Aberrant patterns of brain functional connectivity in the default mode network (DMN) have been observed across different classes of substance use disorder (SUD) and are associated with craving and ...relapse. In addicted individuals resting functional connectivity (RSFC) of the anterior DMN, which participates in attribution of personal value and emotional regulation, tends to be decreased, whereas RSFC of the posterior DMN, which directs attention to the internal world, tends to be increased. Aberrant RSFC within the DMN is believed to contribute to impaired self-awareness, negative emotions and to ruminations in addiction. Additionally, the disrupted connectivity between DMN and cortical regions involved with executive function, memory and emotion could be critical to drug-taking regardless of negative consequences and to stress-triggered relapse. At the system level, the dynamics of DMN interactions with the executive control and the salience networks are also disturbed in addiction. The DMN is prominently engaged during the withdrawal and preoccupation phases of the addiction cycle at the expense of the executive control network and with an enhanced participation of the salience network. In contrast, DMN prominence appears to be transitorily decreased during the intoxication phases. There is also growing evidence that disruption of the DMN in addiction reflects in part changes in dopaminergic, glutamatergic, and GABAergic signaling associated with acute and chronic drug use. Findings are starting to reveal DMN RSFC as a potential biomarker for predicting clinical outcomes in SUD and identify the DMN as a promising target for the treatment of addiction.
•Drug abuse alters DMN connectivity affecting cognitive and emotional processing.•Acute and chronic drug use have different effects on DMN.•Aberrant connectivity of DMN to other regions affects self-related decisions.•DMN loses dynamic interaction with other networks facilitating craving and relapse.•DA dysfunction in drug abusers contributes to DMN dysfunction.
This review aimed to address the question of whether cognitive impairment should be considered a core feature of depression that may be a valuable target for treatment.
We conducted a systematic ...review and meta-analysis of cognitive function, assessed with a single neuropsychological test battery, the Cambridge Neuropsychological Test Automated Battery (CANTAB), in patients with depression during symptomatic and remitted states. Inclusion of studies comparing patients remitted from depression and controls enabled us to investigate whether cognitive impairment persists beyond episodes of low mood in depression.
Our meta-analysis revealed significant moderate cognitive deficits in executive function, memory and attention in patients with depression relative to controls (Cohen's d effect sizes ranging from -0.34 to -0.65). Significant moderate deficits in executive function and attention (Cohen's d ranging from -0.52 to -0.61) and non-significant small/moderate deficits in memory (Cohen's d ranging from -0.22 to -0.54) were found to persist in patients whose depressive symptoms had remitted, indicating that cognitive impairment occurs separately from episodes of low mood in depression.
Both low mood and cognitive impairment are associated with poor psychosocial functioning. Therefore, we argue that remediation of cognitive impairment and alleviation of depressive symptoms each play an important role in improving outcome for patients with depression. In conclusion, this systematic review and meta-analysis demonstrates that cognitive impairment represents a core feature of depression that cannot be considered an epiphenomenon that is entirely secondary to symptoms of low mood and that may be a valuable target for future interventions.
The role of the thalamus in cortical sensory transmission is well known, but its broader role in cognition is less appreciated. Recent studies have shown thalamic engagement in dynamic regulation of ...cortical activity in attention, executive control, and perceptual decision-making, but the circuit mechanisms underlying such functionality are unknown. Because the thalamus is composed of excitatory neurons that are devoid of local recurrent excitatory connectivity, delineating long-range, input-output connectivity patterns of single thalamic neurons is critical for building functional models. We discuss this need in relation to existing organizational schemes such as core versus matrix and first-order versus higher-order relay nuclei. We propose that a new classification is needed based on thalamocortical motifs, where structure naturally informs function. Overall, our synthesis puts understanding thalamic organization at the forefront of existing research in systems and computational neuroscience, with both basic and translational applications.
Halassa and Sherman highlight the role of the thalamus in cortical function and the lack of knowledge surrounding thalamocortical connectivity at single-cell resolution. They propose thalamocortical motifs as units of organization with potential to inform cognitively relevant functional models.
