Predicting Age From Behavioral Test Performance for Screening Early Onset of Cognitive Decline.

Neuronal reactions and cognitive processes slow down during aging. The onset, rate, and extent of changes vary considerably from individual to individual. Assessing the changes throughout the lifespan is a challenging task.

Bilateral parietal contributions to spatial language.

It is commonly held that language is largely lateralized to the left hemisphere in most individuals, whereas spatial processing is associated with right hemisphere regions. In recent years, a number of neuroimaging studies have yielded conflicting results regarding the role of language and spatial processing areas in processing language about space (e.g.

Neuronal injury in the motor cortex after chronic stroke and lower limb motor impairment: a voxel-based lesion symptom mapping study.

Many studies have examined motor impairments using voxel-based lesion symptom mapping, but few are reported regarding the corresponding relationship between cerebral cortex injury and lower limb motor impairment analyzed using this technique. This study correlated neuronal injury in the cerebral cortex of 16 patients with chronic stroke based on a voxel-based lesion symptom mapping analysis. Neuronal injury in the corona radiata, caudate nucleus and putamen of patients with chronic stroke could predict walking speed.

The effect of stimulus duration and motor response in hemispatial neglect during a visual search task.

Patients with hemispatial neglect exhibit a myriad of profound deficits. A hallmark of this syndrome is the patients' absence of awareness of items located in their contralesional space. Many studies, however, have demonstrated that neglect patients exhibit some level of processing of these neglected items.

Conditioning of transcranial magnetic stimulation: evidence of sensory-induced responding and prepulse inhibition.

Background: Transcranial magnetic stimulation (TMS) is a non-invasive method for stimulating the human cortex. Classical conditioning is a phenomenon of developed associations between stimuli. Our primary objective was to determine whether TMS effects could be conditioned.

Neural recruitment for the production of native and novel speech sounds.

Two primary areas of damage have been implicated in apraxia of speech (AOS) based on the time post-stroke: (1) the left inferior frontal gyrus (IFG) in acute patients, and (2) the left anterior insula (aIns) in chronic patients. While AOS is widely characterized as a disorder in motor speech planning, little is known about the specific contributions of each of these regions in speech. The purpose of this study was to investigate cortical activation during speech production with a specific focus on the aIns and the IFG in normal adults.

Modulation of frontal lobe speech areas associated with the production and perception of speech movements.

Purpose: It is unclear whether the production and perception of speech movements are subserved by the same brain networks. The purpose of this study was to investigate neural recruitment in cortical areas commonly associated with speech production during the production and visual perception of speech.

Method: This study utilized functional magnetic resonance imaging (fMRI) to assess brain function while participants either imitated or observed speech movements.

Event related potentials reveal that increasing perceptual load leads to increased responses for target stimuli and decreased responses for irrelevant stimuli.

Lavie (1995) have suggested that perceptual processing is influenced by perceptual load. Specifically, relevant information receives additional processing in high load situations exhausting the available capacity. On the other hand, irrelevant information receives less processing with increasing load on a relevant task, as there is a reduced amount of residual processing available.

Visual extinction: the effect of temporal and spatial bias.

Unlike patients with neglect, neurological patients with extinction can detect a single event presented at any location. However, when shown two brief near-simultaneous stimuli they only report the ipsilesional item. The question of what inter-stimulus delay leads to maximal extinction has clear clinical and theoretical implications.

Motor speech perception modulates the cortical language areas.

Traditionally, the left frontal and parietal lobes have been associated with language production while regions in the temporal lobe are seen as crucial for language comprehension. However, recent evidence suggests that the classical language areas constitute an integrated network where each area plays a crucial role both in speech production and perception. We used functional MRI to examine whether observing speech motor movements (without auditory speech) relative to non-speech motor movements preferentially activates the cortical speech areas.

Activation of brain attention systems in individuals with symptoms of ADHD.

Previous research investigating attention and impulse control in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) has largely ignored the symptomatic differences among the three subtypes of ADHD: ADHD-Inattentive Type, ADHD-Hyperactive/Impulsive Type, and ADHD-Combined Type. The present study examined attention and impulse control by focusing on these subtypes. Based on their self-reported symptoms of ADHD, participants belonged to one of four groups: ADHD-Inattentive, ADHD-Hyperactive/Impulsive, ADHD-Combined, and control.

Extrahippocampal gray matter atrophy and memory impairment in patients with medial temporal lobe epilepsy.

