Search results for " CONDITIONING"
showing 10 items of 400 documents
Replication of fMRI group activations in the neuroimaging battery for the Mainz Resilience Project (MARP)
2020
Abstract Motivated by the recent replicability crisis we tested replicability of functional magnetic resonance imaging (fMRI) group activations in two independent samples. An identical behavioral and fMRI test battery for the longitudinal investigation of stress resilience mechanisms was developed for the Mainz Resilience Project (MARP) and conducted in a discovery (N = 54) and a replication sample (N = 103). The test battery consisted of a stress reactivity task, a reward sensitivity task, a fear conditioning and extinction paradigm, two volitional reappraisal tasks and an emotional interference inhibition task. Replicability of group activations was tested with the Jaccard index and the I…
Sex differences in conditioned stimulus discrimination during context-dependent fear learning and its retrieval in humans: the role of biological sex…
2015
BACKGROUND: Anxiety disorders are more prevalent in women than in men. Despite this sexual dimorphism most experimental studies are conducted in male participants and studies focusing on sex differences are sparse. In addition the role of hormonal contraceptives and menstrual cycle phase in fear conditioning and extinction processes remain largely unknown. METHODS: We investigated sex differences in context-dependent fear acquisition and extinction (day 1) and their retrieval/expression (day 2). Skin conductance responses (SCRs) fear and unconditioned stimulus expectancy ratings were obtained. RESULTS: We included 377 individuals (261 women) in our study. Robust sex differences were observe…
Busulfan systemic exposure after oral administration of extemporeanously prepared high-dose busulfan capsules.
2009
Purpose. The aim of the study was to analyze patients’ busulfan (BU) exposure after oral administration of extemporeanously prepared BU capsules prior to blood stem cell transplantation. Methods. Patients were treated with 1 mg/kg body weight BU administered orally every 6h on each of 4 consecutive days prior to blood stem cell transplantation. Each BU dose was administered in 1 gelatine capsule to be swallowed and containing the individually calculated dose of pure BU active substance. Blood samples were obtained from 6 adult patients 0, 30, 60, 90, 120, 180, 240, 300, and 360 min after the 1st, 5th, and 13th BU dose, frozen and analyzed subsequently by using a HPLC assay with UV detectio…
Affective modulation of conditioned eyeblinks
2009
Affective states are known to modulate reflexive actions. Aversive states potentiate defensive reflexes while appetitive states diminish them. The present study examined whether the same holds for associatively learned defensive eyeblinks to mild, initially neutral auditory stimuli. First, delay eyeblink conditioning was applied to human participants while they viewed emotionally neutral images. Next, the conditioned eyeblink responses (CRs) of the participants were tested during the viewing of unpleasant, neutral, or pleasant images. The most vigorous CRs were found during the unpleasant images, although they did not differ between neutral and pleasant images. The results add to the motiva…
Effect of transcranial direct current stimulation on semantic discrimination eyeblink conditioning
2015
Abstract Background Transcranial direct current stimulation (tDCS) is a neuromodulation method that has been used to modulate learning. We tested whether anodal tDCS targeted at the left DLPFC could enhance learning in a semantic variant of discrimination eyeblink conditioning, i.e., whether the stimulation would have a specific effect on the discrimination ability, rate of acquisition, amplitude of the conditioned response (CR), or all of these. Methods Immediately prior to the eyeblink conditioning, the participants received either active stimulation of 1 mA for 10 min or sham stimulation. The anode was placed over F3 and the cathode over the right supraorbital area. The conditioned stimu…
Learning by heart : cardiac cycle reveals an effective time window for learning
2018
Cardiac cycle phase is known to modulate processing of simple sensory information. This effect of the heartbeat on brain function is likely exerted via baroreceptors, the neurons sensitive for changes in blood pressure. From baroreceptors, the signal is conveyed all the way to the forebrain and the medial prefrontal cortex. In the two experiments reported, we examined whether learning, as a more complex form of cognition, can be modulated by the cardiac cycle phase. Human participants ( experiment 1) and rabbits ( experiment 2) were trained in trace eyeblink conditioning while neural activity was recorded. The conditioned stimulus was presented contingently with either the systolic or dias…
Hematopoietic stem-cell transplantation for advanced systemic mastocytosis
2014
Purpose Advanced systemic mastocytosis (SM), a fatal hematopoietic malignancy characterized by drug resistance, has no standard therapy. The effectiveness of allogeneic hematopoietic stem-cell transplantation (alloHCT) in SM remains unknown. Patients and Methods In a global effort to define the value of HCT in SM, 57 patients with the following subtypes of SM were evaluated: SM associated with clonal hematologic non–mast cell disorders (SM-AHNMD; n = 38), mast cell leukemia (MCL; n = 12), and aggressive SM (ASM; n = 7). Median age of patients was 46 years (range, 11 to 67 years). Donors were HLA-identical (n = 34), unrelated (n = 17), umbilical cord blood (n = 2), HLA-haploidentical (n = 1)…
Breathe out and learn: Expiration-contingent stimulus presentation facilitates associative learning in trace eyeblink conditioning.
2019
Rhythmic variation in heart rate and respiratory pattern are coupled in a way that optimizes the level of oxygen in the blood stream of the lungs and the body as well as saves energy in pulmonary gas exchange. It has been suggested that the cardiac cycle and respiratory pattern are coupled to neural oscillations of the brain. Yet, studies on how this rhythmic coupling is related to behavior are scarce. There is some evidence that, for example, the phase of respiration affects memory retrieval and the electrophysiological oscillatory state of the limbic system. It is also known that the phase of the cardiac cycle and hippocampal electrophysiological oscillations alone affect learning. Here, …
The novel combination of theophylline and bambuterol as a potential treatment of hypoxemia in humans.
2017
Hypoxemia can be life-threatening, both acutely and chronically. Because hypoxemia causes vascular dysregulation that further restricts oxygen availability to tissue, it can be pharmacologically addressed. We hypothesized that theophylline can be safely combined with the β2-adrenergic vasodilator bambuterol to improve oxygen availability in hypoxemic patients. Ergogenicity and hemodynamic effects of bambuterol and theophylline were measured in rats under hypobaric and normobaric hypoxia (12% O2). Feasibility in humans was assessed using randomized, double-blind testing of the influence of combined slow-release theophylline (300 mg) and bambuterol (20 mg) on adverse events (AEs), plasma K+,…
Where There is Smoke There is Fear-Impaired Contextual Inhibition of Conditioned Fear in Smokers
2016
The odds-ratio of smoking is elevated in populations with neuropsychiatric diseases, in particular in the highly prevalent diagnoses of post-traumatic stress and anxiety disorders. Yet, the association between smoking and a key dimensional phenotype of these disorders—maladaptive deficits in fear learning and fear inhibition—is unclear. We therefore investigated acquisition and memory of fear and fear inhibition in healthy smoking and non-smoking participants (N=349, 22% smokers). We employed a well validated paradigm of context-dependent fear and safety learning (day 1) including a memory retrieval on day 2. During fear learning, a geometrical shape was associated with an aversive electric…