Differences In Cerebral Activation Research Articles

Amplitude-integrated electroencephalography showed no differences in cerebral activity between preterm singletons and twins in the first 4 weeks of life.

Genetic influences on cerebral activity have been described previously, but data are scarce in preterms. We aimed to investigate whether a genetic influence causes amplitude-integrated electroencephalography (aEEG) signals to differ between singletons and twin preterm newborns. This was a retrospective single-centre study conducted at Innsbruck Medical University Hospital, Austria. Preterm infants born before 32 weeks of gestation between 6 November 2010 and 6 December 2022 were eligible for the study. The aEEG was analysed for the total maturation score, its component scores and the number of sleep-wake cycles per hour. We enrolled 240 preterm twin infants (57.5% male) with a mean gestational age of 30 (range: 24-32) weeks and a mean birth weight of 1324 (range: 600-2116) grams. We compared 240 singleton matched preterms. No differences were found between preterm singletons and twin preterm infants regarding the total maturation and component scores, or the number of sleep-wake cycles. aEEG showed no difference between monozygotic and dizygotic twins. Compared to singletons, twin infants born preterm showed no differences in aEEG signals in the first 4 weeks of life. Future studies should include more complex non-invasive functional neuroimaging methods to gain more insight into this important topic.

Functional differences in cerebral activation between slow wave-coupled and uncoupled sleep spindles.

Spindles are often temporally coupled to slow waves (SW). These SW-spindle complexes have been implicated in memory consolidation that involves transfer of information from the hippocampus to the neocortex. However, spindles and SW, which are characteristic of NREM sleep, can occur as part of this complex, or in isolation. It is not clear whether dissociable parts of the brain are recruited when coupled to SW vs. when spindles or SW occur in isolation. Here, we tested differences in cerebral activation time-locked to uncoupled spindles, uncoupled SW and coupled SW-spindle complexes using simultaneous EEG-fMRI. Consistent with the "active system model," we hypothesized that brain activations time-locked to coupled SW-spindles would preferentially occur in brain areas known to be critical for sleep-dependent memory consolidation. Our results show that coupled spindles and uncoupled spindles recruit distinct parts of the brain. Specifically, we found that hippocampal activation during sleep is not uniquely related to spindles. Rather, this process is primarily driven by SWs and SW-spindle coupling. In addition, we show that SW-spindle coupling is critical in the activation of the putamen. Importantly, SW-spindle coupling specifically recruited frontal areas in comparison to uncoupled spindles, which may be critical for the hippocampal-neocortical dialogue that preferentially occurs during sleep.

Therapeutic effects and central mechanism of acupuncture and moxibustion for treating functional dyspepsia: study protocol for an fMRI-based randomized controlled trial

BackgroundFunctional dyspepsia (FD) is one of the most common functional gastrointestinal disorders, with a high prevalence and significant influence on the quality of life (QoL). Either acupuncture or moxibustion is effective for dyspepsia, which is confirmed by both ancient documents and modern research. However, the therapeutic advantage and underlying mechanism between acupuncture and moxibustion for FD remain unclear.MethodsThis randomized controlled fMRI trial aims to (i) evaluate the therapeutic advantages of acupuncture and moxibustion treatment for FD, (ii) investigate the similarities and differences in cerebral activity elicited by acupuncture and moxibustion, and (iii) analyze the possible correlations between brain responses and clinical variables thus to explore the potential central mechanism of acupuncture and moxibustion for treating FD. Ninety-two FD patients will be randomly assigned to either the acupuncture group or the moxibustion group in a 1:1 ratio. Twenty sessions of acupuncture or moxibustion treatment over 4 weeks will be performed on each patient. The short form Leeds Dyspepsia Questionnaire, the Nepean Dyspepsia Index, etc., are used to evaluate the therapeutic effects. The heart rate variability will be analyzed to investigate the autonomic nerve function. Thirty-six FD patients in each group will be randomly selected for the fMRI scan to detect cerebral activity changes.DiscussionWe expect the results will deepen our knowledge on the clinical value and underlying mechanism of acupuncture and moxibustion and provide a reference for a better selection of interventions for treating FD.Trial registrationChinese Clinical Trial Registry (www.chictr.org.cn) ChiCTR2100049496. Registered on 2 August 2021

