Passive rotation‐induced theta rhythm and orientation homeostasis response
Passive rotation‐induced theta rhythm and orientation homeostasis response
复制标题
作者：
J. Shin
Rhythmic oscillatory activities at the theta frequency (3–12 Hz) have long attracted attention, as they have been implicated in diverse brain functions. There are two kinds of hippocampal theta rhythms: Type 1 is an atropine‐resistant noncholinergic theta rhythm, and Type 2 is an atropine‐sensitive cholinergic theta rhythm. However, it has not yet been determined whether the theta rhythm generated during passive whole‐body rotation is of Type 1 or 2. To clarify this issue, we investigated passive whole‐body rotation‐induced theta rhythm using C57BL/6J normal and atropine‐treated mice. The results demonstrated that atropine [50 mg/kg, intraperitoneally (i.p.)], a cholinergic antagonist, abolished the theta rhythm generated during passive whole‐body rotation. Therefore, the passive whole‐body rotation‐induced theta rhythm is an atropine‐sensitive Type 2 theta rhythm. In addition, we found that blocking cholinergic receptors using atropine resulted in the loss of the orientation homeostasis response, which is a circling behavior in the direction opposite to that of the rotating circular treadmill that is generated to maintain a constant orientation. These results suggest that atropine‐sensitive Type 2 theta rhythm can be generated by a passive rotation‐induced vestibular sensory signal and may be necessary for spatial orientation homeostasis response behavior. Synapse 64:409–415, 2010. © 2009 Wiley‐Liss, Inc.
