Neuroimaging of Inhibitory Control Areas in Children With Attention Deficit Hyperactivity Disorder Who Were Treatment Naive or in Long-Term Treatment

University of Nottingham, Nottigham, England, United Kingdom
American Journal of Psychiatry (Impact Factor: 12.3). 07/2006; 163(6):1052-60. DOI: 10.1176/appi.ajp.163.6.1052
Source: PubMed


Difficulty with response inhibition is a cardinal symptom of attention deficit hyperactivity disorder (ADHD), combined type. Prefrontal and cingulate brain regions are known to be involved in inhibitory control. Event-related functional magnetic resonance imaging (fMRI) might establish if these regions differ in their activity in ADHD children relative to healthy comparison subjects.
Fifteen healthy comparison subjects and 17 children with ADHD, combined type, completed fMRI studies while performing the Stop Signal Task. Eight ADHD subjects were treatment naive; the remainder had a history of long-term treatment with stimulants, but they were medication free at the time of the fMRI. No subject had a learning disorder or a comorbid psychiatric condition (other than oppositional defiant disorder in the ADHD subjects).
Both the ADHD and comparison subjects activated the right dorsolateral prefrontal cortex on "stop" trials relative to "go" trials; this increase was greater in ADHD subjects. When inhibition was unsuccessful (relative to successful inhibition), healthy comparison subjects strongly activated the anterior cingulate cortex and the left ventrolateral prefrontal cortex. In contrast, the ADHD subjects did not show these differences. Activations in treatment-naive and ADHD subjects treated in the long term did not differ significantly in any brain regions.
In relation to comparison subjects, ADHD subjects failed to activate the anterior cingulate cortex and the left ventrolateral prefrontal cortex after unsuccessful inhibition. These findings appear in treatment-naive ADHD individuals and are unlikely to be an artifact of long-term treatment with stimulants or of abrupt termination of stimulants before imaging.

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    • "From a neuropsychological perspective, ADHD is associated with deficits in well-defined cognitive domains, including sustained attention and executive functioning (Barkley, 1998; Pennington & Ozonoff, 1996). Some theorists focus on executive deficits (Shallice et al., 2001); children with ADHD show deficits in executive functions, including response inhibition, working memory, and conflict resolution (Bush et al., 1999; Casey et al., 1997; Doyle, 2006; Pliszka et al., 2006; Rubia, Smith, Brammer, Toone & Taylor, 2005; Vaidya et al., 2005); other theorists recognize a difficulty in ADHD in the automatic processing of basic skills (Ackerman, Anhalt, Holcomb, & Dykman, 1986; Fabio, 2001, 2009) or in the modality of stimulus presentation (Fabio & Antonietti, 2012). Moreover, Hazell et al. (1999) suggested that participants affected by ADHD show, along with a deficit in the central controlled processes, a deficit in the encoding and in the automaticity of processes. "
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    ABSTRACT: Objective: Deficits in ADHD executive function (EF) task have been widely documented in a number of different studies. The aim of this work is to analyze the characteristics of auditory vigilance in ADHD and control subjects in two conditions: with and without interference. Method: in the first study the Merrill’s (1992) procedure on automaticity with the dualtask interference paradigm was used; in the second study the auditory test with automatic procedure was used. Results: The results of the study confirm that people with ADHD show deficits in auditory vigilance tests and become less careful when interference is introduced. Conclusion: Results were discussed in terms of a deficit in automaticity process. (J. of Att. Dis. 2015; 19(9) 771-778)
    Journal of Attention Disorders 08/2015; 19(9):771-778. DOI:10.1177/1087054712459562 · 3.78 Impact Factor
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    • "Previous ERP studies indicated that behavioral inhibition is associated to the N2 component, whose amplitude increases in Nogo trials according to the response inhibition requirements [26], [42]–[44], as compared to Go trials where no RI activity is needed [15]. "
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    ABSTRACT: The capacity to inhibit prepotent and automatic responses is crucial for proper cognitive and social development, and inhibitory impairments have been considered to be key for some neuropsychiatric conditions. One of the most used paradigms to analyze inhibitory processes is the Go-Nogo task (GNG). This task has been widely used in psychophysical and cognitive EEG studies, and more recently in paradigms using fMRI. However, a technical limitation is that the time resolution of fMRI is poorer than that of the EEG technique. In order to compensate for these temporal constraints, it has become common practice in the fMRI field to use longer inter-stimulus intervals (ISI) than those used in EEG protocols. Despite the noticeable temporal differences between these two techniques, it is currently assumed that both approaches assess similar inhibitory processes. We performed an EEG study using a GNG task with both short ISI (fast-condition, FC, as in EEG protocols) and long ISI (slow-condition, SC, as in fMRI protocols). We found that in the FC there was a stronger Nogo-N2 effect than in the SC. Moreover, in the FC, but not in the SC, the number of preceding Go trials correlated positively with the Nogo-P3 amplitude and with the Go trial reaction time; and negatively with commission errors. In addition, we found significant topographical differences for the Go-P3 elicited in FC and SC, which is interpreted in terms of different neurotransmitter dynamics. Taken together, our results provide evidence that frequency of stimulus presentation in the GNG task strongly modulates the behavioral response and the evoked EEG activity. Therefore, it is likely that short-ISI EEG protocols and long-ISI fMRI protocols do not assess equivalent inhibitory processes.
    PLoS ONE 01/2014; 9(1):e87232. DOI:10.1371/journal.pone.0087232 · 3.23 Impact Factor
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    • "Recent neuroanatomical research suggests that children with ADHD exhibit a marked delay in maturation of the prefrontal areas (Shaw et al., 2007). Moreover, it has been shown that patients with ADHD exhibit weaker prefrontal activation in EF tasks (Pliszka et al., 2006). These studies indicate that patients with ADHD may have functional and anatomical deficits in the prefrontal cortex (Bush et al., 2005). "
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    ABSTRACT: Executive function (EF) refers to the higher-order cognitive control process for the attainment of a specific goal. There are several subcomponents of EF, such as inhibition, cognitive shifting, and working memory. Extensive neuroimaging research in adults has revealed that the lateral prefrontal cortex plays an important role in EF. Developmental studies have reported behavioral evidence showing that EF changes significantly during preschool years. However, the neural mechanism of EF in young children is still unclear. This article reviews recent near-infrared spectroscopy (NIRS) research that examined the relationship between the development of EF and the lateral prefrontal cortex. Specifically, this review focuses on inhibitory control, cognitive shifting, and working memory in young children. Research has consistently shown significant prefrontal activation during tasks in typically developed children, but this activation may be abnormal in children with developmental disorders. Finally, methodological issues and future directions are discussed.
    Frontiers in Human Neuroscience 12/2013; 7:867. DOI:10.3389/fnhum.2013.00867 · 2.99 Impact Factor
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