The effect of automatic priming of behaviour by linguistic cues is well established. However, as yet these effects have not been directly demonstrated for eye movement responses. We investigated the effect of linguistic cues on eye movements using a modified version of the Stroop task in which a saccade was made to the location of a peripheral colour patch which matched the “ink” colour of a centrally presented word cue. The words were either colour words (“red”, “green”, “blue”, “yellow”) or location words (“up”, “down”, “left”, “right”). As in the original version of the Stroop task the identity of the word could be either congruent or incongruent with the response location. The results showed that oculomotor programming was influenced by word identity, even though the written word provided no task relevant information. Saccade latency was increased on incongruent trials and an increased frequency of error saccades was observed in the direction congruent with the word identity. The results argue against traditional distinctions between reflexive and voluntary programming of saccades and suggest that linguistic cues can also influence eye movement programming in an automatic manner.
Oculomotor; Executive control; Response conflict; Automaticity; Language
Children and adolescents, family history positive (FH+) for alcoholism, exhibit differences in brain structure and functional activation when compared to family history negative (FH-) counterparts. Given that frontal brain regions, and associated reciprocal connections with limbic structures, undergo the most dramatic maturational changes during adolescence, the objective of this study was to compare functional brain activation during a frontally-mediated test of response inhibition in 32 adolescents separated into low-risk (FH-) and high-risk (FH+) groups.
Functional magnetic resonance (fMRI) blood oxygen level dependent (BOLD) data were acquired at 1.5 Tesla during performance of Stroop Color Naming, Word Reading and Interference. Preprocessing and statistical analyses, covaried for age, were conducted in SPM99 using a search territory that included superior, middle, and inferior frontal gyri (trigone region), anterior cingulate gyrus, and left and right amygdala.
Significantly greater activation in the fronto-limbic search territory was observed in FH+ relative to FH- subjects during Stroop Interference. In addition, a significant regression between brain activation and family history density was observed, with a greater density being associated with increased activation in regions including middle frontal gyrus (BA9) and cingulate gyrus (BA24).
These data demonstrate a significant influence of FH status on brain activation during the performance of a response inhibition task, perhaps reflecting a neurobiological vulnerability associated with FH status that may include reduced neuronal efficiency and/or recruitment of additional neuronal resources. These findings are important given that the adolescent developmental period is already associated with reduced inhibitory capacity, even prior to the onset of alcohol use.
frontal lobe; fMRI; FH; alcohol abuse; adolescence
The electrophysiological correlates of conflict processing and cognitive control have been well characterized for the visual modality in paradigms such as the Stroop task. Much less is known about corresponding processes in the auditory modality. Here, electroencephalographic recordings of brain activity were measured during an auditory Stroop task, using three different forms of behavioral response (Overt verbal, Covert verbal, and Manual), that closely paralleled our previous visual-Stroop study. As expected, behavioral responses were slower and less accurate for incongruent compared to congruent trials. Neurally, incongruent trials showed an enhanced fronto-central negative-polarity wave (Ninc), similar to the N450 in visual-Stroop tasks, with similar variations as a function of behavioral response mode, but peaking ~150 ms earlier, followed by an enhanced positive posterior wave. In addition, sequential behavioral and neural effects were observed that supported the conflict-monitoring and cognitive-adjustment hypothesis. Thus, while some aspects of the conflict detection processes, such as timing, may be modality-dependent, the general mechanisms would appear to be supramodal.
Auditory; Stroop; Conflict; EEG; Incongruency
Functional neuroimaging studies of ADHD have focused on the neural correlates of cognitive control. However, for many youths with ADHD, emotional lability is an important clinical feature of the disorder. We aimed to identify the neural substrates associated with emotional lability that were distinct from impairments in cognitive control and to assess the effects that stimulants have on those substrates. We used functional magnetic resonance imaging (fMRI) to assess neural activity in adolescents with (N=15) and without (N=15) ADHD while they performed cognitive and emotional versions of the Stroop task that engage cognitive control and emotional processing, respectively. The participants with ADHD were scanned both on and off stimulant medication in a counterbalanced fashion. Controlling for differences in cognitive control, we found that during the emotional Stroop task, adolescents with ADHD as compared with controls demonstrated atypical activity in the medial prefrontal cortex (mPFC). Stimulants attenuated activity in the mPFC to levels comparable with controls.
