Studies in animals demonstrate a crucial role for the amygdala in emotional and social behavior, especially as related to fear and aggression. Whereas lesion and functional-imaging studies in humans indicate the amygdala's participation in assessing the significance of nonverbal as well as paralinguistic cues, direct evidence for its role in the emotional processing of linguistic cues is lacking. In this study, we use a modified Stroop task along with a highsensitivity neuroimaging technique to target the neural substrate engaged specifically when processing linguistic threat. Healthy volunteer subjects were instructed to name the color of words of either threat or neutral valence, presented in different color fonts, while neural activity was measured by using H 2 15 O positron-emission tomography. Bilateral amygdalar activation was significantly greater during color naming of threat words than during color naming of neutral words. Associated activations were also noted in sensory-evaluative and motor-planning areas of the brain. Thus, our results demonstrate the amygdala's role in the processing of danger elicited by language. In addition, the results reinforce the amygdala's role in the modulation of the perception of, and response to, emotionally salient stimuli. The current study further suggests conservation of phylogenetically older mechanisms of emotional evaluation in the context of more recently evolved linguistic function.Both lesion and functional-imaging studies in humans have demonstrated the amygdala's role in the visual recognition of emotional facial expressions (1-3). Studies in humans further indicate the amygdala's participation in assessing the significance of paralinguistic emotional stimuli (1, 4). In humans, emotional cues are also transmitted linguistically. Evidence for the amygdala's function in the emotional processing of linguistic cues, however, has yet to be described. In this experiment, we sought to test the hypothesis that the human amygdala is involved in the emotional processing of linguistic cues specifically related to threat.

Humans produce hand movements to manipulate objects, but also make hand movements to convey socially relevant information to one another. The mirror neuron system (MNS) is activated during the observation and execution of actions. Previous neuroimaging experiments have identified the inferior parietal lobule (IPL) and frontal operculum as parts of the human MNS. Although experiments have suggested that object-directed hand movements drive the MNS, it is not clear whether communicative hand gestures that do not involve an object are effective stimuli for the MNS. Furthermore, it is unknown whether there is differential activation in the MNS for communicative hand gestures and object-directed hand movements. Here we report the results of a functional magnetic resonance imaging (fMRI) experiment in which participants viewed, imitated and produced communicative hand gestures and object-directed hand movements. The observation and execution of both types of hand movements activated the MNS to a similar degree. These results demonstrate that the MNS is involved in the observation and execution of both communicative hand gestures and object-direct hand movements.

No abstract

In this study the authors compared the performance of abstinent drug abusers (n = 21) and nonuser control participants (n = 20) in neurocognitive and emotional functions by use of the Rogers Decision Making Task, Gambling Task, Emotional Stroop, impulsivity continuous performance task (CPT), and vigilance CPT. Skin conductance (SC) and heart rate (HR) monitoring was synchronized with task performance. Groups showed similar performance for vigilance, impulsivity, and emotional interference; however, drug abusers showed stronger SC responses. Drug abusers performed more poorly on the Gambling and Rogers Decision Making Tasks. When making risky decisions, drug abusers showed significantly less increase in SC activity than controls and exhibited lower HRs throughout performance on all tasks. In conclusion, complex tasks involving decision making, sensitivity to consequences, and emotional regulation discriminated between drug abusers and controls.

Environmental sounds convey specific meanings and the neural circuitry for their recognition may have preceded language. To dissociate semantic mnemonic from sensory perceptual processing of non-verbal sound stimuli we systematically altered the inherent semantic properties of non-verbal sounds from natural and man-made sources while keeping their acoustic characteristics closely matched. We hypothesized that acoustic analysis of complex non-verbal sounds would be right lateralized in auditory cortex regardless of meaning content and that left hemisphere regions would be engaged when meaningful concept could be extracted. Using H(2) (15)O-PET imaging and SPM data analysis, we demonstrated that activation of the left superior temporal and left parahippocampal gyrus along with left inferior frontal regions was specifically associated with listening to meaningful sounds. In contrast, for both types of sounds, acoustic analysis was associated with activation of right auditory cortices. We conclude that left hemisphere brain regions are engaged when sounds are meaningful or intelligible.