The Functional Integration of the Anterior Cingulate Cortex during Conflict Processing

Although functional activation of the anterior cingulate cortex (ACC) related to conflict processing has been studied extensively, the functional integration of the subdivisions of the ACC and other brain regions during conditions of conflict is still unclear. In this study, participants performed a task designed to elicit conflict processing by using flanker interference on target response while they were scanned using event-related functional magnetic resonance imaging. The physiological response of several brain regions in terms of an interaction between conflict processing and activity of the anterior rostral cingulate zone (RCZa) of the ACC, and the effective connectivity between this zone and other regions were examined using psychophysiological interaction analysis and dynamic causal modeling, respectively. There was significant integration of the RCZa with the caudal cingulate zone (CCZ) of the ACC and other brain regions such as the lateral prefrontal, primary, and supplementary motor areas above and beyond the main effect of conflict and baseline connectivity. The intrinsic connectivity from the RCZa to the CCZ was modulated by the context of conflict. These findings suggest that conflict processing is associated with the effective contribution of the RCZa to the neuronal activity of CCZ, as well as other cortical regions.

The relation of brain oscillations to attentional networks

Previous studies have suggested the relation of particular frequency bands such as theta (4-8 Hz), alpha (8-14 Hz), beta (14-30 Hz), or gamma (>30 Hz) to cognitive functions. However, there has been controversy over which bands are specifically related to attention. We used the attention network test to separate three anatomically defined brain networks that carry out the functions of alerting, orienting, and executive control of attention. High-density scalp electrical recording was performed to record synchronous oscillatory activity and power spectrum analyses based on functional magnetic resonance imaging constrained dipole modeling were conducted for each attentional network. We found that each attentional network has a distinct set of oscillations related to its activity. The alerting network showed a specific decrease in theta-, alpha-, and beta-band activity 200-450 ms after a warning signal. The orienting network showed an increase in gamma-band activity at approximately 200 ms after a spatial cue, indicating the location of a target. The executive control network revealed a complex pattern when a target was surrounded with incongruent flankers compared with congruent flankers. There was an early (<400 ms) increase in gamma-band activity, a later (>400 ms) decrease in beta- and low gamma-band activity after the target onset, and a decrease of all frequency bands before response followed by an increase after the response. These data demonstrate that attention is not related to any single frequency band but that each network has a distinct oscillatory activity and time course.

Research on attention networks as a model for the integration of psychological science

As Titchener pointed out more than one hundred years ago, attention is at the center of the psychological enterprise. Attention research investigates how voluntary control and subjective experience arise from and regulate our behavior. In recent years, attention has been one of the fastest growing of all fields within cognitive psychology and cognitive neuroscience. This review examines attention as characterized by linking common neural networks with individual differences in their efficient utilization. The development of attentional networks is partly specified by genes, but is also open to specific experiences through the actions of caregivers and the culture. We believe that the connection between neural networks, genes, and socialization provides a common approach to all aspects of human cognition and emotion. Pursuit of this approach can provide a basis for psychology that unifies social, cultural, differential, experimental, and physiological areas, and allows normal development to serve as a baseline for understanding various forms of pathology. D.O. Hebb proposed this approach 50 years ago in his volume Organization of Behavior and continued with introductory textbooks that dealt with all of the topics of psychology in a common framework. Use of a common network approach to psychological science may allow a foundation for predicting and understanding human behavior in its varied forms.

Attention genes

A major problem for developmental science is understanding how the cognitive and emotional networks important in carrying out mental processes can be related to individual differences. The last five years have seen major advances in establishing links between alleles of specific genes and the neural networks underlying aspects of attention. These findings have the potential of illuminating important aspects of normal development and its pathologies. We need to learn how genes and experience combine to influence the structure of neural networks and the efficiency with which they are exercised. Methods for addressing these issues are central to progress in the decade ahead.

Aufmerksamkeit und exekutive Funktionen bei Patienten mit Adipositas per magna

In this paper, attention and temperament are compared between 41 severely obese patients with psychiatric comorbidity and 45 control persons. Networks of attention were assessed by the Attention Network Test: alerting (ability to achieve and maintain an alert state), orienting (ability to orient to a stimulus), and executive attention (ability to resolve conflict). According to hypotheses, obese patients show reduced executive attention, more effortful control, and higher negative affectivity than controls. The concept of attention networks is related to cognitive mechanisms of self-regulation, opening new perspectives for understanding psychiatric disorders.

