A functional MRI study of presurgical cognitive deficits in glioma patients.

Background: The main goal of this functional MRI (fMRI) study was to examine whether cognitive deficits in glioma patients prior to treatment are associated with abnormal brain activity in either the central executive network (CEN) or default mode network (DMN).

Methods: Forty-six glioma patients, and 23 group-matched healthy controls (HCs) participated in this fMRI experiment, performing an N-back task. Additionally, cognitive profiles of patients were evaluated outside the scanner.

When Right Is on the Left (and Vice Versa): A Case Series of Glioma Patients with Reversed Lateralization of Cognitive Functions.

We report a case series of four patients operated on for a glioma in awake conditions and in whom task-based functional magnetic resonance imaging (fMRI) demonstrated right-dominant activity during a language production task. Language functional sites were identified intraoperatively by electrical stimulations only in the patient with a right-sided lesion. Furthermore, the pre- or postoperative cognitive evaluations in the three patients operated on for a left-sided glioma revealed right spatial neglect and dysexecutive syndrome, hence demonstrating that, in patients with right-dominant activity on language fMRI, the left hemisphere is implicated in spatial consciousness and cognitive control.

The effect of response frequency on cognitive brain activity during an alertness task.

A required response forces the brain to react overtly on a stimulus. This may be a factor that influences cognitive activity during a task, as it could facilitate for instance alertness, especially in tasks that are relatively easy. In the current article, we therefore tested the hypothesis that response frequency affects cognitive brain activity in an alertness task.

Brain Activity Associated With Expected Task Difficulty.

Previous research shows that people can use a cue to mentally prepare for a cognitive challenge. The response to a cue has been defined as phasic alertness which is reflected in faster responses and increased activity in frontal, parietal, thalamic, and visual brain regions. We examine if and how phasic alertness can be tuned to the expected difficulty of an upcoming challenge.

Rapid acquisition of dynamic control over DLPFC using real-time fMRI feedback.

It has been postulated that gaining control over activity in the dorsolateral prefrontal cortex (DLPFC), a key region of the working memory brain network, may be beneficial for cognitive performance and treatment of certain psychiatric disorders. Several studies have reported that, with neurofeedback training, subjects can learn to increase DLPFC activity. However, improvement of dynamic control in terms of switching between low and high activity in DLPFC brain states may potentially constitute more effective self-regulation.

Spatiotemporal characteristics of electrocortical brain activity during mental calculation.

Mental calculation is a complex mental procedure involving a frontoparietal network of brain regions. Functional MRI (fMRI) studies have revealed interesting characteristics of these regions, but the precise function of some areas remains elusive. In the present study, we used electrocorticographic (ECoG) recordings to chronometrically assess the neuronal processes during mental arithmetic.

fMRI guided rTMS evidence for reduced left prefrontal involvement after task practice.

Introduction: Cognitive tasks that do not change the required response for a stimulus over time ('consistent mapping') show dramatically improved performance after relative short periods of practice. This improvement is associated with reduced brain activity in a large network of brain regions, including left prefrontal and parietal cortex. The present study used fMRI-guided repetitive transcranial magnetic stimulation (rTMS), which has been shown to reduce processing efficacy, to examine if the reduced activity in these regions also reflects reduced involvement, or possibly increased efficiency.

Give me a sign: decoding complex coordinated hand movements using high-field fMRI.

Decoding movements from the human cortex has been a topic of great interest for controlling an artificial limb in non-human primates and severely paralyzed people. Here we investigate feasibility of decoding gestures from the sensorimotor cortex in humans, using 7 T fMRI. Twelve healthy volunteers performed four hand gestures from the American Sign Language Alphabet.

Practice induces function-specific changes in brain activity.

Background: Practice can have a profound effect on performance and brain activity, especially if a task can be automated. Tasks that allow for automatization typically involve repeated encoding of information that is paired with a constant response. Much remains unknown about the effects of practice on encoding and response selection in an automated task.

Spatial working memory deficits in obsessive compulsive disorder are associated with excessive engagement of the medial frontal cortex.

Recent studies have shown that obsessive compulsive disorder (OCD) is associated with a specific deficit in spatial working memory, especially when task difficulty (i.e., working memory load) is high.