On May 6, 2009, the Journal of Neuroscience published a research article from ION entitled "Entrainment of Slow Oscillations of Auditory Thalamic Neurons by Repetitive Sound Stimuli". This work was carried out by Li-xia Gao, Xian-kai Meng, Chang-quan Ye Chun Xu and other graduate students from the laboratories of Drs. Xiao-hui Zhang and Mu-ming Poo at ION as well as the laboratory of Professor Ju-fang He at Hong Kong Polytechnic University. 

Slow oscillations at frequencies of less than 1 Hz manifest in many brain regions as discrete transitions between a depolarized UP state and a hyperpolarized DOWN state of the neuronal membrane potential. Slow oscillation has been observed during slow wave sleep, under anesthesia or during quiet wakefulness, and interacts strongly with sensory inputs. In this study, by performing in vivo electrophysiological recordings in the auditory thalamus of anesthetized and un-anesthetized guinea pigs, the authors have demonstrated that the transition of membrane potentials from UP to DOWN state in these non-lemniscal oscillating neurons could rapidly time-lock to rhythmic sound stimuli with inter-stimulus intervals (ISIs) on the order of seconds.  Furthermore, they showed that after termination of the sound stimulation, the regular UP/DOWN transitions of the entrained interval persisted for tens of seconds, and the efficacy of sound stimuli in evoking UP to DOWN membrane potential transitions was enhanced specifically at the entrained interval for at least 10 min.  These findings not only reveal a novel of form of sensory input-dependent network plasticity, but also suggest that slow oscillations in the auditory thalamus may help to retain the short-term memory information of rhythmic sound stimulus intervals on the order of seconds.

Entrainment of slow oscillations in thalamic neurons by repetitive rhythmic-sound stimuli.