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Recollecting positive and negative autobiographical memories disrupts working memory

Allen RJ, Schaefer A, Falcon T

Acta Psychol (Amst), 2014 Sep;151:237-43.
PMID: 25086225 DOI: 10.1016/j.actpsy.2014.07.003

The present article reports two experiments examining the impact of recollecting emotionally valenced autobiographical memories on subsequent working memory (WM) task performance. Experiment 1 found that negatively valenced recollection significantly disrupted performance on a supra-span spatial WM task. Experiment 2 replicated and extended these findings to a verbal WM task (digit recall), and found that both negative and positive autobiographical recollections had a detrimental effect on verbal WM. In addition, we observed that these disruptive effects were more apparent on early trials, immediately following autobiographical recollection. Overall, these findings show that both positive and negative affect can disrupt WM when the mood-eliciting context is based on autobiographical memories. Furthermore, these results indicate that the emotional disruption of WM can take place across different modalities of WM (verbal and visuo-spatial).
Variations in prestimulus neural activity predict the emotion-enhanced memory effect

Yick YY, Buratto LG, Schaefer A

Neuroreport, 2016 08 03;27(11):864-8.
PMID: 27295027 DOI: 10.1097/WNR.0000000000000628

Here, we report evidence that electrophysiological neural activity preceding the onset of emotional pictures can predict whether they will be remembered or forgotten 24 h later, whereas the same effect was not observed for neutral pictures. In contrast to previous research, we observed this effect using a paradigm in which participants could not predict the emotional or the neutral content of the pictures before their onset. These effects were obtained alongside significant behavioural effects of superior recognition memory for emotional compared with neutral items. These findings suggest that the preferential encoding of emotional events in memory is determined by fluctuations in the availability of processing resources just before event onset. This explanation argues in favour of mediational models of emotional memory, which contend that emotional information is preferentially encoded because it mobilizes a greater amount of processing resources than neutral information.
The effects of negative emotion on encoding-related neural activity predicting item and source recognition

Yick YY, Buratto LG, Schaefer A

Neuropsychologia, 2015 Jul;73:48-59.
PMID: 25936685 DOI: 10.1016/j.neuropsychologia.2015.04.030

We report here a study that obtained reliable effects of emotional modulation of a well-known index of memory encoding--the electrophysiological "Dm" effect--using a recognition memory paradigm followed by a source memory task. In this study, participants performed an old-new recognition test of emotionally negative and neutral pictures encoded 1 day before the test, and a source memory task involving the retrieval of the temporal context in which pictures had been encoded. Our results showed that Dm activity was enhanced for all emotional items on a late positivity starting at ~400 ms post-stimulus onset, although Dm activity for high arousal items was also enhanced at an earlier stage (200-400 ms). Our results also showed that emotion enhanced Dm activity for items that were both recognised with or without correct source information. Further, when only high arousal items were considered, larger Dm amplitudes were observed if source memory was accurate. Three main conclusions are drawn from these findings. First, negative emotion can enhance encoding processes predicting the subsequent recognition of central item information. Second, if emotion reaches high levels of arousal, the encoding of contextual details can also be enhanced over and above the effects of emotion on central item encoding. Third, the morphology of our ERPs is consistent with a hybrid model of the role of attention in emotion-enhanced memory (Pottage and Schaefer, 2012).
How do Asians perceive Caucasian eyes? Electrophysiological correlates of perceiving racial differences from the eyes region of the face

Yong MH, Lim XL, Schaefer A

Neurosci Lett, 2020 02 16;720:134759.
PMID: 31952988 DOI: 10.1016/j.neulet.2020.134759

