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Schizophrenia is often associated with difficulties in distinguishing between actions of self and of others. This could reflect dysfunction of the mirror neuron system which directly matches observed and executed actions. We studied 11 people with schizophrenia and their co-twins without manifest disease, using stimulus-induced changes in the magnetoencephalographic approximately 20 Hz rhythm as an index of activation in the motor cortex part of the mirror neuron system. During action observation and execution, motor cortex reaction was weaker in those with schizophrenia than in their co-twins, suggesting a disease-related dysfunction of motor cognition.

Purpose: To prospectively evaluate magnetoencephalography (MEG) and functional magnetic resonance (MR) imaging, as compared with intraoperative cortical mapping, for identification of the central sulcus., Materials and Methods: Fifteen patients (six men, nine women; age range, 25-58 years) with a lesion near the primary sensorimotor cortex (13 gliomas, one cavernous hemangioma, and one meningioma) were examined after institutional review board approval and written informed consent from each patient were obtained. At MEG, evoked magnetic fields to median nerve stimulation were recorded; at functional MR imaging, hemodynamic responses to self-paced palmar flexion of the wrist were imaged. General linear model analysis with contextual clustering (P < .01) was used to analyze functional MR imaging data, and dipole modeling was used to analyze MEG data. MEG and functional MR localizations were compared with intraoperative cortical mappings. The distance from the area of functional MR imaging activation to the tumor margin was compared between the patients with discordant and those with concordant intraoperative mapping findings by using unpaired t testing., Results: MEG depicted the central sulcus correctly in all 15 patients, as verified at intraoperative mapping. The functional MR imaging localization results agreed with the intraoperative mappings in 11 patients. In all four patients with a false localization, the primary activation was in the postcentral sulcus region, but it did not differ significantly from the primary activation in the patients with correct localization with respect to proximity to the tumor (P = .38). Furthermore, at functional MR imaging, multiple nonprimary areas were activated, with considerable interindividual variation., Conclusion: Although both MEG and functional MR imaging can provide useful information for neurosurgical planning, in the present study, MEG proved to be superior for locating the central sulcus. Activation of multiple nonprimary cerebral areas may confound the interpretation of functional MR imaging results., ((c) RSNA, 2006.)

We studied attentional modulation of cortical processing of faces and houses with functional MRI and magnetoencephalography (MEG). MEG detected an early, transient face-selective response. Directing attention to houses in "double-exposure" pictures of superimposed faces and houses strongly suppressed the characteristic, face-selective functional MRI response in the fusiform gyrus. By contrast, attention had no effect on the M170, the early, face-selective response detected with MEG. Late (>190 ms) category-related MEG responses elicited by faces and houses, however, were strongly modulated by attention. These results indicate that hemodynamic and electrophysiological measures of face-selective cortical processing complement each other. The hemodynamic signals reflect primarily late responses that can be modulated by feedback connections. By contrast, the early, face-specific M170 that was not modulated by attention likely reflects a rapid, feed-forward phase of face-selective processing.

Subjects with Asperger's syndrome (AS) are impaired in social interaction and imitation, but the underlying brain mechanisms are poorly understood. Because the mirror-neuron system (MNS) that matches observed and executed actions has been suggested to play an important role in imitation and in reading of other people's intentions, we assessed MNS functions in 8 adult AS subjects and in 10 healthy control subjects during imitation of still pictures of lip forms. In the control subjects, cortical activation progressed in 30 to 80-millisecond steps from the occipital cortex to the superior temporal sulcus, to the inferior parietal lobe, and to the inferior frontal lobe, and finally, 75 to 90 milliseconds later, to the primary motor cortex of both hemispheres. Similar activation sites were found in AS subjects but with slightly larger scatter. Activation of the inferior frontal lobe was delayed by 45 to 60 milliseconds and activations in the inferior frontal lobe and in the primary motor cortex were weaker than in control subjects. The observed abnormal premotor and motor processing could account for a part of imitation and social impairments in subjects with AS.

Hand and finger postures of other people are important body language cues that strongly contribute to the observer's decision about the person's intentions, thoughts, and attentional state. We compared neuromagnetic cortical activation elicited by color images of natural and distorted finger postures. The distorted postures contained computer-deformed joint angles and thereby easily caught the observer's attention. From about 260 msec onwards, extrastriate occipital areas of both hemispheres were activated more strongly by distorted than natural finger postures. We interpret this result as an early top-down effect of emotional valence on the processing of unusual hand shapes in the extrastriate visual cortex.

Imitation is crucial for proper development of social and communicative skills. Here, we argue that, based on an error analysis of a behavioral imitation task, adult Asperger and high-functioning autistic subjects suffer from an intriguing deficit of imitation: they lack the natural preference for imitation in a mirror-image fashion. The imitation task consisted of a simple movement sequence of putting a pen with the left or right hand into a green or a blue cup using one of two possible grips. The subjects were asked to imitate the experimenter's hand movements either using the crossed hand (e.g., the subject's right hand corresponding to the experimenter's right hand) for imitation or to imitate as if looking in a mirror (e.g., the subject's left hand corresponding to the experimenter's right hand). When people normally view other persons face-to-face, they prefer to imitate as in a mirror, and observation of mirror-image-like movements speeds up performance in nonimitative tasks. However, our autistic subjects, defective in social cognition, did not profit from mirror-image movements of others. These results provide a new insight into the difficulties that autistic subjects face in viewing and understanding actions of others.

