No Frequency-Specific Effect of Transcranial Random Noise Stimulation on Resting EEG.

BACKGROUND: Transcranial random noise stimulation (tRNS) is a form of noninvasive transcranial electrical stimulation that applies alternating current in various randomized frequencies to the cortex, thereby improving cognitive functioning in multiple domains. However, the precise mechanism of tRNS, as well as its impact on human electroencephalography (EEG), remains unclear. This is partly because most studies have used tRNS in conjunction with a cognitive task, making it difficult to tease apart whether the observed changes in EEG are a result of tRNS, the cognitive task, or their interaction. METHODS: Forty-nine healthy individuals participated in this study and were randomly assigned to active tRNS (n = 24) and sham (n = 25) groups. tRNS was delivered for 20 minutes over Fp1/Fp2 and Oz. Resting-state EEG data were collected before and after either tRNS or sham stimulation. RESULTS: Cluster-based permutation tests using FieldTrip revealed no frequency-specific effect of tRNS on resting-state EEG data across four frequency bands (theta, alpha, beta, gamma). CONCLUSIONS: These observations suggest that tRNS itself does not target or alter specific EEG frequencies. Rather, tRNS most likely interacts with the cognitive task/activity at hand to produce an observable difference in post-tRNS EEG. Positive tRNS-EEG findings from previous studies are also likely to have resulted from the interactive and cognitive activity-dependent nature of tRNS.

Comparative effectiveness of psychotherapies in adults with posttraumatic stress disorder: a network meta-analysis of randomised controlled trials.

BACKGROUND: Evidence on the long-term comparative effectiveness of posttraumatic stress disorder (PTSD) psychotherapies in adults remains unknown. Therefore, we performed an extensive network meta-analysis of randomised controlled trials (RCTs) to determine the comparative effectiveness of psychotherapies for people diagnosed with PTSD. METHODS: A comprehensive search was conducted in Cochrane library, Embase, Medline-OVID, PubMed, Scopus, and Psych-Info until March 2021. Studies on the effectiveness of cognitive processing therapy (CPT), cognitive therapy (CT), eye movement desensitisation reprocessing (EMDR), narrative exposure therapy (NET), prolonged exposure (PE), cognitive behavioural therapy (CBT), present-centred therapy (PCT), brief eclectic psychotherapies (BEP), psychodynamic therapy (PDT) or combination therapies compared to no treatment (NT) or treatment as usual (TAU) in adults with PTSD were included. Frequentist and Bayesian approaches were used for analysis in R-software. RESULTS: We included 98 RCTs with 5567 participants from 18 897 studies. CPT, EMDR, CT, NET, PE, CBT, and PCT were significant to reduce PTSD symptoms (SMD range: -1.53 to -0.75; Certainty: very low to high) at immediate post-treatment and ranked accordingly. Longitudinal analysis found EMDR (1.02) and CPT (0.85) as the significant therapies with large effect size in short-term and long-term follow-up, respectively. NET and CPT showed higher proportion of loss of PTSD diagnosis (RR range: 5.51-3.45) while there were no significant psychotherapies for retention rate compared to NT. CONCLUSIONS: Our findings provide evidence for improving current guidelines and informing clinical decision-making for PTSD management. However, the best PTSD treatment plan should be tailored to patients' needs, characteristics, and clinician expertise. REGISTRATION: PROSPERO CRD42020162143.

Construction and evaluation of multidomain attention training to improve alertness attention, sustained attention, and visual-spatial attention in older adults with mild cognitive impairment: A randomized controlled trial.

OBJECTIVES: We aimed to analyze the effects of multidomain attention training on alertness, sustained attention, and visual-spatial attention in older adults with mild cognitive impairment (MCI). DESIGN: The design used in this study was a two-arm, parallel group, double-blind randomized controlled trial. SETTING AND PARTICIPANTS: The participants of the study were seventy-eight older adults with MCI (mean age: 79.5 ± 7.9 years) from retirement centers and community housing for the elderly. INTERVENTION: The participants were randomly assigned to an experimental group (multidomain attention training, n = 39) or an active control group (n = 39). Both groups underwent training sessions for 45 minutes three times per week for 6 weeks (18 sessions in total). MEASURES: The main efficacy indicator was alertness (Trail Making Test Part B), sustained attention (Digit Vigilance Test), and visual-spatial attention (Trail Making Test Part A). The secondary outcome indicators were other cognitive functions (Mini-Mental State Examination [MMSE] and Montreal Cognitive Assessment [MoCA] subscales). Measurements were obtained at pretest, posttest, and 3 and 6 months after training. RESULTS: The results were analyzed by a generalized estimating equation (GEE), which indicated that attention outcomes (alertness, sustained attention, and visual-spatial attention) of the experimental group did not improve after training. However, the experimental group displayed a significant improvement in the attention, memory, and orientation of MMSE and MoCA subscales over a period of 6 months and also showed superior results compared with the control group. CONCLUSIONS: Multidomain attention training demonstrated improved alertness and visual-spatial attention for posttest after 6 months. We also outline potential future advances in attention training for improving attention in older adults with MCI.

