Self-perspective leads to increased activation of pain processing brain regions in fibromyalgia.

BACKGROUND: Dysfunction of central nervous pain processing is assumed to play a key role in primary fibromyalgia (FM) syndrome. This pilot study examined differences of pain processing associated with adopting different interpersonal perspectives. METHODS: Eleven FM patients and 11 healthy controls (HC) were scanned with functional magnetic resonance imaging. Participants were trained to take either a self-perspective or another person's perspective when viewing the visual stimuli. Stimuli showed body parts in painful situations of varying intensity (low, medium, and high) and visually similar but neutral situations. RESULTS: Patients with FM showed a higher increase in blood oxygen level dependent (BOLD) response, particularly in the supplementary motor area (SMA). All pain-related regions of interest (anterior insula, somatosensory cortices, anterior cingulate cortex, and SMA) showed stronger modulation of BOLD responses in FM patients in the self-perspective. In contrast to pain processing regions, perspective-related regions (e.g. temporoparietal junction) did not differ between FM and HC. CONCLUSIONS: The stronger response of all four pain processing cerebral regions during self-perspective is discussed in the light of disturbed bottom-up processing. Furthermore, the results confirm earlier reports of augmented pain processing in FM, and provide evidence for sensitization of central nervous pain processing.

Three-dimensional MR-encephalography: fast volumetric brain imaging using rosette trajectories.

MR-Encephalography (MREG) is a technique that allows real time observation of functional changes in the brain that appears within 100 msec. The high sampling rate is achieved at the cost of some spatial resolution. The article describes a novel imaging method for fast three-dimensional-MR-encephalography whole brain coverage based on rosette trajectories and the use of multiple small receiver coils. The technique allows the observation of changes in brain physiology at very high temporal resolution. A highly undersampled three-dimensional rosette trajectory is chosen, to perform single shot acquisition of k-space data within 23 msec. By using a 32-channel head coil array and regularized nonuniform Fourier transformation reconstruction, the spatial resolution is sufficient to detect even subtle centers of activation (e.g. human MT+). The method was applied to visual block design paradigms and compared with echo planar imaging-based functional MRI. As a proof-of-principle of the method's ability to detect local differences in the hemodynamic response functions, the analyzed MR-encephalography data revealed a spatially dependent delay of the arrival of the blood oxygenation level dependent response within the visual cortex.

Visual motion, eye motion, and relative motion: A parametric fMRI study of functional specializations of smooth pursuit eye movement network areas.

The ability to pursue moving objects with the eyes is vital to humans. However, it remains unclear how the brain differentiates visual object motion, smooth pursuit eye movements (SPEM), and eye movement-induced relative motion on the retina and where visual-to-oculomotor transformation takes place. To characterize functional differences of SPEM-processing cortical areas, we simultaneously measured functional magnetic resonance imaging (fMRI) and smooth pursuit to visual, oculomotor, and visuo-oculomotor stimuli varying the quantity of background dots of the stimuli. Resulting activations involved the whole visuo-oculomotor network. They varied among regions depending on the functional tasks and parametric changes of the background. Activation in many SPEM regions increased from 1 to 16 background dots but decreased at 36 dots. This could be an effect of coherent-texture perception. Putative MST area was not influenced by the amount of moving or stationary background dots. It probably participates in visuo-oculomotor transformation. Parts of the posterior parietal cortex seem specifically activated with relative motion between eye and background, but not with motion per se. This could be important for the perception of spatial references.

Neural activation associated with corrective saccades during tasks with fixation, pursuit and saccades.

Corrective saccades are small eye movements that redirect gaze whenever the actual eye position differs from the desired eye position. In contrast to various forms of saccades including pro-saccades, recentering-saccades or memory guided saccades, corrective saccades have been widely neglected so far. The fMRI correlates of corrective saccades were studied that spontaneously occurred during fixation, pursuit or saccadic tasks. Eyetracking was performed during the fMRI data acquisition with a fiber-optic device. Using a combined block and event-related design, we isolated the cortical activations associated with visually guided fixation, pursuit or saccadic tasks and compared these to the activation associated with the occurrence of corrective saccades. Neuronal activations in anterior inferior cingulate, bilateral middle and inferior frontal gyri, bilateral insula and cerebellum are most likely specifically associated with corrective saccades. Additionally, overlapping activations with the established pro-saccade and, to a lesser extent, pursuit network were present. The presented results imply that corrective saccades represent a potential systematic confound in eye-movement studies, in particular because the frequency of spontaneously occurring corrective saccades significantly differed between fixation, pursuit and pro-saccades.

