Search results for "startle"
showing 10 items of 29 documents
Ikääntymisen ja synnynnäisen aerobisen suorituskyvyn vaikutukset varhaiseen tiedonkäsittelyyn rotilla
2016
Fyysisen aktiivisuuden vaikutukset aivojen toimintaan ja kognitiivisiin kykyihin ovat viime aikoina herättäneet kiinnostusta tutkijoiden keskuudessa. Näitä teemoja tutkii myös Active, Fit and Smart (AFIS) -tutkimushanke, jonka päämääränä on selvittää liikunnan yhteyksiä oppimiseen ja sen edellytyksiin elämän eri vaiheissa. Tämä tutkielma on toteutettu osana AFIS-projektia, ja se lähestyy aihetta aerobisen suorituskyvyn näkökulmasta. Tutkielman tavoitteena on selvittää, miten synnynnäinen aerobinen suorituskyky ja ikääntyminen vaikuttavat varhaiseen tiedonkäsittelyyn, joka sijoittuu aivan kognitiivisen tiedonkäsittelyketjun alkuun. Tämä tapahtui vertailemalla kahta synnynnäiseltä aerobiselta…
Multimodal Assessment of Long-Term Memory Recall and Reinstatement in a Combined Cue and Context Fear Conditioning and Extinction Paradigm in Humans
2013
Learning to predict danger via associative learning processes is critical for adaptive behaviour. After successful extinction, persisting fear memories often emerge as returning fear. Investigation of return of fear phenomena, e.g. reinstatement, have only recently began and to date, many critical questions with respect to reinstatement in human populations remain unresolved. Few studies have separated experimental phases in time even though increasing evidence shows that allowing for passage of time (and consolidation) between experimental phases has a major impact on the results. In addition, studies have relied on a single psychophysiological dimension only (SCRs/SCL or FPS) which hamper…
Disturbed social behavior and motivation in rats selectively bred for deficient sensorimotor gating
2007
Deficient prepulse inhibition (PPI) of startle reflects disturbed sensorimotor gating found in certain neuropsychiatric disorders. We here tested whether rats selectively bred for deficient PPI are deteriorated in behavioral paradigms used to model negative symptoms of schizophrenia. Rats with low PPI preferred standard rat-chow when having the choice between lever-pressing for reward-pellets or freely available rat-chow, suggesting reduced motivation. Additionally, these rats show deteriorated social behavior during interaction with a juvenile rat. Rats selectively bred for low PPI may therefore be used as a model to study the biological mechanisms and therapeutic strategies of negative sy…
Long-lasting handling affects behavioural reactivity in adult rats of both sexes prenatally exposed to diazepam
2001
Environmental stressors can substantially affect the adaptive response of rats to novelty in a sexually dimorphic manner. Gender-related differences are also observed in neurochemical and behavioural patterns of adult rats following prenatal exposure to diazepam (DZ). In the present study the behavioural reactivity to novelty is investigated in open field (OF) and in acoustic startle reflex (ASR) tests, in non handled (NH), short-lasting handled (SLH) and long-lasting handled (LLH) adult male and female rats prenatally exposed to DZ. A single daily s.c. injection of DZ (1.5 mg/kg) over gestation days 14-20 decreases GABA/BDZ receptor function in both sexes, as shown by the decreased electro…
Preparedness for landing after a self-initiated fall.
2012
A startling auditory stimulus (SAS) causes a faster execution of voluntary actions when applied together with the imperative signal in reaction time tasks (the StartReact effect). However, speeding up reaction time may not be the best strategy in all tasks. After a self-initiated fall, the program for landing has to be time-locked to foot contact to avoid damage, and therefore advanced execution of the program would not be convenient. We examined the effects of SAS on the landing motor program in 8 healthy subjects that were requested to let themselves fall from platforms either 50 or 80 cm high at the perception of a visual imperative signal and land on specific targets. In trials at rand…
Cannabinoid CB1 receptors in distinct circuits of the extended amygdala determine fear responsiveness to unpredictable threat.
2016
The brain circuits underlying behavioral fear have been extensively studied over the last decades. Although the vast majority of experimental studies assess fear as a transient state of apprehension in response to a discrete threat, such phasic states of fear can shift to a sustained anxious apprehension, particularly in face of diffuse cues with unpredictable environmental contingencies. Unpredictability, in turn, is considered an important variable contributing to anxiety disorders. The networks of the extended amygdala have been suggested keys to the control of phasic and sustained states of fear, although the underlying synaptic pathways and mechanisms remain poorly understood. Here, we…
Hyperekplexia caused by dominant-negative suppression of glyra1 function.
2007
Hyperekplexia (HE; startle disease; OMIM#149400) is a rare inheritable neurologic disorder characterized by an exaggerated response to sudden stimuli, muscular rigidity, and hyperreflexia, leading to chronic injuries due to unprotected falls. All symptoms are present at birth but gradually decline during the first year of life, although an exaggerated startle response remains during adulthood.1 Dysfunctional inhibitory neurotransmission by glycine (Gly) plays a central role in HE pathogenesis. All patients with HE carry mutations in genes encoding either for α1 (GLYRA1) or β (GLYRB) Gly receptor subunits, presynaptic Gly transporters (SLC6A5), or proteins involved in Gly receptor (GLYR) clu…
Chemosensory anxiety signals prime defensive behavior in prepubertal girls
2017
indexation en cours; Chemosensory anxiety signals effectively prime motor responses related to withdrawal behavior, such as the startle reflex, in adult humans. As the reproductive status strongly affects the response to social chemosignals, the current study examined whether chemosensory anxiety signals would augment the startle response in prepubertal children as it does in adults. Using cotton pads, axillary sweat was collected from 28 men while waiting for an important oral examination (anxiety condition), and during ergometer training (sport control condition). Using a constant-flow olfactometer, sweat samples and pure cotton samples (cotton control) were presented to 10 prepubertal gi…
Inter-hemispheric remapping between arm proprioception and vision of the hand is disrupted by single pulse TMS on the left parietal cortex.
2013
International audience; Parietal cortical areas are involved in sensori-motor transformations for their respective contralateral hemifield/body. When arms of the subjects are crossed while their gaze is fixed straight ahead, vision of the hand is processed by the hemisphere ipsilateral to the arm position and proprioception of the arm by the contralateral hemisphere. It induces interhemispheric transfer and remapping. Our objective was to investigate whether a single pulse TMS applied to the left parietal cortical area would disturb interhemispheric remapping in a similar case, and would increase a simple reaction time (RT) with respect to a control single pulse TMS applied to the frontal c…
Reversal of prenatal diazepam-induced deficit in a spatial-object learning task by brief, periodic maternal separation in adult rats.
2005
In the rat, prenatal exposure to diazepam (DZ) induces a permanent reduction in GABA/BZ receptor (R) function and behavioural abnormalities. Environmental modifications during early stages of life can influence brain development and induce neurobiological and behavioural changes throughout adulthood. Indeed, a subtle, periodic, postnatal manipulation increases GABA/BZ R activity and produces facilitatory effects on neuroendocrine and behavioural responses. We here investigated the impact of prenatal treatment with DZ on learning performance in adult 3- and 8-month-old male rats and the influence of a brief, periodic maternal separation on the effects exerted by prenatal DZ exposure. Learnin…