Small modulation of ongoing cortical dynamics by sensory input during natural vision

Area of Science:

• Neuroscience
• Visual Cortex Development
• Sensory Processing

Background:

• Visual cortical neurons exhibit response variability to repeated stimuli.
• Spontaneous neural activity, previously considered noise, possesses structured spatio-temporal patterns.
• This structure may significantly influence neural responses during natural vision.

Purpose of the Study:

• To investigate the relationship between spontaneous neural activity and evoked responses in the primary visual cortex.
• To examine how this relationship changes during visual system development in ferrets.
• To understand the role of spontaneous activity in processing dynamic visual scenes.

Main Methods:

• Recorded neural activity in awake, freely viewing ferrets from eye opening to maturity.
• Presented dynamic natural-scene and random-noise stimuli.
• Analyzed the correlation between spontaneous neural firing and evoked responses.
• Assessed changes in spontaneous activity dynamics with age.

Main Results:

• The correspondence between evoked neural activity and sensory input structure improved with age.
• This improvement correlated with a shift in spontaneous activity dynamics.
• Spontaneous neural firing patterns were minimally altered by visual stimulation across all ages.
• Ongoing circuit dynamics are modulated by sensory input rather than directly reflecting it.

Conclusions:

• Sensory evoked neural activity in the visual cortex reflects the modulation of ongoing circuit dynamics.
• Spontaneous activity plays a crucial role in shaping neural responses throughout visual development and in mature animals.
• The visual system's processing of sensory information is intrinsically linked to its intrinsic neural dynamics.