Observing ageism implicitly using the numerical parity judgment task.

Objective magnitude representations may be prone to subjective percepts when judging human beings. An elderly man is clearly "large" in terms of age. But, is he truly perceived as "big" in our minds? We investigated whether "objective" representation of age interacts with subjective stereotypical percepts of aging, using a numeral classification task preceded by prime images containing human figures. First, prime images of children and young adults demonstrated a positive correlation between perceived age and numerical size. Second, negatively and positively valenced prime images were associated with small and big numerical values, respectively. Third, joint effects of age and valence on numerical value perception revealed a linkage between old adults and small numerical values. It seems that magnitude perception is vulnerable to implicit subjective biases and stereotypical judgments dominate objective magnitude representation.

Right anterior cerebellum BOLD responses reflect age related changes in Simon task sequential effects.

Participants are slower to report a feature, such as color, when the target appears on the side opposite the instructed response, than when the target appears on the same side. This finding suggests that target location, even when task-irrelevant, interferes with response selection. This effect is magnified in older adults. Lengthening the inter-trial interval, however, suffices to normalize the congruency effect in older adults, by re-establishing young-like sequential effects (Aisenberg et al., 2014). We examined the neurological correlates of age related changes by comparing BOLD signals in young and old participants performing a visual version of the Simon task. Participants reported the color of a peripheral target, by a left or right-hand keypress. Generally, BOLD responses were greater following incongruent than congruent targets. Also, they were delayed and of smaller amplitude in old than young participants. BOLD responses in visual and motor regions were also affected by the congruency of the previous target, suggesting that sequential effects may reflect remapping of stimulus location onto the hand used to make a response. Crucially, young participants showed larger BOLD responses in right anterior cerebellum to incongruent targets, when the previous target was congruent, but smaller BOLD responses to incongruent targets when the previous target was incongruent. Old participants, however, showed larger BOLD responses to congruent than incongruent targets, irrespective of the previous target congruency. We conclude that aging may interfere with the trial by trial updating of the mapping between the task-irrelevant target location and response, which takes place during the inter-trial interval in the cerebellum and underlays sequential effects in a Simon task.

Lateralisation of emotions: evidence from pupil size measurement.

The way our brain processes emotional stimuli has been studied intensively. One of the main issues still under debate is the laterality of valence processing. Herein, we employed the fact that pupil size increases under conditions of higher mental effort and during emotional processing, in order to contrast three proposed hypotheses in the field. We used different manual response mapping for emotional stimuli: Participants responded with their right hand for positive and with their left hand for negative facial expressions, or vice versa. The hands position was either regular (Experiment 1) or crossed (Experiment 2) in order to rule out a "spatial-valence association" alternate explanation. A third experiment was conducted by employing a passive viewing procedure of peripheral emotional stimuli. In the first two experiments, pupil size was larger when participants responded to positive stimuli with their left hand and to negative with their right hand, compared with the opposite mapping. Results of Experiment 3 strengthen the findings of Experiments 1 and 2. These findings provide significant psychophysiological evidence for the valence hypothesis: Processing positive stimuli involves the left hemisphere, while processing negative stimuli involves the right hemisphere. These results are discussed in relation to contemporary theories of emotion processing.

Attentional bias in clinical depression and anxiety: The impact of emotional and non-emotional distracting information.

Both anxiety and major depression disorder (MDD) were reported to involve a maladaptive selective attention mechanism, associated with bias toward negative stimuli. Previous studies investigated attentional bias using distractors that required processing as part of task settings, and therefore, in our view, these distractors should be regarded as task-relevant. Here, we applied a unique task that used peripheral distractors that presented emotional and spatial information simultaneously. Notably, the emotional information was not associated in any way to the task, and thus was task-irrelevant. The spatial information, however, was task-relevant as it corresponded with task instructions. Corroborating previous findings, anxious patients showed attentional bias toward negative information. MDD patients showed no indication of this bias. Spatial information influenced all groups similarly. These results indicate that anxiety, but not MDD, is associated with an inherent negative information bias, further illustrating that the two closely related disorders are characterized by different processing patterns.

Using executive control training to suppress amygdala reactivity to aversive information.