Background： Accumulating evidence indicates that attention deficit hyperactivity disorder （ADHD） is associated with core deficits in executive function （EF） which predicts poorer academic and ...occupational functioning. This makes early intervention targeting EF impairments important to prevent long-term negative outcomes. Cognitive training is a potential ADHD treatment target. The present study aimed to explore the efficacy, feasibility, and acceptability of a cognitive training program （targeting child＇s multiple EF components and involving parent support in daily life）, as a nonpharmacological intervention for children with ADHD. Methods： Forty-four school-age children with ADHD and their parents participated in 12 sessions of EF training （last for 12 weeks） and 88 health controls （HC） were also recruited. Training effects were explored using both neuropsychological tests （Stroop color-word test, Rey-Osterrieth complex figure test, trail making test, tower of Hanoi, and false-belief task） and reports of daily life （ADHD rating scale-IV, Conners＇ parent rating scale, and behavior rating inventory of executive function BRIEF） by analysis of paired sample t-test and Wilcoxon signed-rank test. The differences on EF performances between children with ADHD after training and HC were explored using multivariate analysis. Results： The results （before vs. after EF training） showed that after intervention, the children with ADHD presented better performances of EF both in neuropsychological tests （word interference of Stroop： 36.1 ± 14.6 vs. 27.1 ± 11.1, t = 4.731, P 〈 0.001 ; shift time of TMT： 194.9 ± 115.4 vs. 124.8 ± 72.4, Z = -4.639, P 〈 0.001 ; false-belief task： χ^2 = 6.932, P = 0.008） and reports of daily life （global executive composite of BRIEF： 148.9 ± 17.5 vs. 127.8 ± 17.5, t =6.433, P 〈 0.001）. The performances on EF tasks for children with ADHD after EF training could match with the level of HC children. The ADHD symptoms （ADHD rating scale total score： 32.4 ± 8.9 vs. 22.9 ± 8.2, t = 6.331, P 〈 0.001） and behavioral problems of the children as reported by parents also reduced significantly after the intervention. Participants reported that the EF training program was feasible to administer and acceptable. Conclusions： The EF training program was feasible and acceptable to children with ADH D and parents. Although replication with a larger sample and an active control group are needed, EF training program with multiple EF focus and parent involving in real-life activities could be a potentially promising intervention associated with significant EF （near transfer） and ADHD symptoms improvement （far transfer）.
•Generalizability of mindfulness benefits to the executive system is unknown.•Mindfulness effects on inhibition, shifting, and updating processes are reviewed.•Results demonstrate a relatively ...specific as opposed to general benefit.•Mindfulness more consistently benefits inhibition than updating or shifting.
This paper focuses on evidence for mindfulness meditation-related benefits to executive functioning, processes important for much of human volitional behaviour. Miyake et al. (2000) have shown that executive functions can be fractionated into three distinct domains including inhibition, working memory updating, and mental set shifting. Considering these separable domains, it is important to determine whether the effects of mindfulness can generalize to all three sub-functions or are specific to certain domains. To address this, the current review applied Miyake et al.’s (2000) fractionated model of executive functioning to the mindfulness literature. Empirical studies assessing the benefits of mindfulness to measures tapping the inhibition, updating, and shifting components of executive functioning were examined. Results suggest a relatively specific as opposed to general benefit resulting from mindfulness, with consistent inhibitory improvement, but more variable advantages to the updating and shifting domains. Recommendations surrounding application of mindfulness practice and future research are discussed.
Beta oscillations (∼13 to 30 Hz) have been observed during many perceptual, cognitive, and motor processes in a plethora of brain recording studies. Although the function of beta oscillations ...(hereafter "beta" for short) is unlikely to be explained by any single monolithic description, we here discuss several convergent findings. In prefrontal cortex (PFC), increased beta appears at the end of a trial when working memory information needs to be erased. A similar "clear-out" function might apply during the stopping of action and the stopping of long-term memory retrieval (stopping thoughts), where increased prefrontal beta is also observed. A different apparent role for beta in PFC occurs during the delay period of working memory tasks: it might serve to maintain the current contents and/or to prevent interference from distraction. We confront the challenge of relating these observations to the large literature on beta recorded from sensorimotor cortex. Potentially, the clear-out of working memory in PFC has its counterpart in the postmovement clear-out of the motor plan in sensorimotor cortex. However, recent studies support alternative interpretations. In addition, we flag emerging research on different frequencies of beta and the relationship between beta and single-neuron spiking. We also discuss where beta might be generated: basal ganglia, cortex, or both. We end by considering the clinical implications for adaptive deep-brain stimulation.
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