Primate superior colliculus neurons activated by unexpected sensation

Area of Science:

• Neuroscience
• Primate research
• Motor control

Background:

• The midbrain superior colliculus (SC) is known for its role in gaze control.
• However, the SC also contains diverse neuronal types involved in other functions.
• Understanding these diverse neuronal roles is crucial for comprehending brain function.

Purpose of the Study:

• To identify and characterize novel neuronal populations within the SC.
• To investigate the role of SC neurons in response to unexpected sensory perturbations during goal-directed movements.
• To explore the functional significance of these neurons in motor control and sensory processing.

Main Methods:

• Single-unit recordings were performed in the SC of rhesus monkeys (Macaca mulatta).
• Monkeys performed a goal-directed arm-movement task with unexpected perturbations.
• Neuronal activity was analyzed during both perturbed and non-perturbed trials.

Main Results:

• A novel class of SC neurons, termed 'perturbation neurons', was identified.
• These neurons were exclusively activated by unexpected task perturbations.
• Perturbation neurons were located in the deep lateral zone of the SC and exhibited long latencies.

Conclusions:

• The identified perturbation neurons in the SC respond specifically to unexpected sensory events during motor tasks.
• Their activity may reflect the saliency of unpredictable sensations, potentially related to the mismatch between motor commands and sensory feedback.
• This discovery expands our understanding of the SC's role beyond gaze control, highlighting its involvement in processing unexpected sensory information during action.