Can visual information encoded in cortical columns be decoded from magnetoencephalography data in humans?

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• The ability of noninvasive human neuroimaging to decode information at the scale of cortical columns remains an open question.
• Cortical columns represent the fundamental functional units of the cerebral cortex.

Purpose of the Study:

• To determine if magnetoencephalography (MEG) can decode visual features encoded at the level of cortical columns.
• To investigate the temporal dynamics of information processing within cortical columns.

Main Methods:

• Five magnetoencephalography (MEG) experiments were conducted.
• The study focused on decoding contrast edge orientation, a feature encoded at the columnar level.
• Statistical analyses controlled for potential confounds like orientation overrepresentation and global form signals.

Main Results:

• MEG signals contained orientation-specific information approximately 50 ms after stimulus onset.
• This information was detectable even after controlling for confounding factors.
• Theoretical modeling supported the empirical findings.

Conclusions:

• Noninvasive MEG can successfully decode information processed at the level of human cortical columns.
• Electrophysiological signals, analyzed multivariately, can access information encoded at the columnar scale.