What Is the Relationship Between ADHD and ODD?

Reactive inhibition (reactive inhition) refers to the phenomenon that the response intensity of an organism to a certain stimulus decreases due to the increase in the number of reactions. Proposed by American psychologist Hull. He believes that reaction inhibition will weaken or even disappear with rest, and uses this principle of action to explain the altitude phenomenon, concentrated and decentralized learning in learning activities. Depends on the number of existing reactions and the length of the interval before the reaction.

Response inhibition mainly refers to three interconnected processing processes: (1) inhibiting the spontaneous response to an environmental event; (2) preventing the current response to ensure a delay in deciding which response to take; (3) protecting this delay Period to prevent interruption of disruptive events and allow self-directed behavior to occur. Depends on the number of existing reactions and the length of the interval before the reaction. ^[1]

Executive function is one of the forefront issues of current research in cognitive neuroscience. One of the important aspects is the response inhibition function, which is mainly to respond to the target superior response and suppress the reaction impulse. School-age children are the key period for brain development and the gradual improvement of various cognitive functions. There is no research on the response inhibition function of normal children in China, and the activation pattern of brain regions involved in executive function is not clear. Continuous performance test (CPT) is an extension of the GO-NOGO paradigm and is a good tool for testing response suppression. Functional magnetic resonance imaging (fMRI) is a non-invasive imaging The examination method can directly observe the neural activity of the human brain from both morphological and functional aspects under living conditions, and is widely used in the study of neurocognition. This study uses a combination of CPT tasks and fMRI to study the activation model of adult and children's response inhibition function, explores the developmental characteristics of child to adult response inhibition function, and provides new methods for the study of some clinical diseases.

Response suppression functional imaging results

Normal children complete non-target tasks, with the main brain activation area in the cingulate gyrus and the left lateral dorsal side

Figure 1 is a brain activation map of normal children

Prefrontal cortex, ventrolateral prefrontal cortex on both sides and cerebellum (Figure 1). Normal adults complete non-target tasks, and mainly activate the brain regions in the central prefrontal lobe, cingulate gyrus, left lateral prefrontal cortex, left lateral prefrontal ventral cortex, and fusiform gyrus (Figure 2). Compared with adults, the intensity and area of activation of the central prefrontal lobe and cingulate gyrus in children were significantly lower than in adults, and the cerebellum, right ventrolateral prefrontal cortex, and left island lobe were more activated than in adults.

Response inhibition discussion

Continuous Performance Test (CPT)

Figure 2 is a brain activation map of a normal adult

Response / non-reaction task (GO / NOGOtask), the basic task is to respond to GO stimulus and inhibit response to NOGO stimulus. The CPT-AX task used in this study only includes the identification of numbers, discarding the color characters and color identification in the STROOP effect and related content; compared with other forms of GO-NOGO tasks, the target task appears The probability is smaller than the background group, the stimulus repetition is less, and it is presented quickly. During the experiment, on the one hand, the subject is required to observe the number, on the other hand, the subject is required to respond quickly to a relatively small (20%) event, and the subject is required. Maintaining effective vigilance and high response efficiency, as well as maintaining vigilance against such continuously occurring stimuli, can effectively complete the task. Studies suggest that the continuous change of this stimulus and the cumulative effect of continuous presentation can regulate repetitive inhibitory effects.