Memory impairment observed in patients with medial temporal lobe epilepsy (MTLE) is classically attributed to hippocampal atrophy. The contribution of extrahippocampal structures in shaping memory impairment in patients with MTLE is not yet completely understood, even though atrophy in MTLE extends beyond the hippocampus. We aimed to evaluate the neuropsychological profile of patients with MTLE focusing on memory, and to investigate whether gray matter concentration (GMC) distribution within and outside the medial portion of the temporal lobes would be associated with their neuropsychological performance.

Neural correlates of phonological and semantic-based anomia treatment in aphasia.

Most naming treatments in aphasia either assume a phonological or semantic emphasis or a combination thereof. However, it is unclear whether semantic or phonological treatments recruit the same or different cortical areas in chronic aphasia. Employing three persons with aphasia, two of whom were non-fluent, the present study compared changes in neural recruitment associated with phonologic and semantic-based naming treatments.

Age-related variability in cortical activity during language processing.

Purpose: The present study investigated the extent of cortical activity during overt picture naming using functional magnetic resonance imaging (fMRI).

Method: Participants comprised 20 healthy, adult participants with ages ranging from 20 to 82 years. While undergoing fMRI, participants completed a picture-naming task consisting of 60 high-frequency nouns.

Measuring the hemodynamic response in chronic hypoperfusion.

Although structural brain scans help assess brain injury in stroke, they cannot identify regions that are functionally disabled due to disrupted perfusion. Perfusion and functional MRI have the potential for determining the functional consequences of stroke. Here we examine the effectiveness of functional MRI to measure brain function in a single patient (LB) with chronic hypoperfusion.

Speech apraxia without oral apraxia: can normal brain function explain the physiopathology?

Apraxia of speech, usually associated with stroke, refers to the inability to perform speech motor movements typically with an intact ability to execute non-speech oral movements. It is uncertain whether apraxia of speech results from damage affecting the insula or the inferior frontal gyrus. The controversy started because of conflicting results from studies investigating patients with disrupted brain structure, when dysfunction of both sites can coexist.

Neural recruitment associated with anomia treatment in aphasia.

The purpose of this study was to investigate changes in the spatial distribution of cortical activity associated with anomia treatment in three persons with aphasia. Participants underwent three fMRI sessions before and after a period of intensive language treatment focused on object naming. The results revealed bilateral hemispheric recruitment associated with improved ability to name items targeted in treatment.

Brain damage and cortical compensation in foreign accent syndrome.

Foreign Accent Syndrome (FAS) is a well-known neurological deficit whose underlying cause has remained obscure despite almost a century of study. Combining structural and functional imaging, our studies suggest that FAS represents a compensatory response to impaired motor regulation of speech. We describe a patient who acquired FAS as a result of an ischemic stroke in the left basal ganglia.

Visual neglect can be object-based or scene-based depending on task representation.

Three patients with visual neglect were tested on their ability to detect target letters at ipsilesional and contralesional locations on a monitor, and at different locations within large shapes on the monitor. When patients were asked to detect targets within the entire monitor, they showed neglect for all the contralesional hemifield. In contrast when they were asked to detect targets within a particular object, they showed object-based neglect.

Auditory extinction: the effect of stimulus similarity and task requirements.

Auditory extinction was examined in six patients with right hemisphere lesions, using an auditory double simultaneous stimulation task using letters spoken in male and female voices. Patients had to detect where the stimuli were located, and identify either the letter or the voice (the task-relevant dimension). Auditory extinction was greatest when the two stimuli were the same on the task-relevant dimension, paralleling previous studies of visual extinction.

The effect of ipsilesional cues on line-bisection errors: the importance of predictive value.

Patients with unilateral neglect were tested on a line-bisection task in which vertical lines were added to the ipsilesional or contralesional end. During some blocks, these vertical lines accurately predicted the horizontal length of the line, while on other blocks the vertical lines had little predictive value. We found that much of the improvement for ipsilesional vertical bars can be explained by their ability to predict the extent of the horizontal line.

Enhanced tactile performance at the destination of an upcoming saccade.

Previous work has demonstrated that upcoming saccades influence visual and auditory performance even for stimuli presented before the saccade is executed. These studies suggest a close relationship between saccade generation and visual/auditory attention. Furthermore, they provide support for Rizzolatti et al.

Visual extinction with double simultaneous stimulation: what is simultaneous?

Patients with unilateral lesions to the parietal lobe leading to extinction were tested with stimuli presented in both hemifields. In addition to simultaneous presentation of two stimuli, trials were given with the contralesional or ipsilesional side having an onset slightly before the other. In the first experiment, subjects were asked to identify the stimuli.