Anxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear...Show moreAnxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear extinction. In the current study the element of novelty was introduced into the process of extinction to explore how to promote fear extinction, as with standard extinction fear frequently returns over time. Extinction by means of novelty was studied in 32 human subjects using a within-subjects design. First, the participants underwent fear conditioning, in which conditioned stimuli (sounds) were paired with fearful images. This phase was directly followed by an extinction phase with a novelty-facilitated, familiar and standard extinction condition. After a time gap of a minimum of 12 to a maximum of 36 hours responses to the conditioned stimuli were tested again. Pupil size measurements and subjective arousal ratings during this post-extinction phase did not indicate an effect for novelty-facilitated extinction on the extent of fear, this may be the result of potential weak conditioning in the current study. The results of this study express the need for more research to understand the effect of novelty on fear extinction. This could contribute to future implementation of novelty in treatment of anxiety disorders.Show less
The objective of the present study was to gain a better understanding on the relationship between intolerance of uncertainty (IU) and novelty-facilitated fear extinction (NFE). Previous research...Show moreThe objective of the present study was to gain a better understanding on the relationship between intolerance of uncertainty (IU) and novelty-facilitated fear extinction (NFE). Previous research found that IU is associated with impaired extinction learning and a higher relapse rate, but not within the context of NFE. Even so, it remains unclear under which conditions and to what extent IU may influence NFE. To investigate this further, the data of 31 participants was collected in a within-subjects design. During the conditioning phase, participants were shown images of negative and neutral valence paired with neutral sounds, followed by the extinction phase where the previously conditioned sounds were paired with novel or familiar images. Both phases included control conditions where no images were presented. All participants returned to the experiment room within 18 to 36 hours for the post-extinction phase, where they heard the sounds again but without any visual stimuli. Pupil dilation was measured as an indication of arousal and IU was measured with the IU scale. The results indicate that the novelty did assist individuals with high IU in the extinction phase. The post-extinction phase showed that individuals with high IU had smaller pupil sizes when they heard sounds paired to a familiar image. Pupil sizes were, however, largest in the control conditions. The implications of NFE may have far-reaching consequences for the development of clinical treatment methods. Future research should study the effects of NFE outside laboratory settings, and explore the various ways individual characteristics might be of influence.Show less
Animal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to...Show moreAnimal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to hold for humans. However, one study failed to find such a positive effect. It is possible that this is due to individual differences in the novelty seeking personality trait. Therefore, in this master thesis the effect of novelty on recall and recognition memory is identified and the role of novelty seeking in these relationships is addressed. Since novelty processing is associated with dopaminergic neuromodulation in the hippocampus and novelty seeking is related to dopamine sensitivity, it was hypothesized that novelty affects hippocampus-dependent memory (recall) and that this effect is moderated by novelty seeking. No effect was expected on hippocampus-independent memory (recognition memory). Participants in the study were familiarized with a virtual environment and later explored the same (familiar) environment again or a novel one. After this exposure, the participants performed a word-learning task, a visuomotor adaptation task and a landmark test. They also filled out questionnaires regarding their mood and the novelty seeking personality trait. Hierarchical regression analyses suggested that novelty exposure has no effect on memory performance. No moderating effect of novelty seeking was found. Bayesian statistics support this null finding. Future studies need to investigate the influence of individual differences further with a wider range of novelty seekers and the inclusion of the variables age and depth of processing.Show less
Anxiety disorders are among the most common mental disorders and this is why developing effective treatments and prevention methods targeting them is highly relevant. Extinction therapy is one of...Show moreAnxiety disorders are among the most common mental disorders and this is why developing effective treatments and prevention methods targeting them is highly relevant. Extinction therapy is one of the possible tools enabling us to combat these highly prevalent disorders. One of the ways to facilitate the process of extinction is introducing a novel stimulus during extinction training, in order to reduce chances of spontaneous recovery of the conditional response, being fear. This research paper investigates the question if subjective stress levels influence the effect of novelty on fear extinction. The aim of the present study was to understand the role of stress in novelty-facilitated extinction and whether there are any sex differences in the effect of novelty on fear extinction. In an experimental setting, participants were conditioned with fear, exposed to the novelty-facilitated extinction procedure and were asked to fill in a Perceived Stress Scale Questionnaire. An effect of stress was found within the male sample, showing that highly stressed men are not as susceptible to the effects of the novelty-facilitated extinction as less stressed men. The main limitations of this study were missing norm values for evaluating the stress questionnaire and missing a tool to establish the kind of stressors, which were affecting participants. For further research, a sample with the same number of males and females is recommended to evaluate gender differences.Show less