Based on the attention-based top-down processing mode, many studies have activated both the frontal lobe (PFC) and the cingulate fold (ACC) when performing control tasks. It is generally believed that the cingulate back passes conflict information to In the frontal lobe, PFC adjusts the activities of the brain area responsible for vision and other processes through the top-down attention adjustment mechanism. The cingulate gyrus and prefrontal lobe constitute a feedback loop. The activation of cingulum reflex in cognitive tasks is related to three factors: the task requires neglecting superior response tasks, insufficiently evidenced responses, and reactions involving false monitoring. In the CPT task used in this study, the subjects were required to ignore the conflicting advantage task and compete in correct responses and abandoned responses. The experimental results show that both the anterior cingulate gyrus and the prefrontal lobe are activated in adults and children. However, the activation of the prefrontal lobe and cingulate gyrus in adults is significantly greater than in children. School-age children are not yet fully developed and the response inhibition function is not yet mature. Evidence can also be obtained from behavioral studies. Many school-age children show behavioral characteristics that are relatively hyperactive and poorly controlled. Some studies have reported that there is no difference in executive functional behavior between the elderly and young people, but the degree of brain area activation is significantly greater than that of young people. Obviously, the elderly need more brain areas to coordinate when performing control functions. In this experiment, there were 2 children whose behavioral performance was similar to that of adults, but their activation of brain regions was significantly higher than the children's average level. Physiologically, they put in more effort to overcome the superior response in the task and reach the adult response level, but the effort is obviously larger than that of adults and requires more brain regions to participate in order to complete the task efficiently . Botvinick and other studies suggest that different parts of the cingulate return involve different processes of executive functions. The rear area of the cingulate mainly involves correct responses to error reactions and highly conflicting tasks, and the front of the cingulate mainly responds to errors. . The results of this experiment show that the activation of children before cingulate gyrus is weakened, while the activation of children after cingulate gyrus is obvious, and no significant activation is seen in adults. Studies have speculated that when performing non-target tasks, children perform more reaction suppression and experience greater levels of error reactions and conflicts than adults, so it reflects the difference in post-cingulate reactivation. This is because children's miss rate is significantly greater than adults. It is corroborated, so the results of this study suggest that normal adults and children adopt different strategies for tasks. At the same time, the results also show that the left fusiform gyrus is activated in adults, but not activated in children. The fusiform gyrus is involved in advanced emotional management. It is speculated that adults may adopt more advanced strategies when performing difficult response inhibition tasks. Patients with prefrontal lobe (PFC) injury are clinically similar to children. Many studies have shown that executive function is related to the gradual maturation of the prefrontal lobe (PFC). When the task requires more attention, and the conflict load increases, the forehead may adjust the attention resources to enable efficient allocation of attention resources. For children, when performing the same conflict tasks, children have a heavier conflict load than adults, and need more brain areas to participate, allocate resources, and reduce conflicts. The results of this study show that adults are more active than children when performing response inhibition tasks in the prefrontal lobe, suggesting that the prefrontal lobe gradually matures with age, and the stronger its ability to allocate resources, the greater its role in cognitive control.

MacDonald and other researchers believe that the dorsal lateral prefrontal cortex (DLPFC) adjusts the activities of the brain area responsible for vision and other processes through the top-down attention adjustment mechanism. DLPFC activation was seen in both children and adults in this study, confirming that DLPFC is involved in the regulation of executive control, and that the ventral lateral prefrontal cortex (VLPFC) is also activated in children and adults. There is still debate about the specific role of DLPFC and VLPFC in cognitive control, whether there is a special inhibition of the processing brain area, whether the inhibition is the function of DLPFC or VLPFC, or the coordination of the two. The results of this study suggest that the coordination of DLPFC and VLPFC is needed in the process of performing response suppression. It should be pointed out that in children, the right ventral prefrontal cortex is more activated in children. Because children experience more conflicts in response to tasks than adults, the right DLPFC is required to process the conflict information. The right VLPFC in children may play an important role in inhibiting processing during the process of response inhibition.

The cerebellum and basal ganglia also play an important role in the process of cognitive control. The basal ganglia are particularly important in regulating the relationship between executive functions and other attentional functions. The basal ganglia, especially the caudate nucleus, are involved in cognitive functions. In recent years, the cerebellum and basal ganglia have been found to have neural connections with the prefrontal cortex. These connections provide an anatomical basis for these subcortical nuclei to participate in working memory, regular learning and planning. The results of this study show that the cerebellum and basal ganglia are activated in normal children, but the activation is significantly weakened compared with adults, indicating that working memory function of school-age children is not yet developed and more brain regions are needed. It is worth mentioning that the activation of children's island leaves is more significant than that of adults. Bush et al. ^[3] found that the island leaves of children with ADHD patients may be involved in the compensatory mechanism of attention when compared with adults. Behavioral and attentional performance are similar to those of patients with ADHD. The prompt continuous operational tasks used in this study presented experimental stimuli quickly and were difficult. The study speculated that the island leaves may be involved in the compensation of attention.

Response Inhibition Study Conclusion

In summary, as children grow older, their ability to perform response inhibition also gradually increases. From the perspective of brain function development, research suggests that the right ventrolateral frontal lobe plays an important role in children's executive function. The central prefrontal cortex and dorsal lateral cortex of the frontal lobe develop, and children's executive functions are gradually improved. Functional magnetic resonance imaging combined with CPT test can be used to study the response inhibition function of children, and provide a reliable basis for the diagnosis and treatment of some neuropsychiatric diseases such as ADHD (Attention Deficit Hyperactivity Syndrome) and Children's Tourette Syndrome. And new methods. Future research needs to design more perfect tasks and further increase the sample content to conduct in-depth research on the development of children's prefrontal lobe and the compensation mechanism for children's ability to perform response inhibition. ^[4]