Search results for "ehdollistuminen"

­Cardiac cycle and respiration phase affect responses to the conditioned stimulus in young adults trained in trace eyeblink conditioning

2022

Rhythms of breathing and heartbeat are linked to each other as well as to rhythms of the brain. Our recent studies suggest that presenting the conditioned stimulus during expiration or during the diastolic phase of the cardiac cycle facilitates neural processing of that stimulus and improves learning an eyeblink classical conditioning task. To date, it has not been examined whether utilizing information from both respiration and cardiac cycle phases simultaneously allows even more efficient modulation of learning. Here we studied whether the timing of the conditioned stimulus to different cardiorespiratory rhythm phase combinations affects learning trace eyeblink conditioning in healthy you…

Configural learning in rabbit nictitating membrane conditioning : acquisition of biconditional discrimination

2004

Most hippocampal CA1 pyramidal cells in rabbits increase firing during awake sharp-wave ripples and some do so in response to external stimulation an…

2020

Hippocampus forms neural representations of real-life events including multimodal information of spatial and temporal context. These representations, i.e. organized sequences of neuronal firing are repeated during following rest and sleep, especially when so-called sharp-wave ripples (SPW-Rs) characterize hippocampal local-field potentials. This SPW-R –related replay is thought to underlie memory consolidation. Here, we set out to explore how hippocampal CA1 pyramidal cells respond to the conditioned stimulus during trace eyeblink conditioning and how these responses manifest during SPW-Rs in awake adult female New Zealand White rabbits. Based on reports in rodents, we expected SPW-Rs to ta…

Effect of emotional picture viewing on classical eyeblink conditioning

2004

Common and separable behavioral and neural mechanisms underlie the generalization of fear and disgust

2021

Generalization represents the transfer of a conditioned responses to stimuli that resemble the conditioned stimulus (CS). Previous studies on generalization of defensive avoidance responses have primarily focused on fear and have neglected disgust generalization, which represents a key pathological mechanism in some anxiety disorders. In the present study we examined common and distinct mechanisms of fear and disgust generalization by means of a fear or disgust multi-CS conditioning and generalization paradigm with concomitant event-related potential (ERPs) acquisition in n = 62 subjects. We demonstrate that compared to fear, disgust-relevant generalized stimuli (GS) elicited larger expecta…

Influence of Perceptual and Conceptual Information on Fear Generalization : A Behavioral and Event-Related Potential Study

2021

Learned fear can be generalized through both perceptual and conceptual information. This study investigated how perceptual and conceptual similarities influence this generalization process. Twenty-three healthy volunteers completed a fear-generalization test as brain activity was recorded in the form of event-related potentials (ERPs). Participants were exposed to a de novo fear acquisition paradigm with four categories of conditioned stimuli (CS): two conceptual cues (animals and furniture); and two perceptual cues (blue and purple shapes). Animals (C+) and purple shapes (P+) were paired with the unconditioned stimulus (US), whereas furniture (C−) and blue shapes (P−) never were. The gener…

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…

Hippocampal theta phase-contingent memory retrieval in delay and trace eyeblink conditioning

2017

Hippocampal theta oscillations (3-12Hz) play a prominent role in learning. It has been suggested that encoding and retrieval of memories are supported by different phases of the theta cycle. Our previous study on trace eyeblink conditioning in rabbits suggests that the timing of the conditioned stimulus (CS) in relation to theta phase affects encoding but not retrieval of the memory trace. Here, we directly tested the effects of hippocampal theta phase on memory retrieval in two experiments conducted on adult female New Zealand White rabbits. In Experiment 1, animals were trained in trace eyeblink conditioning followed by extinction, and memory retrieval was tested by presenting the CS at t…

Transkraniaalisen tasavirtastimulaation vaikutukset erottelu- ja käänteisoppimiseen sekä reagointiherkkyyden muutoksiin

2017

Transkraniaalisella tasavirtastimulaatiolla (tDCS) tarkoitetaan menetelmää, jossa johdetaan heikkoa sähkövirtaa aivokudosten läpi elektrodilta toiselle. Tutkimusten mukaan tDCS:lla näyttäisi olevan monenlaisia kliinisiä ja kognitiivisia vaikutuksia aina masennuksen hoidosta työmuistin parantamiseen. Tulokset ovat kuitenkin monin paikoin varsin ristiriitaisia, eikä stimulaation tarkoista vaikutusmekanismeistakaan olla päästy varmuuteen. Tässä tutkimuksessa halusimme tutkia kokeellisesti tDCS:n vaikutuksia erottelu- ja käänteisoppimiseen sekä reagointiherkkyyden muutoksiin silmäniskuehdollistumisen avulla. Kokeeseen osallistui 39 iältään 18-29-vuotiasta koehenkilöä. Tutkittavat jaettiin kahte…

Social exclusion influences conditioned fear acquisition and generalization: A mediating effect from the medial prefrontal cortex

2020

Abstract Fear acquisition and generalization play key roles in promoting the survival of mammals and contribute to anxiety disorders. While previous research has provided much evidence for the repercussions of social exclusion on mental health, how social exclusion affects fear acquisition and generalization has received scant attention. In our study, participants were divided into two groups according to two Cyberball paradigm conditions (exclusion/inclusion). Both groups underwent a Pavlovian conditioning paradigm, functional near-infrared spectroscopy (fNIRS), and skin conductance response (SCR) assessments. We aimed to determine the effects of social exclusion on fear acquisition and ge…