The Construction and Evaluation of Executive Attention Training to Improve Selective Attention, Focused Attention, and Divided Attention for Older Adults With Mild Cognitive Impairment: A Randomized Controlled Trial.

OBJECTIVES: To examine the immediate and long-term effects of executive attention training on selective attention, focused attention, and divided attention in older adults with mild cognitive impairment. METHODS: A double-blind, multisite randomized controlled trial at five sites. Seventy participants (mean age: 78.19 ± 7.22 years) were assigned to an experimental group (executive attention training, n = 35) or an active control group (n = 35). The training duration was the same for both groups (45 minutes per session, 3 times per week, 18 sessions in total). Primary outcome measure was selective attention (Digit Span Task). Secondary outcome measures included focused attention (Stroop Color Word Test) and divided attention (Trail-Making Test Part B). Data were collected at pretest, post-test, 3-month follow-up, and 6-month follow-up. RESULTS: In GEE analysis, findings indicated a significant improvement in selective attention at post-test, whereas divided attention showed significant reducing omission error at 3-month follow-up. There was no significant effect of group in focused attention associated with the executive attention training compared with active control group. CONCLUSION: The executive attention training significantly improved selective attention and divided attention performance. Future studies should identify transfer effects of attention training, and that can employ early screening to provide integrated attention training, and decrease its relevant risks on competency in performing daily activities, such as falling and driving.

Development and effectiveness of virtual interactive working memory training for older people with mild cognitive impairment: a single-blind randomised controlled trial.

BACKGROUND: memory training is a potential intervention for retaining memory and reducing dementia risk in older adults with mild cognitive impairment (MCI). OBJECTIVE: this study examined the effect of virtual interactive working memory training (VIMT) in older adults with MCI. DESIGN: single-blind, two-arm parallel-group, randomised controlled design. SETTING: retirement homes, institutions, and communities. SUBJECTS: a total of 66 older adults with MCI were recruited (mean age: 78.5 ± 7.6 years). METHODS: participants were randomly assigned to the experimental group (VIMT, n = 33) or active control group (n = 33). The VIMT program used the CogniPlus (includes four training modules). Both groups attended 45 min sessions 3 times per week, a total of 36 sessions. The primary outcome was working memory; secondary outcomes were immediate memory, delayed memory, subjective memory complaints and global cognitive function. All variables were measured at pre-test, post-test, and 3-month follow-up. RESULTS: between group, the effect of working memory adjusted mean difference by 1.75 (95% CI: 0.56 to 2.94; P < 0.01) at post-test. The results were analysed by a generalised estimating equation, which indicated that VIMT group significantly improved working memory at post-test (P = 0.01) relative to the active control group. CONCLUSIONS: the applied VIMT program can enable older adults with MCI to maintain their working memory and reduce the rate of cognitive deterioration. TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov (no.: NCT02462135).

Electrophysiological markers of working memory usage as an index for truth-based lies.

People prefer to lie using altered truthful events from memory, perhaps because doing so can increase their credibility while reducing cognitive and working memory (WM) load. One possible way to counter such deceptive behavior is to track WM usage, since fabricating coherent lies or managing between truth and lies is likely to involve heavy WM load. In this study, participants memorized a list of words in the study session and used these old words to provide deceptive answers when cued later, in the testing session. Our behavioral results showed that people needed more time to make a deceptive response during the execution stage, and this prolonged deceptive reaction time (RT) was negatively correlated with each participant's WM capacity. Event-related potential findings showed a more negative-going frontal amplitude between the lie and truth conditions during the preparation stage, suggesting that WM preparatory processes can be detected long before a deceptive response is verbalized. Furthermore, we observed a larger positive frontal-central amplitude during the execution stage, which was negatively correlated with participants' lie-truth RT differences, suggesting that participants' efficiency in producing deceptive responses can be readily traced electrophysiologically. Together, these findings suggest that WM capacity and preparation are crucial to efficient lying and that their related electrophysiological signatures can potentially be used to uncover deceptive behaviors.