Analyzing and shaping human attentional networks

In this paper we outline a conception of attentional networks arising from imaging studies as connections between activated brain areas carrying out localized mental operations. We consider both the areas of functional activation (nodes) and the structural (DTI) and functional connections (DCM) between them in real time (EEG, frequency analysis) as important tools in analyzing the network. The efficiency of network function involves the time course of activation of nodes and their connectivity to other areas of the network. We outline landmarks in the development of brain networks underlying executive attention from infancy and childhood. We use individual differences in network efficiency to examine genetic alleles that are related to performance. We consider how animal studies might be used to determine the genes that influence network development. Finally we indicate how training may aid in enhancing attentional networks. Our goal is to show the wide range of methods that can be used to suggest and analyze models of network function in the study of attention.

Infant brains detect arithmetic errors

A current debate is whether increased looking time in infancy is related to violation of expectations. In this study, 6- to 9-month-old infants' brain activity was analyzed during presentation of correct and incorrect solutions to simple arithmetic equations [(e.g., presentation of 1 + 1; one doll on a TV monitor, with another doll added from behind a screen, followed by a solution of 2 (correct) or 1 (incorrect)]. Infants looked longer at incorrect solutions than at correct ones. Event-related potentials, time-locked to the presentation of the solution, also differed between conditions, with greater negative activity for the incorrect solution condition. Spectral analysis showed a similar pattern to that of adults observing correct and incorrect arithmetical equations. These findings show (i) that the brain network involved in error detection can be identified in infancy and (ii) that this network can support an association between looking time and violation of expectations.

Neuroimaging and genetic associations of attentional and hypnotic processes

In the aftermath of the human genome project, genotyping is fast becoming an affordable and technologically viable complement to phenotyping. Whereas attempts to characterize hypnotic responsiveness have been largely phenomenological, data emanating from exploratory genetic data may offer supplementary insights into the genetic bases of hypnotizability. We outline our genetic and neuroimaging findings and discuss potential implications to top-down control systems. These results may explain individual differences in hypnotizability and propose new ideas for studying the influence of suggestion on neural systems.

Neurocognitive dysfunction in antidepressant-free, non-elderly patients with unipolar depression: alerting and covert orienting of visuospatial attention

BACKGROUND

Cognition is impaired across various domains in young and middle-age adults with unipolar depression. Performance appears in general worse in effortful tasks requiring executive function and attention. Probing specific cognitive operations in depressed patients, such as alerting and covert orienting of visuospatial attention, can better define and characterize the pathophysiology.

METHODS

Nine antidepressant-free, clinically depressed patients and fourteen age-matched healthy subjects performed a Posner task with components of phasic alerting and covert orienting of visuospatial attention. Reaction times were analyzed by repeated-measures ANOVA with DIAGNOSIS as the between-group measure. Visual field (FIELD), stimulus onset asynchrony (SOA), and orienting CUE condition were within-subject, repeated measures.

RESULTS

ANOVA showed intact attentional orienting in both groups. There were no FIELD differences across groups nor main effects of DIAGNOSIS. Interactions of DIAGNOSIS with SOA and DIAGNOSIS with CUE condition identified a phasic alerting deficit in the depressed patients. There were no significant effects of time-on-task, suggesting adequate vigilance or sustained attention in both groups. Plotting depressed versus control subjects' reaction time for each task condition (Brinley plot) showed linearity with a slope of 1.6 (i.e., patients were 1.6-fold slower) and a correlation coefficient of 0.98 (accounting for 96% of the overall variance).

LIMITATIONS

This study contains a small sample with potential for Type II error. The study addressed depression at the syndrome level. Depressed patients selected on particular symptom dimensions (e.g., anxiety, psychomotor retardation, etc.) could reveal abnormalities in hemisphere asymmetries that were not observed here.

CONCLUSIONS

These data highlight that global slowing is a major cognitive deficit in depression and arises across levels of difficulty. Putative specific deficits in depression need adjustment for the large effects of global slowing which can mimic selective impairments in more effortful task conditions.

