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OpenTrials
Completed

NCT Number: NCT03872999

Attentional Control

The project is dedicated to understanding the integration within the brain of signals of different natures that contribute to attentional control. The investigator will make use of standardized experimental displays involving the discrimination of a target (tilted-bar) presented together with 3 distractor items, with one stimulus in each visual quadrant. Across three fMRI experiments in healthy participants, the investigator will manipulate different types of signals that will guide the subject's attention towards one of the four quadrants: Exp 1 - task instruction & item salience; Exp 2 - probabilistic target location; Exp 3 - probabilistic reward. The investigator expects that irrespective of the nature of the control signal, activity in dorsal parietal cortex will index the currently relevant/attended location. Moreover, The investigator expects that upon changes of the most relevant location, one will observe activation of the ventral parietal cortex, plus increased inter-regional connectivity between ventral and dorsal parietal regions - again irrespective of the nature of the attention guiding signals.

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Key information

Conditions

Attention Control Healthy Volunteers

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Inserm U1028 Equipe Impact

Bron, 69676, France

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Be 18 to 40 years old

Exclusion criteria

  • Previous neurologic or psychiatric disease.
  • Cognitive deficits restricting understanding of the tasks.
  • Pregnant or breath-feeding women.
  • Persons under guardianship, curator or any other administrative or judicial measure of deprivation of rights or liberty.
  • Subjects currently participating in other study.

Additional exclusion criteria for a functional magnetic resonance imaging (fMRI) recording:

  • Neurologic, cardiac electrostimulation or defibrillator.
  • Cardiac prostheses
  • Intracranial clips or clamps
  • Cerebrospinal fluid disorders
  • Metal particles in the eyes
  • Metal dental or articular prostheses
  • Diffusion pomp or other infusion system
  • Claustrophobia
  • Head tattoo, make-up, hair gel
  • Have any copper intrauterine device

Treatment and study plan

Functional brain imaging without any contrast agent

Other

During the functional magnetic resonance imaging (fMRI) protocol, the subject will perform the attentional task while whole-brain activity will be recorded using Echo Planar Imaging (EPI) that measures the Blood Oxygen Level Dependent (BOLD) signal (2x2x2 isotropic voxels, Echo Time (ET) = 30 ms, Repetition Time (RT) = 2.5 sec). The functional session will be subdivided into several parts ("Runs", duration: 10-15 min). Together with the functional data, the protocol will include a structural scan (T1 weighted, 1x1x1 mm voxels; duration 5-7 min) and a field mapping sequence (duration: 1 min).

Primary outcomes

  1. Changes of hemodynamic response in dorsal parietal regions representing specific spatial locations (visual quadrants)

    Time frame: Day 0

    After spatial pre-processing of individual series of functional magnetic resonance imaging (fMRI) scans, normalization and smoothing as suggested for Statistical Parametric Mapping (SPM) analysis, the different attentional conditions will be modeled and convolved with canonical Hemodynamic Response Function (HRF). The model will be estimated according to the algorithm of SPM. Using a Region of Interest (ROI) approach, the investigator will extract the signal in dorsal parietal regions representing the four visual quadrants, and will compare activity as a function of the attended / most relevant location. The main hypothesis will be confirmed by activation of the ROI corresponding to the currently attended location, irrespective of the nature of the signal guiding attention (i.e. common effects in Exp 1-3).

Secondary outcomes

  1. Evaluation of the brain hemodynamic response

    Time frame: Day 0

    The investigator will search for relations between changes over time of the most relevant location (trial history) and the re-organization of attentional representations by investigating the activity and connectivity of the ventral parietal cortex. For this, the investigator will model events corresponding to changes in attention location and test for local activation of the ventral parietal cortex, as well as changes in connectivity (correlation) between ventral and dorsal parietal regions. The secondary hypothesis will be confirmed by increased activation in ventral parietal cortex, plus increased connectivity between ventral and dorsal parietal regions, at the time of a change of the most relevant location, irrespective of the nature of the signal guiding attention (i.e. common effects in Exp 1-3).

  2. Evaluation of the connectivity of the ventral parietal cortex at the time when there is a change of the most relevant spatial location/visual quadrant. x²

    Time frame: Day 0

    The investigator will search for relations between changes over time of the most relevant location (trial history) and the re-organization of attentional representations by investigating the activity and connectivity of the ventral parietal cortex. For this, the investigator will model events corresponding to changes in attention location, and test for local activation of the ventral parietal cortex, as well as changes of connectivity (correlation) between ventral and dorsal parietal regions. The secondary hypothesis will be confirmed by increased activation in ventral parietal cortex, plus increased connectivity between ventral and dorsal parietal regions, at the time of a change of the most relevant location, irrespective of the nature of the signal guiding attention (i.e. common effects in Exp 1-3).

Sponsors and collaborators

Lead sponsor

Hospices Civils de Lyon

Other

Registry information

Official study title

Developing a Multi-scale Account of Attentional Control as the Constraining Interface Between Vision and Action (MAC-Brain).

Acronym: MACBRAIN

Important dates

Study start
2019
Primary completion
2019
Study completion
2021
First posted
Mar 13, 2019
Registry last updated
Jan 11, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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