Journal: Nature Neuroscience
Article Title: Rapid temporal processing in the olfactory bulb underlies concentration-invariant odor identification and signal decorrelation
doi: 10.1038/s41593-026-02250-y
Figure Lengend Snippet: A . Odors were delivered using a multi-cassette air dilution olfactometer. Each cassette had 8 odor vials, 16 odor valves, a mass flow controller (MFCs, 100 mL/min) and a normally open bypass valve. Total flow through both cassettes was controlled by a 1,000 mL/min MFC. To prepare an odor presentation, a pair of valves for a single odor vial was opened and the bypass valve was closed. The odorized air flow (1,000 ml/min) was first directed to the exhaust via the final valve (FV), while a clean air stream 1000 mL/min controlled by an additional MFC was delivered to the odor port. After approximately ~2 sec of flow stabilization, the FV redirected the odorized air to the odor port and the clean air to the exhaust. At the end of odor presentation, the final valve switched back, delivering clean air to the odor port. The concentration was controlled by the ratio of the MFC flow rates. To deliver a mixture, two vials from different cassettes were opened simultaneously. The olfactometer was equipped with a serial diluter, allowing further dilution of the odor concentration up to 20-fold. The airflow from the FV was directed to the odor port and then sucked away through the exhaust line, and both lines were balanced to minimize pressure buildup. The odor port was equipped with a pressure sensor to measure the mouse’s sniff pattern and used to calibrate the airflows. B . The temporal profile of signals related to experimental control. The sniff pattern was continuously monitored by a pressure sensor. The FV was triggered by the onset of exhalation, so that the odor concentration was stabilized before the onset of the first inhalation. This was tested by measuring a temporal profile of odor concentration in the odor port using photo-ionization detector (PID). A TTL pulse was generated with a temporal offset, ΔT after the inhalation onset. The stimulation control consisted of PMT gating, DMD frame trigger, and AOM pulses. Photostimulation was delivered while gating the PMTs to prevent damage and saturation. The PMT gating signal began 2 ms earlier and ended 2 ms later to ensure gating.
Article Snippet: Total clean airflow was maintained at 1 l min −1 by a mass flow controller (MFC) (Alicat, cat. no. MC-1SLPM-D/5M/5IN).
Techniques: Concentration Assay, Control, Generated