Past research has found that several brain event-related potentials (ERPs) were sensitive to the perception of ethnic differences displayed on human faces. This body of research suggests that the phenomenon of "race perception" involves a cascade of cognitive processes that includes both automatic and overt attentional mechanisms. However, most of these studies used stimuli depicting whole faces rather than stimuli depicting separate facial features. Therefore, it is still largely unknown if ERP responses to racial differences are the result of a holistic processing of the whole face, or whether they can be accounted for by the perception of single facial features. To address this issue, we examined whether a single facial feature, the eyes region, can provide sufficient information to trigger known ERP correlates of race perception such as the P2, the N400 and the Late Positive Complex (LPC). Specifically, we showed pictures depicting only the eyes region of Caucasian and Asian faces to a sample of Asian participants. We found that the P2 was larger for other-race (OR) compared to same-race (SR) eyes, and that the N400 was larger for SR compared to OR eyes. The effects on the P2 may suggest an enhanced vigilance response to OR eyes whereas the N400 effect could reflect a signal of familiarity triggered by SR eyes. These results indicate that a specific facial feature, the eyes region, can account for known effects of race perception on early brain potentials. Our findings also indicate that well-known early neural correlates of race perception can be triggered in the absence of a holistic processing of the whole face.
Depressive symptoms mediate the longitudinal association between diabetes and subjective cognitive decline. Findings from a semirural multi-ethnic older population in Malaysia

Johar H, Schaefer A, Su TT

Prev Med, 2023 Feb;167:107390.
PMID: 36528114 DOI: 10.1016/j.ypmed.2022.107390

The potential role of psychological distress as the pathway linking diabetes and subjective cognitive decline (SCD) is still unclear. This study aims to investigate whether depressive symptoms mediate the relationship between diabetes and SCD in older adults. Baseline data from 3428 adults (55-94 years) of the South East Asia Community Observatory (SEACO), Malaysia were utilized. Subjective cognitive complaints (SCC) were recorded at baseline and five years later. Mediation analyses with non-parametric bootstrapping methods were employed. A proportion of 20% of participants without SCC at baseline reported a decline in SCC after 5 years of follow-up. Known diabetes (β = -0.13, SE = 0.05, p = 0.02) and depressive symptoms (ß = -0.18, SE = 0.05, p = 0.001) were independently associated with SCD. Previously diagnosed diabetes was associated with depressive symptoms at baseline (ß = 0.04, SE = 0.02, p = 0.01), and greater SCD at follow-up (β = -0.19, SE = 0.06, p = 0.001). Mediation analyses revealed that 9% of the association between diabetes and SCD was attributable to an indirect effect through depressive symptoms (ß = -0.01, 95% CI 0.02-0.001, p
Fulltext Differential effects of reward and punishment in decision making under uncertainty: a computational study

Duffin E, Bland AR, Schaefer A, de Kamps M

Front Neurosci, 2014;8:30.
PMID: 24600342 DOI: 10.3389/fnins.2014.00030

Computational models of learning have proved largely successful in characterizing potential mechanisms which allow humans to make decisions in uncertain and volatile contexts. We report here findings that extend existing knowledge and show that a modified reinforcement learning model, which has separate parameters according to whether the previous trial gave a reward or a punishment, can provide the best fit to human behavior in decision making under uncertainty. More specifically, we examined the fit of our modified reinforcement learning model to human behavioral data in a probabilistic two-alternative decision making task with rule reversals. Our results demonstrate that this model predicted human behavior better than a series of other models based on reinforcement learning or Bayesian reasoning. Unlike the Bayesian models, our modified reinforcement learning model does not include any representation of rule switches. When our task is considered purely as a machine learning task, to gain as many rewards as possible without trying to describe human behavior, the performance of modified reinforcement learning and Bayesian methods is similar. Others have used various computational models to describe human behavior in similar tasks, however, we are not aware of any who have compared Bayesian reasoning with reinforcement learning modified to differentiate rewards and punishments.
Fulltext Randomised prior feedback modulates neural signals of outcome monitoring

Mushtaq F, Wilkie RM, Mon-Williams MA, Schaefer A

Neuroimage, 2016 Jan 15;125:868-879.
PMID: 26497268 DOI: 10.1016/j.neuroimage.2015.10.046

