Background: Fatigue remains an important factor in major aviation accidents. Stimulants may count... more Background: Fatigue remains an important factor in major aviation accidents. Stimulants may counteract fatigue’s adverse effects, with modafinil as a promising alternative to caffeine. However, the effect of a single dose of modafinil after a limited period of sleep deprivation remains unknown. Aims: This study aims to determine the effect of 200 mg modafinil on vigilance during a limited period of sleep deprivation compared to 300 mg caffeine and placebo. Methods: Thirty-two volunteers of the Royal Netherlands Air Force (RNLAF) were double-blindly administered modafinil, caffeine, and placebo on three non-consecutive trial days after being awake for median 17 h. Afterwards, subjects completed six series of the Vigilance and Tracking test (VigTrack), psychomotor vigilance task (PVT), and Stanford Sleepiness Scale (SSS), yielding six primary endpoints. Results: This study revealed statistically significant effects of caffeine and modafinil compared with placebo on all endpoints, exce...
ABSTRACT BACKGROUND: Semantic network abnormalities in patients with psychotic disorder were exam... more ABSTRACT BACKGROUND: Semantic network abnormalities in patients with psychotic disorder were examined using associative prime-target relations with two stimulus asynchronies (SOAs; -250ms and -500ms) to assess the time course of automatic and more controlled processes of semantic priming. To investigate whether an aberrant semantic network system is part of the familial liability for psychosis, healthy siblings of patients with psychotic disorder were additionally examined. The N400 event-related brain potential (ERP) was used as a probe of semantic processing. METHOD: Twenty-two patients with psychotic disorder, twenty siblings of patients with psychotic disorder and twenty controls participated in a lexical decision task and ERPs were recorded to target words that were associatively, indirectly or not related to their preceding prime word. RESULTS: Associative priming of the N400 amplitude was found across all participants and both SOAs, but no between-group differences were found for the N400 amplitude (both SOAs). The Group×Condition interaction of the indirect priming N400 latency of the three groups was just short of statistical significance (F2,59=2.7, p=.077). Patients showed an increased indirect priming effect of the N400 latency only at short SOA, with decreased latency of the indirectly related compared to the unrelated condition, while controls did not show an indirect priming N400 latency effect. No between-group differences in N400 latency of indirect priming were found at the long SOA. Only a trend towards a Group×Condition interaction of the indirect priming N400 latency between the sibling and the controls was found, but without a main effect of indirect priming in the sibling group. CONCLUSION: These preliminary results support the assumption of a hyperactive semantic network in patients with psychotic disorder, which develops under automatic processes and decreases with more controlled processes, but does not represent clear trait familial liability.
... Acknowledgements We thank Suzanne Teunisse and Natalie Bougie for their efforts during data c... more ... Acknowledgements We thank Suzanne Teunisse and Natalie Bougie for their efforts during data collection. We also wish to thank Edwin Klinkenberg for his insights during the analysis of the data. Page 13. 13 References Amendola CA, Gabrieli JDE, Leberman HR. ...
Eight patients suering from major depression were treated with trazodone 150 or 200 mg bid (non-... more Eight patients suering from major depression were treated with trazodone 150 or 200 mg bid (non-responders) over 5 weeks, preceded and followed by a placebo week. Cognitive functioning was tested in the morning at the end of each treatment week. Before trazodone treatment commenced, patients' cognitive performance was compared with non-depressed controls. The depressed group showed signi®cantly slower reaction times on the memory scanning test, but did not dier from the control group on ®ve other tests including word learning, Critical Flicker/Fusion frequency (CFF), vigilance, tracking and divided attention. CFF threshold decreased signi®cantly during trazodone treatment. CFF returned to its initial baseline level at the end of the placebo withdrawal. During the trazodone treatment period, recall from long-term memory of a previously learnt word list signi®cantly improved, but at the end of the placebo withdrawal period memory performance returned to its initial baseline leve...
Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing ... more Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing performance in-flight (chronic) fatigue has negative long-term health effects. Possible causes of fatigue include sleep loss, extended time awake, circadian phase irregularities and work load. Despite regulations limiting flight time and enabling optimal rostering, fatigue cannot be prevented completely. Especially in military operations, where limits may be extended due to operational necessities, it is impossible to rely solely on regulations to prevent fatigue. Fatigue management, consisting of preventive strategies and operational countermeasures, such as pre-flight naps and pharmaceuticals that either promote adequate sleep (hypnotics or chronobiotics) or enhance performance (stimulants), may be required to mitigate fatigue in challenging (military) aviation operations. This review describes the pathophysiology, epidemiology and effects of fatigue and its impact on aviation, as well...
Human experimental models for anxiety may serve as translational tools for translating preclinica... more Human experimental models for anxiety may serve as translational tools for translating preclinical psychopharmacological investigations into human studies. For the evaluation of drugs of which pharmacokinetics and pharmacodynamics are unidentified, repeating measurements after drug administration is necessary for characterising the time course of drug effects. In experiment 1, a threat-of-shock paradigm and adaptations of the Trier mental arithmetic test and the Stroop colour naming test were repeated four times within a day to evaluate whether anxiety responses to this test battery remain stable after repeated testing. This procedure was repeated on 4 days in a second experiment to evaluate suitability of the paradigm for a crossover design with multiple sessions. Results indicate no reductions or changes in fear potentiated startle, the main outcome measure for the threat paradigm, over test sessions or days. Skin conductance responses and subjective ratings under threat-of-shock ...
People interested in the research are advised to contact the author for the final version of the ... more People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
The section in this book on Clinical Development is a mix of achieving goals by means of answerin... more The section in this book on Clinical Development is a mix of achieving goals by means of answering questions through scientific experimentation and following regulatory agreed guidelines. This is reflected by chapters describing the paths and guidelines for phase 1 (Chap. 16), answering bottom-up questions by utilising biomarkers for peripheral target engagement to determine dose selection for clinical phase 2 studies (Chap. 17). Subsequently, the chapter on microdosing of psychedelics uses the top-down perspective to find underpinning of a mechanism for data pointing to antidepressant effects of drugs taken out of the medical- or drug development context (Chap. 18). Finally, the chapter on interactions with FDA binds it altogether defining the best match for new data to medical needs and how to manage expectations in developers and regulators mutually and how to keep track of it (Chap. 19).
Home > Declarative Memory Declarative Memory Explorable.com38.3K reads Declarative memory, someti... more Home > Declarative Memory Declarative Memory Explorable.com38.3K reads Declarative memory, sometimes known as explicit memory, involves the conscious recollection of memories such as events, facts, figures and locations. Declarative memory is a form of long-term memory of which there are two types with the other known as procedural memory. There are two subcategories: episodic and semantic memories. Episodic memories relate to specific things we have experienced while semantic memories involve information of a factual nature.
Background: Evidence is accumulating that semantic networks are abnormal in patients with psychos... more Background: Evidence is accumulating that semantic networks are abnormal in patients with psychosis. The effect of emotionality on the semantic network is less well understood. The aim of the present study was to investigate with Event-Related potentials whether the N400 of patients is abnormal when presented with posi-tive and negative affective words and whether the affective semantic priming effect can be seen as putative endophenotype. Method: Thirteen patients with non-affective psychosis, 14 siblings and 16 controls partici-pated in an affective lexical decision task with three conditions (positively, negatively and unrelated) and two stimulus onset asynchronies (SOAs), 250ms and 500ms. Results: For SOA250, controls showed no difference between the three conditions in N400 amplitude. Patients showed a decrease in N400 amplitude in the unrelated condition compared to the affective conditions, and an earlier onset of the N400 in the positive condi-tion. Siblings showed no differ...
