Collective remembering and future forecasting during the COVID-19 pandemic: How the impact of COVID-19 affected the themes and phenomenology of global and national memories across 15 countries.

The COVID-19 pandemic created a unique set of circumstances in which to investigate collective memory and future simulations of events reported during the onset of a potentially historic event. Between early April and late June 2020, we asked over 4,000 individuals from 15 countries across four continents to report on remarkable (a) national and (b) global events that (i) had happened since the first cases of COVID-19 were reported, and (ii) they expected to happen in the future. Whereas themes of infections, lockdown, and politics dominated global and national past events in most countries, themes of economy, a second wave, and lockdown dominated future events. The themes and phenomenological characteristics of the events differed based on contextual group factors. First, across all conditions, the event themes differed to a small yet significant degree depending on the severity of the pandemic and stringency of governmental response at the national level. Second, participants reported national events as less negative and more vivid than global events, and group differences in emotional valence were largest for future events. This research demonstrates that even during the early stages of the pandemic, themes relating to its onset and course were shared across many countries, thus providing preliminary evidence for the emergence of collective memories of this event as it was occurring. Current findings provide a profile of past and future collective events from the early stages of the ongoing pandemic, and factors accounting for the consistencies and differences in event representations across 15 countries are discussed.

A comparison of sunitinib with cabozantinib, crizotinib, and savolitinib for treatment of advanced papillary renal cell carcinoma: a randomised, open-label, phase 2 trial.

BACKGROUND: MET (also known as hepatocyte growth factor receptor) signalling is a key driver of papillary renal cell carcinoma (PRCC). Given that no optimal therapy for metastatic PRCC exists, we aimed to compare an existing standard of care, sunitinib, with the MET kinase inhibitors cabozantinib, crizotinib, and savolitinib for treatment of patients with PRCC. METHODS: We did a randomised, open-label, phase 2 trial done in 65 centres in the USA and Canada. Eligible patients were aged 18 years or older with metastatic PRCC who had received up to one previous therapy (excluding vascular endothelial growth factor-directed and MET-directed agents). Patients were randomly assigned to receive sunitinib, cabozantinib, crizotinib, or savolitinib, with stratification by receipt of previous therapy and PRCC subtype. All drug doses were administered orally: sunitinib 50 mg, 4 weeks on and 2 weeks off (dose reductions to 37·5 mg and 25 mg allowed); cabozantinib 60 mg daily (reductions to 40 mg and 20 mg allowed); crizotinib 250 mg twice daily (reductions to 200 mg twice daily and 250 mg once daily allowed); and savolitinib 600 mg daily (reductions to 400 mg and 200 mg allowed). Progression-free survival (PFS) was the primary endpoint. Analyses were done in an intention-to-treat population, with patients who did not receive protocol therapy excluded from safety analyses. This trial is registered with ClinicalTrials.gov, NCT02761057. FINDINGS: Between April 5, 2016, and Dec 15, 2019, 152 patients were randomly assigned to one of four study groups. Five patients were identified as ineligible post-randomisation and were excluded from these analyses, resulting in 147 eligible patients. Assignment to the savolitinib (29 patients) and crizotinib (28 patients) groups was halted after a prespecified futility analysis; planned accrual was completed for both sunitinib (46 patients) and cabozantinib (44 patients) groups. PFS was longer in patients in the cabozantinib group (median 9·0 months, 95% CI 6-12) than in the sunitinib group (5·6 months, 3-7; hazard ratio for progression or death 0·60, 0·37-0·97, one-sided p=0·019). Response rate for cabozantinib was 23% versus 4% for sunitinib (two-sided p=0·010). Savolitinib and crizotinib did not improve PFS compared with sunitinib. Grade 3 or 4 adverse events occurred in 31 (69%) of 45 patients receiving sunitinib, 32 (74%) of 43 receiving cabozantinib, ten (37%) of 27 receiving crizotinib, and 11 (39%) of 28 receiving savolitinib; one grade 5 thromboembolic event was recorded in the cabozantinib group. INTERPRETATION: Cabozantinib treatment resulted in significantly longer PFS compared with sunitinib in patients with metastatic PRCC. FUNDING: National Institutes of Health and National Cancer Institute.

Predictors of obsessive-compulsive symptomology: mind wandering about the past and future.

