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Behavioral flexibility (or set-shifting), which is regulated by the prefrontal cortex (PFC), is often impaired in patients with attention-deficit/hyperactivity disorder (ADHD), which is characterized by poor inhibitory control and reinforcement learning. Transcranial direct current stimulation (tDCS) has been proposed as a means of noninvasive brain stimulation and a potential therapeutic tool for modulating behavioral flexibility. Animal studies can pave the way to know if tDCS application can potentially benefit rule- and goal-based activities in ADHD. Spontaneously hypertensive rats (SHRs) and inbred Wistar-Kyoto (WKY) rats were used as an animal model of ADHD and controls, respectively, and their strategy set-shifting abilities, including initial discrimination, set-shifting, and reversal learning tasks under 0-s or 15-s reinforcer delivery delay conditions, were evaluated. The tDCS treatment had a limited effect on the performance of the SHRs and WKY rats in initial discrimination task under 0-s delay condition. Under the 15-s delay condition, the SHRs had longer lever-press reaction times and/or more trial omissions than the WKY rats did when completing set-shifting and reversal-learning tasks. Among the SHRs, tDCS treatment improved the rats' reaction times and/or reduced their trial omissions in the set-shifting and reversal-learning tasks. Although tDCS may improve delayed reinforcement learning set-shifting performance in SHRs, further studies are required to clarify the responsible mechanism.

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This research surveyed the characteristics of the developmental traits of impulse control behavior in children through parent-report questionnaires. After matching for gender and attention behavior, as well as controlling for variables (motor and perception) which might confound impulse control, 710 participants (355 girls and 355 boys; grade, 1-5; age, 7-12 years) were recruited from a database of 1763 children. Results demonstrated that there was a significant difference between grade 1 and grade 5 in impulse control. Conversely, no significant differences were found when comparing other grades. The present findings indicate that a striking development of impulse control occurs from grade 4 to 5. Moreover, the plateau of impulse control development from grade 1 to 4 implies that a long transition period is needed to prepare children to develop future impulse control. In conclusion, the age-dependent maturation associated with stage-wise development is a critical characteristic of impulse control development in school age children. Further discussions are made regarding this characteristic, such as from the perspective of frontal lobe development.

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BACKGROUD/PURPOSE: Deep pressure input is used to normalize physiological arousal due to stress. Third molar extraction is an invasive dental procedure with high stress for the patient, and an alleviation strategy is rarely applied during tooth extraction. In the present study, we investigated the effects of deep pressure input on autonomic responses during the procedures of third molar extraction in healthy adolescents. METHODS: A randomized controlled crossover design was used for adolescents who were allocated to experimental and control groups that received intervention with or without deep pressure input, respectively. Autonomic indicators, namely the heart rate, percentage of low-frequency heart rate variability (LF-HRV), percentage of high-frequency heart rate variability (HF-HRV), and low-frequency/high-frequency heart rate variability ratio (LF/HF-HRV), were assessed at the baseline, during molar extraction, and in the posttreatment phase. RESULTS: The results indicated that third molar extraction caused significant autonomic parameter changes in both groups; however, differential response patterns were observed between two groups. In particular, application of deep pressure input in the experimental group was associated with higher HF-HRV and lower LF/HF-HRV during third molar extraction compared with those in the control group. CONCLUSION: LF/HF-HRV measurement revealed balanced sympathovagal activation in response to deep pressure application. The present study suggests that the application of deep pressure alters the response of HF-HRV and facilitate maintaining sympathovagal balance during third molar extraction.

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BACKGROUND/PURPOSE: Anxiety induced by dental treatment can become a serious problem, especially for patients with special needs. Application of deep touch pressure, which is a sensory adaptation technique, may ameliorate anxiety in disabled patients. However, few empiric studies have investigated the possible links between the clinical effects of deep touch pressure and its behavioral and physiologic aspects. Equally little progress has been made concerning theoretical development. The current study is a crossover intervention trial to investigate the behavioral and physiological effects of deep touch pressure for participants receiving dental treatment. METHODS: Nineteen disabled participants, who were retrospectively subclassified for positive trend or negative trend, were recruited to receive the papoose board as an application of deep touch pressure. Quantitative analyses of behavioral assessments and physiological measurements, including electrodermal activity and heart rate variability, were conducted. We sought to understand the modulation of the autonomic nervous system and the orchestration of sympathetic and parasympathetic (PsNS) nervous systems. RESULTS: Behavioral assessments reported that higher levels of anxiety were induced by the dental treatment for participants with both groups of positive and negative trends. Although no significant differences were found in the SNS activity, physiologic responses indicated that significantly changes of PsNS activity were observed under the stress condition (dental treatment) when deep touch pressure intervention was applied, especially for participants in the group of positive trend. CONCLUSION: Our results suggest that the PsNS activation plays a critical role in the process of ANS modulation. This study provides not only physiologic evidence for the modulation effects of deep touch pressure on stressful conditions in dental environments but also the evidence that the application of papoose board, as a sensory adaptation technique, is not harmful for dental patients with special needs.

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