An Inside Job: Applications of Intracellular Single Domain Antibodies.

Sera of camelid species contain a special kind of antibody that consists only of heavy chains. The variable antigen binding domain of these heavy chain antibodies can be expressed as a separate entity, called a single domain antibody that is characterized by its small size, high solubility and oftentimes exceptional stability. Because of this, most single domain antibodies fold correctly when expressed in the reducing environment of the cytoplasm, and thereby retain their antigen binding specificity.

How Do Children Deal With Conflict? A Developmental Study of Sequential Conflict Modulation.

This study examined age-related differences in sequential conflict modulation (SCM), elicited in three tasks requiring the inhibition of pre-potent responses; a Simon task, an S-R compatibility (SRC) task and a hybrid Choice-reaction/NoGo task. The primary focus was on age-related changes in performance changes following a conflict trial. A secondary aim was to assess whether SCM follows different developmental trajectories depending on the type of conflict elicited by the tasks.

What happens when children encounter an error?

The current study presents the results of two experiments designed to assess developmental change in post-error slowing (PES) across an age range extending from 5 to 25 years. Both experiments employed two-choice tasks and manipulated response-to-stimulus intervals (RSIs). The results showed that PES decreased with advancing age; a disproportional developmental trend was observed in experiment 2 while the age-related change in PES in experiment 1 was similar to the developmental decrease in basic response speed.

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.

Influence of methylphenidate treatment assumptions on cognitive function in healthy young adults in a double-blind, placebo-controlled trial.

Background: Increasing numbers of students use stimulants such as methylphenidate (MPH) to improve their study capacity, making them prone to subsequent prolonged drug abuse. This study explored the cognitive effects of MPH in students who either assumed they received MPH or assumed they received a placebo.

Methods: In a double-blind, randomized, placebo-controlled trial with a between-subjects design, 21 students were subjected to partial sleep deprivation, receiving no more than 4 hours sleep the night before they were tested.

Short- and long-term effects of conscious, minimally conscious and unconscious brand logos.

Unconsciously presented information can influence our behavior in an experimental context. However, whether these effects can be translated to a daily life context, such as advertising, is strongly debated. What hampers this translation is the widely accepted notion of the short-livedness of unconscious representations.

Cardiac reactivity and preserved performance under stress: two sides of the same coin?

In the present experiment, cognitive control under stress was investigated using a real-life paradigm, namely an evaluation flight for military student pilots. The magnitude of cognitive interference on color-word, numerical and emotional Stroop paradigms was studied during a baseline recording and right before the test flight. Cardio-respiratory parameters were simultaneously assessed during rest and the performance of the Stroop tasks.

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.

Cognitive aspects of freezing of gait in Parkinson's disease: a challenge for rehabilitation.

Freezing of gait (FOG) is a very disabling symptom affecting up to half of the patients with Parkinson's disease (PD). Evidence is accumulating that FOG is caused by a complex interplay between motor, cognitive and affective factors, rather than being a pure motor phenomenon. In the current paper, we review the evidence on the specific role of cognitive factors in FOG.

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.

Conscious, but not unconscious, logo priming of brands and related words.

This study assessed whether real-life stimulus material can elicit conscious and unconscious priming. A typical masked priming paradigm was used, with brand logo primes. We used a rigorous method to assess participants' awareness of the subliminal information.

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).

Conflict and freezing of gait in Parkinson's disease: support for a response control deficit.

We investigated response activation and suppression processes in Parkinson's disease patients with freezing of gait (FOG). Fourteen freezers, 14 nonfreezers, and 14 matched healthy controls performed the attention network task (ANT) and the Stroop task. The former task has more stimulus-response overlap and is expected to elicit stronger irrelevant response activation, requiring more inhibition.

The involvement of bottom-up saliency processing in endogenous inhibition of return.

Participants are faster at detecting a visual target when it appears at a cued, as compared with an uncued, location. In general, a reversal of this cost-benefit pattern is observed after exogenous cuing when the cue-target interval exceeds approximately 250 ms (inhibition of return [IOR]), and not after endogenous cuing. We suggest that, usually, no IOR is found with endogenous cues because no bottom-up saliency-based orienting processes are claimed.