Substantial evidence indicates that decision outcomes are typically evaluated relative to expectations learned from relatively long sequences of previous outcomes. This mechanism is thought to play a key role in general learning and adaptation processes but relatively little is known about the determinants of outcome evaluation when the capacity to learn from series of prior events is difficult or impossible. To investigate this issue, we examined how the feedback-related negativity (FRN) is modulated by information briefly presented before outcome evaluation. The FRN is a brain potential time-locked to the delivery of decision feedback and it is widely thought to be sensitive to prior expectations. We conducted a multi-trial gambling task in which outcomes at each trial were fully randomised to minimise the capacity to learn from long sequences of prior outcomes. Event-related potentials for outcomes (Win/Loss) in the current trial (Outcomet) were separated according to the type of outcomes that occurred in the preceding two trials (Outcomet-1 and Outcomet-2). We found that FRN voltage was more positive during the processing of win feedback when it was preceded by wins at Outcomet-1 compared to win feedback preceded by losses at Outcomet-1. However, no influence of preceding outcomes was found on FRN activity relative to the processing of loss feedback. We also found no effects of Outcomet-2 on FRN amplitude relative to current feedback. Additional analyses indicated that this effect was largest for trials in which participants selected a decision different to the gamble chosen in the previous trial. These findings are inconsistent with models that solely relate the FRN to prediction error computation. Instead, our results suggest that if stable predictions about future events are weak or non-existent, then outcome processing can be determined by affective systems. More specifically, our results indicate that the FRN is likely to reflect the activity of positive affective systems in these contexts. Importantly, our findings indicate that a multifactorial explanation of the nature of the FRN is necessary and such an account must incorporate affective and motivational factors in outcome processing.
Fulltext Local context influences memory for emotional stimuli but not electrophysiological markers of emotion-dependent attention

Barnacle GE, Tsivilis D, Schaefer A, Talmi D

Psychophysiology, 2018 04;55(4).
PMID: 29023754 DOI: 10.1111/psyp.13014

Emotional enhancement of free recall can be context dependent. It is readily observed when emotional and neutral scenes are encoded and recalled together in a "mixed" list, but diminishes when these scenes are encoded separately in "pure" lists. We examined the hypothesis that this effect is due to differences in allocation of attention to neutral stimuli according to whether they are presented in mixed or pure lists, especially when encoding is intentional. Using picture stimuli that were controlled for semantic relatedness, our results contradicted this hypothesis. The amplitude of well-known electrophysiological markers of emotion-related attention-the early posterior negativity (EPN), the late positive potential (LPP), and the slow wave (SW)-was higher for emotional stimuli. Crucially, the emotional modulation of these ERPs was insensitive to list context, observed equally in pure and mixed lists. Although list context did not modulate neural markers of emotion-related attention, list context did modulate the effect of emotion on free recall. The apparent decoupling of the emotional effects on attention and memory, challenges existing hypotheses accounting for the emotional enhancement of memory. We close by discussing whether findings are more compatible with an alternative hypothesis, where the magnitude of emotional memory enhancement is, at least in part, a consequence of retrieval dynamics.
Fulltext The Feedback-Related Negativity and the P300 Brain Potential Are Sensitive to Price Expectation Violations in a Virtual Shopping Task

Schaefer A, Buratto LG, Goto N, Brotherhood EV

PLoS One, 2016 09 22;11(9):e0163150.
PMID: 27658301 DOI: 10.1371/journal.pone.0163150

A large body of evidence shows that buying behaviour is strongly determined by consumers' price expectations and the extent to which real prices violate these expectations. Despite the importance of this phenomenon, little is known regarding its neural mechanisms. Here we show that two patterns of electrical brain activity known to index prediction errors-the Feedback-Related Negativity (FRN) and the feedback-related P300 -were sensitive to price offers that were cheaper than participants' expectations. In addition, we also found that FRN amplitude time-locked to price offers predicted whether a product would be subsequently purchased or not, and further analyses suggest that this result was driven by the sensitivity of the FRN to positive price expectation violations. This finding strongly suggests that ensembles of neurons coding positive prediction errors play a critical role in real-life consumer behaviour. Further, these findings indicate that theoretical models based on the notion of prediction error, such as the Reinforcement Learning Theory, can provide a neurobiologically grounded account of consumer behavior.
Fulltext Effects of Daytime Electric Light Exposure on Human Alertness and Higher Cognitive Functions: A Systematic Review

