In medication-overuse headache, fMRI shows long-lasting dysfunction in midbrain areas.

OBJECTIVE: The primary aim of our study was to evaluate if a group of medication-overuse headache (MOH) patients present dysfunctions in the mesocorticolimbic dopamine circuit. The secondary aim was to disentangle the role of the medication overuse and of the acute/chronic headache in determining these alterations and to investigate their persistence. BACKGROUND: Several researches have suggested that MOH may belong to the spectrum of addictive behavior. Preclinical models and neuroimaging studies have consistently demonstrated that in addiction, critical long-lasting alterations occur in the mesocorticolimbic dopamine circuit. If MOH shares some neurophysiological features with addiction, long-lasting functional alterations of the mesocorticolimbic dopamine system related to medication overuse should be present. METHODS: We collected functional magnetic resonance imaging data during the execution of a decision-making under risk paradigm in 8 MOH patients immediately after beginning medication withdrawal, in 8 detoxified MOH patients at 6 months after beginning medication withdrawal, in 8 chronic migraine patients, and in 8 control subjects. RESULTS: Our results revealed that MOH patients present: (1) reduced task-related activity in the substantia nigra/ventral tegmental area complex and increased activity in the ventromedial prefrontal cortex, when compared with controls; (2) reduced activity in the substantia nigra/ventral tegmental area complex, when compared with chronic migraine patients; (3) increased activity in the ventromedial prefrontal cortex, when compared with detoxified MOH patients. CONCLUSION: Our study showed that MOH patients present dysfunctions in the mesocorticolimbic dopamine circuit, in particular in the ventromedial prefrontal cortex and in the substantia nigra/ventral tegmental area complex. The ventromedial prefrontal cortex dysfunctions seem to be reversible and attributable to the acute/chronic headache, whereas the substantia nigra/ventral tegmental area complex dysfunctions are persistent and possibly related to medication overuse. These dysfunctions might be the expression of long-lasting neuroadaptations related to the overuse of medications and/or a pre-existing neurophysiological condition leading to vulnerability to medication overuse. The observed persistent dysfunctions in the midbrain dopamine suggest that MOH may share some neurophysiological features with addiction.

The Effect of Baseline on Toddler Event-Related Mu-Rhythm Modulation.

Event-related mu-rhythm activity has become a common tool for the investigation of different socio-cognitive processes in pediatric populations. The estimation of the mu-rhythm desynchronization/synchronization (mu-ERD/ERS) in a specific task is usually computed in relation to a baseline condition. In the present study, we investigated the effect that different types of baseline might have on toddler mu-ERD/ERS related to an action observation (AO) and action execution (AE) task. Specifically, we compared mu-ERD/ERS values computed using as a baseline: (1) the observation of a static image (BL1) and (2) a period of stillness (BL2). Our results showed that the majority of the subjects suppressed the mu-rhythm in response to the task and presented a greater mu-ERD for one of the two baselines. In some cases, one of the two baselines was not even able to produce a significant mu-ERD, and the preferred baseline varied among subjects even if most of them were more sensitive to the BL1, thus suggesting that this could be a good baseline to elicit mu-rhythm modulations in toddlers. These results recommended some considerations for the design and analysis of mu-rhythm studies involving pediatric subjects: in particular, the importance of verifying the mu-rhythm activity during baseline, the relevance of single-subject analysis, the possibility of including more than one baseline condition, and caution in the choice of the baseline and in the interpretation of the results of studies investigating mu-rhythm activity in pediatric populations.

Understanding the role and function of maternal touch in children with neurodevelopmental disabilities.

During the first years of life, maternal touch can serve different functions including facilitation of child's gaze orientation to faces which is a key precursor for social attention. Although children with neurodevelopmental disability (ND) may have reduced social skills, the role of maternal touch in contributing to gaze orientation to maternal face has not been explored in previous research. In the present study, we investigate the functions of maternal touch in dyads of mothers and children with ND, compared to dyads of children with typical development (TD). Micro-analytic 2-s coding of maternal touch (i.e., affectionate, playful, facilitating, holding, no touch) and children's gaze orientation (i.e., mother-oriented, object-oriented, non-oriented) occurred during 5-minute interactions between mothers and their 12-to-24-month-old ND and TD children. Dyads were paired for children chronological age and sex. Mothers of children with ND used more touch - especially facilitating and holding types -, compared to mothers of TD peers. Children with ND exhibited more non-orientated gaze compared to TD counterparts. Playful touch associated with increased mother-oriented gaze in children with ND, whereas affectionate and holding touch associated with greater mother-oriented gaze in TD children. Findings suggest that specific types of touch support children's attention to social partners.

