We studied the social and foraging behavior of two captive groups of sooty mangabeys under two di... more We studied the social and foraging behavior of two captive groups of sooty mangabeys under two different spatial food situations. These food conditions were clumped (food was placed in a box) and dispersed (food was dispersed over the entire enclosure). In each group five adult females and two adult males were observed. As a criterion for food competition, individual differences in the relative food intake were used. Adult female mangabeys had a linear, stable, and unidirectional dominance hierarchy. Access to food was rank dependent among females only under clumped food distribution, as current models of the evolution of primate social systems predict. However, feeding success appeared to be mediated not by female but by male agonistic behavior toward females. High-ranking females received relatively less aggression from males and could, therefore, stay and feed longer in the feeding area. Male tolerance of higher-ranking females seems to mediate female feeding success under restri...
Journal of Clinical and Experimental Neuropsychology, 2009
Previous work has found that women with anorexia nervosa and bulimia nervosa have weak coherence.... more Previous work has found that women with anorexia nervosa and bulimia nervosa have weak coherence. The aim of this study was to examine whether women who had recovered from an eating disorder (ED) also had weak coherence. A total of 42 recovered ED women and 42 healthy women were assessed with a battery of five neuropsychological tests that measure aspects
The International journal of eating disorders, 2008
To examine the concept of central coherence in women with bulimia nervosa (BN) and address simila... more To examine the concept of central coherence in women with bulimia nervosa (BN) and address similarities and difference with those with anorexia nervosa (AN) METHOD: Forty two women with BN and 42 matched healthy women, completed neuropsychological testing measuring aspects of central coherence: Rey-Osterrieth Complex Figure (RCFT), Embedded Figures Test (EFT), Block Design Test (BD), Homograph Reading Test (HRT), and Sentence Completion Task (SCT). The BN group showed superiority in local processing as measured by EFT and lesser relative advantage from segmentation in BD, and difficulties in global processing in both visual and verbal domains as examined by RCFT, HRT, and SCT. Anxiety levels were associated with low central coherence indices in RCFT. People with BN displayed a profile consistent with the weak central coherence hypothesis. Their pattern of cognitive performance resembles that seen in AN although some differences are apparent.
The Brain-derived Neurotrophic Factor (BDNF) modulates cognitive processes and is associated with... more The Brain-derived Neurotrophic Factor (BDNF) modulates cognitive processes and is associated with increased risk of schizophrenia. Childhood trauma (CT) is frequent in patients with psychosis and severely affects course and outcome. We investigated the hypothesis that BDNF is associated with both CT and cognitive deficits in a sample of first-episode psychosis (FEP) cases and unaffected controls. Participants with FEP and healthy controls were recruited between August 2008 and July 2011 from South London, UK. Childhood traumatic events were detected using the Childhood Experience of Care and Abuse Questionnaire (CECA-Q). Neuropsychological data were also collected. BDNF plasma levels were measured from fasting blood samples. Data were available on 87 FEP patients and 152 controls. Our results showed a significant effect of separation (F=5.5; df=1,115; p=.02), physical (F=4.7; df=1, 118; p=.03) and sexual abuse (F=5.4; df=1,117; p=.02) on BDNF levels with lower levels among those who experienced the traumatic event compared to those who did not. Physical abuse predicted lower plasma levels of BDNF (β=-.30; p=.03) whereas sexual and/or physical abuse showed a trend (β=-.26; p=.06) in FEP patients but not in unaffected controls. No association between BDNF plasma levels and cognitive functions was found among patients with FEP and controls. Our findings suggest the possible involvement of BDNF in the onset of first-episode psychosis in individuals exposed to early trauma and propose BDNF as a potential clinical biomarker to detect the detrimental effects of CT on human brain plasticity.