Siraji MA, Kalavally V, Schaefer A, Haque S

Front Psychol, 2021;12:765750.
PMID: 35069337 DOI: 10.3389/fpsyg.2021.765750

This paper reports the results of a systematic review conducted on articles examining the effects of daytime electric light exposure on alertness and higher cognitive functions. For this, we selected 59 quantitative research articles from 11 online databases. The review protocol was registered with PROSPERO (CRD42020157603). The results showed that both short-wavelength dominant light exposure and higher intensity white light exposure induced alertness. However, those influences depended on factors like the participants' homeostatic sleep drive and the time of day the participants received the light exposure. The relationship between light exposure and higher cognitive functions was not as straightforward as the alerting effect. The optimal light property for higher cognitive functions was reported dependent on other factors, such as task complexity and properties of control light. Among the studies with short-wavelength dominant light exposure, ten studies (morning: 3; afternoon: 7) reported beneficial effects on simple task performances (reaction time), and four studies (morning: 3; afternoon: 1) on complex task performances. Four studies with higher intensity white light exposure (morning: 3; afternoon: 1) reported beneficial effects on simple task performance and nine studies (morning: 5; afternoon: 4) on complex task performance. Short-wavelength dominant light exposure with higher light intensity induced a beneficial effect on alertness and simple task performances. However, those effects did not hold for complex task performances. The results indicate the need for further studies to understand the influence of short-wavelength dominant light exposure with higher illuminance on alertness and higher cognitive functions.
The Effects of Adult Aging and Culture on Theory of Mind

Yong MH, Lawrie L, Schaefer A, Phillips LH

J Gerontol B Psychol Sci Soc Sci, 2022 Feb 03;77(2):332-340.
PMID: 34036302 DOI: 10.1093/geronb/gbab093

OBJECTIVES: Older adults tend to have poorer Theory of Mind (ToM) than their younger counterparts, and this has been shown in both Western and Asian cultures. We examined the role of working memory (WM) in age differences in ToM, and whether this was moderated by education and culture (the United Kingdom vs. Malaysia).
METHODS: We used 2 ToM tests with differing demands on updating multiple mental states (false belief) and applying social rules to mental state processing (faux pas). We also looked at the role of education, socioeconomic status, and WM. A total of 298 participants from the United Kingdom and Malaysia completed faux pas, false belief, and WM tasks.
RESULTS: Age effects on some aspects of ToM were greater in the Malaysian compared to the UK sample. Malaysian older adults were poorer at faux pas detection, aspects of false belief, and WM compared to young adults. In subsequent moderated mediation analyses, we found that, specifically in the Malaysian sample, the mediating effects of WM on the age and ToM relationship occurred at the lowest levels of education.
DISCUSSION: This pattern of results may reflect changes in the familiarity and cognitive load of explicit mental state attribution, along with cultural differences in the pace and nature of cognitive aging. Cultural differences in education and WM should be considered when researching age differences in ToM.
Fulltext The Relationship Between Socioeconomic Status and Scalp Event-Related Potentials: A Systematic Review

Perera-W A H, Salehuddin K, Khairudin R, Schaefer A

Front Hum Neurosci, 2021;15:601489.
PMID: 33584228 DOI: 10.3389/fnhum.2021.601489

