B. de Gelder

Mismatch negativity predicts recovery from the vegetative state

OBJECTIVEnMismatch negativity (MMN) is an automatic event related brain response, well investigated in the acute phase after severe brain injury: the presence of a MMN is often found to predict the emergence from coma, and the exclusion of shifting into a vegetative state (VS). In the present study MMN was examined during recovery from VS.nnnMETHODSnTen vegetative patients were repeatedly examined every 2 weeks for an average period of 3.5 months. Amplitudes and latencies were related to the patients recovery from VS to consciousness, and to a healthy norm group. In addition, MMN was examined on its prognostic value in VS patients, in predicting recovery to consciousness and long-term functional outcome.nnnRESULTSnWith recovery to consciousness MMN-amplitudes increased. A sudden increase was seen in MMN amplitude when patients started to show inconsistent behavioural responses to simple commands. At this level MMN resembled the MMN response as was seen in the norm group. In addition, the MMN-amplitude and latency during the first measurement predicted the patients outcome on recovery to consciousness.nnnCONCLUSIONSnWith recovery from VS to consciousness the ability to process auditory stimulus deviance increases. A sudden enhancement in MMN-amplitude preceded overt communication with the environment. This might be indicative of the consolidation of neural networks underlying overt communication. Moreover, MMN can be helpful in identifying the ability to recover from VS.nnnSIGNIFICANCEnMMN can be used to track recovery from the vegetative state in the post-acute phase after severe brain injury. In addition, MMN can be used to predict the ability to recover from the vegetative state.

Audiovisual emotion recognition in schizophrenia: Reduced integration of facial and vocal affect

Since Kraepelin called dementia praecox what we nowadays call schizophrenia, cognitive dysfunction has been regarded as central to its psychopathological profile. Disturbed experience and integration of emotions are, both intuitively and experimentally, likely to be intermediates between basic, non-social cognitive disturbances and functional outcome in schizophrenia. While a number of studies have consistently proven that, as part of social cognition, recognition of emotional faces and voices is disturbed in schizophrenics, studies on multisensory integration of facial and vocal affect are rare. We investigated audiovisual integration of emotional faces and voices in three groups: schizophrenic patients, non-schizophrenic psychosis patients and mentally healthy controls, all diagnosed by means of the Schedules of Clinical Assessment in Neuropsychiatry (SCAN 2.1). We found diminished crossmodal influence of emotional faces on emotional voice categorization in schizophrenics, but not in non-schizophrenia psychosis patients. Results are discussed in the perspective of recent theories on multisensory integration.

Tease or threat? Judging social interactions from bodily expressions

We casually observe many interactions that do not really concern us. Yet sometimes we need to be able to rapidly appraise whether an interaction between two people represents a real threat for one of them rather than an innocent tease. Using functional magnetic resonance imaging, we investigated whether small differences in the body language of two interacting people are picked up by the brain even if observers are performing an unrelated task. Fourteen participants were scanned while watching 3-s movies (192 trials and 96 scrambles) showing a male person either threatening or teasing a female one. In one task condition, observers categorized the interaction as threatening or teasing, and in the other, they monitored randomly appearing dots and categorized the color. Our results clearly show that right amygdala responds more to threatening than to teasing situations irrespective of the observers task. When observers attention is not explicitly directed to the situation, this heightened amygdala activation goes together with increased activity in body sensitive regions in fusiform gyrus, extrastriate body area-human motion complex and superior temporal sulcus and is associated with a better behavioral performance of the participants during threatening situations. In addition, regions involved in action observation (inferior frontal gyrus, temporoparietal junction, and inferior parietal lobe) and preparation (premotor, putamen) show increased activation for threat videos. Also regions involved in processing moral violations (temporoparietal junction, hypothalamus) reacted selectively to the threatening interactions. Taken together, our results show which brain regions react selectively to witnessing a threatening interaction even if the situation is not attended because the observers perform an unrelated task.

Modality-specific attention and multisensory integration of emotions in schizophrenia: Reduced regulatory effects

BACKGROUNDnDeficits in emotion perception are a well-established phenomenon in schizophrenic patients and studies have typically used unimodal emotion tasks, presenting either emotional faces or emotional vocalizations. We introduced bimodal emotion conditions in two previous studies in order to study the process of multisensory integration of visible and audible emotion cues. We now build on our earlier work and address the regulatory effects of selective attention mechanisms on the ability to integrate emotion cues stemming from multisensory channels.nnnMETHODSnWe added a neutral secondary distractor condition to the original bimodal paradigm in order to investigate modality-specific selective attention mechanisms. We compared schizophrenic patients (n=50) to non-schizophrenic psychotic patients (n=46), as well as to healthy controls (n=50). A trained psychiatrist used the Schedules of Clinical Assessment in Neuropsychiatry (SCAN 2.1) to diagnose the patients.nnnRESULTSnAs expected, in healthy controls, and to a lesser extent in non-schizophrenic psychotic patients, modality-specific attention attenuated multisensory integration of emotional faces and vocalizations. Conversely, in schizophrenic patients, auditory and visual distractor conditions yielded unaffected and even exaggerated multisensory integration.nnnCONCLUSIONSnThese results suggest that schizophrenics, as compared to healthy controls and non-schizophrenic psychotic patients, have modality-specific attention deficits when attempting to integrate information regarding emotions that stem from multichannel sources. Various explanations for our findings, as well as their possible consequences, are discussed.

Developmental Prosopagnosia In A Patient With Hypoplasia Of The Vermis Cerebelli

Individuals who have not acquired normal face recognition abilities but are otherwise cognitively intact have developmental prosopagnosia (DP). Although DP prevalence is estimated at around 2.5%, the neural underpinnings remain elusive and are presumably more heterogeneous than prosopagnosia acquired in adulthood. Here we report a patient exhibiting severe DP and hypoplasia of …

Repeated measurements of the auditory oddball paradigm is related to recovery from the vegetative state

Summary: The auditory oddball response has been found to be of predictive value for neurologic outcome at the early stages of coma. In the present study, the auditory oddball response was examined longitudinally during the recovery from the vegetative state to consciousness. This response was repeatedly examined every 2 weeks for an average period of 3.5 months in severely brain-injured patients. Results showed that amplitude of the auditory oddball response was unrelated to the behavioral changes during the patients recovery from the vegetative state to consciousness. However, the presence and size of a negative potential at about 350 milliseconds predicted behavioral outcome, both for the short and long term (2 to 3 years after injury). Practical and theoretical implications of these findings are discussed.

Emotion categorization does not depend on explicit face categorization

Face perception and emotion recognition have been extensively studied in the past decade; however, the relation between them is still poorly understood. A traditional view is that successful emotional categorization requires categorization of the stimulus as a face, at least at the basic level. Here we tested whether emotional information could still be recognized accurately without explicit categorization of a stimulus as a face. For this purpose we created a stimulus set in which facial stimuli expressing a range of happy-to-fear emotions were morphed into another object category (shoe). Interestingly, participants categorized emotions with great accuracy in stimuli that contained so little face information that they were explicitly categorized as shoes. Hence, our results show that accurate emotion categorization can take place in stimuli that contain surprisingly little face information. This finding raises interesting questions about the extent to which processes leading to emotion recognition and categorical face perception might be separable.