TY - JOUR T1 - Behavioral Forgetting of Olfactory Learning Is Mediated by Interneuron-Regulated Network Plasticity in <em>Caenorhabditis elegans</em> JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0084-22.2022 VL - 9 IS - 4 SP - ENEURO.0084-22.2022 AU - Jamine Hooi-Min Teo AU - Itsuki Kurokawa AU - Yuuki Onishi AU - Noriko Sato AU - Tomohiro Kitazono AU - Terumasa Tokunaga AU - Manabi Fujiwara AU - Takeshi Ishihara Y1 - 2022/07/01 UR - http://www.eneuro.org/content/9/4/ENEURO.0084-22.2022.abstract N2 - Forgetting is important for animals to manage acquired memories to enable adaptation to changing environments; however, the neural network in mechanisms of forgetting is not fully understood. To understand the mechanisms underlying forgetting, we examined olfactory adaptation, a form of associative learning, in Caenorhabditis elegans. The forgetting of diacetyl olfactory adaptation in C. elegans is regulated by secreted signals from AWC sensory neurons via the TIR-1/JNK-1 pathway. These signals cause a decline of the sensory memory trace in AWA neurons, where diacetyl is mainly sensed. To further understand the neural network that regulates this forgetting, we investigated the function of interneurons downstream of AWA and AWC neurons. We found that a pair of interneurons, AIA, is indispensable for the proper regulation of behavioral forgetting of diacetyl olfactory adaptation. Loss or inactivation of AIA caused the impairment of the chemotaxis recovery after adaptation without causing severe chemotaxis defects in the naive animal. AWA Ca2+ imaging analyses suggested that loss or inactivation of AIA interneurons did not affect the decline of the sensory memory trace after the recovery. Furthermore, AIA responses to diacetyl were observed in naive animals and after the recovery, but not just after the conditioning, suggesting that AIA responses after the recovery are required for the chemotaxis to diacetyl. We propose that the functional neuronal circuit for attractive chemotaxis to diacetyl is changed temporally at the recovery phase so that AIA interneurons are required for chemotaxis, although AIAs are dispensable for attractive chemotaxis to diacetyl in naive animals. ER -