Odor- and state-dependent olfactory tubercle local field potential dynamics in awake rats

Area of Science:

• Neuroscience
• Olfactory System Research
• Mammalian Brain Activity

Background:

• The olfactory tubercle (OT) is a basal forebrain structure crucial for olfaction.
• Previous research focused on OT's role in odor processing, but lacked data from awake animals.

Purpose of the Study:

• To investigate the neural activity of the olfactory tubercle (OT) in awake, freely exploring rats.
• To characterize spontaneous and odor-evoked local field potential (LFP) activity in the OT.
• To explore the connectivity between the OT and the olfactory bulb (OB) in awake animals.

Main Methods:

• Multiday local field potential (LFP) recordings in the olfactory tubercle (OT) of awake Long-Evans rats.
• Simultaneous LFP recordings from the OT and upstream olfactory bulb (OB).
• Analysis of spontaneous and odor-evoked brain activity, including spectral power and coherence.

Main Results:

• Spontaneous theta, beta, and gamma band LFP activity observed in the OT.
• Odor presentation enhanced beta and gamma band power in the OT.
• Strong spectral coherence found between OT and OB LFP activity.
• OB theta rhythm showed stronger coherence with respiration; OT theta cycles followed OB theta cycles.
• Animal's internal state modulated OT LFP activity.

Conclusions:

• The study provides initial insights into the network activity of the awake rat's olfactory tubercle.
• Demonstrated spontaneous rhythmicity, odor-evoked modulation, and OB connectivity within the OT.
• Highlighted the influence of internal state on OT neural activity, crucial for olfactory processing.