Serotonergic-dependent awareness is required for trace conditioning in honeybees

Area of Science:

• Animal Cognition
• Neuroscience
• Evolutionary Biology

Background:

• Trace conditioning in humans requires awareness and is sensitive to distraction.
• Delay conditioning, unlike trace conditioning, does not require awareness.

Purpose of the Study:

• To investigate if honeybees exhibit awareness-like cognitive processes during trace conditioning.
• To explore the neural mechanisms underlying trace conditioning in bees.

Main Methods:

• Olfactory conditioning of the proboscis extension response in honeybees.
• Comparison of trace and delay conditioning paradigms.
• Assessment of learning acquisition, memory, and response dynamics.
• Introduction of visual and mechanosensory distractors.
• Neuropharmacological manipulation of serotonin signaling.
• Computational modeling of the bee olfactory network.

Main Results:

• Honeybees learned through both trace and delay conditioning, but trace conditioning yielded weaker acquisition and memory.
• Trace conditioning performance was impaired by distractors, unlike delay conditioning.
• Serotonin signaling blockade selectively disrupted trace conditioning.
• Computational models supported the role of serotonergic circuits in bridging stimulus gaps.

Conclusions:

• Honeybees demonstrate cognitively demanding processes akin to awareness during trace conditioning.
• These findings suggest that core features of awareness may be evolutionarily conserved across diverse taxa.
• Serotonergic circuits play a crucial role in enabling trace conditioning by bridging temporal gaps between stimuli.