John S. Morris

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Localized amygdalar lesions in humans produce deficits in the recognition of fearful facial expressions. We used functional neuroimaging to test two hypotheses: (i) that the amygdala and some of its functionally connected structures mediate specific neural responses to fearful expressions; (ii) that the early visual processing of emotional faces can be(More)
The amygdala is thought to play a crucial role in emotional and social behaviour. Animal studies implicate the amygdala in both fear conditioning and face perception. In humans, lesions of the amygdala can lead to selective deficits in the recognition of fearful facial expressions and impaired fear conditioning, and direct electrical stimulation evokes(More)
If subjects are shown an angry face as a target visual stimulus for less than forty milliseconds and are then immediately shown an expressionless mask, these subjects report seeing the mask but not the target. However, an aversively conditioned masked target can elicit an emotional response from subjects without being consciously perceived. Here we study(More)
Previous neuroimaging and neuropsychological studies have investigated the neural substrates which mediate responses to fearful, disgusted and happy expressions. No previous studies have investigated the neural substrates which mediate responses to sad and angry expressions. Using functional neuroimaging, we tested two hypotheses. First, we tested whether(More)
Neuroimaging studies have shown differential amygdala responses to masked ("unseen") emotional stimuli. How visual signals related to such unseen stimuli access the amygdala is unknown. A possible pathway, involving the superior colliculus and pulvinar, is suggested by observations of patients with striate cortex lesions who show preserved abilities to(More)
In social environments, multiple sensory channels are simultaneously engaged in the service of communication. In this experiment, we were concerned with defining the neuronal mechanisms for a perceptual bias in processing simultaneously presented emotional voices and faces. Specifically, we were interested in how bimodal presentation of a fearful voice(More)
To determine how vocally expressed emotion is processed in the brain, we measured neural activity in healthy volunteers listening to fearful, sad, happy and neutral non-verbal vocalizations. Enhanced responses to emotional vocalizations were seen in the caudate nucleus, as well as anterior insular, temporal and prefrontal cortices. The right amygdala(More)
To address the question of which brain regions subserve retrieval of emotionally-valenced memories, we used event-related fMRI to index neural activity during the incidental retrieval of emotional and non-emotional contextual information. At study, emotionally neutral words were presented in the context of sentences that were either negatively, neutrally or(More)
We used event-related fMRI to measure neural activity in volunteer subjects during acquisition of an implicit association between a visual conditioned stimulus (CS+) (angry face) and an auditory unconditioned stimulus (UCS) (aversive, loud noise). Three distinct functional regions were identified within left amygdala: a UCS (noise)-related lateral region, a(More)
Patient G.Y. is able to discriminate emotional facial expressions presented in his blind (right) hemifield despite an extensive lesion of the corresponding (left) striate cortex. One proposal is that this residual ability (affective "blindsight") depends on a subcortical visual pathway comprising the superior colliculus, posterior (extrageniculate) thalamus(More)