Heat stress-mediated plasticity in a locust looming-sensitive visual interneuron

Area of Science:

• Neuroscience
• Animal Behavior
• Environmental Physiology

Background:

• Neural circuits are sensitive to temperature fluctuations, with extreme heat causing functional failure.
• Heat shock, a protective response to sublethal high temperatures, can mitigate detrimental effects on neural pathways.

Purpose of the Study:

• To investigate the impact of heat shock on the thermosensitivity of the descending contralateral movement detector (DCMD) neuron in the migratory locust (Locusta migratoria).
• To determine if heat shock enhances the reliability of visually guided behaviors under high-temperature conditions.

Main Methods:

• Recorded DCMD neuron activity in response to looming stimuli using intracellular and extracellular methods.
• Perfused locust thoracic regions with temperature-controlled saline, measuring responses at 5°C intervals from 25°C.
• Compared neural responses between control and heat-shocked locusts.

Main Results:

• Heat-shocked locusts exhibited potentiated DCMD activity, with increased peak firing frequency compared to controls as temperature rose.
• Significant differences in action potential properties and afterdepolarization amplitude were observed between control and heat-shocked animals.
• Heat shock maintained DCMD function at elevated temperatures, enhancing peak firing frequency and action potential properties.

Conclusions:

• Prior heat shock exposure enhances the thermosensitivity and functional reliability of the DCMD neuron in locusts.
• This enhanced neural function at high temperatures may improve the initiation of visually guided behaviors.
• Heat shock represents a potential mechanism for neural adaptation to thermal stress in insects.