Vocal premotor activity in the superior colliculus.

Area of Science:

• Neuroscience
• Animal Behavior
• Bioacoustics

Background:

• The superior colliculus (SC) is involved in sensorimotor processing.
• Echolocating bats use complex sonar calls for navigation and hunting.
• Understanding neural control of vocalizations is key to deciphering sensory processing.

Purpose of the Study:

• To investigate neural activity in the bat SC during echolocation tasks.
• To identify neural correlates of sonar call production and modulation.
• To explore the SC's role in dynamic behavioral adjustments during echolocation.

Main Methods:

• Chronic neural recordings from the midbrain superior colliculus in unrestrained, echolocating bats.
• Utilized two distinct behavioral tasks: virtual target amplitude discrimination (VTAD) and real oscillating target tracking (ROTT).
• Developed novel methods for long-term, in-vivo recordings during complex behaviors.

Main Results:

• Identified two consistent bouts of SC neural activity preceding sonar vocalizations in both tasks.
• A short lead bout was tightly coupled to vocal onset, potentially timing sonar emissions.
• A long lead bout, occurring earlier and over a wider interval, varied with sonar call duration in the ROTT task.

Conclusions:

• The bat SC exhibits distinct pre-vocalization activity patterns.
• These patterns suggest a role in timing sonar emissions and modulating sonar call parameters.
• Findings indicate the SC contributes to range-dependent adjustments of sonar call duration during target tracking.