The ability to regulate emotions is essential for adaptive behavior. This ability is suggested to be mediated by the connectivity between prefrontal brain regions and the amygdala. Yet, it is still unknown whether the ability to regulate emotions can be trained by using a non-emotional procedure, such as the recruitment of executive control (EC). Participants who were trained using a high-frequent executive control (EC) task (80% incongruent trials) showed reduced amygdala reactivity and behavioral interference of aversive pictures. These effects were observed only following multiple-session training and not following one training session. In addition, they were not observed for participants exposed to low-frequent EC training (20% incongruent trials). Resting-state functional connectivity analysis revealed a marginally significant interaction between training group and change in the connectivity between the amygdala and the right inferior frontal gyrus (IFG). Amygdala-IFG connectivity was significantly increased following the training only in the high-frequent EC training group. These findings are the first to show that non-emotional training can induce changes in amygdala reactivity to aversive information and alter amygdala-prefrontal connectivity.

Long trial durations normalise the interference effect and sequential updating during healthy aging.

We examined the effect of a task-irrelevant dimension on response times in young adults and seniors. We used the Simon task with congruent trials where the target and manual response were on the same side, incongruent trials where the target and response were on opposite sides, and neutral trials where the target appeared along the vertical meridian. We observed two age-related effects. First, there was a larger congruency effect in senior participants that was driven by greater interference; namely, their responses were slower on incongruent relative to neutral trials. Second, there was a Gratton effect; namely, a diminished Simon effect was found in young adults but not in seniors when the preceding trial was incongruent. However, these effects of aging were normalised when the inter-trial interval was increased; the Simon effect and interference were reduced and a Gratton effect appeared for seniors. We conclude that aging may impair the ability to quickly adapt to changing environmental circumstances when they require reformulating current behavioral strategies.

Spatial processing in adults with attention deficit hyperactivity disorder.

BACKGROUND: "Global processing bias" is an automatic tendency to process the global picture prior to the local details. The right hemisphere is known to be more dominant in global processing, and some researchers have demonstrated its important role in alertness. Converging evidence implies some dysfunction in right hemisphere activation in people suffering from attention deficit hyperactivity disorder (ADHD). Global processing is yet to be understood in ADHD. OBJECTIVE: We examined whether adults with ADHD show deficient global processing and whether this could be alleviated by the presence of an alerting signal. METHOD: Adult participants (20 ADHD, 20 typically developing controls) responded to a global-local Navon task in which they were asked to respond to the large stimulus or the small component stimuli, and to a Navon-like task with an alerting cue. Reaction time and accuracy were measured. RESULTS: Unlike controls, adults with ADHD did not have global precedence; irrelevant global stimuli (when asked to respond to the local level) and irrelevant local stimuli (when asked to respond to the global level) produced similar interference in ADHD participants. Appearance of an alerting cue increased global processing bias (i.e., increased interference from global stimuli in the local block and reduced interference from local stimuli in the global block) for both groups, such that global processing in ADHD participants was comparable to that of controls. CONCLUSION: ADHD participants showed lack of a global processing bias. Most important, global processing bias was reinstated by an alerting cue. Implications for the definition of ADHD, which currently emphasizes failure to pay close attention to details, will be discussed. Moreover, the current results have important implications for social functioning of people suffering from ADHD.

Individual but not fragile: individual differences in task control predict Stroop facilitation.

The Stroop effect is composed of interference and facilitation effects. The facilitation is less stable and thus many times is referred to as a "fragile effect". Here we suggest the facilitation effect is highly vulnerable to individual differences in control over the task conflict (between relevant color naming and irrelevant word reading in the Stroop task). We replicated previous findings of a significant correlation between stop-signal reaction time (SSRT) and Stroop interference, and also found a significant correlation between SSRT and the Stroop facilitation effect-participants with low inhibitory control (i.e., long SSRT) had no facilitation effect or even a reversed one. These results shed new light on the "fragile" facilitation effect and highlight the necessity of awareness of task conflict, especially in the Stroop task.

Did I turn off the stove? Good inhibitory control can protect from influences of repeated checking.