PURPOSE: Obsessive and compulsive tendencies are known to occur in the general population and involve worry around specific concerns (obsessions) and an urge to resolve the concern with thoughts or behaviours (compulsions). Spontaneous, but not deliberate, mind wandering experiences (when attention turns to internal mentation), have been found to predict obsessive- compulsive tendencies [Seli, P., Risko, E.F., Purdon, C. & Smilek, D. (2017). Intrusive thoughts: linking spontaneous mind wandering and OCD symptomatology. Psychological Research, 81, 392-398. https://doi.org/10.1007/s00426-016-0756-3 ]. Recent cognitive theory suggests a particular role for future-oriented spontaneous thought in obsessive-compulsive (OC) symptoms. Thus, we hypothesised that future-oriented rather than past-oriented spontaneous mind wandering would predict OC symptoms, such that more future-oriented mind wandering would be associated with increases in OC symptoms. METHODS: In an online survey design (nonclinical sample of 104 adults), participants completed three measures: Mind wandering: Spontaneous (MW-S) and Deliberate (MW-D) (Carriere, Seli & Smilek, 2013); Involuntary Autobiographical Memory Inventory (Berntsen, Rubin & Salgado, 2015); and Dimensional Obsessive-Compulsive Scale (DOCS) (Abramowitz et al., 2010). We adopted a linear regression approach to examine our hypotheses. RESULTS: We provided the first replication of the finding that OC symptoms are predicted by the frequency of spontaneous (but not deliberate) mind wandering, with an underlying positive relationship. Additionally, we found that temporality of spontaneous thought had different predictive effects as a function of the dimension of OC symptoms (i.e., responsibility, unacceptable thoughts, need for symmetry/completeness). CONCLUSIONS: We found moderate support for our temporality hypothesis, which highlights how the construct of temporality can add to our understanding of OC symptoms. The present study also adds to recent conceptual debates regarding mind wandering. We suggest new cognitive and methodological approaches to enhance the understanding of obsessive-compulsive disorder, opening new avenues for clinical and experimental research.

Spontaneous and deliberate future thinking: a dual process account.

In this article, we address an apparent paradox in the literature on mental time travel and mind-wandering: How is it possible that future thinking is both constructive, yet often experienced as occurring spontaneously? We identify and describe two 'routes' whereby episodic future thoughts are brought to consciousness, with each of the 'routes' being associated with separable cognitive processes and functions. Voluntary future thinking relies on controlled, deliberate and slow cognitive processing. The other, termed involuntary or spontaneous future thinking, relies on automatic processes that allows 'fully-fledged' episodic future thoughts to freely come to mind, often triggered by internal or external cues. To unravel the paradox, we propose that the majority of spontaneous future thoughts are 'pre-made' (i.e., each spontaneous future thought is a re-iteration of a previously constructed future event), and therefore based on simple, well-understood, memory processes. We also propose that the pre-made hypothesis explains why spontaneous future thoughts occur rapidly, are similar to involuntary memories, and predominantly about upcoming tasks and goals. We also raise the possibility that spontaneous future thinking is the default mode of imagining the future. This dual process approach complements and extends standard theoretical approaches that emphasise constructive simulation, and outlines novel opportunities for researchers examining voluntary and spontaneous forms of future thinking.

Metrics for environmental compensation: A comparative analysis of Swedish municipalities.

Environmental compensation (EC) aims at addressing environmental losses due to development projects and involves a need to compare development losses with compensation gains using relevant metrics. A conceptual procedure for computing no net loss is formulated and used as a point of departure for a comparative analysis of metrics used by five Swedish municipalities as a part of their EC implementation in the spatial planning context of detailed development plans. While Swedish law does not require EC in this context, these municipalities have still decided to introduce EC requirements for development projects that occur on municipality-owned land and to promote voluntary EC among private actors in development projects on private land. There is substantial variation across the municipalities studied with respect to both metrics and attributes subject to measurement, but there are also similarities: The attributes considered when assessing the need for EC in conjunction with development are not only about nature per se, but also about recreational opportunities and other types ecosystem services; semi-quantitative metrics such as scores are common while quantitative or monetary metrics are rare; and metrics are rarely applied to assess compensatory gains, focusing instead on losses from development. Streamlining across municipalities might be warranted for increasing predictability and transparency for developers and citizens, but it also introduces considerable challenges such as a need for developing consistent guidelines for semi-quantitative metrics, and to handle substitutability issues if metrics are not only applied on individual attributes but also on groups of attributes. The broad scope of attributes used by the municipalities is in line with an international tendency to broaden EC to include not only biodiversity aspects but also ecosystem services. Moreover, the EC systems applied by the municipalities are of particular importance for highlighting the crucial role of environmental management for maintaining and enhancing biodiversity and ecosystem services not only in areas having formal protection status but also in the everyday landscape. The municipalities' experience and strengths and weaknesses associated with their EC systems are therefore relevant also in an international perspective.

