Sensory brain activation during rectal balloon distention: a pilot study in healthy volunteers to assess safety and feasibility at 1.5T.

OBJECTIVE: Although increasing evidence suggests a central mechanism of action for sacral neuromodulation, the exact mechanism remains unclear. We set up a scanning paradigm to measure brain activation related to various stages of rectal filling using rectal balloon distention. MATERIALS AND METHODS: Six healthy volunteers underwent rectal balloon distention during MRI scanning at a 1.5T scanner with a Tx/Rx head coil. MR images were collected at four levels of distention: empty balloon (EB), first sensation volume (FSV), desire to defecate volume (DDV), maximum tolerable volume (MTV). Data were analyzed using BrainVoyager 20.4. Whole brain and ROI-based fixed-effects general linear model analyses were performed on the fMRI time-course data from all participants. RESULTS: Rectal filling until FSV evoked the most blood-oxygen-level-dependent responses in several clusters throughout the cortex, followed by the responses evoked by rectal filling until DDV. Interestingly, rectal filling until MTV evoked negative responses compared to baseline throughout the cortex. No negative side effects were found. DISCUSSION: This study shows that a standardized paradigm for functional MRI combined with rectal filling is feasible and safe in healthy volunteers and is ready to be used in fecal incontinent patients to assess whether their brain activity differs from healthy controls.

Neuroimaging in Breast Implant Illness: An fMRI Pilot Study.

BACKGROUND: Some women with breast implants report systemic and cognitive symptoms known as breast implant illness (BII), which are very similar to those of fibromyalgia. Functional MRI (fMRI) has shown altered brain activity in fibromyalgia patients. OBJECTIVES: The aim of this pilot study was to investigate whether brain alterations could be observed in BII patients by fMRI. METHODS: Women aged 18 to 76 with silicone breast implants for cosmetic reasons were recruited through a Dutch online BII support organization (MKS) and through the Maastricht University Medical Center. Study participants comprised 12 women with BII and 12 women without symptoms. Participants completed questionnaires regarding demographic characteristics, medical history, psychosocial complaints (Four-Dimensional Symptom Questionnaire), cognitive failure (Mini-Mental State Examination), and pain intensity and pain-related disability (Chronic Pain Grade Scale). Subsequently, brain images of all participants were obtained by resting-state fMRI and diffusion tensor imaging in a 3-T MRI scanner (Siemens Medical System, Erlangen, Germany). RESULTS: Eleven BII patients and 12 healthy controls were included in the analysis. Baseline characteristics were similar in the 2 groups and the mean silicone exposure was 15 years. Patients scored significantly higher than controls on both pain intensity and disability. Patients scored worse on depression, somatization, distress, and anxiety compared with asymptomatic women. Mini-Mental State Examination scores were normal. However, the analyses of both functional connectivity and structural integrity showed no significant differences between the 2 groups. CONCLUSIONS: This pilot study showed no evidence of brain alterations in BII patients. However, patients scored significantly worse on psychosocial symptoms than controls. Psychological factors appear to play an important role in BII and should be further investigated.

Publisher Correction: Cortical encoding of speech enhances task-relevant acoustic information.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.The original and corrected figures are shown in the accompanying Publisher Correction.

Cortical encoding of speech enhances task-relevant acoustic information.

Speech is the most important signal in our auditory environment, and the processing of speech is highly dependent on context. However, it is unknown how contextual demands influence the neural encoding of speech. Here, we examine the context dependence of auditory cortical mechanisms for speech encoding at the level of the representation of fundamental acoustic features (spectrotemporal modulations) using model-based functional magnetic resonance imaging. We found that the performance of different tasks on identical speech sounds leads to neural enhancement of the acoustic features in the stimuli that are critically relevant to task performance. These task effects were observed at the earliest stages of auditory cortical processing, in line with interactive accounts of speech processing. Our work provides important insights into the mechanisms that underlie the processing of contextually relevant acoustic information within our rich and dynamic auditory environment.

Development from childhood to adulthood increases morphological and functional inter-individual variability in the right superior temporal cortex.

We study the developmental trajectory of morphology and function of the superior temporal cortex (STC) in children (8-9 years), adolescents (14-15 years) and young adults. We analyze cortical surface landmarks and functional MRI (fMRI) responses to voices, other natural categories and tones and examine how hemispheric asymmetry and inter-subject variability change across age. Our results show stable morphological asymmetries across age groups, including a larger left planum temporale and a deeper right superior temporal sulcus. fMRI analyses show that a rightward lateralization for voice-selective responses is present in all groups but decreases with age. Furthermore, STC responses to voices change from being less selective and more spatially diffuse in children to highly selective and focal in adults. Interestingly, the analysis of morphological landmarks reveals that inter-subject variability increases during development in the right--but not in the left--STC. Similarly, inter-subject variability of cortically-realigned functional responses to voices, other categories and tones increases with age in the right STC. Our findings reveal asymmetric developmental changes in brain regions crucial for auditory and voice perception. The age-related increase of inter-subject variability in right STC suggests that anatomy and function of this region are shaped by unique individual developmental experiences.