Altered dynamics of brain connectivity in major depressive disorder at-rest and during task performance.

Major depressive disorder (MDD) has been associated with alterations in several functional brain networks. Previous studies investigating brain networks in MDD during the performance of a task have yielded inconsistent results with the function of the brain at rest. In this study, we used functional magnetic resonance imaging at rest and during a goal-directed task to investigate dynamics of functional connectivity in 19 unmedicated patients with MDD and 19 healthy controls across both experimental paradigms. Patients had spatial differences in the default mode network (DMN), in the executive network (EN), and in the dorsal attention network (DAN) compared to controls at rest and during task performance. In patients the amplitude of the low frequency (LFO) oscillations was reduced in the motor and in the DAN networks during both paradigms. There was a diagnosis by paradigm interaction on the LFOs amplitude of the salience network, with increased amplitude change between task and rest in patients relative to controls. Our findings suggest that the function of several networks could be intrinsically affected in MDD and this could be viable phenotype for the investigation on the neurobiological mechanisms of this disorder and its treatment.

Mapping the brain correlates of borderline personality disorder: A functional neuroimaging meta-analysis of resting state studies.

BACKGROUND: Altered intrinsic function of the brain has been implicated in Borderline Personality Disorder (BPD). Nonetheless, imaging studies have yielded inconsistent alterations of brain function. To investigate the neural activity at rest in BPD, we conducted a set of meta-analyses of brain imaging studies performed at rest. METHODS: A total of seven functional imaging studies (152 patients with BPD and 147 control subjects) were combined using whole-brain Signed Differential Mapping meta-analyses. Furthermore, two conjunction meta-analyses of neural activity at rest were also performed: with neural activity changes during emotional processing, and with structural differences, respectively. RESULTS: We found altered neural activity in the regions of the default mode network (DMN) in BPD. Within the regions of the midline core DMN, patients with BPD showed greater activity in the anterior as well as in the posterior midline hubs relative to controls. Conversely, in the regions of the dorsal DMN they showed reduced activity compared to controls in the right lateral temporal complex and bilaterally in the orbitofrontal cortex. Increased activity in the precuneus was observed both at rest and during emotional processing. Reduced neural activity at rest in lateral temporal complex was associated with smaller volume of this area. LIMITATIONS: Heterogeneity across imaging studies. CONCLUSIONS: Altered activity in the regions of the midline core as well as of the dorsal subsystem of the DMN may reflect difficulties with interpersonal and affective regulation in BPD. These findings suggest that changes in spontaneous neural activity could underlie core symptoms in BPD.

Parsing the intrinsic networks underlying attention: a resting state study.

The attention system functionally modulates brain activity to exert control over thoughts, feelings and actions. Three distinct but mutually interacting components of attention have been hypothesized: alerting, which mediates the maintenance of a state of vigilance toward an upcoming stimulus; orienting, which supports the selection of sensory information, and executive control that is involved in detecting and resolving cognitive conflicts. The performance of tasks probing these components engages fronto-parietal and thalamic regions. Also, general attention has been associated with the activity of resting-state networks (RSNs), which are sets of brain regions with synchronous temporal fluctuations. Importantly, the association between the intrinsic brain activity of RSNs and the efficiency and integration of the specific attentional components remains largely unexplored. For this aim, we recruited twenty healthy volunteers who performed the Attention Network Test-Revised (ANT-R), assessing the alerting, orienting and executive control components as well as their interactions, and underwent resting-state functional magnetic resonance imaging. For each participant RSNs were estimated using double regression. The RSNs spanning across areas previously implicated in attentional processing were correlated with ANT-R scores using multiple regressions. Significant brain behavior correlations emerged between ANT-R scores and RSNs comprising the regions relevant for attentional processing, i.e., left and right prefronto-parietal (PFC-PC), dorsal attentional (DAN), salience (SN), and default mode (DMN) networks. The activity of PFC-PC networks was correlated with alerting in parietal and frontal regions, and with location conflict in the frontal regions. The DAN connectivity was correlated with flanker, location conflict, and their interaction in parietal regions. SN was associated with flanker by location and flanker by orienting interactions in the inferior frontal regions. Finally, the activity of the DMN was associated with flanker conflict in midline structures such as precuneus and anterior cingulate cortex and also in right angular gyrus. These results suggest that the brain is endowed with an intrinsic functional organization to support attention, not only in its global function, but also in its distinct components.