P29. Differential linear and nonlinear brain activation for probabilistic aversive outcomes in pathological gamblers and controls

Objective Functional imaging studies on decision making under uncertain risk of negative (aversive) outcomes are scarce. To get a better understanding of the underlying processes, we tested models of decision making including participants that were gambling regularly despite negative long-term consequences. Primarily, we sought to detect group differences in cortical and subcortical regions involved in decision processes. Also, we wanted to investigate, if current economic decision making models account for observable physiological data. Do we process aversive contingencies of decisions in a linear or a nonlinear manner, or both? Methods We studied 22 pathological and 18 habitual gamblers, as well as 23 control subjects, evaluated by psychologists with a semi-structured interview and self-reported Southern Oaks Gambling Scale. Participants were scanned with blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) and engaged in a card game in which un-ambiguous situations of various risk levels for punishment (unpleasant, but not painful electric shocks) were created. Apart from neural responses to punishment, our paradigm allowed us to measure how neural activity during expectation of a punishment is modulated by the probability to be punished (risk) or the certainty of the outcome (certainty). Results Extending previous work and testing our hypothesis, based on economic studies, we modelled expected outcomes according to the prospect theory. Activations differed spatially when situations were modelled according to risk or certainty. With linearly increasing chances of avoiding punishment we found that the BOLD signal increased in the orbitofrontal cortex, caudate nucleus, precuneus, and the posterior cingulate cortex ( Fig. 1 a). Conversely, with increasing certainty of an outcome (U-shaped from most certain punishment to most certain avoidance), we could demonstrate nonlinear activations in medial superior frontal cortex, anterior cingulate cortex, anterior insula and angular gyrus ( Fig. 1 b). Interestingly, we found no group differences in cerebral activation during the task, which dovetailed with ‘offline’ behavioural analyses of decision making in the same groups. Conclusion Our results support the notion that economic decision making contains both linear and nonlinear cognitive processes largely following contingencies for risk and certainty and provide evidence that these cognitive processes are represented in different sets of brain regions. Correlates of the risk for punishment were found in areas known to be involved in dopaminergic reinforcement learning, while regions known to sub serve decision making, conflict monitoring and punishment show correlation with certainty of the outcome. While differences in reward perception in pathological gamblers are frequently described in the literature, we found no evidence for changes in punishment perception.

A combination of lipidomics, MS imaging, and PET scan imaging reveals differences in cerebral activity in rat pups according to the lipid quality of infant formulas.

We evaluated the effect of adding docosahexaenoic:arachidonic acids (3:2) (DHA+ARA) to 2 representative commercial infant formulas on brain activity and brain and eye lipids in an artificially reared rat pup model. The formula lipid background was either a pure plant oil blend, or dairy fat with a plant oil blend (1:1). Results at weaning were compared to breast milk-fed pups. Brain functional activity was determined by positron emission tomography scan imaging, the brain and eye fatty acid and lipid composition by targeted and untargeted lipidomics, and DHA brain regional location by mass-spectrometry imaging. The brain functional activity was normalized to controls with DHA+ARA added to the formulas. DHA in both brain and eyes was influenced by formula intake, but more than two-thirds of tissue DHA-glycerolipids remained insensitive to the dietary challenge. However, the DHA lipidome correlated better with brain function than sole DHA content ( r = 0.70 vs. r = 0.48; P < 0.05). Brain DHA regional distribution was more affected by the formula lipid background than the provision of PUFAs. Adding DHA+ARA to formulas alters the DHA content and lipidome of nervous tissue in the neonate, making it closer to dam milk-fed controls, and normalizes brain functional activity.-Aidoud, N., Delplanque, B., Baudry, C., Garcia, C., Moyon, A., Balasse, L., Guillet, B., Antona, C., Darmaun, D., Fraser, K., Ndiaye, S., Leruyet, P., Martin, J.-C. A combination of lipidomics, MS imaging, and PET scan imaging reveals differences in cerebral activity in rat pups according to the lipid quality of infant formulas.