Stroop; Medial Prefrontal Cortex; Cognitive Control; Emotional Lability
The results for finding the deficit in the anterior cingulate (ACC) in schizophrenic patients (SZ) have been inconsistent according to the studies that used different Stroop tasks, which is unlike the deficit in the dorsolateral prefrontal cortex (DLPFC). In order to explore for the core region that's responsible for the selective attention deficit in SZ, we examined the results of a functional neuroimaging study, which involved the performance of the Stroop task using high or low prefrontal cortex related loads in SZ.
Ten schizophrenic patients and healthy controls (HC) received functional magnetic resonance imaging (fMRI) during a Short/Long-term latency Stroop task. The changes in the neural activity were determined in well-known Stroop related regions of interest (ROIs) that consisted of the DLPFC, ACC, the parietal lobule and in the whole brain regions for both the main and interaction effects of latency, and the results of the short-term and long-term latency Stroop conditions were compared.
The response times for both the congruency and latency effects were more prolonged in the schizophrenics than in the HC. For the congruency effect, the schizophrenics showed significantly less activation in the same site of the left DLPFC in both the short-term and long-term latency conditions, as compared with the HC. For the latency effect, the regions of the left-side language network were over- or under-activated in the schizophrenics, as compared with the HC. Any interaction effect was not found for both the behavioral and fMRI results.
Our results indicate that the deficit in the left DLPFC is the core impairment of attentional processing in schizophrenics, regardless of other possible interactions such as the latency effect.
Schizophrenia; Attention; Left dorsolateral prefrontal cortex; Magnetic resonance imaging
Methamphetamine (MA) abuse is associated with neurotoxicity to frontostriatal brain regions with concomitant deleterious effects on cognitive processes. Deficits in behavioral control are thought to be one contributing factor to the sustainment of addictive behaviors in chronic MA abuse.
In order to examine patterns of behavioral control relevant to addiction, we employed a fast-event related fMRI design to examine trial to trial reaction time (RT) adjustments in 12 chronic MA abusers who met DSM-IV criteria for MA dependence and 16 non-substance abusing controls. A variant of the Stroop task was employed to contrast the groups on error rates, RT Stroop conflict effect and the level of trial-to-trial adjustments seen after incongruent trials.
The MA abusers exhibited reduced RT adjustments along with reduced activation in the right prefrontal cortex compared to controls on conditions that measured the ability to use exposure to conflict situations (i.e., conflict trials) to regulate behavior. MA abusers did not differ from controls on accuracy rates or within-trial Stroop conflict effects.
The observed deficits in trial to trial RT adjustments suggest that the ability to adapt a behavioral response based on prior experience may be compromised in MA abusers. Such adjustments are critical to everyday functioning and deficits in modifying behavior based on prior events may reflect a key deficit that contributes to maladaptive drug seeking behavior.
Methamphetamine; prefrontal; attention; fMRI; imaging
The human brain executes cognitive control, such as selection of relevant information in the presence of competing irrelevant information, and cognitive control is essential for us to yield a series of optimal behaviors in our daily life. The present study assessed electrocorticographic gamma-oscillations elicited by cognitive control in the context of the Stroop color-naming paradigm, with a temporal resolution of 10 msec and spatial resolution of 1 cm. Subjects were instructed to overtly read a color word printed in an incongruent color in the reading task, and to overtly name the ink color of a color word printed in an incongruent color in the Stroop color-naming task. The latter task specifically elicited larger gamma-augmentations in the dorsolateral-premotor, dorsolateral-prefrontal and supplementary motor areas with considerable inter-subject spatial variability. Such Stroop color-naming-specific gamma-augmentations occurred approximately 500 to 200 msec prior to overt responses. Electrical stimulation of the sites showing Stroop color-naming-specific gamma-augmentations resulted in temporary naming impairment more frequently than that of the remaining sites. This study has provided direct evidence that a critical process of cognitive control in the context of Stroop color-naming paradigm consists of recruitment of neurons essential for naming located in variable portions of the dorsolateral premotor and prefrontal areas.