PTSD comes from a traumatic experience which is often re-experienced and relived, causing long-term stress. To weaken the connection with fear the extinction process is used. This is not always...Show morePTSD comes from a traumatic experience which is often re-experienced and relived, causing long-term stress. To weaken the connection with fear the extinction process is used. This is not always successful due to maladaptive fearful associations surviving the extinction. Therefore a novel aspect is added; by manipulating at stimulus level, and by manipulating the olfactory environment with a novel aspect. This study investigates if the novel aspect creates a new association, aiding in the weakening of the connection that causes fear. The reinstatement of the original context cues, when the fear was created, can cause the fear to return. This study therefore uses novelty in two ways to promote fear extinction. The participants (N=32) took part in a two day experiment were they performed different computer tasks; A working memory task, conditioning phase deciding if the scene was indoor or outdoor, extinction phase and post-extinction phase. The arousal was recorded with a subjective 9-point Likert scale and an objective eye tracker. To examine whether the olfactory environments had an effect on the arousal rate, a mixed subjects analysis of variance was conducted. It was expected that the arousal rate would decrease for the fearful stimuli in the post-extinction phase, compared to the extinction phase. Furthermore, it was expected that the novel olfactory environment would cause a stronger decrease in arousal rate for the fearful stimuli. An increase in arousal was found in the post-extinction phase compared to the extinction phase. Furthermore, there was no difference found between the two olfactory environments in effect on the arousal rate.Show less
Several studies found that recollection improves up to 10 minutes after exploring a novel environment, but recognition does not. This is because recollection is hippocampus-dependent, and...Show moreSeveral studies found that recollection improves up to 10 minutes after exploring a novel environment, but recognition does not. This is because recollection is hippocampus-dependent, and recognition is hippocampus-independent. A novelty signal releases dopamine in the hippocampus. The increase in dopamine can last up to 10 minutes after exploring a new environment and thus also improves recollection up to 10 minutes. This master thesis study aimed to examine the differences of age and sex regarding the effects of novelty on memory performance, distinguishing between recollection and recognition. This cross-sectional study was conducted in NEMO Science Museum in Amsterdam. After excluding participants who did not meet the selection criteria, the sample size was 426, of which 224 men and 202 women. The age range of the participants was between 8 and 77 years old (M = 24.5, SD = 16.8). Age 8 to 11 were considered children in this study, age 12 to 20 were considered adolescents, age 21 to 64 were considered adults, and age 65 and over were considered seniors. The participants explored a virtual environment with several landmarks on the computer twice, of which the second exploration was either a familiar or a novel environment compared to the first exploration. In addition, the participants filled in questionnaires and performed tasks, such as a word-learning task. This task was used to measure recollection and recognition. A significant effect was found between age groups and memory performance. In both the recollection and recognition test, adolescents and adults performed better than children. However, no significant effect was found between the other age groups on memory performance. In addition, no significant main effects of novelty and sex, and no interaction effects on memory performance were found. These results could be helpful to develop a treatment or intervention to combat disease- and age-related memory decline. However, further research is recommended, including all experimental factors in the analyses and equal numbers of participants in the age and sex groups.Show less
Animal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to...Show moreAnimal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to hold for humans. However, one study failed to find such a positive effect. It is possible that this is due to individual differences in the novelty seeking personality trait. Therefore, in this master thesis the effect of novelty on recall and recognition memory is identified and the role of novelty seeking in these relationships is addressed. Since novelty processing is associated with dopaminergic neuromodulation in the hippocampus and novelty seeking is related to dopamine sensitivity, it was hypothesized that novelty affects hippocampus-dependent memory (recall) and that this effect is moderated by novelty seeking. No effect was expected on hippocampus-independent memory (recognition memory). Participants in the study were familiarized with a virtual environment and later explored the same (familiar) environment again or a novel one. After this exposure, the participants performed a word-learning task, a visuomotor adaptation task and a landmark test. They also filled out questionnaires regarding their mood and the novelty seeking personality trait. Hierarchical regression analyses suggested that novelty exposure has no effect on memory performance. No moderating effect of novelty seeking was found. Bayesian statistics support this null finding. Future studies need to investigate the influence of individual differences further with a wider range of novelty seekers and the inclusion of the variables age and depth of processing.Show less
