Three-dimensional shape and velocity changes affect responses of a locust visual interneuron to approaching objects.

Area of Science:

• Neuroethology
• Animal behavior
• Sensory processing

Background:

• Adaptive collision avoidance relies on detecting complex visual properties of approaching objects.
• The locust lobula giant movement detector (LGMD) and descending contralateral movement detector (DCMD) pathway responds to 2D approaching objects.
• Responses to 3D objects and changing velocities are not well understood.

Purpose of the Study:

• To investigate locust DCMD responses to 3D spherical objects.
• To analyze DCMD responses to approaching objects with varying velocities.
• To understand the neural basis of collision avoidance in naturalistic scenarios.

Main Methods:

• Comparing DCMD responses to 2D discs versus 3D spheres.
• Presenting locusts with approaching spheres of changing velocities (decreasing and increasing).
• Analyzing DCMD firing rates in relation to object size, velocity, and trajectory.

Main Results:

• Spheres elicited later peak firing and required larger threshold angles compared to discs.
• Decreasing sphere velocity caused transition-associated firing and subsequent rate increase.
• Increasing sphere velocity led to earlier and more pronounced DCMD firing rate increases.

Conclusions:

• The DCMD pathway provides salient information on 3D object approach and velocity changes.
• This neural pathway supports adaptive collision avoidance behaviors in locusts.
• Findings enhance understanding of sensory processing for dynamic environmental interactions.