cognitive control; executive function; intracranial recording; local field potentials; in-vivo animation of event-related gamma-oscillations
Disturbances in selective attention represent a core characteristic of schizophrenia, whose neural underpinnings have yet to be fully elucidated. Consequently, we recorded brain activation using functional magnetic resonance imaging (fMRI) while 15 patients with schizophrenia and 15 age-matched controls performed a well-established measure of selective attention- color Stroop negative priming task. We focused on two aspects performance: overriding pre-potent responses (Stroop effect) and inhibition of prior negatively-primed trials (negative priming effect). Behaviorally, controls demonstrated both significant Stroop and negative priming effects, while schizophrenic subjects only showed the Stroop effect. For the Stroop effect, fMRI indicated significantly greater activation in frontal regions – medial frontal gyrus/anterior cingulate gyrus and middle frontal gyrus for controls, but greater activation in medial parietal regions (posterior cingulate gyrus/precuneus) for patients. Negative priming elicited significant activation in right dorsolateral prefrontal cortex for both groups, but also in left dorsolateral prefrontal cortex for patients. These different patterns of fMRI activation may reflect faulty interaction in schizophrenia within networks of brain regions that are vital to selective attention.
fMRI; color stroop; negative priming; schizophrenia
Adolescence is commonly characterized by impulsivity, poor decision-making, and lack of foresight. However, the developmental neural underpinnings of these characteristics are not well established.
To test the hypothesis that these adolescent behaviors are linked to under-developed proactive control mechanisms, the present study employed a hybrid block/event-related functional Magnetic Resonance Imaging (fMRI) Stroop paradigm combined with self-report questionnaires in a large sample of adolescents and adults, ranging in age from 14 to 25. Compared to adults, adolescents under-activated a set of brain regions implicated in proactive top-down control across task blocks comprised of difficult and easy trials. Moreover, the magnitude of lateral prefrontal activity in adolescents predicted self-report measures of impulse control, foresight, and resistance to peer pressure. Consistent with reactive compensatory mechanisms to reduced proactive control, older adolescents exhibited elevated transient activity in regions implicated in response-related interference resolution.
Collectively, these results suggest that maturation of cognitive control may be partly mediated by earlier development of neural systems supporting reactive control and delayed development of systems supporting proactive control. Importantly, the development of these mechanisms is associated with cognitive control in real-life behaviors.
Problems inhibiting non-adaptive behaviors have been linked to an increased risk for substance use and other risk taking behaviors in adolescence. This study examines the hypothesis that abnormalities in neural activation during inhibition in early adolescence may predict subsequent substance involvement.
Thirty eight adolescents from local area middle schools, ages 12–14, with very limited histories of substance use, underwent functional magnetic resonance imaging (fMRI) as they performed a go/no-go task of response inhibition and response selection. Adolescents and their parents were then followed annually with interviews covering substance use and other behaviors. Based on follow-up data, youth were classified as transitioning to heavy use of alcohol (TU; n=21), or as healthy controls (CON; n=17).
At baseline, prior to the onset of use, youth who later transitioned into heavy use of alcohol showed significantly less activation than those who went on to remain non to minimal users throughout adolescence. Activation reductions in TU at baseline were seen on no-go trials in 12 brain regions, including right inferior frontal gyrus, left dorsal and medial frontal areas, bilateral motor cortex, cingulate gyrus, left putamen, bilateral middle temporal gyri, and bilateral inferior parietal lobules (corrected p < .01, each cluster ≥ 32 contiguous voxels).
These results support the hypothesis that less neural activity during response inhibition demands predicts future involvement with problem behaviors such as alcohol and other substance use.
alcohol; adolescence; fMRI; inhibition; go/no-go
Cognitive behavioral and related therapies for cocaine dependence may exert their effects, in part, by enhancing cognitive control over drug use behavior. No prior studies have systematically examined the neural correlates of cognitive control as related to treatment outcomes for cocaine dependence.
