Significant Deactivations Research Articles

Interleaved TMS/fMRI shows that threat decreases dlPFC-mediated top-down regulation of emotion processing

The dorsolateral prefrontal cortex (dlPFC) is thought to be a key site in the brain’s cognitive control network, supporting cognitive processes like attention and working memory [1–7]. There is also evidence that the dlPFC is engaged during anxiety regulation tasks, suggesting that anxiety regulation may be mediated in part by dlPFC activity [8–15]. However, the degree to which these two domains of processing overlap is unclear. Therefore, in the current study, we tested the hypothesis that the dlPFC regulates brain regions critical for the expression of anxiety. To do so, we used interleaved TMS/fMRI to record TMS-evoked BOLD responses during periods of threat compared to periods of safety. We hypothesized that TMS pulses would reduce activity in anxiety expression regions during threat. Forty-four healthy controls (no current or history of psychiatric disorders) were recruited to take part in a broader study. Participants completed the neutral, predictable, and unpredictable (NPU) threat task while receiving TMS pulses to either the right dlPFC or a control region. A whole brain analysis identified regions showing significant BOLD responses evoked by dlPFC stimulation. We then extracted these responses and compared those evoked during safe blocks to those evoked during unpredictable threat. We found that responses in the left insula (LI), right sensory/motor cortex (RSM), and a region encompassing the bilateral SMA regions (BSMA) showed significantly different responses during the safe blocks compare to the threat. During the safe periods, these regions showed significant BOLD deactivations. These deactivations were reduced during the threat blocks. Overall, these findings are largely consistent with the hypothesis that the dlPFC plays a role in the top-down control of emotion and suggest that dlPFC activity reduces downstream activity in emotional expression regions, but that this effect is reduced under threat.

Case Report: Atonic PNES Capture in fMRI

Psychogenic Non-Epileptic Seizures (PNES) are a misunderstood and disabling pathology, characterized by a paroxysmal occurrence of clinical signs without the epileptic activity. Resting-state functional MRI (fMRI) studies in patients with PNES have shown abnormal functional connectivity of the resting-state networks, especially in the limbic and motor systems, and in the precuneus. However, the transient nature of PNES episodes prevents us from elucidating the underlying mechanisms of seizures. Here, we report the case of a patient who presented an atonic episode of PNES during a 3T fMRI session. The patient is a 23-year-old woman, suffering from post-traumatic stress disorder, with no neurological comorbidities. The preprocessing of the fMRI images involved realignment, co-registration, segmentation, normalization, denoising (PhysIO toolbox), and smoothing. The time boundary of the seizure was defined according to the patient's reports, and the seizure period was contrasted with the resting state period before the seizure. A whole-brain analysis showed significant activations (left inferior temporal gyrus, left temporo-occipital junction) and deactivations (right precuneus, right superior parietal lobule, right postcentral gyrus, bilateral lingual gyri, inferior occipital gyri, and cerebellar lobules; right insula in a sub-thresholded analysis). Activations and deactivations occurred in four cerebral networks: emotional processing, agency, self-perception, and dissociation. To our knowledge, this report is the first published case of functional MRI during PNES. These results could confirm the emotional and dissociative hypothesis of the physiopathology of PNES and highlight future targets for neuromodulation.

Regulatory effect of drawing on negative emotion: A functional near-infrared spectroscopy study

This study aimed to explore the role of drawing in regulating anger and sadness via functional near-infrared spectroscopy (fNIRS). A 2 (anger vs. sadness) x 2 (drawing vs. calculating) between-subjects design was employed. Participants were randomly assigned to one of four conditions: drawing after triggering anger, drawing after triggering sadness, calculating after triggering anger, or calculating after triggering sadness. An Affect Grid was used to measure the valence and arousal of participants before and after triggering and regulating negative emotion, and the activity data of the prefrontal cortex was measured synchronously by fNIRS. Drawing significantly improved the valence and arousal of sadness, directing it toward more positive and higher arousal. Although drawing significantly improved the valence of anger, its effect on arousal was not evident. Additionally, when drawing regulated sadness, the frontopolar area and left dorsolateral prefrontal cortex showed significant deactivations. During 2–4 min, drawing resulted in minimal activation of the left dorsolateral prefrontal cortex. These brain activity changes during the drawing process demonstrate that drawing is effective in regulating negative emotions, especially sadness. These findings provide an empirical basis for drawing to improve negative emotion and also supplement the study of brain function in drawing.

