Controllability and hippocampal activation during pain expectation in fibromyalgia syndrome.

To examine the role of perceived control in pain perception, fibromyalgia patients and healthy controls participated in a reaction time experiment under different conditions of pain controllability. No significant differences between groups were found in pain intensity and unpleasantness ratings. However, during the expectation of uncontrollable pain, patients compared to controls showed higher hippocampal activation.

Contextual modulation of pain in masochists: involvement of the parietal operculum and insula.

Pain can be modulated by contextual stimuli, such as emotions, social factors, or specific bodily perceptions. We presented painful laser stimuli together with body-related masochistic visual stimuli to persons with and without preferred masochistic sexual behavior and used neutral, positive, and negative pictures with and without painful stimuli as control. Masochists reported substantially reduced pain intensity and unpleasantness in the masochistic context compared with controls but had unaltered pain perception in the other conditions.

Deficient modulation of pain by a positive emotional context in fibromyalgia patients.

This study aimed to investigate the modulating effects of emotional context on pain perception in 16 patients with fibromyalgia syndrome (FMS) and 16 healthy control (HC) subjects. An infrared laser was used to apply individually adapted painful stimuli to the dorsum of the left hand. The emotional background of the painful stimuli was modulated by concurrent presentations of negative, neutral, and positive picture stimuli selected from the International Affective Picture System.

Is the effect of tinnitus on auditory steady-state response amplitude mediated by attention?

Objectives: Auditory steady-state response (ASSR) amplitude enhancement effects have been reported in tinnitus patients. As ASSR amplitude is also enhanced by attention, the effect of tinnitus on ASSR amplitude could be interpreted as an effect of attention mediated by tinnitus. As N1 attention effects are significantly larger than those on the ASSR, if the effect of tinnitus on ASSR amplitude were due to attention, there should be similar amplitude enhancement effects in tinnitus for the N1 component of the auditory-evoked response.

Structural changes of the corpus callosum in tinnitus.

Objectives: In tinnitus, several brain regions seem to be structurally altered, including the medial partition of Heschl's gyrus (mHG), the site of the primary auditory cortex. The mHG is smaller in tinnitus patients than in healthy controls. The corpus callosum (CC) is the main interhemispheric commissure of the brain connecting the auditory areas of the left and the right hemisphere.

Interaction among the components of multiple auditory steady-state responses: enhancement in tinnitus patients, inhibition in controls.

Amplitude and phase of steady-state signals recorded in response to amplitude-modulated (AM) sine tones vary over time, suggesting that the steady-state response (SSR) reflects not only stimulus input but also its interaction with other input streams or internally generated signals. Alterations of the interaction between simultaneous SSRs associated with tinnitus were studied by recording the magnetic field evoked by AM-tones with one of three carrier and one of three modulation frequencies. Single AM-tones were presented in single presentation mode and superpositions of three AM-tones differing in carrier and modulation frequency in multiple presentation mode.

Functional and structural aspects of tinnitus-related enhancement and suppression of auditory cortex activity.

The steady-state auditory evoked magnetic field was recorded in tinnitus patients and controls, both either musicians or non-musicians, all of them with high-frequency hearing loss. Stimuli were AM-tones with two modulation frequencies and three carrier frequencies matching the "audiometric edge", i.e.

An MR-compatible device for automated and safe application of laser stimuli in experiments employing nociceptive stimulation.

In this paper the establishment of an automatic laser application device that reproducibly delivers laser stimuli in a safe, controlled, and reliable manner is presented. Nociceptive stimulation is widely used in functional magnetic resonance imaging (fMRI) experiments and a number of different methods are employed. One major advantage of laser stimulation as a method to administer painful stimuli is that it selectively activates nociceptors.

Reduced volume of Heschl's gyrus in tinnitus.

The neural basis of tinnitus is unknown. Recent neuroimaging studies point towards involvement of several cortical and subcortical regions. Here we demonstrate that tinnitus may be associated with structural changes in the auditory cortex.