Twenty treatment-seeking cocaine-dependent individuals performed a Stroop task while undergoing functional magnetic resonance imaging (fMRI) prior to initiating treatment. The primary outcome measures were percent of urine drug screens negative for cocaine, percent days abstinent, and treatment retention. Correlations between regional brain activation during Stroop task performance and treatment outcome measures were analyzed.
During Stroop performance, individuals activated brain regions similar to those reported in non-addicted individuals, including the anterior cingulate cortex, dorsolateral prefrontal cortex, parietal lobule, insula and striatum. Activations at treatment onset correlated differentially with specific outcomes: longer duration of self-reported abstinence correlated with activation of ventromedial prefrontal cortex, left posterior cingulate cortex, and right striatum, percent drug-free urine screens correlated with striatal activation, and treatment retention correlated with diminished activation of dorsolateral prefrontal cortex. A modest correlation between Stroop effect and treatment retention was found.
The functions of specific brain regions underlying cognitive control relate differentially to discrete outcomes for the treatment of cocaine dependence. These findings implicate neurocircuitry underlying cognitive control in behavioral treatment outcome and provide insight into the mechanisms of behavioral therapies for cocaine dependence. They also suggest neural activation patterns during cognitive control tasks are more sensitive predictors of treatment response than behavioral measures.
While it is commonly accepted that reward is an effective motivator of behavior, little is known about potential costs resulting from reward associations. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural underpinnings of such reward-related performance-disrupting effects in a reward-modulated Stroop task in humans. While reward associations in the task-relevant dimension (i.e., ink color) facilitated performance, behavioral detriments were found when the task-irrelevant dimension (i.e., word meaning) implicitly referred to reward-predictive ink colors. Neurally, only relevant reward associations invoked a typical reward-anticipation response in the nucleus accumbens (NAcc), which was in turn predictive of behavioral facilitation. In contrast, irrelevant reward associations increased activity in a medial prefrontal motor-control-related region, namely the pre-supplementary motor area (pre-SMA), which likely reflects the preemption and inhibition of automatic response tendencies that are amplified by irrelevant reward-related words. This view was further supported by a positive relationship between pre-SMA activity and pronounced response slowing in trials containing reward-related as compared to reward-unrelated incongruent words. Importantly, the distinct neural processes related to the beneficial and detrimental behavioral effects of reward associations appeared to arise from preferential-coding mechanisms in visual-processing areas that were shared by the two stimulus dimensions, suggesting a transfer of reward-related saliency to the irrelevant dimension, but with highly differential behavioral and neural ramifications. More generally, the data demonstrate that even entirely irrelevant reward associations can influence stimulus-processing and response-selection pathways relatively automatically, thereby representing an important flip-side of reward-driven performance enhancements.
reward; Stroop interference; fMRI; nucleus accumbens; pre-supplementary motor area; attention
Alcohol and marijuana are the most widely used intoxicants among adolescents, yet their potential unique and interactive influences on the developing brain are not well established. Brain regions subserving learning and memory undergo continued maturation during adolescence, and may be particularly susceptible to substance-related neurotoxic damage. Here, we characterize brain response during verbal learning among adolescent users of alcohol and marijuana.
Participants performed a verbal paired associates encoding task during fMRI scanning.
Adolescent subjects were recruited from local public schools and imaged at a University-based fMRI Center.
Participants were 74 16- to 18-year-olds, divided into four groups: (1) 22 controls with limited alcohol and marijuana experience, (2) 16 binge drinkers, (3) 8 marijuana users, and (4) 28 binge drinking marijuana users.
Diagnostic interview assured that all teens were free from neurologic or psychiatric disorders; urine toxicology and breathalyzer verified abstinence for 22–28 days before scanning; a verbal paired associates task was administered during fMRI.
Groups demonstrated no differences in performance on the verbal encoding task, yet exhibited different brain response patterns. A main effect of drinking pointed to decreased inferior frontal but increased dorsal frontal and parietal fMRI response among binge drinkers (corrected p < .05). There was no main effect of marijuana use. Binge drinking × marijuana interactions were found in bilateral frontal regions (corrected p < .05), where users of either alcohol or marijuana showed greater response than non-users, but users of both substances resembled non-users.