Cycle-by-cycle analysis of neural oscillations.

Neural oscillations are widely studied using methods based on the Fourier transform, which models data as sums of sinusoids. This has successfully uncovered numerous links between oscillations and cognition or disease. However, neural data are nonsinusoidal, and these nonsinusoidal features are increasingly linked to a variety of behavioral and cognitive states, pathophysiology, and underlying neuronal circuit properties. We present a new analysis framework, one that is complementary to existing Fourier and Hilbert transform-based approaches, that quantifies oscillatory features in the time domain on a cycle-by-cycle basis. We have released this cycle-by-cycle analysis suite as "bycycle," a fully documented, open-source Python package with detailed tutorials and troubleshooting cases. This approach performs tests to assess whether an oscillation is present at any given moment and, if so, quantifies each oscillatory cycle by its amplitude, period, and waveform symmetry, the latter of which is missed with the use of conventional approaches. In a series of simulated event-related studies, we show how conventional Fourier and Hilbert transform approaches can conflate event-related changes in oscillation burst duration as increased oscillatory amplitude and as a change in the oscillation frequency, even though those features were unchanged in simulation. Our approach avoids these errors. Furthermore, we validate this approach in simulation and against experimental recordings of patients with Parkinson's disease, who are known to have nonsinusoidal beta (12-30 Hz) oscillations.NEW & NOTEWORTHY We introduce a fully documented, open-source Python package, bycycle, for analyzing neural oscillations on a cycle-by-cycle basis. This approach is complementary to traditional Fourier and Hilbert transform-based approaches but avoids specific pitfalls. First, bycycle confirms an oscillation is present, to avoid analyzing aperiodic, nonoscillatory data as oscillations. Next, it quantifies nonsinusoidal aspects of oscillations, increasingly linked to neural circuit physiology, behavioral states, and diseases. This approach is tested against simulated and real data.

Spontaneous future cognition: the past, present and future of an emerging topic.

In this Editorial, we discuss the past, present and future of an emerging and fast-developing field-spontaneous future cognition. In tracking the past of this research, the trajectories of research on mind-wandering, episodic future thinking and prospective memory are briefly examined, and their relation with spontaneous future cognition demarcated. Three broad methodological approaches (questionnaire, naturalistic and laboratory) used to study spontaneous future thoughts are described, providing an overview of the field. The present state of this research is represented by a themed analysis of the articles included in this Special Issue. The breadth of studies (covering cognitive mechanisms, developmental stages and psychopathology) have already led to important insights, especially concerning the conditions in which spontaneous future thoughts most commonly arise and who may be predisposed to experiencing them. In the future, greater effort should focus on developing a theoretical account of spontaneous future cognition-this may increase our understanding of how and why spontaneous future thoughts occur. If future research in this area reflects the diversity and depth within this Special Issue, a flourishing of research on spontaneous future cognition will be on the horizon in years or perhaps decades to come.

Nonsinusoidal Beta Oscillations Reflect Cortical Pathophysiology in Parkinson's Disease.

Oscillations in neural activity play a critical role in neural computation and communication. There is intriguing new evidence that the nonsinusoidal features of the oscillatory waveforms may inform underlying physiological and pathophysiological characteristics. Time-domain waveform analysis approaches stand in contrast to traditional Fourier-based methods, which alter or destroy subtle waveform features. Recently, it has been shown that the waveform features of oscillatory beta (13-30 Hz) events, a prominent motor cortical oscillation, may reflect near-synchronous excitatory synaptic inputs onto cortical pyramidal neurons. Here we analyze data from invasive human primary motor cortex (M1) recordings from patients with Parkinson's disease (PD) implanted with a deep brain stimulator (DBS) to test the hypothesis that the beta waveform becomes less sharp with DBS, suggesting that M1 input synchrony may be decreased. We find that, in PD, M1 beta oscillations have sharp, asymmetric, nonsinusoidal features, specifically asymmetries in the ratio between the sharpness of the beta peaks compared with the troughs. This waveform feature is nearly perfectly correlated with beta-high gamma phase-amplitude coupling (r = 0.94), a neural index previously shown to track PD-related motor deficit. Our results suggest that the pathophysiological beta generator is altered by DBS, smoothing out the beta waveform. This has implications not only for the interpretation of the physiological mechanism by which DBS reduces PD-related motor symptoms, but more broadly for our analytic toolkit in general. That is, the often-overlooked time-domain features of oscillatory waveforms may carry critical physiological information about neural processes and dynamics.SIGNIFICANCE STATEMENT To better understand the neural basis of cognition and disease, we need to understand how groups of neurons interact to communicate with one another. For example, there is evidence that parkinsonian bradykinesia and rigidity may arise from an oversynchronization of afferents to the motor cortex, and that these symptoms are treatable using deep brain stimulation. Here we show that the waveform shape of beta (13-30 Hz) oscillations, which may reflect input synchrony onto the cortex, is altered by deep brain stimulation. This suggests that mechanistic inferences regarding physiological and pathophysiological neural communication may be made from the temporal dynamics of oscillatory waveform shape.