Changes in working memory-related cortical responses following pediatric mild traumatic brain injury: A longitudinal fMRI study

Persistent post-concussion symptoms (PPCS) lasting longer than 4 weeks affect 25% of children with mild traumatic brain injury (mTBI) or concussion. Working memory (WM) problems are a common complaint in children with PPCS. Despite normal function on traditional neuropsychological tests, these children exhibit aberrant cortical responses within the dorsolateral prefrontal cortex (dlPFC) and default mode network (DMN) regions – both of which are implicated in WM. Using a prospective, longitudinal cohort study design, we investigated changes in cortical fMRI responses within the dlPFC and DMN during an nback WM task at two timepoints: one and two months post-injury. Across these timepoints, the primary outcome was change in cortical activations (increase in BOLD) and deactivations (decrease in BOLD) of both dlPFC and DMN. Twenty-nine children (mean age 15.49 ± 2.15; 48.3% male) with fMRI scans at both timepoints were included, following data quality control. Student’s t-tests were used to examine cortical activations across time and task difficulty. ANCOVA F-tests examined cortical responses after removal of baseline across time, task difficulty and recovery. Volumes of interest (5 mm sphere) were placed in peak voxel regions of the DMN and dlPFC to compare cortical responses between recovered and unrecovered participants over time (one-way ANOVA). Between one and two months post-injury, we found significant increases in dlPFC activations and significant activations and deactivations in the DMN with increasing task difficulty, alongside improved task performance. Cortical responses of the DMN and bilateral dlPFC displayed increased intensity in recovered participants, together with improved attention and behavioural symptoms. Overall, our findings suggest evidence of neural compensation and ongoing cognitive recovery from pediatric TBI over time between one and two months post injury in children with PPCS. These results highlight the wider and persisting implications of mTBI in children, whose maturing brains are particularly vulnerable to TBI.

Dry reforming of methane over nanostructured nickel – Actinide (Th, U) bimetallic oxides

Dry reforming of methane (DRM) can be an efficient alternative to convert greenhouse gases and to produce valuable feedstock. In this work, nanostructured nickel - actinide bimetallic oxides (2NiO.ThO2 and NiO.UNiO4) were tested for the first time as DRM catalysts. They were very active and highly selective towards the production of syngas at low temperatures. Their catalytic performance is better than that of a commercial rhodium supported catalyst (5 wt % Rh/Al2O3) used as a reference. In particular, the thorium catalyst was more active and selective at 550 °C than the commercial catalyst, which is a significant “low” temperature for DRM. The nanostructured nickel - actinide bimetallic oxides long-term stability was also remarkable and an important improvement if we consider the behavior of others nickel-based catalysts that normally undergoing significant deactivations due to coke or sintering.

Internet addiction and functional brain networks: task-related fMRI study

A common brain-related feature of addictions is the altered function of higher-order brain networks. Growing evidence suggests that Internet-related addictions are also associated with breakdown of functional brain networks. Taking into consideration the limited number of studies used in previous studies in Internet addiction (IA), our aim was to investigate the functional correlates of IA in the default mode network (DMN) and in the inhibitory control network (ICN). To observe these relationships, task-related fMRI responses to verbal Stroop and non-verbal Stroop-like tasks were measured in 60 healthy university students. The Problematic Internet Use Questionnaire (PIUQ) was used to assess IA. We found significant deactivations in areas related to the DMN (precuneus, posterior cingulate gyrus) and these areas were negatively correlated with PIUQ during incongruent stimuli. In Stroop task the incongruent_minus_congruent contrast showed positive correlation with PIUQ in areas related to the ICN (left inferior frontal gyrus, left frontal pole, left central opercular, left frontal opercular, left frontal orbital and left insular cortex). Altered DMN might explain some comorbid symptoms and might predict treatment outcomes, while altered ICN may be the reason for having difficulties in stopping and controlling overuse.

