Basal forebrain cholinergic input mediates adaptive attention allocation to enhance olfactory discrimination

Area of Science:

• Neuroscience
• Cognitive Science
• Olfactory Processing

Background:

• Animals allocate limited cognitive resources by amplifying sensory input, crucial for decision-making.
• The precise neural circuits governing attention, especially in sensory processing, are not fully understood.

Purpose of the Study:

• To identify the specific neural circuit responsible for top-down attentional control in olfactory processing.
• To elucidate how this circuit enhances odor discrimination and decision-making based on behavioral goals and cognitive demand.

Main Methods:

• Utilized optogenetics and electrophysiology in mice to investigate neural activity in the olfactory bulb and basal forebrain.
• Manipulated cholinergic and dopaminergic neuron activity to assess their role in attention.
• Developed a computational model to simulate circuit dynamics and attentional adaptation.

Main Results:

• Identified a circuit where cholinergic neurons in the horizontal nucleus of the diagonal band control dopaminergic short-axon cells in the olfactory bulb.
• Cholinergic activity triggers preparatory disinhibition of olfactory sensory axons, enhancing responses to relevant odors and improving decisions.
• Found that this preparatory cholinergic activity decreases in proficient animals, indicating a trade-off between task proficiency and attention.

Conclusions:

• This disinhibitory circuit provides top-down attentional control over olfactory sensory processing.
• The circuit's dynamic adaptation explains how animals balance attention and efficiency during learning and routine tasks.
• Direct manipulation of the circuit can restore attentional effects without causing general arousal.