Silent echo-planar imaging for auditory FMRI.

Introduction: The effect of the acoustic scanner noise produced by gradient coil switching on the auditory evoked BOLD signal represents a well-known problem in auditory functional MRI (FMRI). In this paper, a new low-noise echo-planar imaging (EPI) sequence is presented that is optimized for auditory FMRI measurements.

Methods: The sequence produces a narrow-band acoustic frequency spectrum by using a sinusoidal readout echo train and a constant phase encoding gradient.

Extinction training for tinnitus.

Recent accounts of tinnitus development and maintenance assign an important role to central mechanisms. Residual inhibition is a frequent phenomenon in individuals with tinnitus, and refers to the fact that tinnitus can temporarily be reduced by presenting sounds or noises that inhibit tinnitus for a limited time even after termination of the sound. This kind of stimulation-induced inhibition of tinnitus could potentially be used for treatment by combining it with additional interventions to enhance the extinction of tinnitus.

Alteration in the response properties of primary somatosensory cortex related to differential aversive Pavlovian conditioning.

The effects of differential aversive Pavlovian conditioning on the functional organization of primary somatosensory cortex (SI) were examined in 17 healthy participants. Neuroelectric source imaging from 60 electrodes was employed while nine subjects received an innocuous electric stimulus (conditioned stimulus, CS) to one finger (left or right) that was followed by painful electric shock to the lower back (unconditioned stimulus, US) and an innocuous stimulus to the other finger that was never followed by pain. Eight subjects received a presentation of the innocuous and painful stimuli with equal probability to both fingers (control group).

Central processing of acute muscle pain in chronic low back pain patients: an EEG mapping study.

The presence of perceptual sensitization and related brain responses was examined in 14 chronic low back pain (CLBP) patients and 13 healthy controls comparable in age and sex. Multichannel EEG recordings and pain ratings were obtained during the presentation of 800 painful electrical intramuscular and intracutaneous stimuli each to the left m. erector spinae and the left m.

Auditory discrimination training for the treatment of tinnitus.

This paper presents a series of 12 cases of chronic tinnitus patients who participated in 4 weeks of auditory discrimination training either close to or far removed from the tinnitus frequency. The training was based on the assumption that tinnitus is related to a shift of the representation of the tinnitus frequency in auditory cortex outside of the normal tonotopic map and that training close to but not removed from the tinnitus frequency should result in a reduction in the severity of the tinnitus. Tinnitus severity was measured 4 times per day during the entire treatment and other tinnitus-related variables were assessed 1 week before and 1 month posttreatment.

Enhancement of steady-state auditory evoked magnetic fields in tinnitus.

The steady-state auditory evoked magnetic field and the Pbm, the magnetic counterpart of the second frontocentrally positive middle latency component of the transitory auditory evoked potential, were measured in ten tinnitus patients using a 122-channel gradiometer system. The patients had varying degrees of hearing loss. In all patients, the tinnitus frequency was located above the frequency of the audiometric edge, i.

Parietal activation during visual search in the absence of multiple distractors.

Search for a target object embedded in a visual scene involves the posterior parietal cortex. This region is thought to play a role in visual attention by counteracting the effects of distractors on targets or by inhibiting distractors. Using fMRI, we investigated whether the parietal cortex is also engaged in visual search without distractors.

A perceptual interference account of acquisition difficulties for non-native phonemes.

This article presents an account of how early language experience can impede the acquisition of non-native phonemes during adulthood. The hypothesis is that early language experience alters relatively low-level perceptual processing, and that these changes interfere with the formation and adaptability of higher-level linguistic representations. Supporting data are presented from an experiment that tested the perception of English /r/ and /l/ by Japanese, German, and American adults.

Visual feature and conjunction searches of equal difficulty engage only partially overlapping frontoparietal networks.