Several decades of behavioral research have established that variations in socioeconomic status (SES) are related to differences in cognitive performance. Neuroimaging and psychophysiological techniques have recently emerged as a method of choice to better understand the neurobiological processes underlying this phenomenon. Here we present a systematic review of a particular sub-domain of this field. Specifically, we used the PICOS approach to review studies investigating potential relationships between SES and scalp event-related brain potentials (ERP). This review found evidence that SES is related to amplitude variations in a diverse range of ERPs: P1, N1, N2, Error-Related Negativities (ERN), N400, auditory evoked potentials, negative difference waves (Nd), P3 and slow waves (SW). These ERPs include early, mid-latency and late potentials that reflect a broad range of cognitive processes (e.g., automatic attentional processes, overt attention, language, executive function, etc.). In this review, all SES effects on ERPs appeared to reflect an impairment or a less efficient form of task-related neural activity for low-SES compared to high-SES individuals. Overall, these results confirm that a wide variety of distinct neural processes with different functional meanings are sensitive to SES differences. The findings of this review also suggest that the relationship between SES and some ERP components may depend on the developmental stage of study participants. Results are further discussed in terms of the current limitations of this field and future avenues of research.
Fulltext The effects of a distracting N-back task on recognition memory are reduced by negative emotional intensity

Buratto LG, Pottage CL, Brown C, Morrison CM, Schaefer A

PLoS One, 2014;9(10):e110211.
PMID: 25330251 DOI: 10.1371/journal.pone.0110211

Memory performance is usually impaired when participants have to encode information while performing a concurrent task. Recent studies using recall tasks have found that emotional items are more resistant to such cognitive depletion effects than non-emotional items. However, when recognition tasks are used, the same effect is more elusive as recent recognition studies have obtained contradictory results. In two experiments, we provide evidence that negative emotional content can reliably reduce the effects of cognitive depletion on recognition memory only if stimuli with high levels of emotional intensity are used. In particular, we found that recognition performance for realistic pictures was impaired by a secondary 3-back working memory task during encoding if stimuli were emotionally neutral or had moderate levels of negative emotionality. In contrast, when negative pictures with high levels of emotional intensity were used, the detrimental effects of the secondary task were significantly attenuated.
Fulltext Feedback-related potentials in a gambling task with randomised reward

Mushtaq F, Guillen PP, Wilkie RM, Mon-Williams MA, Schaefer A

Data Brief, 2016 Mar;6:378-85.
PMID: 26862585 DOI: 10.1016/j.dib.2015.11.060

Event-related potentials (ERPs) time-locked to decision outcomes are reported. Participants engaged in a gambling task (see [1] for details) in which they decided between a risky and a safe option (presented as different coloured shapes) on each trial (416 in total). Each decision was associated with (fully randomised) feedback about the reward outcome (Win/Loss) and its magnitude (varying as a function of decision response; 5-9 points for Risky decisions and 1-4 points for Safe decisions). Here, we show data demonstrating: (a) the influence of Win feedback in the preceding outcome (Outcome t-1) on activity related to the current outcome (Outcome t ); (b) difference wave analysis for outcome expectancy- separating Expected Outcomes (consecutive Loss trials subtracted from consecutive reward) from Unexpected Outcomes (subtracting Loss t-1Win t trials from Win t-1Loss t trials); (c) difference waves separating Switch and Stay responses for Outcome Expectancy; (d) the effect of magnitude induced by decisions (Risk t vs. Safe t ) on Outcome Expectancy; and finally, (e) expectations reflected by response switch direction (Risk to Safe responses vs. Safe to Risk t ) on the FRN at Outcome t .
Fulltext Can Brain Waves Really Tell If a Product Will Be Purchased? Inferring Consumer Preferences From Single-Item Brain Potentials

Goto N, Lim XL, Shee D, Hatano A, Khong KW, Buratto LG, et al.

