Search results for "Stimulus"

General principles in motion vision: Color blindness of object motion depends on pattern velocity in honeybee and goldfish

2011

AbstractVisual systems can undergo striking adaptations to specific visual environments during evolution, but they can also be very “conservative.” This seems to be the case in motion vision, which is surprisingly similar in species as distant as honeybee and goldfish. In both visual systems, motion vision measured with the optomotor response is color blind and mediated by one photoreceptor type only. Here, we ask whether this is also the case if the moving stimulus is restricted to a small part of the visual field, and test what influence velocity may have on chromatic motion perception. Honeybees were trained to discriminate between clockwise- and counterclockwise-rotating sector disks. S…

Differential electrodermal and phasic heart rate responses to personally relevant information: Comparing sleep and wakefulness

2010

This study examined autonomic physiological responses to personally relevant information presented during sleep and wakefulness. Heart rate and electrodermal reactions to subjects’ own first name and other first names were measured during sleep stage 2, rapid eye movement (REM) sleep, and wakefulness. Across all conditions, larger skin conductance responses were elicited by subjects’ own first name. During REM sleep, personally relevant information led to larger heart rate acceleration, whereas an enhanced deceleration was examined during wakefulness. These findings suggest that auditory information is processed on a semantic level even during sleep. However, personally relevant information…

Flow field, swimming velocity and boundary layer: parameters which affect the stimulus for the lateral line organ in blind fish

1988

The data presented support the hypothesis that the flow field supplies the stimulus to the lateral line organ (LLO) in blind cave fish (Anoptichthys jordani). Two basic predictions from the theoretical analysis of the flow field were confirmed: (i) individual blind cave fish prefer particular swimming velocities, (ii) the velocity preferred depends on the cross-sectional area (CSA) of the fish, i.e. the smaller the CSA the higher the swimming velocity. This relationship was found also in experimentally blinded fish of other species. Furthermore, when placed in unfamiliar surroundings, blind cave fish swim at higher velocities than in familiar surroundings for a certain habituation period. T…

TMS activation of interhemispheric pathways between the posterior parietal cortex and the contralateral motor cortex

2009

Using a twin coil transcranial magnetic stimulation (tc-TMS) approach we have previously demonstrated that facilitation may be detected in the primary motor cortex (M1) following stimulation over the ipsilateral caudal intraparietal sulcus (cIPS). Here we tested the interhemispheric interactions between the IPS and the contralateral motor cortex (M1). We found that conditioning the right cIPS facilitated contralateral M1 when the conditioning stimulus had an intensity of 90% resting motor threshold (RMT) but not at 70% or 110% RMT. Facilitation was maximal when the interstimulus interval (ISI) between cIPS and M1 was 6 or 12 ms. These facilitatory effects were mediated by interactions with …

Decomposing encoding and decisional components in visual-word recognition: a diffusion model analysis.

2014

In a diffusion model, performance as measured by latency and accuracy in two-choice tasks is decomposed into different parameters that can be linked to underlying cognitive processes. Although the diffusion model has been utilized to account for lexical decision data, the effects of stimulus manipulations in previous experiments originated from just one parameter: the quality of the evidence. Here we examined whether the diffusion model can be used to effectively decompose the underlying processes during visual-word recognition. We explore this issue in an experiment that features a lexical manipulation (word frequency) that we expected to affect mostly the quality of the evidence (the dri…

The bulbar respiratory centre in the rabbit. I. Changes of respiratory parameters caused by intermittent electrical bulbar stimulation during inspira…

1976

In anesthetized rabbits, spirogram and diaphragmatic activity were examined during electrical stimulation of the bulbar lateral reticular formation. The activity of bulbar respiratory neurons was recorded contra-or ipsilaterally to the stimulation site. One volley of repetitive stimuli per breath was delivered during either inspiration or expiration. 1. Each volley of about 120 ms duration at 100 pulses per second, delivered early ininspiration, caused an immediate and transient inhibition of the diaphragmatic activity. An inspiratory, rebound comprising lengthening of inspiration and increase in tidal volume occurred. a) “Inspiratory” and “expiratory-inspiratory” phase-spanning neurons exh…

Differences in Inhibitory Control between Impulsive and Premeditated Aggression in Juvenile Inmates

2017

Inhibitory control dysfunction was considered a universal characteristic of violent offenders. The aim of this study was to examine differences in inhibitory control between two subtypes of violent youth; those displaying predominantly impulsive and those presenting predominantly premeditated aggression (PM). Forty-four juvenile offenders, defined on the basis of the Procedures for the Classification of Aggressive/Violent Acts (Stanford and Barratt, 2001) participated (N = 23: impulsive; N = 21 premeditated). A visual Go/NoGo task was used to compare behavioral responses and event-related potentials (ERPs) between groups. The task contained two letters (W and M), W was the Go stimulus and M…

Context-dependent minimisation of prediction errors involves temporal-frontal activation

2020

According to the predictive coding model of perception, the brain constantly generates predictions of the upcoming sensory inputs. Perception is realised through a hierarchical generative model which aims at minimising the discrepancy between predictions and the incoming sensory inputs (i.e., prediction errors). Notably, prediction errors are weighted depending on precision of prior information. However, it remains unclear whether and how the brain monitors prior precision when minimising prediction errors in different contexts. The current study used magnetoencephalography (MEG) to address this question. We presented participants with repetition of two non-predicted probes embedded in cont…

Two-step principal component analysis (PCA) as a method for separating auditory N1 and N250 elicited from 9-year-old children using a dense electrode…

2008

Reaction time paradigms in subjects at risk for schizophrenia.

1994

Abstract Deviant response patterns in experimental reaction time paradigms in schizophrenic probands are well documented. Although simple reaction times are strongly influenced by the current psychopathological status of the proband (e.g. florid psychotic patients versus remitted patients) these influences are less clear for measures obtained from more complex reaction time paradigms. These include the crossover paradigm (reaction time to stimuli presented after constant preparatory intervals in comparison to reaction time to stimuli presented after irregular preparatory intervals) and the modality shift paradigm (reaction time to a stimulus (light or tone) when the modality of the stimulus…