Studies using event-related potential (ERP) suggests that the hippocampus, a medial temporal lobe (MTL) structure, can distinguish new and old stimuli. However, it remains unclear whether age...Show moreStudies using event-related potential (ERP) suggests that the hippocampus, a medial temporal lobe (MTL) structure, can distinguish new and old stimuli. However, it remains unclear whether age deficits in MTL processes contribute to age deficits in novelty processing. The present study aimed to investigate this knowledge gap and to confirm previous findings reported by Schomaker et al. (2021) regarding the role of the MTL in novelty detection and later processing. Twenty-one patients with epilepsy with unilateral MTL resection and twenty-four matched healthy controls performed an adapted visual novelty oddball task, with two streams of stimuli presented left and right of a fixation cross, while their electroencephalogram (EEG) was recorded. The participants had to respond to infrequent target stimuli while ignoring standard and novel stimuli. Novelty detection, indexed by the N2, was reduced by MTL resections, shown by a smaller N2 for patients compared to healthy controls. Novelty processing, indexed by the P3, was not reduced in patients, shown by a larger P3 for patients compared to healthy controls. However, this might be due to collapsing of data in the patient group, since resection side was outside the scope of this study. Target processing, indexed by the P3b, was unaffected by MTL resections: no differences were found between patients and healthy controls. These results suggest that MTL structures, including the hippocampus and the amygdala, play a role in novelty processing. In contrast, MTL structures do not play a role in target processing since this was unaffected by MTL resections.Show less
Sensorimotor adaptation is needed to adjust motor behaviour to the needs of different situations. A distinction can be made between early and late adaptation. Early adaptation means a fast...Show moreSensorimotor adaptation is needed to adjust motor behaviour to the needs of different situations. A distinction can be made between early and late adaptation. Early adaptation means a fast improvement, where mainly cognitive processes are of importance. Fast adaptation is slower and more automatic. This master thesis study examined when the ability to adapt movements is developed in children and from which age declines start to occur in adults. While former studies looked into one side of the age range, this study took both the developmental and aging perspective into account. A sample of 463 participants between 8 and 73 years old took part in the experiment, conducted in the NEMO Science Museum in Amsterdam. The participants completed a motor task in which they had to use a joystick to move a cursor towards a target that was presented on a computer screen. In the baseline phase they received normal visual feedback. In the adaptation phase a 45 degree rotation was introduced, causing a different response when moving the joystick. The participants had to adapt their movements to this rotation in order to still be able to hit the targets. After the adaptation phases, the feedback returned back to normal. Participants needed to de-adapt in order to hit the targets again. The typical adaptation pattern was replicated, meaning that participants performed well in the baseline phase, had difficulty hitting the targets in the adaptation phase but improved after practicing. In the de-adaptation phase the participants again had some difficulty and also improved after some practice. In all phases an effect of age was found, meaning that young children and older adults both had more difficulty to successfully adapt. Children are able to adapt from their early teenage years. Declines in adults occur around their fourth decade of life. De-adaptation develops a bit later in children compared to adaptation. In adults declines in de-adaptation occur from the third decade of life. This knowledge can be used during treatment of motor problems, where treatments can be longer or more frequent for certain groups because they have more difficulty with adaptation.Show less
Novelty exposure has been found to elicit a positive impact on declarative learning. It is currently unknown whether this effect is also present in procedural learning. This study aimed to evaluate...Show moreNovelty exposure has been found to elicit a positive impact on declarative learning. It is currently unknown whether this effect is also present in procedural learning. This study aimed to evaluate the effect of spatial novelty exposure and age on sensorimotor adaptation learning by using a mixed between-within subjects, cross-sectional design. A total of 463 healthy participants aged from 8 to 73 years (M = 23.8, SD = 16.5) were divided into 5 age groups: children (8-12), adolescents (13- 18), young adults (19-34), middle-aged adults (35-54), and older adults (≥ 55). Participants explored either a novel or familiar virtual environment before completing a manual adaptation task in which they