Errors on the Trail Making Test Are Associated with Right Hemispheric Frontal Lobe Damage in Stroke Patients.

Measures of performance on the Trail Making Test (TMT) are among the most popular neuropsychological assessment techniques. Completion time on TMT-A is considered to provide a measure of processing speed, whereas completion time on TMT-B is considered to constitute a behavioral measure of the ability to shift between cognitive sets (cognitive flexibility), commonly attributed to the frontal lobes. However, empirical evidence linking performance on the TMT-B to localized frontal lesions is mostly lacking.

Disorganized behavior on Link's cube test is sensitive to right hemispheric frontal lobe damage in stroke patients.

One of Luria's favorite neuropsychological tasks for challenging frontal lobe functions was Link's cube test (LCT). The LCT is a cube construction task in which the subject must assemble 27 small cubes into one large cube in such a manner that only the painted surfaces of the small cubes are visible. We computed two new LCT composite scores, the constructive plan composite score, reflecting the capability to envisage a cubical-shaped volume, and the behavioral (dis-) organization composite score, reflecting the goal-directedness of cube construction.

Age-related changes in neural recruitment for cognitive control.

The dual mechanisms of control (DMC; Braver, Gray, & Burgess, 2007) framework postulates a distinction between proactive and reactive modes of cognitive control. Event-related brain potentials (ERPs) were used to examine age differences in the neural correlates of proactive and reactive control for task-switching. Whereas proactive control is associated with brain activity for anticipatory task preparation, reactive control is accompanied by reduced preparatory activity, but increased activation during task execution.

Performance on the Frontal Assessment Battery is sensitive to frontal lobe damage in stroke patients.

Background: The Frontal Assessment Battery (FAB) is a brief battery of six neuropsychological tasks designed to assess frontal lobe function at bedside [Neurology 55:1621-1626, 2000]. The six FAB tasks explore cognitive and behavioral domains that are thought to be under the control of the frontal lobes, most notably conceptualization and abstract reasoning, lexical verbal fluency and mental flexibility, motor programming and executive control of action, self-regulation and resistance to interference, inhibitory control, and environmental autonomy.

Methods: We examined the sensitivity of performance on the FAB to frontal lobe damage in right-hemisphere-damaged first-ever stroke patients based on voxel-based lesion-behavior mapping.

A model-based approach to trial-by-trial p300 amplitude fluctuations.

It has long been recognized that the amplitude of the P300 component of event-related brain potentials is sensitive to the degree to which eliciting stimuli are surprising to the observers (Donchin, 1981). While Squires et al. (1976) showed and modeled dependencies of P300 amplitudes from observed stimuli on various time scales, Mars et al.

A hypothesis of local intrinsic cortical signal processing.

Nearly a century ago, Ramón y Cajal [1] speculated that cortical interneurones underlie specific functions that are fundamental to human thought. Here we develop a computational analysis of the function of local cortical loops and their synaptic connections. Specifically, we propose that the function of cortical interneurones is to reduce redundancy and to contribute to compute saliency of information represented in neurones by implementing divisive normalization and multiplicative filtering functions.

Event-related brain potentials and the efficiency of visual search for vertically and horizontally oriented stimuli.

Reports that visual search is more efficient for vertically than for horizontally shaded objects suggested that search is influenced by a priori knowledge about the source of light. In this study, we examined search for targets defined by the orientation of luminance gradients and measured event-related brain potentials (ERPs). In Experiment 1, we examined search for stimuli that comprised gradual luminance differences.

Event-related brain potentials and cognitive processes related to perceptual-motor information transmission.

In the present study, event-related potentials (ERPs) were recorded to investigate cognitive processes related to the partial transmission of information from stimulus recognition to response preparation. Participants classified two-dimensional visual stimuli with dimensions size and form. One feature combination was designated as the go-target, whereas the other three feature combinations served as no-go distractors.

Psychometric characteristics and practice effects of the Brunswick Trail Making Test.

Three trail-making tasks were designed to yield measures of visuomotor speed, efficiency of visual search, and cognitive flexibility (attentional switching). Scores on paper-and-pencil trail-making performance tasks were analyzed in 54 neurologically nonimpaired participants (21 men, 33 women; M=40 yr., SD=15 yr.

Temporal dynamics of selective attention and conflict resolution during cross-dimensional Go-NoGo decisions.

Background: Decision-making is a fundamental capacity which is crucial to many higher-order psychological functions. We recorded event-related potentials (ERPs) during a visual target-identification task that required go-nogo choices. Targets were identified on the basis of cross-dimensional conjunctions of particular colors and forms.

Fractionating the neural mechanisms of cognitive control.

Modifications of the Wisconsin Card Sorting Test were established. In these new task variants, participants were asked to exert sequential control over attentional sets or over intentional sets (task domain factor). Attentional set shifting requires changing the priorities by which sensory stimuli are selected, whereas intentional set shifting requires changing the priorities by which motor responses are selected.

On the role of the cerebellum in exploiting temporal contingencies:; evidence from response times and preparatory EEG potentials in patients with cerebellar atrophy.

Patients with degenerative cerebellar disease were compared to healthy controls in their ability to adapt behaviour to temporal contingencies, both according to instructions and according to acquired experience. Participants had to press the cued key whenever the inside of a clock face changed its colour, which could occur when the pointer, rotating once every 4s, was at "10h" or at "12h" or at "2h". Probabilities varied between blocks at which of these three time points the colour change occurred, with participants being instructed accordingly.

Modulation of cerebellar activation by predictive and non-predictive sequential finger movements.

We investigated the modulation of cerebellar activation by predictive and non-predictive sequential finger movements. It is hypothesized that the prediction of desired movement sequences and adaptation to new movement parameters is mediated by the cerebellum. Using functional MRI at 1.