Skip Navigation



Cerebral Cortex Advance Access published online on May 22, 2009
Cerebral Cortex, doi:10.1093/cercor/bhp103
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Data
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Ojima, H.
Right arrow Articles by Iriki, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ojima, H.
Right arrow Articles by Iriki, A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2009. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org

Adaptive Changes in Firing of Primary Auditory Cortical Neurons following Illumination Shift from Light to Dark in Freely Moving Guinea Pigs

Hisayuki Ojima1,2, Miki Taoka1 and Atsushi Iriki1,2

1 Cognitive Neurobiology, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, Tokyo 113-8549, Japan, 2 Laboratory for Symbolic Cognitive Development, BSI, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

Address correspondence to Hisayuki Ojima, PhD, Cognitive Neurobiology, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, Tokyo 113-8549, Japan. Email: yojima.cnb{at}tmd.ac.jp.

Some animals are forced to rely more on non-visual signals, such as audition or olfaction, than on vision when a bright environment becomes dark. By recording from a primary-like auditory cortex (field A) in freely moving guinea pigs, possible changes in the responsiveness of single units were explored in association with illumination changes. For a subset of units, we found that robust decreases (off-decrease) or increases (off-increase) in baseline discharge (BsD) were initiated soon after room light was silently extinguished. These neuronal changes were accompanied by the initiation of explorative locomotion, possibly reflecting a changed internal brain state. Preferred acoustic stimuli evoked salient excitatory responses against the reduced BsD level in the dark for the off-decrease units, and salient inhibitory responses against the increased BsD level for the off-increase units. Histological verification indicated that the units showing such BsD changes were located predominantly in layer V or its vicinity. These results are discussed in the context of the effects of the brainstem neuromodulatory systems that are activated during behavioral adaptation to new environments.

Key Words: baseline discharge • free moving • laminar specificity • light and dark • natural sounds


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.