Effect of acupuncture plus conventional treatment on brain activity in ischemic stroke patients: a regional homogeneity analysis

ObjectiveTo determine differences in cerebral activity evoked by acupuncture and conventional stroke treatment, and identify the treatment targets. MethodsIn total, 21 patients were randomly divided into two groups. Group A (11 patients) received both acupuncture and conventional treatment, while Group B (10 patients) received conventional treatment only. Resting-state functional magnetic resonance imaging (fMRI) was performed on each participant before and after treatment. Regional homogeneity (ReHo) analysis was performed to investigate the potential mechanism of acupuncture treatment by comparing differences in cerebral activity between treatments. ResultsGroup A showed higher ReHo in the frontal lobe (BA6, BA46), supra-marginal gyrus (BA40), middle temporal gyrus (BA21), cerebellum, and insula. Group B showed higher ReHo in the frontal lobe (BA6) and parietal lobe (BA3, BA7). ConclusionAcupuncture and conventional treatment triggered relatively different clinical efficacy and brain responses. Acupuncture treatment more significantly improved the symptoms of stroke patients. More marked changes in sensory, emotional, and motor areas (including the frontal lobe, middle temporal gyrus, cerebellum, and insula) might reflect the specific acupuncture mechanism.

Neuroimaging in cockroach phobia: An experimental study

Background/ObjectiveIn this study we explored the neuroimaging characteristics of persons with specific small animal (cockroach) phobia to determine whether there are differences in cerebral activity between persons with and without cockroach phobia under conditions of phobic and non-phobic stimulation. Method: 24 adult persons (12 with phobia) were studied. The diagnosis of phobia was obtained with a structured interview and questionnaires. All participants were exposed to a 3D video presentation during an fMRI session. Results: The phobic group showed significant differential activations that were congruent with a dual route model of fear processing through the thalamus-amygdala (route I) and the thalamus-sensory and association cortex-entorhinal cortex-hippocampus-subiculum-amygdala (route II). Apart from this dual route, we also found differential activations in the globus pallidum, parahippocampal gyrus, insula, pars orbitalis, triangularis and opercularis of the frontal cortex, and cerebellum. Respect to non-phobic group, no activations were found in the insula or the anterior cingulate cortex. Conclusions: There seems to be a dual route depending on how persons with phobia to cockroaches process phobic stimuli. This double processing can have implications for the psychological treatment of specific phobias.

An fMRI Study of the Emotional Perception of Erotic Images in Men Aged 49–74 Years

Psychological studies have indicated that erotic images are evaluated in the context of positive emotions as the most intense, associated with the greatest degree of emotional arousal, among the whole gamut of pleasant and unpleasant stimuli. It is difficult to discriminate the cortical zones directly associated with emotional arousal from the activity of structures responsible for assessing emotional stimuli in the inducement/reward system. The aim of the present work was to identify differences in cerebral activity using functional MRI scans (fMRI) in men during assessment of the intensity of pleasant images, including erotic images, or unpleasant and neutral images. Comparison of tasks involving the assessment of pleasant images of the erotic type with tasks containing neutral or unpleasant stimuli revealed significantly more marked activation in the posterior cingulate cortex, the prefrontal cortex, and the globus pallidus on the right side. Comparison of tasks with pleasant and neural stimuli revealed an increase in the activity of the right anterior central gyrus. Thus, the process of assessment of the intensity of emotional images of erotic type was related to activation of brain areas belonging not only to the neural representation of the emotions, but also to the cognitive system controlling emotional arousal and the motivational domain, which needs to be considered when using erotic images as powerful positive emotional stimuli.

Examining the Efficacy of the Modified Story Memory Technique (mSMT) in Persons With TBI Using Functional Magnetic Resonance Imaging (fMRI): The TBI-MEM Trial.