Mantra Meditation Suppression of Default Mode Beyond an Active Task: a Pilot Study

Within the field of neuroimaging, the discovery of a constellation of brain regions silently active when we are “resting” has provided a new view into the elusive effects of meditative practice. This network, called the default mode network (DMN), has been shown by functional neuroimaging to be active when an individual is at rest. Meta-analyses of the fMRI neurocorrelates of meditation have shown that across diverse practices, the most common general effect appears to be modulation of regions within the DMN. The specific practice of mantra meditation is a form of task-positive concentration. These kinds of task-positive activities are regarded by many to be an anti-correlate of DMN activity, thereby in theory, reducing activations within the DMN as concentration on a particular task increases. Yet previous studies on mantra meditation using language tasks as controls have reported only activations, not deactivations within the DMN. A study by Berkovich-Ohana showed that word repetition as control task could mask some of the effects of mantra, which may explain why previous studies using language repetition as control task failed to find significant DMN deactivations during mantra meditation. To investigate these differences, we analyzed mantra meditation using a finger-tapping control task which required a minimal amount of focused attention, yet enough to reduce blood flow to the major hubs of the DMN and minimally reduce network activity. Using a finger-tapping control thus modifies the research question: Can a brief course of this kind be shown to modulate DMN activations during mantra practice beyond that of a minimally active/non-language finger-tapping control condition; and if so, can we see a training effect over time? Our results show that over a 2-week period of Kundalini yoga/meditation, participants successfully decreased activations within subregions of the DMN, namely the pregenual anterior cingulate cortex (PACC) and the precuneus, during mantra meditation with trends toward decreased activation in the posterior cingulate cortex (PCC) as well. These decreased activations were significant despite use of a finger-tapping control task known to deactivate these regions, indicating that mantra practice suppresses activation in these DMN regions beyond the active control task. These results emphasize the importance of the choice of control task and provide insight into the “mantra effect.” Here, we show that training in mantra meditation, like other practices such as focused attention and open monitoring, also has a suppressive effect on activity within the DMN.

A quantitative and qualitative review of the effects of testosterone on the function and structure of the human social-emotional brain.

Social and affective research in humans is increasingly using functional and structural neuroimaging techniques to aid the understanding of how hormones, such as testosterone, modulate a wide range of psychological processes. We conducted a meta-analysis of functional magnetic resonance imaging (fMRI) studies of testosterone administration, and of fMRI studies that measured endogenous levels of the hormone, in relation to social and affective stimuli. Furthermore, we conducted a review of structural MRI i.e. voxel based morphometry (VBM) studies which considered brain volume in relation to testosterone levels in adults and in children. In the included testosterone administration fMRI studies, which consisted of female samples only, bilateral amygdala/parahippocampal regions as well as the right caudate were significantly activated by social-affective stimuli in the testosterone condition. In the studies considering endogenous levels of testosterone, stimuli-invoked activations relating to testosterone levels were noted in the bilateral amygdala/parahippocampal regions and the brainstem. When the endogenous testosterone studies were split by sex, the significant activation of the brain stem was seen in the female samples only. Significant stimuli-invoked deactivations relating to endogenous testosterone levels were also seen in the right and left amygdala/parahippocampal regions studies. The findings of the VBM studies were less consistent. In adults larger volumes in the limbic and temporal regions were associated with higher endogenous testosterone. In children, boys showed a positive correlation between testosterone and brain volume in many regions, including the amygdala, as well as global grey matter volume, while girls showed a neutral or negative association between testosterone levels and many brain volumes. In conclusion, amygdalar and parahippocampal regions appear to be key target regions for the acute actions of testosterone in response to social and affective stimuli, while neurodevelopmentally the volumes of a broader network of brain structures are associated with testosterone levels in a sexually dimorphic manner.Electronic supplementary materialThe online version of this article (doi:10.1007/s11011-015-9692-y) contains supplementary material, which is available to authorized users.

The impacts of cognitive-behavioral therapy on the treatment of phobic disorders measured by functional neuroimaging techniques: a systematic review

Functional neuroimaging techniques represent fundamental tools in the context of translational research integrating neurobiology, psychopathology, neuropsychology, and therapeutics. In addition, cognitive-behavioral therapy (CBT) has proven its efficacy in the treatment of anxiety disorders and may be useful in phobias. The literature has shown that feelings and behaviors are mediated by specific brain circuits, and changes in patterns of interaction should be associated with cerebral alterations. Based on these concepts, a systematic review was conducted aiming to evaluate the impact of CBT on phobic disorders measured by functional neuroimaging techniques. A systematic review of the literature was conducted including studies published between January 1980 and April 2012. Studies written in English, Spanish or Portuguese evaluating changes in the pattern of functional neuroimaging before and after CBT in patients with phobic disorders were included. The initial search strategy retrieved 45 studies. Six of these studies met all inclusion criteria. Significant deactivations in the amygdala, insula, thalamus and hippocampus, as well as activation of the medial orbitofrontal cortex, were observed after CBT in phobic patients when compared with controls. In spite of their technical limitations, neuroimaging techniques provide neurobiological support for the efficacy of CBT in the treatment of phobic disorders. Further studies are needed to confirm this conclusion.

