John G. Kerns

Anterior cingulate and prefrontal cortex activity in an FMRI study of trial-to-trial adjustments on the Simon task

People alter their task performance on a trial-to-trial basis, for example after an incongruent trial on tasks involving response conflict. Previous research has found that these adjustments are most robust in the Simon task. One explanation for behavioral adjustments is the conflict-monitoring hypothesis, which posits that the dorsal anterior cingulate cortex (ACC) responds to conflict and that this serves as a signal to recruit other brain regions such as the prefrontal cortex (PFC) to minimize conflict and improve performance. However, another independently supported explanation for behavioral adjustments on the Simon task is the feature integration view, which can account for behavioral adjustments as the result of stimulus repetitions and alternations. Hence, by itself, evidence for behavioral adjustments on the Simon task does not clearly provide evidence for the conflict-monitoring hypothesis. However, the conflict-monitoring hypothesis does predict that behavioral adjustments on the Simon task should involve ACC conflict activity and PFC post-conflict activity. In the current study, consistent with the conflict-monitoring hypothesis, behavioral adjustments in performance on the Simon task were predicted by ACC conflict-related activity. In addition, subsequent behavioral adjustments were associated with PFC activity, with previous trial ACC conflict-related activity predicting greater PFC activity on subsequent trials. These results provide additional evidence that behavioral adjustments on the Simon task are due in part to ACC conflict monitoring and the subsequent recruitment of PFC to minimize conflict.

The dimensions of emotional intelligence, alexithymia, and mood awareness: Associations with personality and performance on an emotional stroop task

This study examined the different facets of emotional intelligence, alexithymia, and mood awareness. Undergraduate students (N = 129) completed the Trait Meta-Mood Scale (TMMS), the Toronto Alexithymia Scale (TAS-20), and the Mood Awareness Scale (MRS). A factor analysis revealed two dimensions, attention to and clarity of emotions, that cut across all three instruments. These two dimensions were differentially associated with personality, as measured by the neuroticism, extra-version, and openness to experience portions of the NEO-FFI, and with performance on an emotional Stroop task. We discuss the implications for the conceptualisation of broad constructs such as emotional intelligence and alexithymia, as well as the potential utility of more narrowly defined individual differences.

Schizotypy facets, cognitive control, and emotion.

This research examined whether facets of schizotypy were differentially related to cognitive control and emotion-processing traits. In a confirmatory factor analysis (N = 261), a 3-factor model of schizotypy exhibited good fit and fit significantly better than a 2-factor model. In addition, only disorganized schizotypy was associated with poor cognitive control (specifically, prepotent inhibition). Moreover, disorganized but not positive schizotypy was associated with increased emotional confusion and increased emotionality. In contrast, negative schizotypy was associated with increased emotional confusion but decreased emotionality. These results suggest that disorganized schizotypy is related to dysregulation of both cognition and emotion and that negative schizotypy might reflect deficits in the experience and processing of emotion and not just in emotional expression.

Executive Functioning Component Mechanisms and Schizophrenia

BACKGROUND Executive functioning refers to a set of processes involved in complex, goal-directed thought and behavior involving multiple brain regions (e.g., prefrontal cortex, parietal cortex, basal ganglia) and multiple neurotransmitters (e.g., dopamine, glutamate, gamma-aminobutyric acid). People with schizophrenia exhibit executive functioning deficits that are associated with treatment-refractory aspects of the disorder. Although there is general consensus about what cognitive tasks involve executive functioning, there is disagreement about the specific cognitive mechanisms that comprise executive functioning. METHODS This article discusses a number of possible candidate executive functioning mechanisms and provides a summary of the consensus reached by the executive functioning discussion group at the first CNTRICS (Cognitive Neuroscience for Treatment Research to Improve Cognition in Schizophrenia) meeting in Washington, DC. RESULTS The consensus was that two constructs have a well-founded basis in basic cognitive neuroscience research and seem to be impaired in schizophrenia: 1) rule generation and selection; and 2) dynamic adjustments in control (i.e., after conflict and errors). CONCLUSIONS The consensus of the first CNTRICS meeting was that immediate translation of measures of these constructs for use in schizophrenia should be pursued. A number of other constructs (e.g., scheduling, sequencing) could also be very important for schizophrenia and are in need of more basic and more clinical research.

