Investigating the neural basis of auditory false perceptions in a signal detection paradigm using transcranial direct current stimulatio

Completed

Conditions: auditory perception
false signal detection

Registration Number: NL-OMON46726

Lead Sponsor: Durham University

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 54

Inclusion Criteria

1) participants are aged between 18-35
2) participants are right-handed
3) speak fluent English;
4) do not report any known hearing impairments (to be tested before the first tDCS-session)
5) signed informed consent

Exclusion Criteria

1) (suspected) pregnancy
2) not signing the informed consent
3) family history of epilepsy
4) non-removable metallic objects on the head or arms,
5) a history of skin conditions (e.g., eczema).

Study & Design

Study Type: Observational non invasive

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>The dependent variable which will serve as the primary outcome measure will be<br /><br>response bias () on the signal detection task, corresponding to the<br /><br>externalising bias. This will be calculated according to the following<br /><br>formula, as recommended by Stanislaw and Todorov (1999): =e{(Z(FA)^2- Z(H)<br /><br>^2)/2}. Z(FA) refers to the standardized false alarm rate (that is, the<br /><br>proportion of trials on which a participant incorrectly responds yes when no<br /><br>voice or tone is actually present), whilst Z(H) refers to the standardized hit<br /><br>rate (that is, the proportion of trials on which a participant correctly<br /><br>responds yes when a voice or tone is presented). Lower * values refer to a<br /><br>more liberal response bias.<br /><br><br /><br>-3x2x2 way ANOVA [stimulus condition x stimulus type x time point] with a<br /><br>Bayes factor as an evidence </p><br>

Secondary Outcome Measures

Name	Time	Method
<p>we will repeat the analysis with:<br /><br>- task sensitivity (d') on the signal detection task as the dependent<br /><br>variable, which will be calculated as d' = Z(H) * Z(FA).<br /><br>- raw false alarm rate on the signal detection task as a dependent variable.<br /><br>False alarm rate will be defined as the percentage of trials on which no<br /><br>stimulus is presented on which the participant responds yes.<br /><br>- planned contrast between superior temporal condition and mean of the two<br /><br>other conditions for voice auditory stimuli.<br /><br>- the interaction between stimulus condition (superior temporal, sham or non<br /><br>auditory cortex) and stimulus type (voice or non-voice). </p><br>