Does consolidation of visuospatial sequence knowledge depend on eye movements?

In the current study, we assessed whether visuospatial sequence knowledge is retained over 24 hours and whether this retention is dependent on the occurrence of eye movements. Participants performed two sessions of a serial reaction time (SRT) task in which they had to manually react to the identity of a target letter pair presented in one of four locations around a fixation cross. When the letter pair 'XO' was presented, a left response had to be given, when the letter pair 'OX' was presented, a right response was required.

The effect of attentional load on implicit sequence learning in children and young adults.

We investigated the effect of a secondary task on implicit sequence learning in children and young adults. A serial reaction time (SRT) task was administered to 8-to-10 year old children and 18-to-22 year old adults. Participants reacted to the location of a target presented in one of four locations on the screen with a spatially corresponding response key.

The effect of cognitive aging on implicit sequence learning and dual tasking.

We investigated the influence of attentional demands on sequence-specific learning by means of the serial reaction time task (Nissen and Bullemer, 1987) in young (age 18-25) and aged (age 55-75) adults. Participants had to respond as fast as possible to a stimulus presented in one of four horizontal locations by pressing a key corresponding to the spatial position of the stimulus. During the training phase sequential blocks were accompanied by (1) no secondary task (single), (2) a secondary tone counting task (dual tone), or (3) a secondary shape counting task (dual shape).

Head-pelvis coupling is increased during turning in patients with Parkinson's disease and freezing of gait.

Turning is the most important trigger for freezing of gait (FOG). The aim of this study was to investigate the relationship between impaired head-pelvis rotation during turning and FOG. Head, trunk, and pelvic rotation were measured at onset and throughout a 180-degree turn in 13 freezers and 14 nonfreezers (OFF medication).

Impaired implicit sequence learning in Parkinson's disease patients with freezing of gait.

Objective: Freezing of gait (FOG) in Parkinson's disease (PD) may involve specific impairments in acquiring automaticity under working memory load. This study examined whether implicit sequence learning, with or without a secondary task, is impaired in patients with FOG.

Method: Fourteen freezers (FRs), 14 nonfreezers (nFRs), and 14 matched healthy controls (HCs) performed a serial reaction time (SRT) task with a deterministic stimulus sequence under single-task (ST) and dual-task (DT) conditions.

Freezing of gait in Parkinson's disease: disturbances in automaticity and control.

Recent studies emphasize a key role of controlled operations, such as set-shifting and inhibition, in the occurrence of freezing of gait (FOG) in Parkinson's disease (PD). However, FOG can also be characterized as a de-automatization disorder, showing impairments in both the execution and acquisition of automaticity. The observed deficits in automaticity and executive functioning indicate that both processes are malfunctioning in freezers.

Explaining freezing of gait in Parkinson's disease: motor and cognitive determinants.

Freezing of gait (FOG) is part of a complex clinical picture in Parkinson's disease (PD) and is largely refractory to standard care. Diverging hypotheses exist about its origins, but a consolidated view on what determines FOG is lacking. The aim of this study was to develop an integrative model of FOG in people with PD.

Visuospatial perceptual sequence learning and eye movements.

We examined perceptual sequence learning by means of an adapted serial reaction time task in which eye movements were unnecessary for performing the sequence learning task. Participants had to respond to the identity of a target letter pair ("OX" or "XO") appearing in one of four locations. On the other locations, similar distractor letter pairs ("QY" or "YQ") were shown.

Cognitive control: a role for implicit learning?

We investigated the influence of implicit learning on cognitive control. In a sequential Stroop task, participants implicitly learned a sequence placed on the color of the Stroop words. In Experiment 1, Stroop conflict was lower in sequenced than in random trials (learning-improved control).

Abnormalities and cue dependence of rhythmical upper-limb movements in Parkinson patients with freezing of gait.

Background: Freezing of gait (FOG) is a significant clinical problem in Parkinson disease (PD). Similar freezing-like episodes occur during finger movements, but little is known about ongoing motor problems during repetitive hand movements.

Objective: To investigate if the regulation of bimanual movements is impaired in those with FOG and if withdrawal of an auditory cue amplifies this problem.

Freezing in Parkinson's disease: a spatiotemporal motor disorder beyond gait.

Freezing of gait (FOG) is an incapacitating problem in Parkinson's disease that is difficult to manage therapeutically. We tested the hypothesis that impaired rhythm and amplitude control is a common mechanism of freezing which is also present during other rhythmic tasks. Therefore, we compared the occurrence and spatiotemporal profiles of freezing episodes during upper limb motion, lower limb motion, and FOG.

Freezing of gait in Parkinson disease is associated with impaired conflict resolution.

Background: Freezing of gait (FOG) in Parkinson disease (PD) may involve executive dysfunction. This study examined whether executive functioning and attention are more affected in patients with FOG compared with those without and determined whether these processes are influenced by anti-Parkinson medication.

Methods: A total of 11 PD patients with FOG, 11 without FOG, and 10 healthy control subjects, matched for age, gender, and education, participated.

Target-flanker discriminability affects conflict size but not sustained suppression.

On successive trials, repetitions of irrelevant information often tend to reduce congruency effects as compared to alternations of irrelevant information. The preferred explanation for this congruency modulation is the sustained-suppression hypothesis, suggesting that suppression of the irrelevant information on a given trial perseveres into the subsequent trial. However, in contrast to the generality of this idea, this modulation is only stable when the irrelevant information contains spatial features, which coincided in the existing research with large conflict sizes and response conflicts.

Does implicit learning in non-demented Parkinson's disease depend on the level of cognitive functioning?

We investigated the influence of the level of cognitive functioning on sequence-specific learning in Parkinson's disease (PD). This was done by examining the relationship between the scales for outcomes in Parkinson's disease-cognition [SCOPA-COG, Marinus, J., Visser, M.