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Several convergent lines of evidence have suggested that the presence of an emotion signal in a visual stimulus can influence processing of that stimulus. In the current study, we picked up on this idea, and explored the hypothesis that the presence of an emotional facial expression (happiness) would facilitate the identification of familiar faces. We studied two groups of normal participants (overall N=54), and neurological patients with either left (n=8) or right (n=10) temporal lobectomies. Reaction times were measured while participants named familiar famous faces that had happy expressions or neutral expressions. In support of the hypothesis, naming was significantly faster for the happy faces, and this effect obtained in the normal participants and in both patient groups. In the patients with left temporal lobectomies, the effect size for this facilitation was large (d=0.87), suggesting that this manipulation might have practical implications for helping such patients compensate for the types of naming defects that often accompany their brain damage. Consistent with other recent work, our findings indicate that emotion can facilitate visual identification, perhaps via a modulatory influence of the amygdala on extrastriate cortex.

The neural correlates of naming concrete entities such as tools (with nouns) and naming actions (with verbs) are partially distinct: the former are linked to the left inferotemporal (IT) region, whereas the latter are linked to the left frontal opercular (FO) and left posterior middle temporal (MT) regions. This raises an intriguing question: How would such neural patterns be influenced by noun-verb homonymy, specifically, naming tasks in which the target words denote objects or actions (e.g., ''comb'')? To explore this, we conducted a PET study in which 10 normal participants named visually presented tools or actions. The factor of homonymy yielded interesting effects: For tools, non-homonymous nouns (e.g., ''camera'') activated left IT, whereas homonymous nouns (e.g., ''comb'') activated both left IT and left FO. For actions, non-homonymous (e.g., ''juggle'') and homonymous (e.g., ''comb'') verbs activated left FO, MT, and IT, but there was evidence that the FO and MT activations were less widespread for the homonymous verbs. We also found that retrieval of the same exact words (e.g., ''comb'' and ''comb'') produced differential activation in left MT-there was greater MT activation when the words were being used to name actions, than when they were being used to name tools. Our results suggest that noun-verb homonymy has an important influence on the patterns of neural activation associated with words denoting objects and actions, and that even when the phonological forms are identical, the patterns of neural activation are different according to the demands of the task.

Using both the lesion method and functional imaging (positron emission tomography) in large cohorts of subjects investigated with the same experimental tasks, we tested the following hypotheses: (A) that the retrieval of words which denote concrete entities belonging to distinct conceptual categories depends upon partially segregated regions in higher-order cortices of the left temporal lobe; and (B) that the retrieval of conceptual knowledge pertaining to the same concrete entities also depends on partially segregated regions; however, those regions will be different from those postulated in hypothesis A, and located predominantly in the right hemisphere (the second hypothesis tested only with the lesion method). The analyses provide support for hypothesis A in that several regions outside the classical Broca and Wernicke language areas are involved in name retrieval of concrete entities, and that there is a partial segregation in the temporal lobe with respect to the conceptual category to which the entities belong, and partial support for hypothesis B in that retrieval of conceptual knowledge is partially segregated from name retrieval in the lesion study. Those regions identified here are seen as parts of flexible, multi-component systems serving concept and word retrieval for concrete entities belonging to different conceptual categories. By comparing different approaches the article also addresses a number of method issues that have surfaced in recent studies in this field.

A study of patients with preferential amygdala lesions reveals that bilateral damage to human amygdala impairs specific recognition of facial expressions. Human amygdala is crucial for recognition of fear in facial expressions and recognition of multiple emotions in a single facial expression. However, recognition of personal identity from faces does not involve amygdala.

Pick's disease is often thought of as being a degenerative disease involving the frontal lobes of the brain, and indeed it is often a dementing illness characterized by frontal lobe signs. Yet, even the first case described by Pick himself involved the left temporal lobe and was characterized by aphasia (impaired speech). The authors present the case of a 59-year-old physician with deteriorating ability to use words, although his speech was fluent and his comprehension appeared to be intact. Death resulting from pneumonia provided an opportunity for autopsy and the confirmation of Pick's disease. At the time of his initial presentation, the patient reported noticing a decline in his ability to choose the proper word over a three-year period. Six months later, he retired from his practice because of his difficulty naming things, but there was no sign of deterioration of his other skills. In fact, his skill at performing surgical procedures was intact at the time of retirement. After retirement he played tennis with his friends with no signs of loss of skill, and managed his investment portfolio without error. The patient developed psychiatric problems after a car accident, which occurred about two years after his initial presentation, and he died of pneumonia four months later. Gross examination of the patient's brain revealed the presence of atrophy, which was more pronounced on the left than the right hemisphere. Neurofibrillary tangles, which are common in Alzheimer's disease and other brain diseases, were not seen. Neuritic plaques, a characteristic feature of Alzheimer's disease, were not present. However, Pick's bodies (round structures visible in the cytoplasm of affected neurons) were identified, confirming that this case was indeed Pick's disease. The authors suggest that in cases of aphasia, particularly when anomia (the inability to name objects) is the primary symptom, Pick's disease be considered as a possible diagnosis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Arising from: M. Koenigs et al. Nature 446, 908-911 (2007) Neuroscience has recently turned to the study of utilitarian and nonutilitarian moral judgement. Koenigs et al. (1) examine the responses [...]