Distinct context- and content-dependent population codes in superior colliculus during sensation and action.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Cognitive Neuroscience

Background:

• Sensorimotor transformation links sensory input to motor output.
• The superior colliculus (SC) is crucial for visually guided eye movements (saccades).
• SC neurons exhibit distinct activity during stimulus detection and movement initiation.

Purpose of the Study:

• To investigate if neural signatures of sensation and action in the SC are context-dependent.
• To determine if task requirements modulate neural activity during visually guided saccades.
• To compare single-unit versus population activity in revealing context-dependent neural dynamics.

Main Methods:

• Recorded Rhesus monkey spiking activity in the SC using laminar probes.
• Compared neural activity during saccades to predictable targets versus those requiring executive control (delayed response).
• Utilized dimensionality reduction and discriminability analyses on neural population data.

Main Results:

• Subspaces of neural activity during visual and motor epochs were distinct within and across tasks.
• Single-unit analysis showed no difference in movement-related activity between tasks.
• Population activity, not single neurons, revealed context-dependent neural signatures in the SC.

Conclusions:

• Cognitive task requirements are multiplexed in SC population activity during both sensation and action.
• Downstream brain structures can potentially extract task context from SC population activity.
• The full neural manifolds for sensory and motor responses may exceed explored subspaces.