Attention and adolescent tobacco use: A potential self-regulatory dynamic underlying nicotine addiction

Examines the covariation of attention processes in childhood and adolescence with tobacco use in middle adolescence, controlling for both comorbid antisocial behavior and psychosocial risk. Childhood ratings of inattention increased the risk of early-onset smoking (odds ratio = 4.12). During adolescence, high performance on an attention task was associated with increased risk (odds ratio = 2.07) for patterned tobacco use after controlling for antisocial behavior and known psychosocial risk factors. These analyses suggest a possible regulatory dynamic linking patterned tobacco use and inattention. Given the role of attention in the regulation of negative affect, it is possible that tobacco use among vulnerable youth results in enhanced sense of well-being, compared to less vulnerable youth. Future research requires repeated assessments of attention, affective states and tobacco use to clarify issues of temporal ordering.

Psychological processes and neural mechanisms for action: the legacy of Steven W. Keele

The recent untimely illness and death of Steven W. Keele is a great loss for psychology in general and for the field of motor control in particular. Steve Keele was a pioneer in the study of the psychological processes and neural mechanisms underlying attention and motor control. Steve was a Consulting Editor for the Journal of Motor Behavior from 1969 to 1974 and served on the Editorial Board from 1974 to 1977, and again from 1980 until his retirement in 1997. Steve served as head of the University of Oregon Psychology Department from 1992-1995, and, although he retired in 1997, he continued to perform important research until he became ill in early 2005.

Selective impairment of attentional networks of orienting and executive control in schizophrenia

BACKGROUND

Difficulty attending is a common deficit of schizophrenic patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network.

METHOD

This study used the attention network test to compare schizophrenic patients (N=77) with controls (N=53) on the efficiency of three anatomically defined attentional networks: alerting, orienting, and executive control.

RESULTS

Schizophrenic patients showed a large and highly significant deficit in the executive network and a smaller but significant deficit in the orienting network as well as in overall RT and accuracy. There was no deficit in the alerting network.

CONCLUSION

These results suggest some specificity in the attentional networks influenced by the disorder. The executive attention network has been shown in normal subjects to activate the anterior cingulate and lateral prefrontal areas. Previous data using neuroimaging with schizophrenic patients has shown abnormal control by the anterior cingulate. Our findings support this previous research by indicating that the major attentional deficit in schizophrenic patients is in a network that includes the anterior cingulate.

Influencing brain networks: implications for education

In our view, a central issue in relating brain development to education is whether classroom interventions can alter neural networks related to cognition in ways that generalize beyond the specific domain of instruction. This issue depends upon understanding how neural networks develop under the influence of genes and experience. Imaging studies have revealed common networks underlying many important tasks undertaken at school, such as reading and number skills, and we are beginning to learn how genes and experience work together to shape the development of these networks. The results obtained appear sufficient to propose research-based interventions that could prove useful in improving the ability of children to adjust to the school setting and to acquire skills like literacy and numeracy.

The Development of Executive Attention: Contributions to the Emergence of Self-Regulation

Over the past decade, developmental studies have established connections between executive attention, as studied in neurocognitive models, and effortful control, a temperament system supporting the emergence of self-regulation. Functions associated with the executive attention network overlap with the more general domain of executive function in childhood, which also includes working memory, planning, switching, and inhibitory control (Welch, 2001). Cognitive tasks used with adults to study executive attention can be adapted to children and used with questionnaires to trace the role of attention and effortful control in the development of self-regulation. In this article we focus on the monitoring and control functions of attention and discuss its contributions to self-regulation from cognitive, temperamental, and biological perspectives.

Training, maturation, and genetic influences on the development of executive attention

A neural network underlying attentional control involves the anterior cingulate in addition to lateral prefrontal areas. An important development of this network occurs between 3 and 7 years of age. We have examined the efficiency of attentional networks across age and after 5 days of attention training (experimental group) compared with different types of no training (control groups) in 4-year-old and 6-year-old children. Strong improvement in executive attention and intelligence was found from ages 4 to 6 years. Both 4- and 6-year-olds showed more mature performance after the training than did the control groups. This finding applies to behavioral scores of the executive attention network as measured by the attention network test, event-related potentials recorded from the scalp during attention network test performance, and intelligence test scores. We also documented the role of the temperamental factor of effortful control and the DAT1 gene in individual differences in attention. Overall, our data suggest that the executive attention network appears to develop under strong genetic control, but that it is subject to educational interventions during development.