Machine learning and other computer intensive pattern recognition methods are successfully applie... more Machine learning and other computer intensive pattern recognition methods are successfully applied to a variety of fields that deal with high-dimensional data and often small sample sizes such as genetic microarray, functional magnetic resonance imaging (fMRI) and, more recently, electroencephalogram (EEG) data. The aim of this article is to discuss the use of machine learning and discrimination methods and their
Background: Disturbances in gastrointestinal hormones have been widely identified in persons with... more Background: Disturbances in gastrointestinal hormones have been widely identified in persons with eating disorders (EDs) and have been implicated in their clinical pathologies. Objective: The objective was to identify, critically examine, and summarize studies investigating the short-term response of gastro- intestinal hormones to food in persons with an ED, including the subtypes anorexia nervosa and bulimia nervosa. Design: A priori inclusion and exclusion criteria were set and in- cluded a procedure in which a test meal or glucose load was given and blood hormone concentrations measured. All studies included a healthy control group for comparison. The outcome variable was defined as the mean difference between fasting plasma hormone concentrations and the maximum postprandial peak or nadir. The difference in baseline values between groups was also examined. Pooled standardized mean differences were calculated and analyzed where possible. Results: A total of 28 studies were identi...
Background Repetitive transcranial magnetic stimulation (rTMS) holds promise for treating general... more Background Repetitive transcranial magnetic stimulation (rTMS) holds promise for treating generalised anxiety disorder (GAD) but has only been studied in uncontrolled research. Aims This is the first randomised controlled trial (clinicaltrials.gov: NCT01659736) to investigate the efficacy and neural correlates of rTMS in GAD. Method Twenty five participants (active n = 13; sham, n = 12) enrolled. rTMS was targeted at the right dorsolateral prefrontal cortex (DLPFC, 1 Hz, 90% resting motor threshold). Results Response and remission rates were higher in the active v. sham groups and there were significant group6time interactions for anxiety, worry and depressive symptoms, favouring active v. sham. In addition, right DLPFC activation during a decision-making gambling task increased at post-treatment for active rTMS only, and changes in neuroactivation correlated significantly with changes in worry symptoms. Conclusions Findings provide preliminary evidence that rTMS may improve GAD symptoms in association with modifying neural activity in the stimulation site.
We studied the social and foraging behavior of two captive groups of sooty mangabeys under two di... more We studied the social and foraging behavior of two captive groups of sooty mangabeys under two different spatial food situations. These food conditions were clumped (food was placed in a box) and dispersed (food was dispersed over the entire enclosure). In each group five adult females and two adult males were observed. As a criterion for food competition, individual differences in the relative food intake were used. Adult female mangabeys had a linear, stable, and unidirectional dominance hierarchy. Access to food was rank dependent among females only under clumped food distribution, as current models of the evolution of primate social systems predict. However, feeding success appeared to be mediated not by female but by male agonistic behavior toward females. High-ranking females received relatively less aggression from males and could, therefore, stay and feed longer in the feeding area. Male tolerance of higher-ranking females seems to mediate female feeding success under restri...
Journal of Clinical and Experimental Neuropsychology, 2009
Previous work has found that women with anorexia nervosa and bulimia nervosa have weak coherence.... more Previous work has found that women with anorexia nervosa and bulimia nervosa have weak coherence. The aim of this study was to examine whether women who had recovered from an eating disorder (ED) also had weak coherence. A total of 42 recovered ED women and 42 healthy women were assessed with a battery of five neuropsychological tests that measure aspects
The International journal of eating disorders, 2008
To examine the concept of central coherence in women with bulimia nervosa (BN) and address simila... more To examine the concept of central coherence in women with bulimia nervosa (BN) and address similarities and difference with those with anorexia nervosa (AN) METHOD: Forty two women with BN and 42 matched healthy women, completed neuropsychological testing measuring aspects of central coherence: Rey-Osterrieth Complex Figure (RCFT), Embedded Figures Test (EFT), Block Design Test (BD), Homograph Reading Test (HRT), and Sentence Completion Task (SCT). The BN group showed superiority in local processing as measured by EFT and lesser relative advantage from segmentation in BD, and difficulties in global processing in both visual and verbal domains as examined by RCFT, HRT, and SCT. Anxiety levels were associated with low central coherence indices in RCFT. People with BN displayed a profile consistent with the weak central coherence hypothesis. Their pattern of cognitive performance resembles that seen in AN although some differences are apparent.