BACKGROUND AND OBJECTIVES: Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by compulsions aimed at reducing anxiety associated with intrusive cognitions. However, compulsive behaviors such as repeated checking were found to increase rather than decrease uncertainty related to obsessive thoughts (e.g., whether the gas stove was turned off). Some recent studies illustrate that OCD patients and their family members have inhibitory deficits, often demonstrated by the stop-signal task. The current study aims to investigate relations between inhibitory control and effects of repeated checking. METHODS: Fifty-five healthy participants carried out a stop-signal task followed by a repeated-checking task. Additionally, participants were asked to complete self-report questionnaires measuring OCD, anxiety and depression symptoms. RESULTS: Confirming our hypothesis, participants with poor inhibitory capabilities demonstrated greater uncertainty and memory distrust as a consequence of repeated checking than participants with good inhibitory control. LIMITATIONS: Our findings concern an initial investigation on a sample of healthy participants and should be replicated and extended to clinical populations. CONCLUSIONS: These results suggest that deficits in inhibitory control may underlie cognitive vulnerability in OCD. An updated model integrating neuropsychological findings with current OCD models is suggested.

Is it for real? Evaluating authenticity of musical pitch-space synesthesia.

In spatial-sequence synesthesia, ordinal sequences are visualized in explicit spatial locations. We examined a recently documented subtype in which musical notes are represented in spatial configurations, to verify consistency and automaticity of musical pitch-space (M-S) synesthesia. An M-S synesthete performed a mapping pre-task (Exp. 1) used to indicate the locations of 7 auditory or visually presented notes, in 2 sessions a month apart. Results revealed strong correlations between sessions, suggesting the synesthete's musical forms were consistent over time. Experiment 2 assessed automaticity of M-S synesthesia. The same synesthete and matched controls preformed a spatial Stroop-like task. Participants were presented with an auditory or visual musical note and then had to reach for an asterisk (target) with a mouse cursor. The target appeared in a compatible or incompatible location (according to the synesthete's spatial representation). A compatibility effect was found for the synesthete but not for controls. The synesthete was significantly faster when the target appeared in compatible locations than in incompatible ones. Our findings show that for synesthetes, auditory and visually presented notes automatically trigger attention to specific spatial locations according to their specific M-S associations.

When a line is a number: color yields magnitude information in a digit-color synesthete.

The phenomenon of synesthesia has received a great deal of interest recently in the scientific literature. Many previous studies stressed the unidirectional nature of this phenomenon. For example, color-grapheme synesthetes automatically perceive achromatic numbers as colored (e.g. 7 is turquoise). Conversely, colors do not automatically give rise to any sort of number experience (e.g. turquoise is 7). In contrast to the common view, we report on a digit-color synesthete in whom colors can evoke numerical representations in the absence of any digit presentation. It is concluded that in synesthesia there is a reciprocal rather than unidirectional flow of information between dimensions.

Attentional asymmetry in schizophrenia: disengagement and inhibition of return deficits.

This research examined 2 components of visual orienting in medicated schizophrenia patients: the validity effect and the inhibition of return (IOR). In the 1st experiment, patients showed the expected asymmetry in orienting attention, that is, larger validity effect in the right visual field than in the left. However, this asymmetry was due to a deficit in facilitatory processes rather than a disengagement deficit. In addition, patients showed a deficit in IOR. In the 2nd experiment, a 2nd central cue for summoning attention, explicitly, back to the center was used. In this experiment, normal IOR in schizophrenia patients was found. Because it was shown that schizophrenia patients do not have a disengagement deficit, IOR possibly could not be observed because of the increased facilitation in that location. It was proposed that the abnormality in visual attention in schizophrenia is due to a deficit in inhibitory processes.

Interpreting Stroop interference: an analysis of differences between task versions.

The present study investigated methodological differences between the clinical version of the Stroop Color and Word Test and the computerized single-trial version. Three experiments show that different presentations of the Stroop task can produce different levels of interference. The 1st experiment examined the effect of blocking; the 2nd experiment examined different control conditions. Greater interference in the blocked clinical version appears to result from lower response times (RTs) in the neutral condition, not from greater RTs in the incongruent condition. Experiment 3 examined the impact of shifting attention across locations while responding to Stroop stimuli. The present set of findings sheds light on the inconsistency in the clinical literature and demonstrates that the method and selection of neutral stimuli (that provide the baseline by which interference is measured) are critical because they clearly can change performance.

The endogenous modulation of IOR is nasal-temporal asymmetric.

