Week 4 Reading (Capaldi et al.)

What is the main goal of neuroethology of spatial learning?

To determine whether common organizational principles underlie spatial learning across diverse taxa (vertebrates and invertebrates).

What is spatial learning?

The formation of memories that allow discrimination of place relative to environmental surroundings and orientation of the learner within that space.

What is the difference between orientation and navigation?

• Orientation: Moment-to-moment alignment of body direction

• Navigation: Using cues to determine position relative to a goal while moving

What is piloting?

Finding a goal using familiar landmarks while maintaining sensory contact with them.

What is compass orientation?

Moving in a specific compass direction using cues like the sun or magnetic field, without familiar landmarks.

Example of path integration in insects?

• process where an animal calculates its position relative to a starting point by integrating distance traveled and angles turned.

• Desert ants (Cataglyphis) roam randomly, then return home in a straight line using celestial compass cues and optic flow.

What brain structure is most strongly linked to spatial learning in vertebrates?

The hippocampus.

What neurotransmitter receptor is critical for hippocampal spatial learning?

NMDA glutamate receptors.

What insect brain structure may function like the hippocampus?

Mushroom bodies (corpora pedunculata).

What are mushroom bodies made of?

Kenyon cells with dendritic calyces and axonal lobes

Why are mushroom bodies considered hippocampus-like?

• Involved in spatial learning

• Show plasticity

• Show synaptic changes similar to long-term potentiation

• High expression of learning-related genes

Why is volume plasticity useful in neuroethology?

It links ecological behavior to structural brain changes across species.

Which bird families are famous for food storing?

Corvidae (jays, nutcrackers) and Paridae (chickadees, titmice).

What happens to the hippocampus in food-storing birds?

It is larger relative to brain size compared to non-storing species.

Does hippocampal volume increase before or after food-storing begins?

After — suggesting experience-dependent growth.

Does hippocampal size change seasonally?

Yes. It peaks during peak food-storing season (e.g., October in chickadees)

What cellular mechanism may contribute to hippocampal volume change?

Seasonal neurogenesis.

What is the key conclusion from food-storing birds?

Spatial memory demands can shape brain structure through experience-dependent plasticity.

What is age polyethism?

Division of labor based on age in social insects.

What tasks do young worker bees perform?

Hive tasks (nursing, cleaning).

What do older worker bees do?

Forage outside the hive.

What happens to mushroom body volume in foragers?

It increases ~15% compared to newly emerged bees.

Is mushroom body expansion caused by age alone?

No — it correlates with behavioral maturation.

Is juvenile hormone required for mushroom body expansion?

No — expansion occurs even without adult JH exposure

What is the major comparative insight from birds and bees?

Spatial learning demands are associated with enlargement and plasticity of specific brain regions across taxa.

What is the key evolutionary implication?

Similar cognitive demands may produce similar neural solutions even in distantly related animals.