Presentation modality influences behavioral measures of alerting, orienting, and executive control

The Attention Network Test (ANT) uses visual stimuli to separately assess the attentional skills of alerting (improved performance following a warning cue), spatial orienting (an additional benefit when the warning cue also cues target location), and executive control (impaired performance when a target stimulus contains conflicting information). This study contrasted performance on auditory and visual versions of the ANT to determine whether the measures it obtains are influenced by presentation modality. Forty healthy volunteers completed both auditory and visual tests. Reaction-time measures of executive control were of a similar magnitude and significantly correlated, suggesting that executive control might be a supramodal resource. Measures of alerting were also comparable across tasks. In contrast, spatial-orienting benefits were obtained only in the visual task. Auditory spatial cues did not improve response times to auditory targets presented at the cued location. The different spatial-orienting measures could reflect either separate orienting resources for each perceptual modality, or an interaction between a supramodal orienting resource and modality-specific perceptual processing

The implosion of reality: schizophrenia, the anterior cingular cortex and anticipation

In contemporary neuroscientific and psychiatric research into schizophrenia, we can observe a shift in focus from the clinical dysfunctions (positive and negative symptoms) towards a mapping of the cognitive function. In this paper we look at a specific cognitive problem area in schizophrenic brain functioning, the Anterior Cingulate Cortex (ACC). We show what the ACC is, what it probably does and how this is relevant in research concerning certain psychiatric disorders. Then we explain the role of the ACC in choice anticipation. In this we underline the possible link between choice anticipation and the lack of ‘Error Related Negativity’ (ERN) in this specific area. Lastly we incorporate this approach to the problem of schizophrenic anticipation within the neuropsychoanalytical framework and the role it might play in the formation of hallucinations and delusion

Risky decision-making and the intensity of opioid drug dependency in early phase of methadone maintenance protocol

Several studies show positive effect of MMT on decision-making in substance dependents, but severity of the disorder has been ignored by most of them. This study used Iowa Gambling Task(IGT) to find correlation between severity of the disorders in early phase of MMT and risky decision-making in three groups of subjects (mild, sever, control). The study shows no significant difference among groups in risky decision-making, which might be related to the effect of opioid on cognitive functions independent of the severity of the disorder, and stabilization in MMT can repair deficit in decision making shortly during the early phase

Age of second language acquisition affects nonverbal conflict processing in children : an fMRI study

Background: In their daily communication, bilinguals switch between two languages, a process that involves the selection of a target language and minimization of interference from a nontarget language. Previous studies have uncovered the neural structure in bilinguals and the activation patterns associated with performing verbal conflict tasks. One question that remains, however is whether this extra verbal switching affects brain function during nonverbal conflict tasks. Methods: In this study, we have used fMRI to investigate the impact of bilingualism in children performing two nonverbal tasks involving stimulus-stimulus and stimulus-response conflicts. Three groups of 8-11-year-old children - bilinguals from birth (2L1), second language learners (L2L), and a control group of monolinguals (1L1) - were scanned while performing a color Simon and a numerical Stroop task. Reaction times and accuracy were logged. Results: Compared to monolingual controls, bilingual children showed higher behavioral congruency effect of these tasks, which is matched by the recruitment of brain regions that are generally used in general cognitive control, language processing or to solve language conflict situations in bilinguals (caudate nucleus, posterior cingulate gyrus, STG, precuneus). Further, the activation of these areas was found to be higher in 2L1 compared to L2L. Conclusion: The coupling of longer reaction times to the recruitment of extra language-related brain areas supports the hypothesis that when dealing with language conflicts the specialization of bilinguals hampers the way they can process with nonverbal conflicts, at least at early stages in life

The role of the left head of caudate in suppressing irrelevant words

Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Participants indicated with a finger press whether a visual stimulus was colored pink or blue. The stimulus was either the written word "BLUE," the written word "PINK," or a string of four Xs, with word interference introduced when the meaning of the word and its color were "incongruent" (e.g., BLUE in pink hue) relative to congruent (e.g., BLUE in blue) or neutral (e.g., XXXX in pink). The participants also made color decisions in the presence of spatial interference rather than word interference (i.e., the Simon task). By blocking incongruent, congruent, and neutral trials, we identified activation related to the mechanisms that suppress interference as that which was greater at the end relative to the start of incongruency. This highlighted the role of the left head of caudate in the control of word interference but not spatial interference. The response in the left head of caudate contrasted to bilateral inferior frontal activation that was greater at the start than at the end of incongruency, and to the dorsal anterior cingulate gyrus which responded to a change in the motor response. Our study therefore provides novel insights into the role of the left head of caudate in the mechanisms that suppress word interference

Response interference and working memory in 12-year-old children

A group of 69 12-year-old children performed three well-known response interference tasks: the Stroop task, the Eriksen flanker task, and the Simon task. Individual differences in accuracy and speed correlated across the tasks. However, there was no correlation between the interference effects on these three tasks. Stroop interference, but not the Simon or flanker effect, was correlated with working memory capacity, as obtained from the WISC-R. These results may help clarify the nature of ADHD, which is characterized by problems with response interference

Neural correlates of spatial location mapping on the Simon effect

Previous studies show that the effect of practice with incompatible location mapping results in a reverse Simon effect. However, the neural correlates of this phenomenon are yet to be clarified. This study used functional magnetic resonance imaging (fMRI) to explore the neural correlates of the Simon effect after location mapping in 20 healthy young adults who are native English speakers. The results show that incompatible location mapping leads to reduced activation in the premotor, primary motor, supplementary motor area (SMA) and mid-cingulate cortex. As practice with the Simon effect reveals subtle changes in motor function, application of the Simon task in rehabilitation training programs is recommended.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science