Inhibition of return (IOR) refers to a reflexive mechanism mediated by phylogenetically primitive extrageniculate visuomotor pathways, which apparently serves to favor novel spatial locations by inhibiting those recently sampled. We demonstrate an asymmetry between temporal and nasal hemifields in the strategic modulation of IOR by endogenously controlled attention. Exogenous and endogenous precues were manipulated independently on each trial such that precues to initiate endogenous spatial orienting were presented after IOR had been activated by exogenous visual signals. Both types of precues manifested their characteristic effects on reaction time (RT) to detect subsequent targets: facilitation by endogenous precues, and IOR by exogenous precues. Under monocular viewing, an asymmetric interaction between these two mechanisms was observed. While endogenous allocation of attention to the nasal hemifield reduced IOR, no endogenous modulation of IOR was present in the temporal hemifield where the effects of the two types of precues were independent. These observations suggest a framework for understanding the neurobiology of automaticity and control - from an evolutionary perspective.

Task set switching in schizophrenia.

The authors used a task-switching paradigm to investigate set shifting ability in schizophrenia. This paradigm included 2 choice reaction time (RT) tasks: up-down and right-left. Switching tasks were associated with costs (i.e., longer RT in task-switch trials than in task-repetition trials); patients responded more slowly than controls and suffered greater switching costs, were as efficient as controls in engaging in an upcoming task set, and were faster than controls in disengaging from the previous task set. There were indications that patients quickly forgot what each keypress indicated, making it necessary for them to acquire response meaning information anew in each trial. To test this notion, the authors subsequently tested normal participants in conditions in which response meaning information needed to be acquired anew in each trial. These participants produced a pattern of switching costs resembling that of patients. Results suggest that set switching difficulties in schizophrenia, as exhibited in the present paradigm, reflect poor memory for task context information.

Stroop effect in words that differ from color words in one letter only.

In two experiments, participants named the color of a colored word, which was a Hebrew color word or a word in Hebrew that was different from a color word in one letter only. The magnitude of the Stroop effect increased with the location of the changed letter. It was smallest when the first letter of the color word was replaced, resulting in a noncolor word, and it was largest when the last letter was replaced. These results challenge the assumption that automatic reading, as indicated by the Stroop effect, can be explained exclusively by memory retrieval accounts of automaticity. The results also have implications for the sources of facilitation and inhibition in the Stroop effect.

Interactions between color and word processing in a flanker task.

To examine interactions between color and word attributes, participants responded, either manually or vocally, to a central target (color patch or word) flanked by a Stroop stimulus. Color and word attributes of the flanker affected both vocal and manual responding to color patches. Color and word flankers also affected manual responding to word targets, but only word flanker affected vocal responding to word targets. These results are not consistent with models (e.g., translational models) of Stroop tasks, which posit that interactions between colors and words occur only when vocal responding is required.

Automaticity and consciousness: is perceiving the word necessary for reading it?

Definitions of automaticity imply insensitivity of the Stroop effect to conscious perceiving of the word. Subjects in the Stroop task reported the meaning of the stimulus word (in addition to its color) in 7% of the trials. The magnitude of the Stroop effect in these trials was correlated with subjects' ability to report the stimulus meaning. Furthermore, the effect was absent when subjects failed to report the stimulus meaning. These findings challenge the assumption that automatic processing is unconscious. A distinction between automatic and non-automatic processing in terms of modes of consciousness is discussed.

Transcranial magnetic stimulation of the prefrontal cortex delays contralateral endogenous saccades.

The contributions of the superior prefrontal cortex (SPFC) and the superior parietal lobule (SPL) in generating voluntary endogenous and reflexive visually guided saccades were investigated using transcranial magnetic stimulation (TMS). Subjects made choice saccades to the left or right visual field in response to a central arrowhead (endogenous go signal) or a peripheral asterisk (exogenous go signal) that were presented along with a single TMS pulse at varying temporal intervals. TMS over the SPFC increased latencies for saccades made in response to an endogenous go signal toward the contralateral hemifield. No effects were observed when the go signal was exogenous and TMS was over the SPFC or when TMS was over the SPL for either saccade type. The delayed contralateral endogenous saccades observed in this study are likely a consequence of disruption in the normal operations of the human frontal eye field.