Front Integr Neurosci, 2019;13:19.
PMID: 31316357 DOI: 10.3389/fnint.2019.00019

Recent research has shown that event-related brain potentials (ERPs) recorded while participants view lists of different consumer goods can be modulated by their preferences toward these products. However, it remains largely unknown whether ERP activity specific to a single consumer item can be informative about whether or not this item will be preferred in a shopping context. In this study, we examined whether single-item ERPs could reliably predict consumer preferences toward specific consumer goods. We recorded scalp EEG from 40 participants while they were viewing pictures of consumer goods and we subsequently asked them to indicate their preferences for each of these items. Replicating previous results, we found that ERP activity averaged over the six most preferred products was significantly differentiated from ERP activity averaged across the six least preferred products for three ERP components: The N200, the late positive potential (LPP) and positive slow waves (PSW). We also found that using single-item ERPs to infer behavioral preferences about specific consumer goods led to an overall predictive accuracy of 71%, although this figure varied according to which ERPs were targeted. Later positivities such as the LPP and PSW yielded relatively higher predictive accuracy rates than the frontal N200. Our results suggest that ERPs related to single consumer items can be relatively accurate predictors of behavioral preferences depending on which type of ERP effects are chosen by the researcher, and ultimately on the level of prediction errors that users choose to tolerate.
Fulltext The Effects of Adult Ageing and Culture on the Tower of London Task

Phillips LH, Lawrie L, Schaefer A, Tan CY, Yong MH

Front Psychol, 2021;12:631458.
PMID: 33692728 DOI: 10.3389/fpsyg.2021.631458

Planning ability is important in everyday functioning, and a key measure to assess the preparation and execution of plans is the Tower of London (ToL) task. Previous studies indicate that older adults are often less accurate than the young on the ToL and that there may be cultural differences in performance on the task. However, potential interactions between age and culture have not previously been explored. In the current study we examined the effects of age on ToL performance in an Asian culture (Malaysia) and a Western culture (British) (n = 191). We also explored whether working memory, age, education, and socioeconomic status explained variance in ToL performance across these two cultures. Results indicated that age effects on ToL performance were greater in the Malaysian sample. Subsequent moderated mediation analysis revealed differences between the two cultures (British vs Malaysians), in that the age-related variance in ToL accuracy was accounted for by WM capacity at low and medium education levels only in the Malaysian sample. Demographic variables could not explain additional variance in ToL speed or accuracy. These results may reflect cultural differences in the familiarity and cognitive load of carrying out complex planning tasks.
Fulltext Neural signals of selective attention are modulated by subjective preferences and buying decisions in a virtual shopping task

Goto N, Mushtaq F, Shee D, Lim XL, Mortazavi M, Watabe M, et al.

Biol Psychol, 2017 09;128:11-20.
PMID: 28666891 DOI: 10.1016/j.biopsycho.2017.06.004

We investigated whether well-known neural markers of selective attention to motivationally-relevant stimuli were modulated by variations in subjective preference towards consumer goods in a virtual shopping task. Specifically, participants viewed and rated pictures of various goods on the extent to which they wanted each item, which they could potentially purchase afterwards. Using the event-related potentials (ERP) method, we found that variations in subjective preferences for consumer goods strongly modulated positive slow waves (PSW) from 800 to 3000 milliseconds after stimulus onset. We also found that subjective preferences modulated the N200 and the late positive potential (LPP). In addition, we found that both PSW and LPP were modulated by subsequent buying decisions. Overall, these findings show that well-known brain event-related potentials reflecting selective attention processes can reliably index preferences to consumer goods in a shopping environment. Based on a large body of previous research, we suggest that early ERPs (e.g. the N200) to consumer goods could be indicative of preferences driven by unconditional and automatic processes, whereas later ERPs such as the LPP and the PSW could reflect preferences built upon more elaborative and conscious cognitive processes.
Distinct Neural Signatures of Outcome Monitoring After Selection and Execution Errors

Mushtaq F, McDougle SD, Craddock MP, Parvin DE, Brookes J, Schaefer A, et al.