Gait adaptability and brain activity during unaccustomed treadmill walking in healthy elderly females

This study evaluated brain activity during unaccustomed treadmill walking using positron emission tomography (PET) and [18F]fluorodeoxyglucose. Twenty-four healthy elderly females (75–82years) participated in this study. Two PET scans were performed after 25min of rest and after walking for 25min at 2.0km/h on a treadmill. Participants were divided into low and high step-length variability groups according to the median coefficient of variation in step length during treadmill walking. We compared the regional changes in brain glucose metabolism between the two groups. The most prominent relative activations during treadmill walking compared to rest in both groups were found in the primary sensorimotor areas, occipital lobe, and anterior and posterior lobe of the cerebellum. The high step-length variability group showed significant relative deactivations in the frontal lobe and the inferior temporal gyrus during treadmill walking. There was a significant relative activation of the primary sensorimotor area in the low step-length variability group compared to the high step-length variability group (P=0.022). Compared to the low step-length variability group, the high step-length variability group exhibited a greater relative deactivation in the white matter of the middle and superior temporal gyrus (P=0.032) and hippocampus (P=0.034) during treadmill walking compared to resting. These results suggest that activation of the primary sensorimotor area, prefrontal area, and temporal lobe, especially the hippocampus, is associated with gait adaptability during unaccustomed treadmill walking.

Motor and non-motor inhibition in the Go/NoGo task: An ERP and fMRI study

The contribution of movement-related activity to Go/NoGo ERP differences has been debated for 25years. In this study, we examined ERP and fMRI measures of activity in twenty adults performing non-motor (count) and motor (right-handed button press) trials of the Go/NoGo task. Task performance was highly accurate and similar in the ERP and fMRI environments. No significant task-related effects were observed for the N2 component; however, we observed a substantial increase in positivity for Press NoGo compared to Count NoGo trials. The fMRI results also revealed significant deactivations for Press NoGo relative to Count NoGo trials in several left-lateralised motor-related areas, including the inferior frontal gyrus, precentral gyrus and supplementary motor area. Together, the results indicate that the P3 NoGo>Go effect in motor tasks is caused not by movement-related negativity on Go trials but by inhibition-related positivity on NoGo trials, and that this is associated with deactivation of motor areas involved in the Go response.

Aging of human supraspinal locomotor and postural control in fMRI

Standing, walking, and running are sensorimotor tasks that develop during childhood. Thereafter they function automatically as a result of a supraspinal network that controls spinal pattern generators. The present study used functional magnetic resonance imaging (fMRI) to investigate age-dependent changes in the supraspinal locomotor and postural network of normal subjects during mental imagery of locomotion and stance. Sixty healthy subjects (ages: 24–78 years), who had undergone a complete neurological, neuro-ophthalmological, and sensory examination to rule out disorders of balance and gait, were trained for the conditions lying, standing, walking, and running in order to imagine these conditions on command in 20-second sequences with the eyes closed while lying supine in an magnetic resonance imaging (MRI) scanner. The following blood oxygen level-dependent (BOLD) signal changes during locomotion and stance were found to be independent of age: (1) prominent activations in the supplementary motor areas, the caudate nuclei, visual cortical areas, vermal, and paravermal cerebellum; (2) significant deactivations in the multisensory vestibular cortical areas (posterior insula, parietoinsular vestibular gyrus, superior temporal gyrus), and the anterior cingulate during locomotion. The following differences in brain activation during locomotion and stance were age-dependent: relative increases in the cortical BOLD signals in the multisensory vestibular cortices, motion-sensitive visual cortices (MT/V5), and somatosensory cortices (right postcentral gyrus). In advanced age this multisensory activation was most prominent during standing, less during walking, and least during running. In conclusion, the functional activation of the basic locomotor and postural network, which includes the prefrontal cortex, basal ganglia, brainstem, and cerebellar locomotor centers, is preserved in the elderly. Two major age-dependent aspects of brain activation during locomotion and stance were found: the mechanism of cortical inhibitory reciprocal interaction between sensory systems during locomotion and stance declines in advanced age; and consequently, multisensory cortical control of locomotion and stance increases with age. These findings may indicate a more conscious locomotor and postural strategy in the elderly.

