Search results for "Brain mapping"
showing 10 items of 396 documents
Dissociable contributions of left and right dorsolateral prefrontal cortex in planning.
2010
It is well established that the mid-dorsolateral prefrontal cortex (dlPFC) plays a critical role in planning. Neuroimaging studies have yielded predominantly bilateral dlPFC activations, but the existence and nature of functionally specific contributions of left and right dlPFC have remained elusive. In recent experiments, 2 independent parameters have been identified which substantially determine planning: 1) the degree of interdependence between consecutive steps (search depth) and 2) the degree to which the configuration of the goal state renders the order of single steps either clearly evident or ambiguous (goal hierarchy). Thus, search depth affects the actual mental generation and eva…
Gaming is related to enhanced working memory performance and task-related cortical activity
2017
Gaming experience has been suggested to lead to performance enhancements in a wide variety of working memory tasks. Previous studies have, however, mostly focused on adult expert gamers and have not included measurements of both behavioral performance and brain activity. In the current study, 167 adolescents and young adults (aged 13–24 years) with different amounts of gaming experience performed an n-back working memory task with vowels, with the sensory modality of the vowel stream switching between audition and vision at random intervals. We studied the relationship between self-reported daily gaming activity, working memory (n-back) task performance and related brain activity measured u…
Mismatch negativity (MMN) in freely-moving rats with several experimental controls.
2014
Mismatch negativity (MMN) is a scalp-recorded electrical potential that occurs in humans in response to an auditory stimulus that defies previously established patterns of regularity. MMN amplitude is reduced in people with schizophrenia. In this study, we aimed to develop a robust and replicable rat model of MMN, as a platform for a more thorough understanding of the neurobiology underlying MMN. One of the major concerns for animal models of MMN is whether the rodent brain is capable of producing a human-like MMN, which is not a consequence of neural adaptation to repetitive stimuli. We therefore tested several methods that have been used to control for adaptation and differential exogenou…
Atypical perceptual narrowing in prematurely born infants is associated with compromised language acquisition at 2 years of age
2010
Abstract Background Early auditory experiences are a prerequisite for speech and language acquisition. In healthy children, phoneme discrimination abilities improve for native and degrade for unfamiliar, socially irrelevant phoneme contrasts between 6 and 12 months of age as the brain tunes itself to, and specializes in the native spoken language. This process is known as perceptual narrowing, and has been found to predict normal native language acquisition. Prematurely born infants are known to be at an elevated risk for later language problems, but it remains unclear whether these problems relate to early perceptual narrowing. To address this question, we investigated early neurophysiolog…
Verbal suppression and strategy use: a role for the right lateral prefrontal cortex?
2015
Verbal initiation, suppression and strategy generation/use are cognitive processes widely held to be supported by the frontal cortex. The Hayling Test was designed to tap these cognitive processes within the same sentence completion task. There are few studies specifically investigating the neural correlates of the Hayling Test but it has been primarily used to detect frontal lobe damage. This study investigates the components of the Hayling Test in a large sample of patients with unselected focal frontal (n = 60) and posterior (n = 30) lesions. Patients and controls (n = 40) matched for education, age and sex were administered the Hayling Test as well as background cognitive tests. The sta…
Bilaterally recorded multiple-unit activity of the cingulate cortex during head turning conditioning with unilateral medial forebrain bundle stimulat…
1993
Cats were conditioned to turn their heads using a tone conditioned stimulus (CS) and medial forebrain bundle stimulation (MFB) unconditioned stimulus (US). The CS+ was delivered to one ear at a time, in random order, followed by the US. A tone of a different frequency was used as a CS-. The cats learned to respond differentially to the CSs showing head movements of greater acceleration to the CS+ than CS- over sessions. Bilateral recordings of cingulate cortex multiple-unit activity showed increased response amplitudes over sessions and larger responses in the hemisphere ipsilateral to the US. Since ipsilateral multiple-unit responses did not differ for the CSs, the asymmetry was probably d…
Correlation between fatigue and brain atrophy and lesion load in multiple sclerosis patients independent of disability.
2007
Abstract Background Fatigue is a major problem in multiple sclerosis (MS), and its association with MRI features is debated. Objective To study the correlation between fatigue and lesion load, white matter (WM), and grey matter (GM), in MS patients independent of disability. Methods We studied 222 relapsing remitting MS patients with low disability (scores ≤ 2 at the Kurtzke Expanded Disability Status Scale). Lesion load, WM and GM were measured by fully automated, operator-independent, multi-parametric segmentation method. T1 and T2 lesion volume were also measured by a semi-automated method. Fatigue was assessed by the Fatigue Severity Scale (FSS), and patients divided in high-fatigue (FS…
A method for rapid implantation of multielectrode systems.
1991
The implantation of several chronic electrodes at the same time was needed for the studies in which both evoked slow potential and multiple unit neural activity of different brain sites were recorded during classical conditioning in freely moving cats. The recording electrodes were made of 25-75 microns insulated stainless steel or nichrome wires which were inserted into a thin hypodermic needle of a fixed, calibrated length. The fast implantation system described here is based on the use of a stereotaxic frame as a stand for a drill and as a support for an electrode holder with which the electrodes were implanted through precision holes drilled directly according to the coordinates of the …
Effects of Selective Attention on Syntax Processing in Music and Language
2010
Abstract The present study investigated the effects of auditory selective attention on the processing of syntactic information in music and speech using event-related potentials. Spoken sentences or musical chord sequences were either presented in isolation, or simultaneously. When presented simultaneously, participants had to focus their attention either on speech, or on music. Final words of sentences and final harmonies of chord sequences were syntactically either correct or incorrect. Irregular chords elicited an early right anterior negativity (ERAN), whose amplitude was decreased when music was simultaneously presented with speech, compared to when only music was presented. However, t…
Expectation of sensory stimulation modulates brain activation during visual motion stimulation.
2005
The differential effects of visual hemifield motion stimulation during fixation of a stationary target were compared under two conditions: fixation straight ahead without any further instructions and fixation straight ahead with attention shifted to the "dark hemifield." Data from nine right-handed volunteers revealed that striate and extrastriate right hemispheric visual areas exhibited larger activations during left hemifield motion stimulation when attention was shifted to the right dark hemifield. Montreal Neurological Institute (MNI) coordinates (26, -98, -4) of the additional clusters activated in the latter condition corresponded best to the kinetic occipital region, which is known t…