J Cogn Neurosci, 2022 Jan 28.
PMID: 35104323 DOI: 10.1162/jocn_a_01824

Losing a point in tennis could result from poor shot selection or faulty stroke execution. To explore how the brain responds to these different types of errors, we examined feedback-locked EEG activity while participants completed a modified version of a standard three-armed bandit probabilistic reward task. Our task framed unrewarded outcomes as the result of either errors of selection or errors of execution. We examined whether amplitude of a medial frontal negativity (the feedback-related negativity [FRN]) was sensitive to the different forms of error attribution. Consistent with previous reports, selection errors elicited a large FRN relative to rewards, and amplitude of this signal correlated with behavioral adjustment after these errors. A different pattern was observed in response to execution errors. These outcomes produced a larger FRN, a frontocentral attenuation in activity preceding this component, and a subsequent enhanced error positivity in parietal sites. Notably, the only correlations with behavioral adjustment were with the early frontocentral attenuation and amplitude of the parietal signal; FRN differences between execution errors and rewarded trials did not correlate with subsequent changes in behavior. Our findings highlight distinct neural correlates of selection and execution error processing, providing insight into how the brain responds to the different classes of error that determine future action.
Moving into a new era of periodontal genetic studies: relevance of large case-control samples using severe phenotypes for genome-wide association studies

Vaithilingam RD, Safii SH, Baharuddin NA, Ng CC, Cheong SC, Bartold PM, et al.

J Periodontal Res, 2014 Dec;49(6):683-95.
PMID: 24528298 DOI: 10.1111/jre.12167

Studies to elucidate the role of genetics as a risk factor for periodontal disease have gone through various phases. In the majority of cases, the initial 'hypothesis-dependent' candidate-gene polymorphism studies did not report valid genetic risk loci. Following a large-scale replication study, these initially positive results are believed to be caused by type 1 errors. However, susceptibility genes, such as CDKN2BAS (Cyclin Dependend KiNase 2B AntiSense RNA; alias ANRIL [ANtisense Rna In the Ink locus]), glycosyltransferase 6 domain containing 1 (GLT6D1) and cyclooxygenase 2 (COX2), have been reported as conclusive risk loci of periodontitis. The search for genetic risk factors accelerated with the advent of 'hypothesis-free' genome-wide association studies (GWAS). However, despite many different GWAS being performed for almost all human diseases, only three GWAS on periodontitis have been published - one reported genome-wide association of GLT6D1 with aggressive periodontitis (a severe phenotype of periodontitis), whereas the remaining two, which were performed on patients with chronic periodontitis, were not able to find significant associations. This review discusses the problems faced and the lessons learned from the search for genetic risk variants of periodontitis. Current and future strategies for identifying genetic variance in periodontitis, and the importance of planning a well-designed genetic study with large and sufficiently powered case-control samples of severe phenotypes, are also discussed.
Fulltext Frontal theta brain activity varies as a function of surgical experience and task error

Balkhoyor AM, Awais M, Biyani S, Schaefer A, Craddock M, Jones O, et al.

BMJ Surg Interv Health Technol, 2020;2(1):e000040.
PMID: 35047792 DOI: 10.1136/bmjsit-2020-000040

OBJECTIVE: Investigations into surgical expertise have almost exclusively focused on overt behavioral characteristics with little consideration of the underlying neural processes. Recent advances in neuroimaging technologies, for example, wireless, wearable scalp-recorded electroencephalography (EEG), allow an insight into the neural processes governing performance. We used scalp-recorded EEG to examine whether surgical expertise and task performance could be differentiated according to an oscillatory brain activity signal known as frontal theta-a putative biomarker for cognitive control processes.
DESIGN SETTING AND PARTICIPANTS: Behavioral and EEG data were acquired from dental surgery trainees with 1 year (n=25) and 4 years of experience (n=20) while they performed low and high difficulty drilling tasks on a virtual reality surgical simulator. EEG power in the 4-7 Hz range in frontal electrodes (indexing frontal theta) was examined as a function of experience, task difficulty and error rate.
RESULTS: Frontal theta power was greater for novices relative to experts (p=0.001), but did not vary according to task difficulty (p=0.15) and there was no Experience × Difficulty interaction (p=0.87). Brain-behavior correlations revealed a significant negative relationship between frontal theta and error in the experienced group for the difficult task (r=-0.594, p=0.0058), but no such relationship emerged for novices.
CONCLUSION: We find frontal theta power differentiates between surgical experiences but correlates only with error rates for experienced surgeons while performing difficult tasks. These results provide a novel perspective on the relationship between expertise and surgical performance.

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