Manipulating critical period closure across different sectors of the primary auditory cortex.
During early brain development and through 'adult' experience-dependent plasticity, neural circuits are shaped to represent the external world with high fidelity. When raised in a quiet environment, the rat primary auditory cortex (A1) has a well-defined 'critical period', lasting several days, for its representation of sound frequency. The addition of environmental noise extends the critical period duration as a variable function of noise level. It remains unclear whether critical period closure should be regarded as a unified, externally gated event that applies for all of A1 or if it is controlled by progressive, local, activity-driven changes in this cortical area. We found that rearing rats in the presence of a spectrally limited noise band resulted in the closure of the critical period for A1 sectors representing the noise-free spectral bands, whereas the critical period appeared to remain open in noise-exposed sectors, where the cortex was still functionally and physically immature.
de Villers-Sidani
Etienne
E
W.M. Keck Center for Integrative Neuroscience, Coleman Laboratory, Department of Otolaryngology, University of California, San Francisco, 513 Parnassus Avenue, Room HSE-808, Box 0732, San Francisco, California 94143, USA. etienne@phy.ucsf.edu
Simpson
Kimberly L
KL
Lu
Y-F
YF
Lin
Rick C S
RC
Merzenich
Michael M
MM
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D000831:Animals, Newborn; D001303:Auditory Cortex / Q000033:anatomy & histology* / Q000254:growth & development / Q000502:physiology*; D001931:Brain Mapping; D003423:Critical Period, Psychological; D004567:Electrodes, Implanted; D005260:Female; D006320:Hearing Tests; D009474:Neurons / Q000502:physiology; D009622:Noise; D010320:Parvalbumins / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D013057:Spectrum Analysis; D013997:Time Factors
D010320:Parvalbumins