Superior colliculus neuronal ensemble activity signals optimal rather than subjective confidence

Area of Science:

• Neuroscience
• Decision-making
• Sensory processing

Background:

• Neurons in sensorimotor circuits are implicated in perceptual decision-making and confidence.
• Confidence is often viewed as an optimal indicator of decision accuracy.
• Previous studies often conflated accuracy-linked and behavior-linked confidence signals.

Purpose of the Study:

• To investigate whether the superior colliculus (SC) differentiates between optimal and subjective confidence signals.
• To dissociate neuronal signals related to decision accuracy from those related to behavioral confidence reports.

Main Methods:

• Recorded neuronal activity from the SC in monkeys performing two tasks.
• Task 1: decision accuracy and confidence covaried.
• Task 2: stimuli were matched for accuracy but varied in reported confidence; used multivariate decoding to predict choices.

Main Results:

• Neuronal decoding performance correlated with decision accuracy, consistent with previous findings.
• When decision accuracy was matched across conditions, decoder performance was similar for high and low subjective confidence.
• The SC's activity reflected decision accuracy but not subjective confidence levels.

Conclusions:

• The superior colliculus (SC) likely encodes optimal decision confidence, analogous to cortical mechanisms.
• The SC does not appear to play a critical role in generating subjective confidence.
• Further research is needed to identify brain regions responsible for subjective confidence.