| 1. |
|
|
| 2. |
- Almby, Kristina E., et al.
(författare)
-
Effects of Gastric Bypass Surgery on the Brain : Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia
- 2021
-
Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 70:6, s. 1265-1277
-
Tidskriftsartikel (refereegranskat)abstract
- While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by F-18-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
|
|
| 3. |
|
|
| 4. |
- Bannbers, Elin, 1984-, et al.
(författare)
-
Prefrontal activity during response inhibition decreases over time in the postpartum period
- 2013
-
Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 241, s. 132-138
-
Tidskriftsartikel (refereegranskat)abstract
- The postpartum period is characterized by complex hormonal changes, but human imaging studies in the postpartum period have thus far predominantly focused on the neural correlates of maternal behavior or postpartum depression, whereas longitudinal studies on neural correlates of cognitive function across the postpartum period in healthy women are lacking. The aim of this study was to longitudinally examine response inhibition, as a measure of executive function, during the postpartum period and its neural correlates in healthy postpartum women and non-postpartum controls. Thirteen healthy postpartum women underwent event-related functional magnetic resonance imaging while performing a Go/NoGo task. The first assessment was made within 48 h of delivery, and the second at 4-7 weeks postpartum. In addition, 13 healthy women examined twice during the menstrual cycle were included as non-postpartum controls. In postpartum women region of interest analyses revealed task-related decreased activations in the right inferior frontal gyrus, right anterior cingulate, and bilateral precentral gyri at the late postpartum assessment. Generally, postpartum women displayed lower activity during response inhibition in the bilateral inferior frontal gyri and precentral gyri compared to non-postpartum controls. No differences in performance on the Go/NoGo task were found between time-points or between groups. In conclusion, this study has discovered that brain activity in prefrontal areas during a response inhibition task decreases throughout the course of the first postpartum weeks and is lower than in non-postpartum controls. Further studies on the normal adaptive brain activity changes that occur during the postpartum period are warranted. (C) 2012 Elsevier B.V. All rights reserved.
|
|
| 5. |
|
|
| 6. |
- Bannbers, Elin, et al.
(författare)
-
The effect of premenstrual dysphoric disorder and menstrual cycle phase on brain activity during response inhibition
- 2012
-
Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327 .- 1573-2517. ; 142:1-3, s. 347-350
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Premenstrual dysphoric disorder (PMDD) has generally not been associated with impulsive behavior. However, some studies suggest that women with PMDD have higher impulsivity scores than healthy controls and that brain activity during response inhibition may vary across the menstrual cycle. Therefore, our aim was to unravel potentially important cognitive aspects of PMDD by investigating brain activity during response inhibition in women with PMDD and healthy controls in relation to menstrual cycle phase.METHODS:Fourteen PMDD patients and 13 healthy controls performed a Go/NoGo task to measure brain activity during response inhibition by use of event-related functional magnetic resonance imaging.RESULTS:Women with PMDD displayed decreased activity during both menstrual cycle phases compared to healthy controls in several task-related parietal areas. A significant group by phase interactions was found in the left insula, driven by enhanced activity among healthy controls in the follicular phase and by enhanced insula activity during the luteal phase among PMDD patients.LIMITATIONS:The limitations of the present study are the relatively limited sample size, the relatively small number of NoGo trials and the lack of a baseline contrast for the NoGo trials.CONCLUSIONS:During response inhibition women with PMDD have reduced activity in areas associated with attention and motor function which is unrelated to menstrual cycle phase. Insular cortex activity, involved in both affective and cognitive processing, was significantly activated during the luteal phase among PMDD women. These findings are relevant for the understanding of how ovarian steroids influence mood symptoms in women.
|
|
| 7. |
- Benedict, Christian, et al.
