Search results for "Percept"

Early cortical processing of vection-inducing visual stimulation as measured by event-related brain potentials (ERP)

2019

Abstract Visual motion stimuli can induce the perception of self-motion in stationary observers (known as vection). In the present study, we investigated the sensory processing underlying vection by measuring the human event-related brain potentials (ERPs) elicited by the movement onset of a visual stimulus. We presented participants a visual stimulus consisting of alternating black-and-white vertical bars that moved in horizontal direction, creating the sensation of vection. The stimulus was presented on a screen that was divided into a central and a surrounding peripheral visual area. Both areas moved independently from each other, resulting in four different movement patterns: the periph…

Interference of Illusory Contour Perception by a Distractor

2021

The visual system is capable of recognizing objects when object information is widely separated in space, as revealed by the Kanizsa-type illusory contours (ICs). Attentional involvement in perception of ICs is an important topic, and the present study examined whether and how the processing of ICs is interfered with by a distractor. Discrimination between thin and short deformations of an illusory circle was investigated in the absence or presence of a central dynamic patch, with difficulty of discrimination varied in three levels (easy, medium, and hard). Reaction time (RT) was significantly shorter in the absence compared to the presence of the distractor in the easy and medium condition…

Weighted Integration of Duration Information Across Visual and Auditory Modality Is Influenced by Modality-Specific Attention.

2021

We constantly integrate multiple types of information from different sensory modalities. Generally, such integration is influenced by the modality that we attend to. However, for duration perception, it has been shown that when duration information from visual and auditory modalities is integrated, the perceived duration of the visual stimulus leaned toward the duration of the auditory stimulus, irrespective of which modality was attended. In these studies, auditory dominance was assessed using visual and auditory stimuli with different durations whose timing of onset and offset would affect perception. In the present study, we aimed to investigate the effect of attention on duration integr…

Illusory contours and specific regions of human extrastriate cortex: evidence from rTMS

2003

Functional magnetic resonance imaging studies showed that perception of illusory contours is associated with extrastriate cortex activation prevailing on the right side. 1 Hz repetitive transcranial magnetic stimulation (rTMS) is able to induce lasting inhibition of cortical activity. The objective of the study was to investigate the role of extrastriate cortex in illusory contour perception inducing 1 Hz rTMS interference in healthy subjects. Eight healthy subjects underwent 1 Hz rTMS (600 pulses) through a figure-of-eight coil over right and left occipital cortex (O1 and O2 of 10/20 EEG system); sham magnetic stimulation on the same sites and right motor cortex rTMS (in three subjects) we…

Mapping of the human visual cortex using image-guided transcranial magnetic stimulation

2002

We describe a protocol using transcranial magnetic stimulation (TMS) to systematically map the visual sensations induced by focal and non-invasive stimulation of the human occipital cortex. TMS is applied with a figure of eight coil to 28 positions arranged in a 2x2-cm grid over the occipital area. A digitizing tablet connected to a PC computer running customized software, and audio and video recording are used for detailed and accurate data collection and analysis of evoked phosphenes. A frameless image-guided neuronavigational device is used to describe the position of the actual sites of the stimulation coils relative to the cortical surface. Our results show that TMS is able to elicit p…

2017

The mere presence of a depiction of eyes can elicit a sense of being watched in the perceiver. To this date, the factors affecting the intensity of this sense of being watched, however, have not been investigated. In the present experiment, we tested the impact of two potentially relevant variables: arousal (manipulated using specific musical pieces) and duration of the perceptual episode (manipulated using presentation times of 200 ms and 10 s, respectively). We asked participants to report how intensely they felt being watched while we exposed them to various observation cues ranging from human eyes to surveillance cameras. We found that, on average, reported intensities were higher if pa…

The Role of Mental Rigidity and Alcohol Consumption Interaction on Intimate Partner Violence: A Spanish Study

2017

ABSTRACTIntimate partner violence (IPV) has often been linked to alcohol consumption. Alcohol abuse affects cognitive processing through its effects on the prefrontal cortex, generating influence in mental rigidity (MR). This study analyzes the influence of MR as a predisposing factor to violence. The sample consisted of 136 men with a history of IPV. Participants with high MR had lower empathy and perception of the severity of IPV, and higher alcohol consumption and hostile sexism than participants with lower MR. These results should be considered in the development of prevention and intervention programs with the goal of increasing their effectiveness.

Somatosensory Illusions Elicited by Sham Electromagnetic Field Exposure: Experimental Evidence for a Predictive Processing Account of Somatic Symptom…

2020

OBJECTIVE According to the predictive processing theory of somatic symptom generation, body sensations are determined by somatosensory input and central nervous predictions about this input. We examined how expectations shape predictions and consequently bodily perceptions in a task eliciting illusory sensations as laboratory analogue of medically unexplained symptoms. METHODS Using the framework of signal detection theory, the influence of sham Wi-Fi on response bias (c) and somatosensory sensitivity (d') for tactile stimuli was examined using the somatic signal detection task (SSDT). A healthy student sample (n = 83) completed the SSDT twice (sham Wi-Fi on/off) in a randomized order after…

Happiness: role of dopamine and serotonin on mood and negative emotions

2017

Dopamine is a hormone associated with happiness and serotonin regulates our mood. When a person is physically attracted to another, an activation of dopamine, serotonin increased and production of oxytocin, a hormone that reduces pain perception and increases the emotional connection we have with the other occurs. Disconnecting the amygdala, the parts of the brain that are active against negative emotions like fear. The combination of all these elements leads to crush the other. After our beliefs, the way we understand ourselves and understand the world around us, eventually determining if I made a good choice. These are questions necessary to understand the functioning of our brain and hum…

Relationship of subjective helplessness and pain perception after electric skin stimuli

2000

Objective and subjective controllability of painful stimuli are important factors in pain perception. The present study investigated direct and indirect effects of uncontrollability on perceived pain intensity in humans. Forty-eight healthy male volunteers participated in a laboratory experiment using a reaction time paradigm to induce controllable or uncontrollable feedback conditions in two randomly selected groups. Under controllable conditions, unpleasant electric skin shocks were applied, only when the actual time exceeded an individual threshold; under uncontrollable conditions, skin shocks were applied randomly using a yoked control design. Subjective helplessness, perceived pain int…