Device:  T-maze

Objective: The T-maze is a device used to measure the olfactory memory of flies (Fig. A). Conditioning odors used are 0.12% 3-octanol and 0.08% benzaldehyde in mineral oil. During training, flies are exposed to an odor paired with an electric shock (CS+) for 1 minute, followed by 30 seconds of air, and then another odor without shock (CS−) for 1 minute (Fig. B). For testing, flies are loaded into the T-maze and allowed to choose between the CS+ and CS− odors for 2 minutes. The performance index (PI) is calculated using the following equation:

PI = (X−Y) / (X+Y)

where:

• X is the number of flies that chose the CS− odor

• Y is the number of flies that chose the CS+ odor

Reference:

Tanabe K, Itoh M, Tonoki A. Age-Related Changes in Insulin-like Signaling Lead to Intermediate-Term Memory Impairment in Drosophila. Cell Rep. 2017 Feb 14;18(7):1598-1605.

Tonoki A, Nagai S, Yu Z, Yue T, Lyu S, Hou X, Onuki K, Yabana K, Takahashi H, Itoh M. Nitric oxide-soluble guanylyl cyclase pathway as a contributor to age-related memory impairment in Drosophila. Aging Cell. 2022 Sep;21(9):e13691. doi: 10.1111/acel.13691. Epub 2022 Aug 13. PMID: 35963012; PMCID: PMC9470885.

Hou X, Hayashi R, Itoh M, Tonoki A. Small-molecule screening in aged Drosophila identifies mGluR as a regulator of age-related sleep impairment. Sleep. 2023 May 10;46(5):zsad018. doi: 10.1093/sleep/zsad018. PMID: 36721967.

Lyu S, Terao N, Nakashima H, Itoh M, Tonoki A. Neuropeptide diuretic hormone 31 mediates memory and sleep via distinct neural pathways in Drosophila. Neurosci Res. 2023 Jul;192:11-25. doi: 10.1016/j.neures.2023.02.003. Epub 2023 Feb 11. PMID: 36780946.