Catalytic Steam and Autothermal Reforming of Used Lubricating Oil (ULO) over Rh- and Ni-Based Catalysts

The steam reforming of used lubricating oil (ULO) over Ni- and Rh-based catalysts supported by Ce-ZrO2 and Al2O3 is studied in the present work. Among all catalysts, Rh/Ce-ZrO2 (5 wt % Rh) provides relatively higher reforming reactivity (in terms of ULO conversion and H2 yield) with excellent resistance toward carbon deposition compared to the other three catalysts. At 850 °C after exposure in the steam reforming condition for 72 h, H2 yield of 78.1% can be achieved from the reaction over Rh/Ce-ZrO2. For Ni/Ce-ZrO2 and Ni/Al2O3, significant deactivations with time are detected and H2 yields of 55.3−58.7% are achieved after exposure for 72 h; in addition, considerable amounts of C2H4, C2H6 and C3H6 are also found in the product along with H2, CO, CO2, and CH4. The effect of O2 addition was further studied over Ni/Ce-ZrO2 and Ni/Al2O3. It was found that this addition significantly reduces the degree of carbon deposition as well as promoting the conversion of hydrocarbons to CO and H2. At a suitable amount o...

DIURNAL PATTERNS OF ACTIVITY OF THE ORIENTING AND EXECUTIVE ATTENTION NEURONAL NETWORKS IN SUBJECTS PERFORMING A STROOP-LIKE TASK: A FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDY

Attentional processes are fundamental to good cognitive functioning of human operators. The purpose of this study was to analyze the activity of neuronal networks involved in the orienting attention and executive control processes from the perspective of diurnal variability. Twenty-three healthy male volunteers meeting magnetic resonance (MR) inclusion criteria performed the Stroop Color-Word task (block design) in the MR scanner five times/day (06:00, 10:00, 14:00, 18:00, 22:00 h). The first scanning session was scheduled 1–1.5 h after waking. Between MR sessions, subjects performed simulated driving tasks in stable environmental conditions, with controlled physical activity and diet. Significant activation was found in brain regions related to the orienting attentional system: the parietal lobe (BA40) and frontal eye-fields (FEFs). There were also activations in areas of the executive control system: the fronto-insular cortex (FIC), dorsal anterior cingulate cortex (dACC), presupplementary motor area (preSMA), supplementary motor area (SMA), basal ganglia, middle temporal (MT; BA21), and dorsolateral prefrontal cortex (DLPFC), as a part of the central executive network. Significant deactivations were observed in the rostral anterior cingulate cortex (rACC), posterior cingulate cortex (PCC), superior frontal gyrus (SF), parietal lobe (BA39), and parahippocampal that are thought to comprise the default mode network (DMN). Additionally, the activated regions included bilaterally lingual gyrus and fusiform gyrus. The insula was bilaterally deactivated. Visual attention controlled by the goal-oriented attention system and comprising top-down and bottom-up mechanisms, activated by Stroop-like task, turned out to be prone to diurnal changes. The study results show the occurrence of time-of-day–related variations in neural activity of brain regions linked to the orienting attentional system (left parietal lobe—BA40, left and right FEFs), simultaneously providing arguments for temporal stability of the executive system and default mode network. These results also seem to suggest that the involuntary, exogenous (bottom-up) mechanism of attention is more vulnerable to circadian and fatigue factors than the voluntary (top-down) mechanism, which appear to be maintained at the same functional level during the day. The above phenomena were observed at the neural level. (Author correspondence: marek@uj.edu.pl)

Disturbed sexual dimorphism of brain activation during mental rotation in schizophrenia