New learning and memory deficits are common following traumatic brain injury (TBI). Yet few studies have examined the efficacy of memory retraining in TBI through the most methodologically vigorous randomized clinical trial. Our previous research has demonstrated that the modified Story Memory Technique (mSMT) significantly improves new learning and memory in multiple sclerosis. The present double-blind, placebo-controlled, randomized clinical trial examined changes in cerebral activation on functional magnetic resonance imaging following mSMT treatment in persons with TBI. Eighteen individuals with TBI were randomly assigned to treatment (n = 9) or placebo (n = 9) groups. Baseline and follow-up functional magnetic resonance imaging was collected during a list-learning task. Significant differences in cerebral activation from before to after treatment were noted in regions belonging to the default mode network and executive control network in the treatment group only. Results are interpreted in light of these networks. Activation differences between the groups likely reflect increased use of strategies taught during treatment. This study demonstrates a significant change in cerebral activation resulting from the mSMT in a TBI sample. Findings are consistent with previous work in multiple sclerosis. Behavioral interventions can show significant changes in the brain, validating clinical utility.

Cerebral Activity Changes in Different Traditional Chinese Medicine Patterns of Psychogenic Erectile Dysfunction Patients.

Background. Pattern differentiation is the foundation of traditional Chinese medicine (TCM) treatment for erectile dysfunction (ED). This study aims to investigate the differences in cerebral activity in ED patients with different TCM patterns. Methods. 27 psychogenic ED patients and 27 healthy subjects (HS) were enrolled in this study. Each participant underwent an fMRI scan in resting state. The fractional amplitude of low-frequency fluctuation (fALFF) was used to detect the brain activity changes in ED patients with different patterns. Results. Compared to HS, ED patients showed an increased cerebral activity in bilateral cerebellum, insula, globus pallidus, parahippocampal gyrus, orbitofrontal cortex (OFC), and middle cingulate cortex (MCC). Compared to the patients with liver-qi stagnation and spleen deficiency pattern (LSSDP), the patients with kidney-yang deficiency pattern (KDP) showed an increased activity in bilateral brainstem, cerebellum, hippocampus, and the right insula, thalamus, MCC, and a decreased activity in bilateral putamen, medial frontal gyrus, temporal pole, and the right caudate nucleus, OFC, anterior cingulate cortex, and posterior cingulate cortex (P < 0.005). Conclusions. The ED patients with different TCM patterns showed different brain activities. The differences in cerebral activity between LSSDP and KDP were mainly in the emotion-related regions, including prefrontal cortex and cingulated cortex.

Asymmetrical effect of levodopa on the neural activity of motor regions in PD.

Parkinson's disease (PD) is a neurodegenerative illness often characterized by asymmetrical symptoms. However, the reason for this asymmetry and the cerebral correlates underlying symptom asymmetry are still not well understood. Furthermore, the effects of levodopa on the cerebral correlates of disease asymmetry have not been investigated. In this study, right-handed PD patients performed self-initiated, externally triggered and repetitive control finger movements with both their right and left hands during functional magnetic resonance imaging (fMRI) to investigate asymmetrical effects of levodopa on the hemodynamic correlates of finger movements. Patients completed two experimental sessions OFF and ON medication after a minimum of 12 hours medication withdrawal. We compared the effect of levodopa on the neural activation patterns underlying the execution of both the more affected and less affected hand for self-initiated and externally triggered movements. Our results show that levodopa led to larger differences in cerebral activity for movements of the more affected, left side: there were significant differences in activity after levodopa administration in regions of the motor cortico-striatal network when patients performed self-initiated and externally triggered movements with their left hand. By contrast, when patients used their right hand, levodopa led to differences in cerebellar activity only. As our patients were affected more severely on their left side, we propose that levodopa may help provide additional dopaminergic input, improving movements for the more severely affected side. These results suggest that the impact of reduced dopamine in the cortico-striatal system and the action of levodopa is not symmetrical.