The Brain-derived Neurotrophic Factor (BDNF) modulates cognitive processes and is associated with... more The Brain-derived Neurotrophic Factor (BDNF) modulates cognitive processes and is associated with increased risk of schizophrenia. Childhood trauma (CT) is frequent in patients with psychosis and severely affects course and outcome. We investigated the hypothesis that BDNF is associated with both CT and cognitive deficits in a sample of first-episode psychosis (FEP) cases and unaffected controls. Participants with FEP and healthy controls were recruited between August 2008 and July 2011 from South London, UK. Childhood traumatic events were detected using the Childhood Experience of Care and Abuse Questionnaire (CECA-Q). Neuropsychological data were also collected. BDNF plasma levels were measured from fasting blood samples. Data were available on 87 FEP patients and 152 controls. Our results showed a significant effect of separation (F=5.5; df=1,115; p=.02), physical (F=4.7; df=1, 118; p=.03) and sexual abuse (F=5.4; df=1,117; p=.02) on BDNF levels with lower levels among those who experienced the traumatic event compared to those who did not. Physical abuse predicted lower plasma levels of BDNF (β=-.30; p=.03) whereas sexual and/or physical abuse showed a trend (β=-.26; p=.06) in FEP patients but not in unaffected controls. No association between BDNF plasma levels and cognitive functions was found among patients with FEP and controls. Our findings suggest the possible involvement of BDNF in the onset of first-episode psychosis in individuals exposed to early trauma and propose BDNF as a potential clinical biomarker to detect the detrimental effects of CT on human brain plasticity.
Machine learning and other computer intensive pattern recognition methods are successfully applie... more Machine learning and other computer intensive pattern recognition methods are successfully applied to a variety of fields that deal with high-dimensional data and often small sample sizes such as genetic microarray, functional magnetic resonance imaging (fMRI) and, more recently, electroencephalogram (EEG) data. The aim of this article is to discuss the use of machine learning and discrimination methods and their
Background: Disturbances in gastrointestinal hormones have been widely identified in persons with... more Background: Disturbances in gastrointestinal hormones have been widely identified in persons with eating disorders (EDs) and have been implicated in their clinical pathologies. Objective: The objective was to identify, critically examine, and summarize studies investigating the short-term response of gastro- intestinal hormones to food in persons with an ED, including the subtypes anorexia nervosa and bulimia nervosa. Design: A priori inclusion and exclusion criteria were set and in- cluded a procedure in which a test meal or glucose load was given and blood hormone concentrations measured. All studies included a healthy control group for comparison. The outcome variable was defined as the mean difference between fasting plasma hormone concentrations and the maximum postprandial peak or nadir. The difference in baseline values between groups was also examined. Pooled standardized mean differences were calculated and analyzed where possible. Results: A total of 28 studies were identi...
Background Repetitive transcranial magnetic stimulation (rTMS) holds promise for treating general... more Background Repetitive transcranial magnetic stimulation (rTMS) holds promise for treating generalised anxiety disorder (GAD) but has only been studied in uncontrolled research. Aims This is the first randomised controlled trial (clinicaltrials.gov: NCT01659736) to investigate the efficacy and neural correlates of rTMS in GAD. Method Twenty five participants (active n = 13; sham, n = 12) enrolled. rTMS was targeted at the right dorsolateral prefrontal cortex (DLPFC, 1 Hz, 90% resting motor threshold). Results Response and remission rates were higher in the active v. sham groups and there were significant group6time interactions for anxiety, worry and depressive symptoms, favouring active v. sham. In addition, right DLPFC activation during a decision-making gambling task increased at post-treatment for active rTMS only, and changes in neuroactivation correlated significantly with changes in worry symptoms. Conclusions Findings provide preliminary evidence that rTMS may improve GAD symptoms in association with modifying neural activity in the stimulation site.
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Papers by Daniel Stahl