Background: Fatigue remains an important factor in major aviation accidents. Stimulants may count... more Background: Fatigue remains an important factor in major aviation accidents. Stimulants may counteract fatigue’s adverse effects, with modafinil as a promising alternative to caffeine. However, the effect of a single dose of modafinil after a limited period of sleep deprivation remains unknown. Aims: This study aims to determine the effect of 200 mg modafinil on vigilance during a limited period of sleep deprivation compared to 300 mg caffeine and placebo. Methods: Thirty-two volunteers of the Royal Netherlands Air Force (RNLAF) were double-blindly administered modafinil, caffeine, and placebo on three non-consecutive trial days after being awake for median 17 h. Afterwards, subjects completed six series of the Vigilance and Tracking test (VigTrack), psychomotor vigilance task (PVT), and Stanford Sleepiness Scale (SSS), yielding six primary endpoints. Results: This study revealed statistically significant effects of caffeine and modafinil compared with placebo on all endpoints, exce...
ABSTRACT BACKGROUND: Semantic network abnormalities in patients with psychotic disorder were exam... more ABSTRACT BACKGROUND: Semantic network abnormalities in patients with psychotic disorder were examined using associative prime-target relations with two stimulus asynchronies (SOAs; -250ms and -500ms) to assess the time course of automatic and more controlled processes of semantic priming. To investigate whether an aberrant semantic network system is part of the familial liability for psychosis, healthy siblings of patients with psychotic disorder were additionally examined. The N400 event-related brain potential (ERP) was used as a probe of semantic processing. METHOD: Twenty-two patients with psychotic disorder, twenty siblings of patients with psychotic disorder and twenty controls participated in a lexical decision task and ERPs were recorded to target words that were associatively, indirectly or not related to their preceding prime word. RESULTS: Associative priming of the N400 amplitude was found across all participants and both SOAs, but no between-group differences were found for the N400 amplitude (both SOAs). The Group×Condition interaction of the indirect priming N400 latency of the three groups was just short of statistical significance (F2,59=2.7, p=.077). Patients showed an increased indirect priming effect of the N400 latency only at short SOA, with decreased latency of the indirectly related compared to the unrelated condition, while controls did not show an indirect priming N400 latency effect. No between-group differences in N400 latency of indirect priming were found at the long SOA. Only a trend towards a Group×Condition interaction of the indirect priming N400 latency between the sibling and the controls was found, but without a main effect of indirect priming in the sibling group. CONCLUSION: These preliminary results support the assumption of a hyperactive semantic network in patients with psychotic disorder, which develops under automatic processes and decreases with more controlled processes, but does not represent clear trait familial liability.
... Acknowledgements We thank Suzanne Teunisse and Natalie Bougie for their efforts during data c... more ... Acknowledgements We thank Suzanne Teunisse and Natalie Bougie for their efforts during data collection. We also wish to thank Edwin Klinkenberg for his insights during the analysis of the data. Page 13. 13 References Amendola CA, Gabrieli JDE, Leberman HR. ...
Eight patients suering from major depression were treated with trazodone 150 or 200 mg bid (non-... more Eight patients suering from major depression were treated with trazodone 150 or 200 mg bid (non-responders) over 5 weeks, preceded and followed by a placebo week. Cognitive functioning was tested in the morning at the end of each treatment week. Before trazodone treatment commenced, patients' cognitive performance was compared with non-depressed controls. The depressed group showed signi®cantly slower reaction times on the memory scanning test, but did not dier from the control group on ®ve other tests including word learning, Critical Flicker/Fusion frequency (CFF), vigilance, tracking and divided attention. CFF threshold decreased signi®cantly during trazodone treatment. CFF returned to its initial baseline level at the end of the placebo withdrawal. During the trazodone treatment period, recall from long-term memory of a previously learnt word list signi®cantly improved, but at the end of the placebo withdrawal period memory performance returned to its initial baseline leve...
Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing ... more Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing performance in-flight (chronic) fatigue has negative long-term health effects. Possible causes of fatigue include sleep loss, extended time awake, circadian phase irregularities and work load. Despite regulations limiting flight time and enabling optimal rostering, fatigue cannot be prevented completely. Especially in military operations, where limits may be extended due to operational necessities, it is impossible to rely solely on regulations to prevent fatigue. Fatigue management, consisting of preventive strategies and operational countermeasures, such as pre-flight naps and pharmaceuticals that either promote adequate sleep (hypnotics or chronobiotics) or enhance performance (stimulants), may be required to mitigate fatigue in challenging (military) aviation operations. This review describes the pathophysiology, epidemiology and effects of fatigue and its impact on aviation, as well...
Human experimental models for anxiety may serve as translational tools for translating preclinica... more Human experimental models for anxiety may serve as translational tools for translating preclinical psychopharmacological investigations into human studies. For the evaluation of drugs of which pharmacokinetics and pharmacodynamics are unidentified, repeating measurements after drug administration is necessary for characterising the time course of drug effects. In experiment 1, a threat-of-shock paradigm and adaptations of the Trier mental arithmetic test and the Stroop colour naming test were repeated four times within a day to evaluate whether anxiety responses to this test battery remain stable after repeated testing. This procedure was repeated on 4 days in a second experiment to evaluate suitability of the paradigm for a crossover design with multiple sessions. Results indicate no reductions or changes in fear potentiated startle, the main outcome measure for the threat paradigm, over test sessions or days. Skin conductance responses and subjective ratings under threat-of-shock ...
People interested in the research are advised to contact the author for the final version of the ... more People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement:
The section in this book on Clinical Development is a mix of achieving goals by means of answerin... more The section in this book on Clinical Development is a mix of achieving goals by means of answering questions through scientific experimentation and following regulatory agreed guidelines. This is reflected by chapters describing the paths and guidelines for phase 1 (Chap. 16), answering bottom-up questions by utilising biomarkers for peripheral target engagement to determine dose selection for clinical phase 2 studies (Chap. 17). Subsequently, the chapter on microdosing of psychedelics uses the top-down perspective to find underpinning of a mechanism for data pointing to antidepressant effects of drugs taken out of the medical- or drug development context (Chap. 18). Finally, the chapter on interactions with FDA binds it altogether defining the best match for new data to medical needs and how to manage expectations in developers and regulators mutually and how to keep track of it (Chap. 19).
Home > Declarative Memory Declarative Memory Explorable.com38.3K reads Declarative memory, someti... more Home > Declarative Memory Declarative Memory Explorable.com38.3K reads Declarative memory, sometimes known as explicit memory, involves the conscious recollection of memories such as events, facts, figures and locations. Declarative memory is a form of long-term memory of which there are two types with the other known as procedural memory. There are two subcategories: episodic and semantic memories. Episodic memories relate to specific things we have experienced while semantic memories involve information of a factual nature.
Background: Evidence is accumulating that semantic networks are abnormal in patients with psychos... more Background: Evidence is accumulating that semantic networks are abnormal in patients with psychosis. The effect of emotionality on the semantic network is less well understood. The aim of the present study was to investigate with Event-Related potentials whether the N400 of patients is abnormal when presented with posi-tive and negative affective words and whether the affective semantic priming effect can be seen as putative endophenotype. Method: Thirteen patients with non-affective psychosis, 14 siblings and 16 controls partici-pated in an affective lexical decision task with three conditions (positively, negatively and unrelated) and two stimulus onset asynchronies (SOAs), 250ms and 500ms. Results: For SOA250, controls showed no difference between the three conditions in N400 amplitude. Patients showed a decrease in N400 amplitude in the unrelated condition compared to the affective conditions, and an earlier onset of the N400 in the positive condi-tion. Siblings showed no differ...
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