Role of 5-HTTLPR Polymorphism in the Development of the Inward/Outward Personality Organization: A Genetic Association Study

Reciprocity with primary caregivers affects subjects' adaptive abilities toward the construction of the most useful personal meaning organization (PMO) with respect to their developmental environment. Within cognitive theory the post-rationalist approach has outlined two basic categories of identity construction and of regulation of cognitive and emotional processes: the Outward and the Inward PMO. The presence of different, consistent clinical patterns in Inward and Outward subjects is paralleled by differences in cerebral activation during emotional tasks on fMRI and by different expression of some polymorphisms in serotonin pathways. Since several lines of evidence support a role for the 5-HTTLPR polymorphism in mediating individual susceptibility to environmental emotional stimuli, this study was conducted to investigate its influence in the development of the Inward/Outward PMO.PMO was assessed and the 5-HTTLPR polymorphism investigated in 124 healthy subjects who were subdivided into an Inward (n = 52) and an Outward (n = 72) group.Case-control comparisons of short allele (S) frequencies showed significant differences between Inwards and Outwards (p = 0.036, χ2 test; p = 0.026, exact test). Genotype frequencies were not significantly different although values slightly exceeded p≤0.05 (p = 0.056, χ2 test; p = 0.059, exact test). Analysis of the 5-HTTLPR genotypes according to the recessive inheritance model showed that the S/S genotype increased the likelihood of developing an Outward PMO (p = 0.0178, χ2 test; p = 0.0143, exact test; OR = 3.43, CI (95%) = 1.188–9.925). A logistic regression analysis confirmed the association between short allele and S/S genotypes with the Outward PMO also when gender and age were considered. However none of the differences remained significant after correction for multiple testing, even though using the recessive model they approach significance.Overall our data seem to suggest a putative genetic basis for interindividual differences in PMO development.

How Subjectivity can be Investigated in the Post-rationalist Cognitive Approach: Clinical and Psycho-diagnostic Tools

Reciprocity with primary care-givers affects subjects’ adaptive abilities towards the construction of the most useful Personal Meaning Organization (PMO) with respect to their developmental environment. Over the last ten years we analyzed the post-rationalist approach focusing on the construction of a specific framework for distinguishing immediate experience from explanations of the experience, the slow-motion (“moviola”) technique, and the analysis of awareness and resistance. Neuroimaging (functional Magnetic Resonance Imaging, fMRI), genetic polymorphism investigations and new psychodiagnostic post-rationalist tests (Mini Questionnaire of Personal Organization, MQPO, and Post-Rationalist Projective Reactive, PRPR) were used to conduct a scientific in vivo study of PMO. The presence of specific and stable clinical patterns both in inward and outward subjects was supported by parallel differences in cerebral activation during emotional tasks at fMRI and in the different expression of some polymorphisms concerning serotonin pathways; Furthermore, validation data concerning both a questionnaire (as MQPO) and, crucially, a projective test (as PRPR) allowed to distinguish four organizational profiles, confirming their adaptive significance in assimilation of experience. Focusing on the PMO promotes the emergence of adaptive individual resources, thereby improving skills needed to control perturbing emotions and to apply more flexible behaviour strategies.

Moving and being moved: Differences in cerebral activation during recollection of whole-body motion

While moving through the world, humans as well as animals can make use of motion cues during both active and passive whole-body motion to track their own position in space. However, the functional neuroanatomy of self-motion processing remains poorly understood. In the present study we aimed to characterize brain networks reflecting whole-body self-motion experience. We used retrieval of previously experienced events, which is known to involve cortical representations of the modalities used to perceive these events. Recollection of self-motion experience may thus engage motor and sensory brain areas, reflecting the active or passive nature of the experienced movement, but may engage also common brain areas processing self-motion. We further compared the retrieval networks of self- and observed motion: even though actual action observation has been shown to recruit brain networks similar to those active during mental simulation, it is unclear to which extent recollection networks of these experiences overlap. Brain activation patterns were recorded using fMRI during mental simulation of recent episodes of (1) experiencing linear whole-body motion (active locomotion and passive transport) and (2) observing another person performing the same tasks. Following the experiential phase, participants recalled the episodes during a MR session. We found that primary sensorimotor brain areas dominate the composition of the recollection network of active walking, while recalling passive transport recruits higher level association areas. Common to both self-motion conditions was activation in the medial temporal lobe. Recollection of self-experienced and observed movement overlapped in motor planning areas. Our results provide evidence that the medial temporal lobe is specifically relevant for retrieval of self-motion information and that motor coding during action observation is reflected in recollection networks.