Hypnotic suggestion reduces conflict in the human brain

Many studies have suggested that conflict monitoring involves the anterior cingulate cortex (ACC). We previously showed that a specific hypnotic suggestion reduces involuntary conflict and alters information processing in highly hypnotizable individuals. Hypothesizing that such conflict reduction would be associated with decreased ACC activation, we combined neuroimaging methods to provide high temporal and spatial resolution and studied highly and less-hypnotizable participants both with and without a suggestion to interpret visual words as nonsense strings. Functional MRI data revealed that under posthypnotic suggestion, both ACC and visual areas presented reduced activity in highly hypnotizable persons compared with either no-suggestion or less-hypnotizable controls. Scalp electrode recordings in highly hypnotizable subjects also showed reductions in posterior activation under suggestion, indicating visual system alterations. Our findings illuminate how suggestion affects cognitive control by modulating activity in specific brain areas, including early visual modules, and provide a more scientific account relating the neural effects of suggestion to placebo.

The activation of attentional networks

Alerting, orienting, and executive control are widely thought to be relatively independent aspects of attention that are linked to separable brain regions. However, neuroimaging studies have yet to examine evidence for the anatomical separability of these three aspects of attention in the same subjects performing the same task. The attention network test (ANT) examines the effects of cues and targets within a single reaction time task to provide a means of exploring the efficiency of the alerting, orienting, and executive control networks involved in attention. It also provides an opportunity to examine the brain activity of these three networks as they operate in a single integrated task. We used event-related functional magnetic resonance imaging (fMRI) to explore the brain areas involved in the three attention systems targeted by the ANT. The alerting contrast showed strong thalamic involvement and activation of anterior and posterior cortical sites. As expected, the orienting contrast activated parietal sites and frontal eye fields. The executive control network contrast showed activation of the anterior cingulate along with several other brain areas. With some exceptions, activation patterns of these three networks within this single task are consistent with previous fMRI studies that have been studied in separate tasks. Overall, the fMRI results suggest that the functional contrasts within this single task differentially activate three separable anatomical networks related to the components of attention.

Ecological nuances in functional magnetic resonance imaging (fMRI): psychological stressors, posture, and hydrostatics

Brain imaging techniques such as functional magnetic resonance imaging (fMRI) have forged an impressive link between psychology and neuroscience. Whereas most experiments in cognitive psychology require participants to perform while sitting upright in front of display devices, fMRI obliges participants to perform cognitive tasks while lying supine and motionless inside a narrow bore. In addition to introducing psychological and physical stressors, such as loud thumps and head restraints, fMRI procedures also alter brain hydrostatics. The ecological factors associated with current fMRI technology, such as supine posture, may skew cognitive processing and influence hemodynamic and electrophysiological measurements, especially in extreme age groups and pathological populations. Recognizing the central role of fMRI in unraveling the neural mechanisms of cognition, we outline ways to address these limitations.

Genes and experience shape brain networks of conscious control

One aspect of consciousness involves voluntary control over thoughts and feelings, often called will. Progress in neuroimaging and in sequencing the human genome makes it possible to think about voluntary control in terms of a specific neural network that includes midline and lateral frontal areas. A number of cognitive tasks involving conflict as well as the control of emotions have been shown to activate these brain areas. Studies have traced the development of this network in the ability to regulate cognition and emotion from about 2.5 to 7 years of age. Individual differences in this network have been related to parental reports of the ability of children to regulate their behavior, to delay reward and to develop a conscience. In adolescents these individual differences predict the propensity for antisocial behavior. Differences in specific genes are related to individual efficiency in performance of the network, and by neuroimaging, to the strength of its activation of this network. Future animal studies may make it possible to learn in detail how genes influence the common pattern of development of self-regulation made possible by this network. Moreover, a number of neurological and psychiatric pathologies involving difficulties in awareness and volition show deficits in parts of this network. We are now studying whether specific training experiences can influence the development of this network in 4-year-old children and if so, for whom it is most effective. Voluntary control is also important for the regulation of conscious input from the sensory environment. It seems likely that the same network involved in self-regulation is also crucial for focal attention to the sensory world.