According to a classical view of visual object recognition, targets are detected "pre-attentively" if they carry unique features, whereas attention has to be deployed serially to object locations for feature binding if the targets can be distinguished from distracters only in terms of their feature conjunctions. Consistent with this view, recent reports suggest a contribution of the posterior parietal cortex (PPC; one major region controlling spatial attention) to conjunction search as opposed to feature search. However, PPC engagement in conjunction search might also reflect feature-based attention or the difficulty of target selection.

Multiple frequency steady-state evoked magnetic field mapping of digit representation in primary somatosensory cortex.

Magnetic source imaging of multiple frequency steady-state somatosensory evoked responses was examined using a 151-channel magnetoencephalography (MEG) system and a dual-channel electrical stimulator. Somatotopy of digit representation was studied in healthy subjects and effects of injury-related cortical plasticity in patients with unilateral transections of the median or the ulnar nerve. Dipole source locations exhibited somatotopic order with overlap between neighboring digits.

Topographic and temporal indices of vowel spectral envelope extraction in the human auditory cortex.

The auditory-evoked neuromagnetic field elicited by single vowel formants and two-formant vowels was recorded under active listening conditions using a 37-channel magnetometer. There were three single formants with formant frequencies of 200, 400, and 800 Hz, another single formant with a formant frequency of 2600 Hz, and three vowels that were constructed by linear superimposition of the high- onto one of the low-frequency formants. P50 m and N100 m latency values were inversely correlated with the formant frequency of single formants.

Involvement of the human frontal eye field and multiple parietal areas in covert visual selection during conjunction search.

Searching for a target object in a cluttered visual scene requires active visual attention if the target differs from distractors not by elementary visual features but rather by a feature conjunction. We used functional magnetic resonance imaging (fMRI) in human subjects to investigate the functional neuroanatomy of attentional mechanisms employed during conjunction search. In the experimental condition, subjects searched for a target defined by a conjunction of colour and orientation.

Measuring the perceptual magnet effect in the perception of /i/ by German listeners.

In a study of the internal category structure of the vowel /i/, Kuhl found a "perceptual magnet effect": Discrimination sensitivity was poorer for category instances that were acoustically similar to the category prototype than it was for category instances that were not. The typicality of category exemplars was determined by goodness judgments and was found to correlate with the acoustics of average production. Analysis and interpretation of discrimination performance relied on two important assumptions: that listeners perceived all stimuli presented as exemplars of the same vowel category and that, apart from the influence of phonetic coding, discrimination sensitivity was the same across the investigated part of the vowel space.

The magnetic mismatch field elicited by words and phonological non-words.

The speech-evoked magnetic mismatch field was measured using a 49-channel gradiometer. The standard stimuli were words in one condition and phonological non-words in another condition. The deviants were non-words throughout.

Magnetic fields elicited by tones and vowel formants reveal tonotopy and nonlinear summation of cortical activation.

A long-latency response component (N1m) and the sustained field (SF) of the auditory evoked magnetic field elicited by two composite stimuli (a two-tone combination and a two-formant vowel) and their individually presented components (a 600-Hz and a 2100-Hz pure tone and two single-vowel formants with formant frequencies matched to the tone frequencies) were recorded using a 37-channel magnetometer. The response to the composite stimuli differed from the linear sum of the responses to the respective components in latency, equivalent dipole moment, and equivalent dipole location, suggesting an interaction among the processes elicited by the constituents of composite stimuli. N1m and SF source locations were more medial for the response to the high tone than to the low tone and more medial for the response to the high vowel formant than to the low vowel formant.

Magnetic mismatch fields elicited by vowels and consonants.

Auditory-evoked mismatch fields (MMFs) elicited by vowel contrasts and plosive stop consonant place-of-articulation contrasts were recorded over the left hemisphere of neurologically and audiologically normal subjects. Two experiments were conducted: vowels were presented in isolation in experiment 1 and embedded in consonant-vowel syllables in experiment 2. Bestfit equivalent MMF sources were obtained using the model of a single, spatiotemporal current dipole in a sphere.