Comparison of cerebral activation involved in oral and manual stereognosis

Brain activity associated with manual stereognosis has been the focus of increasing recent research effort. However, although oral stereognosis, defined as the ability to recognize and discriminate the food bolus in the mouth, is important for mastication and swallowing, there is little information available about the neural network relating to this function. In the present study, cerebral activation associated with oral stereognosis was evaluated as compared with manual stereognosis. Brain imaging data were acquired by functional MRI (fMRI). fMRI experiments were performed on 16 healthy right-handed young adults without any history of neurological or psychiatric disorders. All subjects had all teeth without malocclusion. Ten stereognosis test shape pieces sized approximately 20 mm × 20 mm × 10 mm were fabricated for this experiment. All test pieces had a complicated form that made them difficult to recognize with ease. Subjects were instructed to assess the shape of the test piece in the mouth or hand. The ten test pieces were randomly assigned to each subject and each run. Stereognosis-specific activation was found in the primary somatosensory area, primary motor area, supramarginal gyrus, premotor area, supplementary motor area, fusiform gyrus, frontopolar area and dorsolateral prefrontal cortex. Differences in cerebral activation between oral and manual stereognosis were found in the insular cortex and visual association cortex.

Empty nose syndrome: Limbic system activation observed by functional magnetic resonance imaging

Empty nose syndrome (ENS) patients have a persistent sense of impaired nasal patency despite radical resection of nasal turbinates. The aim of this study was to elucidate differences in cerebral activation during free breathing and after inhalation of a fragrance (lemonene) and a pseudodecongestant (menthol) over a nasofacial mask. Our hypothesis was that menthol would be perceived as beneficial and that cerebral activation would show differences in areas corresponding to emotional suffering and air hunger in ENS patients. Prospective, controlled intervention with lemonene and menthol during functional magnetic resonance imaging (f-MRI) experiment. Ten right-handed ENS patients were compared to 15 controls using f-MRI and fully automated data analysis with SPM software. Nasal patency was measured with rhinomanometry and rated on a four-point scale. Despite similar objective nasal flow, ENS patients rated nasal patency significantly worse than did controls. Menthol was perceived to increase nasal patency. In patients, f-MRI data showed different activation of temporal cortex areas after inhalation of menthol. The comparison of patients and controls showed ENS-specific activation of temporal and cerebellar areas and amygdala during the rating task itself. Our experiments showed different cerebral processing of the feeling of nasal patency in ENS patients with prominent activation of areas belonging to the limbic system. The beneficial effect of menthol seems to correspond to activation differences in the temporal pole. These results demonstrate a neuronal substrate for both symptoms and their relief in ENS patients.

Altered patterns of cortical activation in ALS patients during attention and cognitive response inhibition tasks

Since amyotrophic lateral sclerosis (ALS) can be accompanied by executive dysfunction, it is hypothesised that ALS patients will have impaired performance on tests of cognitive inhibition. We predicted that ALS patients would show patterns of abnormal activation in extramotor regions when performing tests requiring the inhibition of prepotent responses (the Stroop effect) and the inhibition of prior negatively primed responses (the negative priming effect) when compared to healthy controls. Functional magnetic resonance imaging was used to measure activation during a sparse sequence block design paradigm investigating the Stroop and negative priming effects in 14 ALS patients and 8 healthy age- and IQ-matched controls. Behavioural measures of performance were collected. Both groups’ reaction times (RTs) reflected the Stroop effect during scanning. The ALS and control groups did not differ significantly for any of the behavioural measures but did show significant differences in cerebral activation during both tasks. The ALS group showed increased activation predominantly in the left middle temporal gyrus (BA 20/21), left superior temporal gyrus (BA 22) and left anterior cingulate gyrus (BA 32). Neither group’s RT data showed clear evidence of a negative priming effect. However the ALS group showed decreased activation, relative to controls, particularly in the left cingulate gyrus (BA 23/24), left precentral gyrus (BA 4/6) and left medial frontal gyrus (BA 6). Greater cerebral activation in the ALS group accompanying the performance of the Stroop effect and areas of decreased activation during the negative priming comparison suggest altered inhibitory processing in ALS, consistent with other evidence of executive dysfunction in ALS. The current findings require further exploration in a larger study.