The 72-year-old grad student.

The work of Bruce Bridgeman touches on a wide range of topics that include masking, saccadic suppression, microsaccades, space constancy, perception, action, and consciousness. In this tribute, I try to introduce some of Bruce's work, while adding some personal stories. I hope this tribute would serve as a pointer for the readership to more of Bruce's pioneering work.

Attention and memory-driven effects in action studies.

We provide empirical examples to conceptually clarify some items on Firestone & Scholl's (F&S's) checklist, and to explain perceptual effects from an attentional and memory perspective. We also note that action and embodied cognition studies seem to be most susceptible to misattributing attentional and memory effects as perceptual, and identify four characteristics unique to action studies and possibly responsible for misattributions.

Brain stimulation improves cognitive control by modulating medial-frontal activity and preSMA-vmPFC functional connectivity.

Previous research has demonstrated that brain stimulation can improve inhibitory control. However, the neural mechanisms underlying such artificially induced improvement remain unclear. In this study, by coupling anodal transcranial direct current stimulation (atDCS) with functional MRI, we found that atDCS over preSMA effectively improved stopping speed, which was associated with increased BOLD response in the preSMA and ventromedial prefrontal cortex (vmPFC). Furthermore, such atDCS-induced BOLD increase in vmPFC was positively correlated with participants' improvement in stopping efficiency, and the functional connectivity between preSMA and vmPFC increased during successful stop. These results suggest that the rapid behavioral improvement from preSMA brain stimulation involves modulated medial-frontal activity and preSMA-vmPFC functional connectivity.

The relationship between aerobic fitness and neural oscillations during visuo-spatial attention in young adults.

While the cognitive benefits of aerobic fitness have been widely investigated, current findings in young adults remain unclear. Specifically, little is known about how these effects are reflected in the time-frequency domain. This study thus assessed the relationship between aerobic fitness and neural oscillations during visuo-spatial attention. A between-subjects design that included 20 participants with higher aerobic fitness (age = 21.95 ± 2.24 years; VO2max = 58.98 ± 6.94 ml/kg/min) and 20 age- and gender-matched lower aerobic fitness participants (age = 23.25 ± 2.07 years; VO2max = 35.87 ± 3.41 ml/kg/min) was used to examine the fitness-related differences in performance and neuroelectric indexes during a Posner visuo-spatial attention paradigm. The results demonstrated that high-fitness participants, in comparison with their low-fitness counterparts, showed faster reaction times as well as greater modulation of oscillatory theta and beta power during target processing, regardless of cue types. Moreover, the neurocognitive correlation showed that higher theta power was related to better task performance. Collectively, these findings suggest that aerobic fitness is associated with general enhanced attentional control in relation to visuo-spatial processing, as evidenced through greater motor preparation and in particular the up-regulation of attentional processing in healthy young adults. The present study may contribute to current knowledge by revealing the relationship between aerobic fitness and modulation of brain oscillations.

Transcranial direct current stimulation over right posterior parietal cortex changes prestimulus alpha oscillation in visual short-term memory task.

Alpha band activity changes accompanied with the level attentional state, and recent studies suggest that such oscillation is associated with activities in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively-charged electric current through the skull can rapidly and effortlessly change people's prestimulus alpha power and improve subsequent performance on a visual short-term memory (VSTM) task. This modulation of alpha power and behavioral performance, however, is dependent on people's natural VSTM capability such that only the low performers benefitted from the stimulation, whereas high performers did not. This behavioral dichotomy is accounted by prestimulus alpha powers around the parieto-occipital regions: low performers showed decreased prestimulus alpha power, suggesting improvement in attention deployment in the current paradigm, whereas the high performers did not benefit from tDCS as they showed equally-low prestimulus alpha power before and after the stimulation. Together, these results suggest that prestimulus alpha power, especially in low performers, can be modulated by anodal stimulation and alter subsequent VSTM performance/capacity. Thus, measuring alpha before stimulus onset may be as important as measuring other VSTM-related electrophysiological components such as attentional allocation and memory capacity related components (i.e. N2 posterior-contralateral, N2pc, or contralateral delay activity, CDA). In addition, low VSTM performers perhaps do not suffer not only from poor VSTM capacity, but also from broad attentional mechanisms, and prestimulus alpha may be an useful tool in understanding the nature of individual differences in VSTM.

Revealing the brain's adaptability and the transcranial direct current stimulation facilitating effect in inhibitory control by multiscale entropy.

