Magnetic resonance imaging brain scans of Patient S. Sagittal (a), coronal (b), and axial (c) T1-weighted scans show the extent of lesions in the right orbitofrontal cortex (OFC). Bilateral olfactory bulbs (indicated by arrows) are clearly identifiable in a coronal T2-weighted scan (d). Approximate Montreal Neurological Institute coordinates for the scans are as follows: (a) x = 28, (b) y = 32, (c) z = −16, and (d) y = 48.

Behavioral, physiological, and imaging evidence of unconscious olfactory processing in Patient S. The graph in (a) shows the percentage of “yes” responses (indicating that S. detected an odor) in each condition of the odor-detection task. Unpleasant odors (“Unpl”), neutral odors (“Ntrl”), and air only were delivered in separate trials to the left nostril (L) and the right nostril (R). The dashed line indicates the chance percentage of “yes” responses (80%), and it reflects the fact that 80% of trials contained odors. Areas in the left orbitofrontal cortex (OFC) showing greater activation in response to odors delivered to the left nostril, in comparison with air only, are shown in (b). Cyan curves demarcate the right OFC lesion. Amplitudes of the skin conductance response (SCR) to odor presentation are shown in (c), and areas showing greater left anterior OFC activity following unpleasant odors, compared with neutral odors, delivered to the left nostril are shown in (d). The display threshold for images in (b) and (d) is p < .005, uncorrected. Error bars in (c) represent standard deviations.

Physiological and neuroimaging responses in control subjects. Magnitude of skin conductance responses (SCRs) to unpleasant odors (“Unpl”), neutral odors (“Ntrl”), and air only following monorhinal stimulation at either the left nostril (L) or the right nostril (R) is shown in (a). Error bars represent standard errors of the mean. Activations in the amygdala (“Amg”) and orbitofrontal cortex (“OFC”) in response to unpleasant odors (relative to neutral odors) are shown in (b). Clusters in the right piriform cortex with greater response to odor stimulation than air-only stimulation are shown in (c). Effects are overlaid on (b) axial and (c) sagittal sections of the mean T1-weighted anatomical scan; thresholds for display are p < .001 in (b) and p < .005 in (c).

Magnitude of Patient S.’s skin conductance responses (SCRs) to subliminal presentations of fearful faces and neutral faces. Faces were presented in either the left visual field (L) or the right visual field (R). Error bars represent standard deviations.