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Updated: Aug 16, 2026

Measuring Attention and Visual Processing Speed by Model-based Analysis of Temporal-order Judgments
Published on: January 23, 2017
The speed of visual cognition
Christoph M Michel1, Margitta Seeck, Micah M Murray
1The Functional Brain Mapping Laboratory, Neurology Clinic, University Hospital of Geneva, 1211 Geneva, Switzerland. christoph.michel@medecine.unige.ch
Abstract:
Intracranial electrophysiological recordings in primates showed repeatedly that neurons in several cortical areas are activated very early after visual stimulus presentation, practically at the same time (or even before) the activation of primary sensory neurons. Even neurons at the highest hierarchical levels of the visual system are activated in less than 100 ms. These findings challenge the classical interpretation of human evoked potential (EP) data that assume that the first, "exogenous", EP components from 50 to 150 ms reflect the initial volley of sensory activation in the striate and extrastriate visual cortex and are not yet influenced by cognitive task demands. Indeed, several recent EP studies using analysis methods that go beyond the classical approach of defining "components" at certain scalp positions indicate that highly complex stimulus features can influence EP responses within the first 100 ms. This indicates that sophisticated cognitive processing is much faster than previously thought and opens new perspectives with respect to the role of both, bottom-up as well as top-down mechanisms in visual processing.
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