The abilities to inhibit impulses and withdraw certain responses are critical for human's survival in a fast-changing environment. These processes happen fast, in a complex manner, and sometimes are difficult to capture with fMRI or mean electrophysiological brain signal alone. Therefore, an alternative measure that can reveal the efficiency of the neural mechanism across multiple timescales is needed for the investigation of these brain functions. The present study employs a new approach to analyzing electroencephalography (EEG) signal: the multiscale entropy (MSE), which groups data points with different timescales to reveal any occurrence of repeated patterns, in order to theoretically quantify the complexity (indicating adaptability and efficiency) of neural systems during the process of inhibitory control. From this MSE perspective, EEG signals of successful stop trials are more complex and information rich than that of unsuccessful stop trials. We further applied transcranial direct current stimulation (tDCS), with anodal electrode over presupplementary motor area (preSMA), to test the relationship between behavioral modification with the complexity of EEG signals. We found that tDCS can further increase the EEG complexity of the frontal lobe. Furthermore, the MSE pattern was found to be different between high and low performers (divided by their stop-signal reaction time), where the high-performing group had higher complexity in smaller scales and less complexity in larger scales in comparison to the low-performing group. In addition, this between-group MSE difference was found to interact with the anodal tDCS, where the increase of MSE in low performers benefitted more from the anodal tDCS. Together, the current study demonstrates that participants who suffer from poor inhibitory control can efficiently improve their performance with 10min of electrical stimulation, and such cognitive improvement can be effectively traced back to the complexity within the EEG signals via MSE analysis, thereby offering a theoretical basis for clinical intervention via tDCS for deficits in inhibitory control.

Modulating the interference effect on spatial working memory by applying transcranial direct current stimulation over the right dorsolateral prefrontal cortex.

Spatial working memory (SWM) is the ability to temporarily store and manipulate spatial information. It has a limited capacity and is quite vulnerable to interference. Dorsolateral prefrontal cortex (DLPFC) has been shown to be a part of the SWM network but its specific functional role still remains unknown. Here we applied transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique that provides polarity-specific stimulation over the targeted region, to investigate the specific role of the right DLPFC in resolving interference in SWM. A forward- and backward-recall computerized Corsi Block Tapping task (CBT), both with and without a concurrent motor interference task (the modified Luria manual sequencing task) was used to measure SWM capacity and reaction time. The results showed that motor interference impeded accuracy and prolonged reaction time in forward and backward recall for SWM. Anodal tDCS over right DLPFC yielded the tendency to shorten participants' reaction time in the conditions with interference (forward with interference, and backward with interference). Most importantly, anodal tDCS significantly improved participants' SWM span when cognitive demand was the highest (the "backward-recall with motor interference" condition). These results suggest that (1) the right DLPFC plays a crucial role in dealing with the cross-domain motor interference for spatial working memory and (2) the anodal tDCS over right DLPFC improved SWM capacity particularly when task difficulty demands more complex mental manipulations that could be due to the facilitatory effect of anodal tDCS which enhanced the DLPFC function within central executive system at the top-down attentional level.

The association of physical activity to neural adaptability during visuo-spatial processing in healthy elderly adults: A multiscale entropy analysis.

Physical activity has been shown to benefit brain and cognition in late adulthood. However, this effect is still unexplored in terms of brain signal complexity, which reflects the level of neural adaptability and efficiency during cognitive processing that cannot be acquired via averaged neuroelectric signals. Here we employed multiscale entropy analysis (MSE) of electroencephalography (EEG), a new approach that conveys important information related to the temporal dynamics of brain signal complexity across multiple time scales, to reveal the association of physical activity with neural adaptability and efficiency in elderly adults. A between-subjects design that included 24 participants (aged 66.63±1.31years; female=12) with high physical activity and 24 age- and gender-matched low physical activity participants (aged 67.29±1.20years) was conducted to examine differences related to physical activity in performance and MSE of EEG signals during a visuo-spatial cognition task. We observed that physically active elderly adults had better accuracy on both visuo-spatial attention and working memory conditions relative to their sedentary counterparts. Additionally, these physically active elderly adults displayed greater MSE values at larger time scales at the Fz electrode in both attention and memory conditions. The results suggest that physical activity may be beneficial for adaptability of brain systems in tasks involving visuo-spatial information. MSE thus might be a promising approach to test the effects of the benefits of exercise on cognition.

Functional blindsight and its diagnosis.