Differences in cerebral activation during perception of optokinetic computer stimuli and video clips of living animals: An fMRI study

Aims: There is behavioral evidence of increased spontaneous recruitment of visual attention to ancestral evolved categories, such as animals, compared with expertise-derived categories, such as a computer. In order to investigate the association between visual perception and spontaneous visual attention, a study was performed to determine if brain activation whilst viewing moving animals was increased compared with optokinetic computer stimuli. Methods: Functional MRI was performed in 12 healthy volunteers using a standard block-design paradigm, consisting of three consecutive experiments. Subjects viewed the following images: Experiment one — optokinetic computer stimuli alternating with static computer stimuli; Experiment two — moving animals alternating with non-moving animals; Experiment three — moving animals alternating with optokinetic computer stimuli. Results: Moving animals evoked motion-dependent activation bilaterally in the middle and superior temporal gyri, right inferior temporal gyrus, left occipital gyrus, right supramarginal gyrus, and left straight gyrus. Integrated object-and-motion-dependent activation was found bilateral in inferior and middle temporal gyri, right superior temporal gyrus, right superior parietal lobule, left dorsal putamen, and right amygdala. Conclusions: These results suggest that there is increased cerebral activity in the visuo-attentional network whilst viewing moving animals compared with optokinetic computer stimuli.

Differences in cortical and pituitary activity in response to hypoglycaemia and cognitive testing in healthy men with different basal activity of the renin-angiotensin system

High renin-angiotensin system (RAS) activity has been associated with a high risk of severe hypoglycaemia in patients with type 1 diabetes and with cognitive deterioration during experimental hypoglycaemia in healthy subjects. The aim of this study was to describe possible differences in cerebral activity during hypoglycaemia and cognitive testing in two groups of healthy men with different basal RAS activity. Ten healthy men with high RAS activity and 10 with low activity underwent six oxygen-15-labelled water positron emission tomography scans: twice during normoglycaemia, twice during insulin-induced hypoglycaemia and twice during post-hypoglycaemia. During the scans, the subjects performed a computer-based reaction time test. Occipital areas were consistently more activated in the low RAS group than in the high RAS group throughout all three conditions. During normoglycaemia, the frontal region was more activated in the low RAS group than in the high RAS group. During hypoglycaemia, the high RAS group was more activated in the pituitary gland than the low RAS group. Basal RAS activity influenced cerebral activity. Low RAS was associated with more pronounced cortical activation in all glycaemic conditions. High RAS was associated with pituitary activation during hypoglycaemia and post-hypoglycaemia, and this was associated with a greater growth hormone response.

Functional magnetic resonance imaging in primary writing tremor and writer's cramp: A pilot study.

Objectives:The precise pathophysiology of primary writing tremor (PWT) and writer’s cramp (WC) is not known. The aim of this study is to compare the cerebral activation patterns in patients of PWT, WC and healthy controls, during a task of signing on paper, using functional magnetic resonance imaging (fMRI).Materials and Methods:Six subjects with PWT, three with WC and six healthy volunteers were examined using a 1.5-Tesla scanner. The paradigm consisted of three times repetition of a set of period of rest and activity. Each set consisted of 10 blood oxygen level dependent (BOLD) echo-planar imaging (EPI) acquisitions at rest followed by 10 BOLD EPI acquisitions while signing their names on paper using the dominant right hand. Entire brain was covered. SPM99 analysis was done.Results:In comparison to the healthy controls, the following differences in cerebral activation were noted in the patients: (a) primary and supplementary motor areas showed overactivation in patients of PWT and underactivation in patients of WC, (b) the cingulate motor area showed underactivation in patients of PWT and overactivation in patients of WC and (c) the cerebellar activity was reduced in both WC and PWT.Conclusion:Our preliminary findings suggest that the cerebral and cerebellar activation patterns in PWT and WC during signing on paper are distinct from each other and from healthy controls. There may be cerebellar dysfunction in addition to motor dysfunctions in the pathogenesis of these disorders.