(författare)
-
Acute Sleep Deprivation Enhances the Brain's Response to Hedonic Food Stimuli : An fMRI Study
- 2012
-
Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 97:3, s. E443-447
-
Tidskriftsartikel (refereegranskat)abstract
- Context:There is growing recognition that a large number of individuals living in Western society are chronically sleep deprived. Sleep deprivation is associated with an increase in food consumption and appetite. However, the brain regions that are most susceptible to sleep deprivation-induced changes when processing food stimuli are unknown.Objective:Our objective was to examine brain activation after sleep and sleep deprivation in response to images of food.Intervention:Twelve normal-weight male subjects were examined on two sessions in a counterbalanced fashion: after one night of total sleep deprivation and one night of sleep. On the morning after either total sleep deprivation or sleep, neural activation was measured by functional magnetic resonance imaging in a block design alternating between high- and low-calorie food items. Hunger ratings and morning fasting plasma glucose concentrations were assessed before the scan, as were appetite ratings in response to food images after the scan.Main Outcome Measures:Compared with sleep, total sleep deprivation was associated with an increased activation in the right anterior cingulate cortex in response to food images, independent of calorie content and prescan hunger ratings. Relative to the postsleep condition, in the total sleep deprivation condition, the activation in the anterior cingulate cortex evoked by foods correlated positively with postscan subjective appetite ratings. Self-reported hunger after the nocturnal vigil was enhanced, but importantly, no change in fasting plasma glucose concentration was found.Conclusions:These results provide evidence that acute sleep loss enhances hedonic stimulus processing in the brain underlying the drive to consume food, independent of plasma glucose levels. These findings highlight a potentially important mechanism contributing to the growing levels of obesity in Western society.
|
|
| 8. |
- Bengtsson, Johan, et al.
(författare)
-
Autonomic modulation networks in schizophrenia : The relationship between heart rate variability and functional and structural connectivity in the brain
- 2020
-
Ingår i: Psychiatry Research. - : Elsevier BV. - 0925-4927 .- 1872-7506. ; 300
-
Tidskriftsartikel (refereegranskat)abstract
- Heart rate variability (HRV), a measurement of autonomic nervous system (ANS) activity, has been found reduced in schizophrenia. The anterior cingulate cortex (ACC), which is important in regulating the ANS, is structurally and functionally affected in schizophrenia. We investigate the relationship between HRV and functional and structural connectivity of the ACC in patients with schizophrenia and healthy controls. Ten patients with a diagnosis of schizophrenia and ten healthy controls were recruited. Heart rate was monitored in a naturalistic out-of-clinic setting. Magnetic resonance imaging (MRI) was performed, including resting-state functional MRI and diffusion tensor imaging. Patients with schizophrenia had significantly lower HRV compared to controls. A positive correlation between ACC connectivity with the bilateral cerebellum and HRV was found in the patients. HRV was also positively correlated with amplitude of low frequency fluctuations (ALFF) in the cerebellum, and with axial diffusivity in the middle cerebellar peduncle, in the patients. There was a significant negative relationship between antipsychotic medication dosage, HRV and all neuroimaging measures related to HRV. We conclude that ACC connectivity seems to be affected in schizophrenia, both structurally and functionally, and that the ACC-cerebellum connectivity, as well as cerebellar function, is associated with ANS regulation in patients with schizophrenia.
|
|
| 9. |
- Bengtsson, Johan, et al.
(författare)
-
Blinding integrity of dorsomedial prefrontal intermittent theta burst stimulation in depression
- 2023
-
Ingår i: International Journal of Clinical and Health Psychology. - : Elsevier BV. - 1697-2600 .- 2174-0852. ; 23:4
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The antidepressant effect of repetitive transcranial magnetic stimulation (rTMS) is partly placebo, making blinding integrity important. Blinding of high-frequency rTMS and intermittent theta burst stimulation (iTBS) has been reported as successful at study end. However, blinding integrity at study start is rarely reported. The aim of this study was to investigate blinding integrity during a treatment course of iTBS over the dorsomedial prefrontal cortex (DMPFC) in depression.Methods: Forty-nine patients with depression from a double-blind-designed randomized controlled trial (NCT02905604) were included. Patients received either active or sham iTBS over the DMPFC with a placebo coil. The sham group received iTBS-synchronized transcutaneous electrical nerve stimulation.Results: After one session, 74% of participants were able to correctly guess their treatment allocation. This was above chance level (p = 0.001). The percentage dropped to 64% and 56% after the fifth and last sessions. Belong-ing to the active group influenced the choice to guess "active" (odds ratio: 11.7, 95% CI 2.5-53.7). A higher treat-ment intensity of the sham treatment increased the probability to guess "active", but pain did not influence the choice.Conclusions: Blinding integrity in iTBS trials must be investigated at study start to avoid uncontrolled confounding. Better sham methods are needed.
|
|
| 10. |
|
|
