehavioral/cognitive scientists in general to nominate books you would like to see accorded BBS multiple book review. (Authors may self-nominate, but books can only be selected on the basis of multiple nominations.) It would be very helpful if you indicated in what way a BBS Multiple Book Review of the book(s) you nominate would be useful to the field (and of course a rich list of potential reviewers would be the best evidence of its potential impact!). *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Please note: Your email address has been added to our user database for Calls for Commentators, the reason you received this email. If you do not wish to receive further Calls, please feel free to change your mailshot status through your User Login link on the BBSPrints homepage, using your username and password. Or, email a response with the word "remove" in the subject line. *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Jeffrey Gray Editor Behavioral and Brain Sciences bbs(a)bbsonline.org http://www.bbsonline.org -------------------------------------------------------------------