Neurons in area F5 of the monkey premotor cortex are activated during both execution and observation of hand actions. A similar "mirror-neuron system" seems to exist also in the human brain, including at least the superior temporal sulcus region, Broca's area, and the primary motor cortex. We recorded somatosensory evoked fields in response to median nerve stimulation from nine healthy subjects during (i) rest, (ii) manipulation of a small object, and (iii) observation of the same action to find out to what extent the somatosensory cortices display behavior similar to the human mirror-neuron system. SI signals were enhanced and SII signals suppressed during both manipulation and observation, except when the right manipulating hand was stimulated. Our results suggest that the SI and SII cortices contribute to the human mirror-neuron system, possibly providing information necessary for preserving the sense of self during action observation., (©2002 Elsevier Science (USA).)

The monkey premotor cortex contains neurons that are activated both when the monkey performs motor acts and when he observes actions made by others. A similar mirror neuron system, involving several brain areas, has been found in humans. We recorded neuromagnetic oscillatory activity from the primary motor cortex of 10 healthy subjects when they observed live and videotaped finger movements. The left and right median nerves were stimulated alternatingly and the poststimulus level of the approximately 20 Hz rhythm was quantified. Compared with the rest condition, the approximately 20 Hz rhythm was dampened 15-19% more when the subjects observed live rather than videotaped hand movements, indicating stronger activation of the primary motor cortex. These results suggest that the human mirror neuron system differentiates natural and artificially presented movements.

We studied 12 patients with brain tumors in the vicinity of the sensorimotor region to provide a preoperative three-dimensional visualization of the functional anatomy of the rolandic cortex. We also evaluated the role of cortex-muscle coherence analysis and anatomical landmarks in identifying the sensorimotor cortex. The functional landmarks were based on neuromagnetic recordings with a whole-scalp magnetometer, coregistred with magnetic resonance images. Evoked fields to median and tibial nerve and lip stimuli were recorded to identify hand, foot and face representations in the somatosensory cortex. Oscillatory cortical activity, coherent with surface electromyogram during isometric muscle contraction, was analyzed to reveal the hand and foot representations in the precentral motor cortex. The central sulcus was identified also by available anatomical landmarks. The source locations, calculated from the neuromagnetic data, were displayed on 3-D surface reconstructions of the individual brains, including the veins. The preoperative data were verified during awake craniotomy by cortical stimulation in 7 patients and by cortical somatosensory evoked potentials in 5 patients. Sources of somatosensory evoked fields identified correctly the postcentral gyrus in all patients. Useful corroborative information was obtained from anatomical landmarks in 11 patients and from cortex-muscle correlograms in 8 patients. The preoperative visualization of the functional anatomy of the sensorimotor strip assisted in designing the operational strategy, facilitated orientation of the neurosurgeon during the operation, and speeded up the selection of sites for intraoperative stimulation or mapping, thereby helping to prevent damage of eloquent brain areas during surgery.

Patients with autism and Asperger syndrome (AS) are impaired in mindreading and imitation skills. One possibility would be that their 'mirror neuron' system, which matches action execution and observation, does not function properly. To test this hypothesis we compared action-viewing related motor cortex functions in an AS group (one autistic and four AS subjects) and eight control subjects. In both groups viewing hand actions modified the neuromagnetic approximately 20 Hz oscillatory activity in the primary motor cortex to the same extent. Thus impaired mindreading and imitation skills found in AS and autism do not seem to result from dysfunction of the motor cortex part of the action execution/observation system.

Background and Purpose: The onset of spontaneous intracerebral hemorrhage (ICH) is often accompanied by transient blood pressure (BP) elevation. The prognostic value and the determinants of this BP reaction have not entirely been solved, and the present study was focused on these questions., Methods: From 1985 to 1991 in Central Finland (population, 246,000), a total of 425 patients had first-ever ICH verified by CT or necropsy. The hematoma was supratentorial in 337 patients. Of the 306 patients with supratentorial ICH who had CT, 282 had the BP measured at least once within 24 hours of onset, and they formed the study population. The case notes and CT films were reviewed, and mean arterial pressure (MAP) was calculated from the highest BP reading., Results: The fatality rate was high; 43% of the patients were dead within 28 days of onset. Six independent predictors of the 28-day survival were identified by multiple logistic regression; these predictors were consciousness on admission, first-day MAP, subarachnoid spread of the bleed, lateral shift of hemispheral midline structures, admission blood glucose, and vomiting. The MAPs varied between 66.7 and 203.3 mm Hg, and the cutoff points of the MAP quartiles were 118, 132, and 145 mm Hg. Patients in the first three MAP quartiles had relatively fair outcome, with 71%, 65%, and 60%, respectively, alive 28 days after onset. This was in sharp contrast to the fourth quartile, with only 33% surviving the first 28 days (log-rank, P < .0001 to P = .0010). Patients unconscious/ comatose on admission had significantly higher MAPs than did those who were alert or somnolent/disoriented (ANOVA, P = .0079). However, at all levels of consciousness, the 28-day fatality rate increased from the first to the fourth MAP quartile: 69% in the alert, 186% in the somnolent/disoriented, and 45% in the unconscious/comatose patients. Stepwise multiple regression analysis gave four independent predictors of the first-day MAP: hypertension, age (in an inverse fashion), admission blood glucose, and hematoma volume., Conclusions: The most important predictor of the 28-day survival was the level of consciousness on admission, followed by first-day MAP. Hypertension was the most important predictor of the first-day MAP, followed by age, which had an inverse effect on the MAP level. At all levels of consciousness, high first-day MAP (especially if > 145 mm Hg) worsened the 28-day survival rate.