Biology subjects

Tamm, S.

Publications and source records attributed to Tamm, S..

5 recordsLinked to original sources

bioRxiv2022

The effect of sleep continuity disruption on multimodal emotion processing and regulation: a laboratory-based, randomized, controlled experiment in good sleepers

Previous research shows that experimental sleep deprivation alters emotion processing, suggesting a potential mechanism linking sleep disruption to mental ill-health. Extending previous work, we experimentally disrupted sleep continuity in good sleepers and assessed next-day emotion processing and regulation using tasks with established sensitivity to depression. In a laboratory-based study, 51 good sleepers (37 female; mean age = 24 years, SD= 3.63) were randomized to one night (23:00-07:00) of uninterrupted sleep (n=24) or sleep continuity disruption (n=27). We assessed emotion perception, attention, and memory the following day. Participants also completed an emotion regulation task and measures of self-reported affect, anxiety, sleepiness, overnight declarative memory consolidation, and psychomotor vigilance. Confirming the effects of the manipulation, sleep continuity disruption led to a marked decrease in polysomnography-defined total sleep time (229.98 mins vs 434.57 mins), increased wake-time after sleep onset (260.66 mins vs 23.84 mins) and increased sleepiness (d=0.81). Sleep continuity disruption led to increased anxiety (d=0.68), decreased positive affect (d=-0.62), reduced overnight declarative memory consolidation (d=-1.08) and reduced psychomotor vigilance [longer reaction times (d=0.64) and more lapses (d=0.74)], relative to control. However, contrary to our hypotheses, experimental sleep disruption had no effect on perception of, or bias for, emotional facial expressions, emotional memory for words, or emotion regulation following worry induction. In conclusion, one night of sleep continuity disruption had no appreciable effect on objective measures of emotion processing or emotion regulation in response to worry induction, despite clear effects on memory consolidation, vigilance, and self-reported affect and anxiety.

neuroscience↗

bioRxiv2020

Spontaneous eye-movements during eyes-open rest reduce resting-state-network modularity by increasing visual-sensorimotor connectivity

During wakeful rest, individuals make small eye movements when asked to fixate. We examined how these endogenously-driven oculomotor patterns impact topography and topology of functional brain networks. We used a dataset consisting of eyes-open resting-state (RS) fMRI data with simultaneous eye-tracking (Nilsonne et al., 2016). The eye-tracking data indicated minor movements during rest, on the order of 1.0 degree on average when analyzed over 2sec epochs, which correlated modestly with RS BOLD data. However, the eye-tracking data correlated well with echo-planar imaging (EPI) time series sampled from the area of the Eye-Orbit (EO-EPI), which is a signal previously used to identify eye movements during exogenous saccades and movie viewing. We found that EO-EPI data correlated with activity in an extensive motor and sensory-motor network, but also some components of the dorsal attention network including the frontal and supplementary eye fields. Partialling out variance related to EO-EPI from RS data reduced connectivity, primarily between sensory-motor and visual areas. For three different network sparsity levels, the resulting RS connectivity networks showed higher modularity, lower mean connectivity strength, and lower mean clustering coefficient. Our results highlight new aspects of endogenous eye movement control during wakeful rest. They show that oculomotor-related contributions form an important component of RS network topology, and that those should be considered in interpreting differences in network structure between populations, or as a function of different experimental conditions.

neuroscience↗

bioRxiv2019

Oxazepam and cognitive reappraisal: a randomised experiment

BackgroundCognitive reappraisal is a strategy for emotional regulation, important in the context of anxiety disorders. It is not known whether anxiolytic effects of benzodiazepines affect cognitive reappraisal. AimsWe aimed to investigate the effect of 25 mg oxazepam on cognitive reappraisal. MethodsIn a preliminary investigation, 33 healthy male volunteers were randomised to oxazepam or placebo, and then underwent an experiment where they were asked to use cognitive reappraisal to upregulate or downregulate their emotional response to images with negative or neutral emotional valence. We recorded unpleasantness ratings, skin conductance, superciliary corrugator muscle activity, and heart rate. Participants completed rating scales measuring empathy (Interpersonal Reactivity Index, IRI), anxiety (State-Trait Anxiety Inventory, STAI), alexithymia (Toronto Alexithymia Scale-20, TAS-20), and psychopathy (Psychopathy Personality Inventory-Revised, PPI-R). ResultsUpregulation to negative-valence images in the cognitive reappraisal task caused increased unpleasantness ratings, corrugator activity, and heart rate compared to downregulation. Upregulation to both negative- and neutral-valence images caused increased skin conductance responses. Oxazepam caused lower unpleasantness ratings to negative-valence stimuli, but did not interact with reappraisal instruction on any outcome. Self-rated trait empathy was associated with stronger responses to negative-valence stimuli, whereas self-rated psychopathic traits were associated with weaker responses to negative-valence stimuli. ConclusionsWhile 25 mg oxazepam caused lower unpleasantness ratings in response to negative-valence images, we did not observe an effect of 25 mg oxazepam on cognitive reappraisal.

neuroscience↗

bioRxiv2019

Defecation by the ctenophore Mnemiopsis leidyi occurs with an ultradian rhythm through a single transient anal pore

Defecation in the ctenophore Mnemiopsis leidyi is a stereotyped sequence of effector responses that occur with a regular ultradian rhythm. Time intervals between repeated defecations of individual animals depend on body size, ranging from ~10 min in small larvae to ~1 hr in large adults. New features and corrections of previous reports of the gastrovascular system during and between defecations are described in detail by video microscopy. Contrary to the scientific literature, the defecating organ of the excretory complex is just one of the two anal canals which possesses the animals only anal pore. The anal pore is not visible as a permanent structure as depicted in textbooks, but appears at defecation and disappears afterward. DIC microscopy reveals that opening and closing of the anal pore resemble a reversible ring of tissue fusion between apposed endodermal and ectodermal layers at the aboral end. Mnemiopsis thus appears to have an intermittent anus and therefore an intermittent through-gut that reoccur at regular intervals. The temporality of a visible anal pore in Mnemiopsis is novel, and may shed light on the evolution of a permanent anus and through-gut in animals. In addition, mirror image dimorphism of the diagonal anal complex occurs in larval ctenophores but not in adults, indicating developmental flexibility in diagonal symmetry of the anal complex.

zoology↗

bioRxiv2018

Sleep restriction caused impaired emotional regulation without detectable brain activation changes - a functional magnetic resonance imaging study

Sleep restriction has been proposed to cause impaired emotional processing and emotional regulation by inhibiting top-down control from prefrontal cortex to amygdala. Intentional emotional regulation after sleep restriction has however never been studied using brain imaging. We here aimed to investigate the effect of sleep restriction on emotional regulation through cognitive reappraisal. Forty-seven young (age 20-30) and 33 older (age 65-75) participants (38/23 with complete data and successful sleep intervention) performed a cognitive reappraisal task during fMRI after a night of normal sleep and after restricted sleep (3h). Emotional downregulation was associated with significantly increased activity in dorsolateral prefrontal cortex (pFWE < 0.05) and lateral orbital cortex (pFWE < 0.05) in young, but not in older subjects. Sleep restriction was associated with a decrease in self-reported regulation success to negative stimuli (p < 0.01) and a trend towards perceiving all stimuli as less negative (p = 0.07), in young participants. No effects of sleep restriction on brain activity nor connectivity were found in either age group. In conclusion, our data do not support the idea of a prefrontal-amygdala disconnect after sleep restriction, and neural mechanisms underlying behavioural effects on emotional regulation after insufficient sleep require further investigation.

neuroscience↗