Signals of threat--such as fearful faces--are processed with priority and have privileged access to awareness. This fear advantage is commonly believed to engage a specialized subcortical pathway to the amygdala that bypasses visual cortex and processes predominantly low-spatial-frequency information but is largely insensitive to high spatial frequencies. We tested visual detection of low- and high-pass-filtered fearful and neutral faces under continuous flash suppression and sandwich masking, and we found consistently that the fear advantage was specific to high spatial frequencies. This demonstrates that rapid fear detection relies not on low- but on high-spatial-frequency information--indicative of an involvement of cortical visual areas. These findings challenge the traditional notion that a subcortical pathway to the amygdala is essential for the initial processing of fear signals and support the emerging view that the cerebral cortex is crucial for the processing of ecologically relevant signals.

The processing of color and form is largely segregated within the visual brain. But there is also evidence to suggest that these features are coded in combination early in visual processing. Here, we combined high-resolution functional magnetic resonance imaging (fMRI) together with multivariate pattern classification to examine where in the visual cortex specific color form "conjunctions" are represented. Human subjects viewed visual displays containing colored spiral patterns. The spiral patterns could be red or green, and oriented either clockwise or counterclockwise, leading to 4 possible stimulus configurations. Two additional displays combined 2 of the above single color-form pairings, leading to double conjunctions. We applied linear classifiers to voxel activation patterns obtained while subjects viewed such displays. Our findings not only show that color and form information is coded across retinotopically defined visual areas, but also that the 2 double-conjunction stimuli can be distinguished. The voxels most informative about conjunctions were distinct from those most informative about color or form alone. Our results indicate that conjunctions of form and color may be coded by separate functional units as early as primary visual cortex. The results of this study have implications for theories concerning the segregation and binding of color and form information.

The results show that conjunctions can be decoded from spatial activation patterns already in V1, indicating an explicit coding of conjunctions at early stages of visual processing. Our findings raise the possibility that the solution of what has been taken as the prime example of the binding problem engages neural mechanisms as early as V1.

Schizophrenia is typically associated with higher-level cognitive symptoms, such as disorganized thoughts, delusions, and hallucinations. However, deficits in visual processing have been consistently reported with the illness. Here, we provide strong neurophysiological evidence for a marked perturbation at the earliest level of cortical visual processing in patients with paranoid schizophrenia. Using functional magnetic resonance imaging (fMRI) and adapting a well-established approach from electrophysiology, we found that orientation-specific contextual modulation of cortical responses in human primary visual cortex (V1)--a hallmark of early neural encoding of visual stimuli--is dramatically reduced in patients with schizophrenia. This indicates that contextual processing in schizophrenia is altered at the earliest stages of visual cortical processing and supports current theories that emphasize the role of abnormalities in perceptual synthesis (eg, false inference) in schizophrenia.