Adolescent substance users demonstrated altered fMRI response relative to nonusing controls, yet binge drinking appeared associated with more differences in activation than marijuana use. Alcohol and marijuana may have interactive effects that alter these differences, particularly in prefrontal brain regions.
adolescence; functional magnetic resonance imaging; verbal learning; cannabis; alcohol; binge drinking
Research studying attention and gait stability has suggested the process of recovering gait stability requires attentional resources, but the effect of performing a secondary task on stability during obstacle avoidance is poorly understood. Using a dual-task paradigm, the present experiment investigated the extent to which young adults are able to respond to a secondary auditory Stroop task (requiring executive attentional network resources) concurrently with obstacle crossing during gait as compared to performing unobstructed walking or sitting (control task). Our results demonstrated that as the level of difficulty in the postural task increased, there was a significant reduction in verbal response time from congruent to incongruent conditions in the Stroop task, but no differences in gait parameters, indicating that these postural tasks require attention, and that young adults use a strategy of modulating the auditory Stroop task performance while keeping stable gait performance under the dual-task situations. Our findings suggest the existence of a hierarchy of control within both postural task (obstacle avoidance requires the most information processing resources) and dual-task (with gait stability being a priority) conditions.
Adolescence is a period marked by changes in motivational and cognitive brain systems. However, the development of the interactions between reward and cognitive control processing are just beginning to be understood. Using event-related functional neuroimaging and an incentive modulated antisaccade task, we compared blood-oxygen level dependent activity underlying motivated response inhibition in children, adolescents, and adults. Behaviorally, children and adolescents performed significantly worse than adults during neutral trials. However, children and adolescents showed significant performance increases during reward trials. Adults showed no performance changes across conditions. fMRI results demonstrated that all groups recruited a similar circuitry to support task performance, including regions typically associated with rewards (striatum and orbital frontal cortex), and regions known to be involved in inhibitory control (putative frontal and supplementary eye fields, and posterior parietal cortex, and prefrontal loci). During rewarded trials adolescents showed increased activity in striatal regions, while adults demonstrated heightened activation in the OFC relative to children and adolescents. Children showed greater reliance on prefrontal executive regions that may be related to increased effort inhibiting responses. Overall, these results indicate that response inhibition is enhanced with reward contingencies over development. Adolescents’ heightened response in striatal regions may be one factor contributing to reward-biased decision making and perhaps risk taking behavior.
adolescence; reward; inhibitory control; antisaccade; fMRI
We used the Stroop task as a measure of the ability to inhibit a prepotent response tendency and examined its association with relative glucose metabolism in selected prefrontal brain regions in cocaine addicts, alcoholics, and controls (17 per group). Results revealed that for the substance abusers, higher orbitofrontal gyrus (OFG) activation was associated with lower conflict (higher score; r = 0.32, p < 0.05). For the controls, higher OFG activation was associated with higher conflict (lower score; r = 0.42, p < 0.05). Thus, at baseline, increased relative activation of the OFG is associated with worse performance in controls and better performance in substance abusers on the Stroop task, suggesting reversal of the role of the OFG as a function of addiction. NeuroReport 12:2595–2599
Alcohol; Anterior cingulate; Cocaine; Drug addiction; Orbitofrontal cortex; PET FDG; Stroop interference score
Here we report preliminary findings from a small-sample functional magnetic resonance imaging (fMRI) study of healthy adolescents who completed a working memory task in the context of a chronic sleep restriction experiment. Findings were consistent with those previously obtained on acutely sleep-deprived adults. Our data suggest that, when asked to maintain attention and burdened by chronic sleep restriction, the adolescent brain responds via compensatory mechanisms that accentuate the typical activation patterns of attention-relevant brain regions. Specifically, it appeared that regions that are normally active during an attention-demanding working memory task in the well-rested brain became even more active to maintain performance after chronic sleep restriction. In contrast, regions in which activity is normally suppressed during such a task in the well-rested brain showed even greater suppression to maintain performance after chronic sleep restriction. Although limited by the small sample, study results provide important evidence of feasibility, as well as guidance for future research into the functional neurological effects of chronic sleep restriction in general, the effects of sleep restriction in children and adolescents, and the neuroscience of attention and its disorders in children.