On the automaticity of pure perceptual sequence learning.

We investigated the automaticity of implicit sequence learning by varying perceptual load in a pure perceptual sequence learning paradigm. Participants responded to the randomly changing identity of a target, while the irrelevant target location was structured. In Experiment 1, the target was presented under low or high perceptual load during training, whereas testing occurred without load.

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.

Testing the attention shift hypothesis as an account for the flanker sequence-based congruency modulation in spatial flanker tasks.

Smaller Simon effects when stimulus locations are repeated on successive trials rather than alternated have been explained by the attention shift hypothesis, suggesting that shifts of attention result in interfering response codes. We investigated whether the attention shift hypothesis can also explain smaller flanker effects for repeated flankers than for alternated flankers, which occur only with directional information. In 3 peripheral letter identification tasks, target locations were cued by partial or complete flanker stimuli.

Verbal memory improved by D-amphetamine: influence of the testing effect.

Objective: The improvement of long-term retention of verbal memory after an acute administration of D-amphetamine in recall and recognition tasks has been ascribed to an influence of the drug on memory consolidation. Because recent research has demonstrated that intermediate testing is of overriding importance for retention, we investigated whether D-amphetamine modulates the repeated testing effect in verbal long-term recognition.

Method: Forty men participated in two double blind placebo controlled studies.

Effect of an acute d-amphetamine administration on context information memory in healthy volunteers: evidence from a source memory task.

Rationale: Previous research demonstrated a positive effect of d-amphetamine on long-term verbal memory. An improvement in memory for contextual information is proposed as a possible mechanism underlying the d-amphetamine facilitation effect.

Objectives: A double blind, placebo controlled experiment was used to examine the processes involved in episodic memory affected by an acute administration of d-amphetamine.

Congruency reversals in an accessory signal Simon task with auditory and visual stimuli.

In visual two-choice reaction-time tasks, a Simon-like effect occurs when a peripheral accessory signal is presented shortly before or together with the response signal. However, the effect reverses when the peripheral signal appears shortly after the response signal. This pattern also occurs when the peripheral signal appears relative to a go (nogo) signal, with the relevant signal presented well in advance.

Practice-induced and sequential modulations of the Simon effect.

People react more quickly and more accurately to stimuli presented in locations corresponding to the response, as compared with noncorresponding locations, even when stimulus location is irrelevant (Simon effect [SE]). The explanation that SEs are caused by the automatic priming of a corresponding response has been questioned, because of the many exceptions to the effect. We replicated practice-induced and sequential modulations of the SE in two experiments--first, by training participants with blocks of location-relevant stimuli, and second, by mixing location-relevant and location-irrelevant trials.

Intact first- and second-order implicit sequence learning in secondary-school-aged children with developmental dyslexia.

We examined the influence of task complexity on implicit sequence learning in secondary-school-aged children with developmental dyslexia (DD). This was done to determine whether automatization problems in reading extend to the automatization of all skill and depend on the complexity of the to-be-learned skill. A total of 28 dyslexic children between 12 and 15 years and 28 matched control children carried out two serial reaction time tasks using a first-order conditional (FOC) and second-order conditional (SOC) sequence.

Feature integration and spatial attention: common processes for endogenous and exogenous orienting.

Briand (J Exp Psychol Hum Percept Perform 24:1243-1256, 1998) and Briand and Klein (J Exp Psychol Hum Percept Perform 13:228-241, 1987) demonstrated that spatial cueing effects are larger for detecting conjunction of features than for detecting simple features when spatial attention is oriented exogenously, and not when attention is oriented endogenously. Their results were interpreted as if only exogenous attention affects the posterior spatial attention system that performs the feature binding function attributed to spatial attention by Treisman's feature integration theory (FIT; 1980). In a series of 6 experiments, we attempted to replicate Briand's findings.