Causal Evidence for Task Regulation by Anterior Cingulate Cortex
Causal Evidence for Task Regulation by Anterior Cingulate Cortex
The exact function of the anterior cingulate cortex (ACC) is one of the largest riddles in
 cognitive neuroscience and a major challenge in mental health research. ACC dysfunction
 contributes to a broad spectrum of neurological and psychiatric disorders, such as
 depression, ADHD, Parkinson's disease, OCD and many others, but nobody knows what it actually
 does. Recently a new theory has been developed about ACC function; the HRL-ACC (Hierarchical
 Reinforcement Learning Theory of ACC). This theory proposes that the ACC selects and
 motivates high-level tasks based on the principles of hierarchical reinforcement learning.
 The ACC associates values with tasks (these values are based on the reward positivity
 produced by the midbrain dopamine system), selects the correct tasks and applies control over
 other neural networks (such as the dorsolateral prefrontal cortex and basal ganglia), which
 execute the tasks. The goal of this study is to investigate the consequences of ACC damage
 (and other areas of the frontal lobe) on task regulation within a group of patients who have
 suffered a stroke in the frontal lobe. Furthermore, the correlation between ACC damage and
 mood disorders such as depression and apathy is going to be investigated.
This is a monocentric prospective interventional clinical trial that will include patients
 with a stroke in the frontal lobe. Depending on the recruitment manner, participants will
 undergo one or two sessions of cognitive experiments. The patients will be recruited in two
 ways, through the Stroke unit and through the outpatient clinic:

 1. If a patient with an acute stroke in the frontal lobe is admitted to the Stroke unit and
 is eligible for this study, the patient will be asked if he is willing to participate.
 After giving informed consent, the first session will take place once the patient has
 been transferred to a regular neurological ward. After discharge, a second session will
 take place 6 to 12 months later at the outpatient clinic, preferably combined with a
 consultation (as part of the standard of care of stroke patients).

 2. Patients who have had a stroke are followed at the outpatient clinic. Patients who are
 eligible for this study, will be contacted by the treating stroke supervisor during
 their consultation (either Prof. Veerle De Herdt or Dr. Dimitri Hemelsoet). If they are
 willing to participate, the first session will take place either right after the
 consultation at the outpatient clinic, or - if the patient is not available at that time
 - a new appointment will be made.

 One experimental session consists of the following steps:

 -  Clinical neurological examination with determining of NIHSS score.

 -  First cognitive task: the coffee-tea task. During this task, a sequence of 7 images is
 shown and each image contains three objects. The patient has to choose the right objects
 to make either coffee or tea. At the end of each sequence they get feedback if they have
 prepared the beverage correctly or not.

 -  Short break with positioning of 21 EEG electrodes.

 -  Second task: the virtual T-maze task with video-EEG recording. During this task, a
 virtual T-maze is shown and the patient has to choose at each junction whether they go
 left or right. Depending on which direction they choose, they either get positive or
 negative feedback. This task is known to elicit the reward positivity. During this task,
 video-EEG will be recorded and this EEG-data will later on be analysed using ERP
 analysis.

 -  If second session, administering of questionnaires: Oxford Cognitive Screen, Becker
 Depression Inventory, DEX apathy questionnaire.

 Furthermore, the investigators are going to use voxel-based lesion symptom mapping to analyze
 the relationship between tissue damage and behavioural problems and reward positivity
 amplitude.

 It is expected that the coffee-tea task will be more difficult for patients with ACC damage
 compared to patients with lesions in other areas of the frontal lobe. Also, the amplitude of
 the ERP signals during the virtual T-maze task will be smaller in patients with ACC damage.
 Furthermore, the investigators expect to find a connection between ACC damage and mood
 disorders.
Inclusion Criteria:

 -  Stroke patients: ischemic stroke or intracranial hemorrhage

 -  Involvement of the frontal lobe

 -  Lesion is visible on CT and/or MRI and is concordant with clinical presentation during
 the time of onset

 -  Patients have to be able to give informed consent themselves

 Exclusion Criteria:

 -  Patients with a TIA, i.e. no visible lesion on CT and/or MRI or symptoms less than 24
 hours

 -  Patients with decreased alertness or disorders of consciousness, which makes it
 impossible for these patients to participate in the experiments

 -  Active alcohol and/or drug abuse/addiction

 -  Patients diagnosed with dementia or another neurodegenerative disease, or severe
 cognitive and/or psychiatric disorders that make it impossible for these patients to
 participate in the study

 -  Patients with severe aphasia (as defined by NIHSS score)

 -  A history of stroke in the frontal lobe is NOT an exclusion criteria (except when the
 patient has been diagnosed with poststroke frontal dysfunction).