Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT03981913 |
Other study ID # |
35RC19_8963_EEGControl |
Secondary ID |
2019-A00608-49 |
Status |
Completed |
Phase |
|
First received |
|
Last updated |
|
Start date |
June 6, 2019 |
Est. completion date |
March 10, 2022 |
Study information
Verified date |
May 2023 |
Source |
Rennes University Hospital |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational
|
Clinical Trial Summary
Cognitive action control allows resisting to irrelevant information to easily produce desired
goal-directed behaviors. This cognitive process is disturbed in patients with Parkinson's
disease (PD). However, the neural signature of this impairment has not been clarified yet.
Several studies using electroencéphalography (EEG) showed that conflict situations in healthy
participants are inevitably associated with a power increase of neuronal oscillations in the
theta frequency band (~4-8Hz) in the medial frontal cortex (MFC). Conflict situations are
also associated with theta functional connectivity between the MFC and task-relevant brain
areas. The theta power increase and connectivity are respectively interpreted as a marker of
the integration of conflicting information and as a candidate for communication between the
brain areas involved in implementing cognitive action control. The objective of this project
is to test the hypothesis that the deficit of cognitive action control observed in PD comes
from a lack of integration of the conflict information and / or communication of this
information between the MFC and other task-relevant brain areas. Investigators willl study
this cognitive process using a classic conflict task, the Simon task, and by recording brain
activity using high density EEG coupled with cortical source connectivity analyses. The
results will allow us to evaluate whether theta oscillations can serve as a marker of
cognitive control disorders in Parkinson's disease.
Description:
Alterations in cognitive action control in patients with PD are well described from a
behavioral point of view. However, there is currently very little information to directly
link these difficulties to functional alterations of brain areas, or of efficient
communication within large scale brain networks. Thus, the objective of this project is to
specify the neuronal substrates linked to the difficulties in cognitive action control
observed in patients with PD. The rational is based on the recent findings on the role of
theta (4-8 Hz) neuronal oscillations in cognitive action control. Indeed, converging evidence
linked this process to an increase in theta oscillatory power around midfrontal electrodes
(FCz, Cz) and to an increase in theta functional connectivity with task-relevant brain areas.
The working hypotheses are based on the hypothesis proposed by Cohen (2014). It proposes that
the medial frontal cortex (MFC; around the pre-SMA) would be involved in the integration of
conflicting information, observable by studying theta oscillations' power. On the other hand,
the phase synchronization of theta oscillations between the MFC and the other task-relevant
cortical areas would reflect the degree of recruitment of the entire network participating in
the implementation of an efficient cognitive control. Thus, according to this model, a
conflict situation would lead to two main measurable electrophysiological reactions in the
cortex: i) an increase in the power of theta oscillations around the MFC, ii) an increase in
theta phase synchronization between the MFC and the other cortical areas (such as the lateral
prefrontal and parietal cortices) involved in implementing cognitive action control. These
two electrophysiological effects will be the main judgment criteria of this study.
The hypothesis is that the behavioral difficulties in cognitive action control observed in PD
patients stem from a lack of integration of the conflicting information and / or a weaker
communication of this information to the areas implementing the cognitive control of the
action. The alteration of one or both of these aspects may explain the weaker cognitive
action control observed in patients. Moreover, by inspecting the disrupted brain networks, it
will be able to make hypotheses explaining the alteration of cognitive control in PD. For
example, a weaker functional connectivity between the MFC and the posterior parietal cortex
could indicate a lower redirection of attentional resources following the presentation of a
conflictual stimulus. Another possibility would be a weaker functional connectivity between
the MFC and the inferior prefrontal cortex, which would rather indicate a lack of recruitment
of the inhibitory system.
The main hypothesis will be tested by comparing the performance of a group of PD patients to
that of a group of healthy participants whose brain activity will be collected during the
realization of a Simon task via a high resolution electroencephalography system. The
behavioral performances will be compared as well as the source-reconstructed
electrophysiological data. Specifically, the power of the theta oscillations within the
medial frontal cortex, as well as the phase synchronization between the other cortical areas
involved will be compared between the two groups. Brain-behavior relationships will also be
investigated in order to try to link PD behavioral impairments to changes in theta
oscillatory power/connectivity.