The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results often do not differentiate between general effects of sleep deprivation on performance and effects specifically on interference in the Stroop task. To examine the effect of prolonged wakefulness on performance on the Stroop task, we studied participants in a 40-hour “constant routine” protocol during which they remained awake in constant conditions and performed a Stroop color-naming task every two hours. We found that reaction time was slowest when the color and word did not match (incongruent), fastest when the color and word did match (congruent), and intermediate when participants named the color of the non-word stimulus (neutral). Performance on all three trial types degraded significantly as a function of time awake. Extended wakefulness did not significantly change the additional time needed respond when the color and word did not match (Stroop interference), nor did it change the amount of facilitation when color and word matched. These results indicate that one night of sleep deprivation influences performance on the Stroop task by an overall increase in response time, but does not appear to impact the underlying processes of interference or facilitation. The results suggest that the degree to which an “executive function” is affected by sleep deprivation may depend on the particular executive function studied and the degree to which it is subserved by the prefrontal cortex.
sleep deprivation; executive function; sleep loss; constant routine; performance
Attentional models of psychopathy hold that psychopathic individuals fail to process information that conflicts with goal-directed behavior. However, they display normal interference on color-word Stroop tasks. To determine whether psychopathic individuals’ attention deficits are specific to conditions associated with the anterior cingulate (ACC) conflict monitoring system, we administered a Stroop task with a mostly-congruent condition associated with ACC activation, and a mostly-incongruent condition that is not, to 128 criminal offenders assessed for psychopathy using Hare’s (2003) PCL-R. Despite replicating previous condition Effects associated with differential ACC activation (Carter et al., 2000), psychopathic offenders and controls performed very similarly in both conditions. Results do not support an association between ACC-related deficits in conflict monitoring and the attention deficits of psychopathic offenders.
Psychopathy; Conflict monitoring; Anterior cingulate cortex
Attentional control difficulties in individuals with attention-deficit/ hyperactivity disorder (ADHD) might reflect poor working memory (WM) ability, especially as WM ability and attentional control rely on similar brain regions. The current study examined whether WM ability might explain group differences in brain activation between adults with ADHD and normal controls during attentional demand.
Participants were 20 adults with ADHD combined subtype with no comorbid psychiatric or learning disorders, and 23 controls similar in age, IQ, and gender. WM measures were obtained from the WAIS-III and WMS-R. Brain activation was assessed with functional magnetic resonance imaging (fMRI) while performing a Color-Word Stroop task.
Group differences in WM ability explained a portion of the activation in left dorsolateral prefrontal cortex (DLPFC), which has been related to the creation and maintenance of an attentional set for task-relevant information. In addition, greater WM ability predicted increased activation of brain regions related to stimulus-driven attention and response selection processes in the ADHD group, but not in the control group.
The inability to maintain an appropriate task set in young adults with combined type ADHD, associated with decreased activity in left DLPFC, may in part be due to poor WM ability. Furthermore, in individuals with ADHD, higher WM ability may relate to increased recruitment of stimulus-driven attention and response selection processes, perhaps as a compensatory strategy.
attention-deficit/hyperactivity disorder; ADHD; working memory; attentional control; Stroop task; functional magnetic resonance imaging; fMRI; adults
The presence of peers increases risk taking among adolescents but not adults. We posited that the presence of peers may promote adolescent risk taking by sensitizing brain regions associated with the anticipation of potential rewards. Using fMRI, we measured brain activity in adolescents, young adults, and adults as they made decisions in a simulated driving task. Participants completed one task block while alone, and one block while their performance was observed by peers in an adjacent room. During peer observation blocks, adolescents selectively demonstrated greater activation in reward-related brain regions, including the ventral striatum and orbitofrontal cortex, and activity in these regions predicted subsequent risk taking. Brain areas associated with cognitive control were less strongly recruited by adolescents than adults, but activity in the cognitive control system did not vary with social context. Results suggest that the presence of peers increases adolescent risk taking by heightening sensitivity to the potential reward value of risky decisions.