BackgroundSex differences in visuo-spatial abilities have been well documented in the general population, but there are only a few inconsistent reports in schizophrenia. The purpose of the present study was to examine potential sex differences in performance and pattern of brain activations during mental rotation in schizophrenia patients relative to control participants. MethodsThirty three schizophrenia patients (17 women and 16 men) were compared to thirty five healthy control participants (17 women and 18 men), while performing a classic mental rotation task (3-D figures). Blood oxygen level dependent (BOLD) echo-planar images were acquired on a 3-Tesla Siemens TRIO system. Random-effect analyses were performed using SPM5 (UK Wellcome Institute). ResultsBehavioural data revealed a diagnosis-by-sex interaction with healthy men (HM) performing significantly better than schizophrenia men (SZ-M) and no significant difference between healthy women (HW) and schizophrenia women (SZ-W). fMRI results revealed an overall similar pattern of extensive cerebral activations (in the parietal and lateral prefrontal cortex) and deactivations (in the medial prefrontal cortex) in HM and SZ-W during performance of the mental rotation versus control task. In contrast, both HW and SZ-M showed much more restricted activations and no significant deactivations. ConclusionsSex differences in performance and cerebral activations during mental rotation in schizophrenia patients deviated significantly from what we observed in healthy volunteers. This finding supports and extends existing evidence of a disturbed sexual dimorphism in schizophrenia. Moreover, the results emphasize the importance of including both sexes in neurocognitive and neuroimaging studies of schizophrenia.

Locomotor and postural changes over age: a fMRI study

Objectives: Characterization of supraspinal locomotor and postural regions in a group of normal persons of different age during imagined locomotion and stance in fMRI. Methods: 60 normal subjects (age: 24–78y) were trained for the conditions lying, standing, walking and running in order to imagine these conditions in 20s sequences with eyes closed while lying supine in a MRI scanner (3T, GE). For functional imaging a T2*-weighted gradient echo multislice sequence (EPI, TR 4500ms, TE 60ms, voxel size 3.75*3.75*3.75mm3, matrix 64*64) was used to aquire 34 slices covering the whole brain and cerebellum. Each condition was tested 14 times per subject. Data processing was done using statistical parametric mapping software (SPM5). SPMs were computed for the comparisons standing vs. lying, walking vs. lying, running vs. lying. Both BOLD (blood oxygen level dependent) signal increases and decreases were calculated and considered significant for p<0.05, corrected for multiple comparisons using the FDR method. Results: During locomotion and stance the most prominent infratentorial activations were found in the vermal and paravermal cerebellum, with extensions via the superior cerebellar peduncle to the pontomesencephalic tegmentum. Furthermore BOLD signal increase was shown in the parahippocampal gyri and visual cortical areas, both of which are important for visually guided navigation, and in the prefrontal region. Significant deactivations were found in the posterior insulae and the adjacent cortices, which are related to vestibular function (parieto-insular vestibular cortex), and in the anterior cingulate. The basic pattern of activations in the locomotion network was found irrespective of age. However, cortical sensory control of locomotion and stance was increased in the elderly as could be shown by positive correlation of age with BOLD signal. This included the multisensory vestibular cortices, the motion-sensitive visual cortices (MT/V5) and the somatosensory areas (postcentral gyrus). A negative correlation of age and BOLD response indicated reduced frontal impulse control and basal ganglia input (caput of the caudate nucleus) in the elderly. Conclusions: The basic locomotion network including the prefrontal cortex, basal ganglia, subthalamic, mesencephalic and cerebellar locomotor regions is preserved up to advanced age. In the elderly multisensory cortical control of locomotion and stance is pronounced. Furthermore frontal control of locomotion impulses seems to be diminished in old age. These changes possibly indicate a reduction of automated functioning in the locomotion network in the elderly and a compensation by cortical sensory recruitment.

Acupuncture needling sensation: The neural correlates of deqi using fMRI

The needling sensation of deqi is considered by most acupuncturists to be an important component of acupuncture, yet neuroimaging research that investigates this needle sensation has been limited. In this study we have investigated the effect of deqi and acute pain needling sensations upon brain fMRI blood oxygen level-dependent (BOLD) signals . Seventeen right-handed participants who received acupuncture at the right LI-4 ( Hegu) acupoint were imaged in a 3T MRI scanner. fMRI datasets were classified, on the basis of psychophysical participants' reports of needling scores, into those that were associated with predominantly deqi sensations versus those with predominantly acute pain sensations. Brain areas showing changes in BOLD signal increases (activations) and decreases (deactivations) were identified. Differences were demonstrated in the pattern of activations and deactivations between groupings of scans associated with deqi versus pain sensations. For the deqi grouping, significant deactivations occurred, whereas significant activations did not. In contrast, the predominantly acute pain grouping was associated with a mixture of activations and deactivations. For the comparison between the predominately deqi sensation grouping and the acute pain sensation grouping (deqi > pain contrast), only negative Z value voxels resulted (mainly from deactivations in the deqi grouping and activations in the pain grouping) in the limbic/sub-cortical structures and the cerebellum regions of interest. Our results show the importance of collecting and accounting for needle sensation data in neuroimaging studies of acupuncture.