Interindividual synchronization of brain activity during live verbal communication.

Verbal social interaction plays an important role both in the etiology and treatment of psychiatric disorders. However, the neural basis of social interaction has primarily been studied in the individual brain, neglecting the inter-individual perspective. Here, we show inter-individual neuronal coupling of brain activity during live verbal interaction, by investigating 11 pairs of good female friends who were instructed to speak about autobiographical life events during simultaneous fMRI acquisition. The analysis revealed that the time course of neural activity in areas associated with speech production was coupled with the time course of neural activity in the interlocutor's auditory cortex. This shows the feasibility of the new methodology, which may help elucidate basic reciprocal mechanisms of social interaction and the underpinnings of disordered communication. In particular, it may serve to study the process of psychotherapy on a neuronal level.

Medial prefrontal dysfunction and prolonged amygdala response during instructed fear processing in borderline personality disorder.

OBJECTIVES: Affective dysregulation is a clinical hallmark of borderline personality disorder (BPD). This study used an instructed fear task combined with functional MRI (fMRI) and skin conductance response (SCR) to test hypotheses about mechanisms of disturbed fronto-limbic neural circuitry underlying dysfunctional emotional processing in BPD. METHODS: Female BPD patients and matched control subjects were exposed to two visual stimuli during fMRI scanning and SCR recording. Subjects were instructed shortly before scanning that one stimulus (Threat) potentially represents an aversive event whereas another stimulus (Safe) represents safety. The aversive event (electrodermal stimulation) itself was only experienced before this instruction and never occurred during fMRI scanning. RESULTS: Both groups showed stronger SCR to Threat compared to Safe indicating differential fear response which habituated over time. BPD compared to control subjects did not show fMRI signal decrease of amygdala activity or relative ventromedial prefrontal cortex (vmPFC) activity increase over time. Moreover, BPD patients showed increased connectivity of the amygdala with vmPFC but decreased connectivity of subgenual ACC with dorsal ACC compared to control subjects. CONCLUSIONS: Prolonged amygdala response and a functional disconnection between ventral and dorsal mPFC regions may be part of the neural mechanisms underlying emotional dysregulation in BPD patients.

Optic flow stimuli in and near the visual field centre: a group FMRI study of motion sensitive regions.

Motion stimuli in one visual hemifield activate human primary visual areas of the contralateral side, but suppress activity of the corresponding ipsilateral regions. While hemifield motion is rare in everyday life, motion in both hemifields occurs regularly whenever we move. Consequently, during motion primary visual regions should simultaneously receive excitatory and inhibitory inputs. A comparison of primary and higher visual cortex activations induced by bilateral and unilateral motion stimuli is missing up to now. Many motion studies focused on the MT+ complex in the parieto-occipito-temporal cortex. In single human subjects MT+ has been subdivided in area MT, which was activated by motion stimuli in the contralateral visual field, and area MST, which responded to motion in both the contra- and ipsilateral field. In this study we investigated the cortical activation when excitatory and inhibitory inputs interfere with each other in primary visual regions and we present for the first time group results of the MT+ subregions, allowing for comparisons with the group results of other motion processing studies. Using functional magnetic resonance imaging (fMRI), we investigated whole brain activations in a large group of healthy humans by applying optic flow stimuli in and near the visual field centre and performed a second level analysis. Primary visual areas were activated exclusively by motion in the contralateral field but to our surprise not by central flow fields. Inhibitory inputs to primary visual regions appear to cancel simultaneously occurring excitatory inputs during central flow field stimulation. Within MT+ we identified two subregions. Putative area MST (pMST) was activated by ipsi- and contralateral stimulation and located in the anterior part of MT+. The second subregion was located in the more posterior part of MT+ (putative area MT, pMT).