Schizophrenia patients display impaired performance and brain activity during facial affect recognition. These impairments may reflect stimulus-driven perceptual decrements and evaluative processing abnormalities. We differentiated these two processes by contrasting responses to identical stimuli presented under different contexts. Seventeen healthy controls and 16 schizophrenia patients performed an fMRI facial affect detection task. Subjects identified an affective target presented amongst foils of differing emotions. We hypothesized that targeting affiliative emotions (happiness, sadness) would create a task demand context distinct from that generated when targeting threat emotions (anger, fear). We compared affiliative foil stimuli within a congruent affiliative context with identical stimuli presented in an incongruent threat context. Threat foils were analysed in the same manner. Controls activated right orbitofrontal cortex (OFC)/ventrolateral prefrontal cortex (VLPFC) more to affiliative foils in threat contexts than to identical stimuli within affiliative contexts. Patients displayed reduced OFC/VLPFC activation to all foils, and no activation modulation by context. This lack of context modulation coincided with a 2-fold decrement in foil detection efficiency. Task demands produce contextual effects during facial affective processing in regions activated during affect evaluation. In schizophrenia, reduced modulation of OFC/VLPFC by context coupled with reduced behavioural efficiency suggests impaired ventral prefrontal control mechanisms that optimize affective appraisal.
schizophrenia; social cognition; face; emotion; amygdala; ventrolateral prefrontal cortex (VLPFC); orbitofrontal cortex (OFC); fMRI
Negative affective style and depressive disorders share a common pattern of brain activation asymmetry in adults, characterized by reduced left relative to right prefrontal activation. It is not clear whether a similar pattern of asymmetry is related to depressive mood state during the period of adolescence, an important stage of emotional and brain development. We correlated Beck Depression Inventory (BDI) scores from 16 adolescents with prefrontal, anterior cingulate, and amygdala activity during functional magnetic resonance imaging (fMRI) of the Stroop Interference task. Depressed mood correlated positively with activity in the left dorsolateral prefrontal cortex (DLPFC) and anterior cingulate gyrus, and negatively with activity in the right DLPFC. When interpreted from a compensatory recruitment perspective, findings suggest that affective lateralization in adolescents is consistent with that seen in adulthood.
FMRI; Neuroimaging; Adolescence; Depression; Mood; Dorsolateral Prefrontal Cortex; Anterior Cingulate; Amygdala; Limbic System; Development
The color-word Stroop is a popular measure in psychological assessments. Evidence suggests that Stroop performance relies heavily on reading, an ability that improves over childhood. One way to influence reading proficiency is by orthographic manipulations. To determine the degree of interference posed by orthographic manipulations with development, in addition to standard color-Words (purple) we manipulated letter-positions: First/last letter in correct place (prulpe) and Scrambled (ulrpep). We tested children 7–16 years (n = 128) and adults (n = 23). Analyses showed that Word- and First/last-incongruent were qualitatively similar, whereas Word-congruent was different than other conditions. Results suggest that for children and adults, performance was hindered the most for incongruent and incorrectly spelled words and was most facilitated when words were congruent with the ink color and correctly spelled. Implications on visual word recognition and reading are discussed.
color-word Stroop; orthographic manipulation; children; interference; facilitation
A portion of Stroop interference is thought to arise from a failure to maintain goal-oriented behaviour (or goal neglect). The aim of the present study was to investigate whether goal- relevant primes could enhance goal maintenance and reduce the Stroop interference effect. Here it is shown that primes related to the goal of responding quickly in the Stroop task (e.g. fast, quick, hurry) substantially reduced Stroop interference by reducing reaction times to incongruent trials but increasing reaction times to congruent and neutral trials. No effects of the primes were observed on errors. The effects on incongruent, congruent and neutral trials are explained in terms of the influence of the primes on goal maintenance. The results show that goal priming can facilitate goal-oriented behaviour and indicate that automatic processing can modulate executive control.