Cortical deactivations during gastric fundus distension in health: visceral pain‐specific response or attenuation of ‘default mode’ brain function? A H215O‐PET study

Gastric distension activates a cerebral network including brainstem, thalamus, insula, perigenual anterior cingulate, cerebellum, ventrolateral prefrontal cortex and potentially somatosensory regions. Cortical deactivations during gastric distension have hardly been reported. To describe brain areas of decreased activity during gastric fundus distension compared to baseline, using data from our previously published study (Gastroenterology, 128, 2005 and 564). H(2) (15)O-brain positron emission tomography was performed in 11 healthy volunteers during five conditions (random order): (C(1)) no distension (baseline); isobaric distension to individual thresholds for (C(2)) first, (C(3)) marked, (C(4)) unpleasant sensation and (C(5)) sham distension. Subtraction analyses were performed (in SPM2) to determine deactivated areas during distension compared to baseline, with a threshold of P(uncorrected_voxel_level) < 0.001 and P(corrected_cluster_level) < 0.05. Baseline-maximal distension (C(1)-C(4)) yielded significant deactivations in: (i) bilateral occipital, lateral parietal and temporal cortex as well as medial parietal lobe (posterior cingulate and precuneus) and medial temporal lobe (hippocampus and amygdala), (ii) right dorsolateral and dorso- and ventromedial PFC, (iii) left subgenual ACC and bilateral caudate head. Intragastric pressure and epigastric sensation score correlated negatively with brain activity in similar regions. The right hippocampus/amygdala deactivation was specific to sham. Gastric fundus distension in health is associated with extensive cortical deactivations, besides the activations described before. Whether this represents task-independent suspension of 'default mode' activity (as described in various cognitive tasks) or an visceral pain/interoception-specific process remains to be elucidated.

Developmental dyscalculia: Compensatory mechanisms in left intraparietal regions in response to nonsymbolic magnitudes

BackgroundFunctional magnetic resonance imaging (fMRI) studies investigating the neural mechanisms underlying developmental dyscalculia are scarce and results are thus far inconclusive. Main aim of the present study is to investigate the neural correlates of nonsymbolic number magnitude processing in children with and without dyscalculia.Methods18 children (9 with dyscalculia) were asked to solve a non-symbolic number magnitude comparison task (finger patterns) during brain scanning. For the spatial control task identical stimuli were employed, instructions varying only (judgment of palm rotation). This design enabled us to present identical stimuli with identical visual processing requirements in the experimental and the control task. Moreover, because numerical and spatial processing relies on parietal brain regions, task-specific contrasts are expected to reveal true number-specific activations.ResultsBehavioral results during scanning reveal that despite comparable (almost at ceiling) performance levels, task-specific activations were stronger in dyscalculic children in inferior parietal cortices bilaterally (intraparietal sulcus, supramarginal gyrus, extending to left angular gyrus). Interestingly, fMRI signal strengths reflected a group × task interaction: relative to baseline, controls produced significant deactivations in (intra)parietal regions bilaterally in response to number but not spatial processing, while the opposite pattern emerged in dyscalculics. Moreover, beta weights in response to number processing differed significantly between groups in left – but not right – (intra)parietal regions (becoming even positive in dyscalculic children).ConclusionOverall, findings are suggestive of (a) less consistent neural activity in right (intra)parietal regions upon processing nonsymbolic number magnitudes; and (b) compensatory neural activity in left (intra)parietal regions in developmental dyscalculia.

Young Investigator Award Abstracts

In an investigation of the neural circuits that may mediate the subjective experience of social phobia (SP), six male patients with a primary DSM-IV diagnosis of generalized social phobia watched, in the presence of a group of “communication experts,” a videotape of themselves giving an impromptu talk (Exposure condition). In the control Baseline condition, they viewed a videotape of a socially competent stranger giving a talk. Regional cerebral blood flow was measured thrice under each condition. The study revealed significant deactivations from Baseline during Exposure in the right lingual gyrus (BA 18) and in the right medial frontal gyrus (BA 11); significant activations during Exposure were not observed. Deactivation of these regions may reflect a strategy of visual avoidance employed by the patients to dampen their phobic experience.