were exposed to a perturbation in visuomotor feedback. Direction Error (DE), the angle between the optimal trajectory of the joystick and the actual trajectory at peak movement velocity was measured for each movement. A mixed factorial ANOVA was run on DEs and showed a significant difference between age groups F(4, 453) = 2.70, p = .030, ηp 2 = .03. A typical adaptation pattern was present F(7, 6.46) = 434.26, p < .001, η² = .49 and was found to be significantly different between age groups F(28, 3171) = 2.86, p < .001, η² = .03. The learning rate was determined by calculating the decay constant for the early adaptation, late adaptation, and de-adaptation phase of the sensorimotor adaptation task and was fit using an exponential decay function. A mixed factorial ANOVA was run on learning rate and showed a significant difference between all three phases F(1.56, 704.43) = 146.24, p < .001, ηp 2 = .24. Age groups differed in their learning rate per phase F(6.22, 704.43) = 12.00, p < .001, ηp 2 = .10. Novelty exposure did not significantly influence DE or learning rate, nor was age found to be an influencing factor on this. The results from this study did not find that spatial novelty influences sensorimotor adaptation. In conjunction with previous research results, this implies that novelty exposure does not elicit the same positive effect on procedural learning as it has been found to have on declarative learning.Show less
Background The current study was the first to investigate the association between burn-out and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL),...Show moreBackground The current study was the first to investigate the association between burn-out and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), a rare hereditary microangiopathy caused by mutations in the NOTCH3-gene. Previous research investigating burn-out and related factors provided evidence for a possible association between burn-out and mild cognitive impairment (MCI), lacune count, disease severity, stroke incidence and level of education. The current study investigated whether burn-out is an early symptom of incipient CADASIL. Methods The study population consisted of 151 individuals aged 20 years and older, with cysteine altering NOTCH3-mutations. For the current study, an MRI-scan of the brain and neuropsychological assessment (attention, executive functioning and memory) were performed. Results A history of burn-out was found in 33 participants. History of burn-out was associated with both MCI (p = .025, OR [Odds Ratio] = 3.46) and disease severity (p < .010, OR = 2.854), but not with lacune count (p = .926, OR = 1.038), stroke (p = .823, OR = .897) or level of education (p = .725, OR = 1.163). Conclusion In this sample of persons with a NOTCH3-mutation, burn-out was associated with MCI, and with disease severity. Hypothetically, in persons with a NOTCH3-mutation, burnout could be a consequence of MCI, and thus an early symptom of CADASIL. The ability to recognise the clinical onset of CADASIL more timely could be helpful in the clinical setting, because this could allow for better guidance and education of the patient and their support system.Show less
Background: Schizophrenia (SZ) and Bipolar disorder (BD) are severe mental disorders with a substantial genetic component. Cognitive dysfunction is a core feature of SZ and BD, and cognitive...Show moreBackground: Schizophrenia (SZ) and Bipolar disorder (BD) are severe mental disorders with a substantial genetic component. Cognitive dysfunction is a core feature of SZ and BD, and cognitive problems also occur in the offspring of SZ and BD patients. It is unclear how mood symptoms relate to cognition in this offspring group. This study examined the influence of the degree of mood symptoms, and therefore a more negative mood, on cognition in this high-risk offspring group by looking at mood symptoms as a continuous measure. As a follow-up, the effect of mood symptoms on cognition was examined again after four years. Methods: 134 SZ and BD offspring, and 49 controls performed the KSADS- PL (The Schedule for Affective Disorders and Schizophrenia for School-Age Children Present and Lifetime Version) and the ANT (Amsterdam Neuropsychological Tasks) at baseline (T1) and after approximately four years (T2). To examine if mood symptoms, age, sex, group (offspring or control), and the number of errors could predict cognitive scores on sustained attention, inhibition, and attentional flexibility, multiple linear regressions were performed. Results: At T1, sustained attention was the only cognitive domain that was associated with mood symptoms (B= .05, p= .001), indicating that more mood symptoms were related to worse sustained attention. Lower inhibition and attentional flexibility scores were predicted by age. At T2, sustained attention was significantly predicted by mood symptoms at T1 (B= .05, p= .001), indicating that more mood symptoms at T1 were associated with worse sustained attention after four years. Inhibition scores at T2 were not predicted by mood at T1, sex or age. At T2, attentional flexibility was predicted by age and sex. Group status (offspring or control) did not predict cognition. Conclusions: More mood symptoms are related to worse sustained attention in offspring and controls at baseline and after 4 years. Indicating that more mood symptoms in both the offspring and the control group caused lower sustained attention, rather than a genetic predisposition. Attentional flexibility and inhibition scores were not affected by mood symptoms at T1 and T2, but by age. Focusing on mood symptoms and their influence on cognition in high-risk offspring could help to refine and create screening and preventive methods and treatments.Show less
