To characterize the neural interactions underlying simple perceptual decisions about the target disappearance during motion-induced blindness.
ID
Source
Brief title
Condition
- Other condition
Synonym
Health condition
The study is basic research that does not address any condition.
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Based on our previous fMRI (Donner et al, Journal of Neuroscience, 2008) and
MEG (Donner et al, Current Biology, 2009) results, we expect the following
modulations of cortical activity to occur around the time of the subjects*
behavioral (button press) report of the target disappearance:
(1) A decrease of the specific response to the target in the visual cortex.
This decrease will be specific to the cortical representation of the target
stimulus, thus confined to the contralateral hemisphere, and it will precede
subjects* behavioral report.
(2) An increase of activity in motor cortex contralateral to the upcoming
button press that reflects subjects* evolving plan to make the perceptual
report.
(3) A *global* response decrease throughout visual cortex, be expressed
throughout both hemispheres. We predict that this global response modulation
will succeed both response components (1) and (2), as well as subjects*
behavioral report.
We will interpret the target-specific response decrease in visual cortex (1) as
the neural basis of the subjective target disappearance, the motor build-up
activity (2) as a correlate of subjects* subsequent perceptual decision, and
the global response decrease in visual cortex (3) as a feedback signal
re-entering early visual cortex. Specifically, based on the latencies relative
to (2), we may conclude that this global modulation in visual cortex is
triggered by the preceding perceptual decision.
Secondary outcome
Not applicable.
Background summary
Our brain sometimes *decides* that even salient visual stimuli are not actually
present in the external world and hence makes them disappear from our conscious
perception, as if erased from the visual scene. For example, when surrounded by
a moving visual pattern, a salient visual target disappears completely from
conscious perception, only to reappear several seconds later. This phenomenon
is called *motion-induced blindness* (Bonneh et al., Nature, 2001). It provides
an excellent opportunity for probing the intrinsic neural interactions
governing the simple perceptual decision about the presence/absence of simple
visual targets. Our previous functional magnetic resonance imaging (fMRI)
studies of motion-induced blindness have provided a first window into these
neural interactions (Donner et al, Journal of Neuroscience, 2008). In the
proposed project, we plan to use magnetoencephalography (MEG) to characterize
these neural interactions at higher temporal resolution in the intact human
brain. Specifically, the objective of the study is to characterize the temporal
sequence the neural events around the time of the target disappearance
decision.
Study objective
To characterize the neural interactions underlying simple perceptual decisions
about the target disappearance during motion-induced blindness.
Study design
We will record the magnetoencephalogram (MEG) in healthy, adult human subjects,
while they experience and report the motion-induced blindness illusion. Stimuli
will be presented on a screen and subjects will report their ongoing target
perception (*visible/invisible*) by pressing one of two response buttons with
their left of right hand. We will use spectral analysis of the MEG signals
(e.g., Donner et al, Journal of Neurophysiology, 2007; Donner et al, Current
Biology, 2009) to characterize the time course of modulations of different
components of cortical activity around the time subjects* behavioral report of
the target disappearance.
Study burden and risks
There is no specific risk and burden associated with this study.
Roeterstraat 15
1018 WB Amsterdam
NL
Roeterstraat 15
1018 WB Amsterdam
NL
Listed location countries
Age
Inclusion criteria
Young, healthy adults. Age range 18-40 years. Experienced participants in psychophysical and neuroimaging experiments. Written informed consent. Normal or corrected-to-normal vision.
Exclusion criteria
Significant neurological or psychiatric history (in particular, epilepsy). Significant visual disturbance. Claustrophobia. Metal items attached to or inside the volunteers* body that cannot be removed.
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL32325.029.10 |