Even when brain scans fail to detect a striate lesion, functional evidence for blindsight can be adduced. In the aftermath of an automobile accident, JK became blind. Results of ophthalmic exams indicated that the blindness must be cortical. Nevertheless, multiple MRI scans failed to detect structural damage to the striate cortex. Prior to the accident JK had been an athlete; after the accident he retained some athletic abilities, arousing suspicions that he might be engaged in fraud. His residual athletic abilities-e.g., hitting a handball or baseball, or catching a Frisbee-coupled with his experienced blindness, suggested blindsight. But due to the apparent absence of striate lesions, we designed a series of tasks for temporal and spatial dimensions in an attempt to detect functional evidence of his disability. Indeed, test results revealed compelling neural evidence that comport with his subjective reports. This spatiotemporal task-related method that includes contrasts with healthy controls, and detailed understanding of the patient's conscious experience, can be generalized for clinical, scientific and forensic investigations of blindsight.

Unleashing potential: transcranial direct current stimulation over the right posterior parietal cortex improves change detection in low-performing individuals.

The limits of human visual short-term memory (VSTM) have been well documented, and recent neuroscientific studies suggest that VSTM performance is associated with activity in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively charged electric current through the skull can rapidly and effortlessly improve people's VSTM performance. This artificial improvement, however, comes with an interesting twist: it interacts with people's natural VSTM capability such that low performers who tend to remember less information benefitted from the stimulation, whereas high performers did not. This behavioral dichotomy is explained by event-related potentials around the parietal regions: low performers showed increased waveforms in N2pc and contralateral delay activity (CDA), which implies improvement in attention deployment and memory access in the current paradigm, respectively. Interestingly, these components are found during the presentation of the test array instead of the retention interval, from the parietal sites ipsilateral to the target location, thus suggesting that transcranial direct current stimulation (tDCS) was mainly improving one's ability to suppress no-change distractors located on the irrelevant side of the display during the comparison stage. The high performers, however, did not benefit from tDCS as they showed equally large waveforms in N2pc and CDA, or SPCN (sustained parietal contralateral negativity), before and after the stimulation such that electrical stimulation could not help any further, which also accurately accounts for our behavioral observations. Together, these results suggest that there is indeed a fixed upper limit in VSTM, but the low performers can benefit from neurostimulation to reach that maximum via enhanced comparison processes, and such behavioral improvement can be directly quantified and visualized by the magnitude of its associated electrophysiological waveforms.

Right temporoparietal junction and attentional reorienting.

The interaction between goal-directed and stimulus-driven attentional control allows humans to rapidly reorient to relevant objects outside the focus of attention--a phenomenon termed contingent reorienting. Neuroimaging studies have observed activation of the ventral and dorsal attentional networks, but specific involvement of each network remains unclear. The present study aimed to determine whether both networks are critical to the processes of top-down contingent reorienting. To this end, we combined the contingent attentional capture paradigm with the use of transcranial magnetic stimulation (TMS) to interfere with temporoparietal junction (TPJ; ventral network) and frontal eye field (dorsal network) activity. The results showed that only right TPJ (rTPJ) TMS modulated contingent orienting. Furthermore, this modulation was highly dependent on visual fields: rTPJ TMS increased contingent capture in the left visual field and decreased the effect in the right visual field. These results demonstrate a critical involvement of the ventral network in attentional reorienting and reveal the spatial selectivity within such network.

Family favouring effects across intent and outcome-based moral judgements and decisions.

Doing harm is a moral violation, but helping a family member is morally obligatory. In this study, participants encountered this ethical dilemma through stories featuring their sibling (i.e., brother) as either the perpetrator or victim in various moral scenarios. Subsequently, they provided their moral judgements (i.e., moral acceptability and perceived transgression) and made decisions (i.e., willingness and difficulty to disclose what the agent did to the police) regarding the perpetrator. The manipulation of family membership was integrated into the moral scenarios, which were crafted based on whether the perpetrator had malicious intent and whether those intentions resulted in a harmful outcome (i.e., intentional harm, failed attempts to harm, accidental harm, and a harmless/baseline). While we initially expected that individuals would exhibit favouritism towards their brother when harmful intent or outcomes were absent, our findings revealed that both agent/victim identities (brother/stranger) and intent-outcome-based moral scenarios had an additive effect on both measures of moral judgement. This suggests that the family favouring effect was observed across all intent-outcome scenarios, with a slightly more pronounced effect when the brother accidentally harmed a stranger compared to a stranger accidentally harming the brother. Regarding moral decisions, participants demonstrated a willingness to disclose what they witnessed regardless of their familial relationship with the agent or victim, but it was universally perceived as a difficult decision to make. Together, our results underscore the context-specific nature of moral judgements and decisions, emphasising the significant impact of family members when they are involved as moral characters.