Positive schizotypy and emotion processing

This study examined whether emotion processing traits and task performance are associated with positive schizotypy. Positive schizotypy individuals (n=34, assessed with the Magical Ideation and Perceptual Aberration Scales) reported greater attention to emotions but less emotional clarity than controls (n=56). Moreover, a significantly larger percentage of the schizotypy group was classified as emotionally overwhelmed. Positive schizotypy individuals also exhibited absent affective priming and increased incongruent errors at a short stimulus onset asynchrony and an absence of an effect of emotion on recognition memory, but an increased memory response bias for negative words. Results could not be accounted for by level of neuroticism or current mood. These results suggest that positive schizotypy is associated with the processing of emotional information.

Prefrontal Cortex Guides Context-Appropriate Responding during Language Production

Although language processing is thought to frequently require cognitive control, little is known about the cognitive and neural basis of the control of language. Here, we demonstrate that processing of context by the PFC plays an important role in the control of language comprehension and production. Using a missing letter paradigm and fMRI, we found that increased activation in the PFC (but not in posterior regions), while encoding and maintaining context information, predicted context-appropriate responses. Furthermore, greater selection demands increased activity during responding in the same regions engaged during the encoding and maintenance of context. Overall, as in other cognitive task domains, these results suggest that PFC context processing plays an important role in the control of language.

The Influence of Positive Mood on Different Aspects of Cognitive Control

Some evidence suggests that positive mood influences cognitive control. The current research investigated whether positive mood has differential effects on two aspects of cognitive control, working memory and prepotent response inhibition. In Study 1, following either a positive or neutral mood induction, participants completed the Running Memory Span (RMS), a measure primarily of working memory storage capacity, and the Stroop task, a measure of prepotent response inhibition. Results were that the positive mood group performed worse on the RMS task but not on the Stroop task. In Study 2, participants completed the RMS and another measure of prepotent response inhibition, the Flanker task. Results were that when in a positive mood state participants performed worse on the RMS but not on the Flanker task. Overall, this research suggests that positive mood has differential effects on cognitive control, impairing working memory but having no effect on prepotent response inhibition.

The relationship between formal thought disorder and executive functioning component processes.

In 2 studies, associations between formal thought disorder (FTD) and 2 components of executive functioning, processing of context and interference resolution, were investigated. One study, involving people with schizophrenia, examined associations between performance on processing of context (N-back) and interference resolution (interference in Steinberg probe recognition) tasks and FTD. The second study, involving nonpsychiatric participants, was an analogue study that examined the effects of simulated processing of context (performance of 1-back with distraction) and interference resolution (telling new stories about previously seen pictures) deficits on FTD in a speech production task. In both studies, processing of context deficits predicted FTD. Moreover, in both studies, the effect of processing of context deficits on FTD was especially pronounced when combined with interference resolution deficits.

Aberrant semantic and affective processing in people at risk for psychosis

Semantic and affective processing were examined in people at risk for psychosis. The participants were 3 groups of college students: 41 people with elevated Perceptual Aberration and Magical Ideation (PerMag) scores, 18 people with elevated Social Anhedonia (SocAnh) scores, and 100 control participants. Participants completed a single-word, continuous presentation pronunciation task that included semantically related words, affectively valenced words, and semantically unrelated and affectively neutral words. PerMag participants exhibited increased semantic priming and increased sensitivity to affectively valenced primes. SocAnh participants had increased sensitivity to affectively valenced targets.

Word production in schizophrenia and its relationship to positive symptoms.

We explored relationships between positive symptoms of schizophrenia and neurocognitive functions (language and memory). The semantic and phonemic associations among words produced in a verbal fluency task by 26 participants diagnosed with DSM-III-R schizophrenia were examined. Formal thought disorder was associated with producing fewer contextually related words and with producing more unrelated words. In contrast, hallucinations were associated with producing more related words. Our results suggest associations between formal thought disorder and impaired memory, and between hallucinations and increased lexical activation/excessive synaptic pruning.