Systemic Allergic Response in the Setting of a Metallic Intraorbital Foreign Body With Intraoperative Magnet-Assisted Retrieval.

A 12-year-old boy with a past medical history of nickel allergy was referred to our service after sustaining an air rifle injury with a retained BB in his left inferior orbit. On examination, he had a palpable orbital mass and systemic urticaria. Plain films demonstrated a spherical metallic foreign body adjacent to the left inferior orbital rim. Given his worsening systemic reaction despite oral antihistamine therapy, decision was made to remove the foreign body. In the operating room, the Allergan Magna Finder-a prepackaged, sterile device normally used for retrieval of a port used in tissue expansion surgery-was placed over the inferior conjunctiva of the lower eyelid. With the magnet holding gentle anterior traction on the foreign body, it was easily dissected and removed. The patient tolerated the procedure well, and had rapid resolution of his systemic allergic response following removal of the BB.

Osteolytic Sarcoidosis of the Orbital Roof Masquerading as a Malignant Orbital Lesion.

A 51-year-old man without a significant past medical history presented with 4 weeks of progressive swelling and drooping of his left upper eyelid. A CT of the left orbit revealed an osteolytic mass lesion in the area of the lacrimal gland. A left orbitotomy with excisional biopsy was performed. The excised tissue was sent for infectious workup and histopathological examination, which revealed osteolytic sarcoidosis. The patient was treated with systemic and local injection corticosteroids, and followed over 10 months without evidence of recurrence. Systemic workup with CT of his chest, abdomen, and pelvis revealed no further evidence of sarcoidosis. To the best of the authors knowledge, this is the first report of an otherwise healthy patient presenting with isolated osteolytic sarcoidosis of the orbit and a negative systemic workup.

Inducing involuntary and voluntary mental time travel using a laboratory paradigm.

Although involuntary past and future mental time travel (MTT) has been examined outside the laboratory in diary studies, MTT has primarily been studied in the context of laboratory studies using voluntary construction tasks. In this study, we adapted and extended a paradigm previously used to elicit involuntary and voluntary memories (Schlagman & Kvavilashvili in Memory & Cognition, 36, 920-932, 2008). Our aim was - for the first time - to examine involuntary and voluntary future MTT under controlled laboratory conditions. The involuntary task involved a monotonous task that included potential cues for involuntary MTT. Temporal direction was manipulated between participants whereas retrieval mode was manipulated within participants. We replicated robust past-future differences, such as the future positivity bias. Additionally, we replicated key voluntary-involuntary differences: Involuntary future representations had similar characteristics as involuntary memories in that they were elicited faster, were more specific, and garnered more emotional impact than their voluntary counterparts. We also found that the future and past involuntary MTT led to both positive and negative mood impact, and that the valence of the impact was associated with the emotional valence of the event. This study advances scientific understanding of involuntary future representations in healthy populations and validates a laboratory paradigm that can be flexibly and systematically utilized to explore different characteristics of voluntary and involuntary MTT, which has not been possible within naturalistic paradigms.

Amnesia and future thinking: Exploring the role of memory in the quantity and quality of episodic future thoughts.

OBJECTIVES: To examine the impact of memory accessibility on episodic future thinking. DESIGN: Single-case study of neurological patient HCM and an age-matched comparison group of neurologically Healthy Controls. METHODS: We administered a full battery of tests assessing general intelligence, memory, and executive functioning. To assess autobiographical memory, the Autobiographical Memory Interview (Kopelman, Wilson, & Baddeley, 1990. The Autobiographical Memory Interview. Bury St. Edmunds, UK: Thames Valley Test Company) was administered. The Past Episodic and Future Episodic sections of Dalla Barba's Confabulation Battery (Dalla Barba, 1993, Cogn. Neuropsychol., 1, 1) and a specifically tailored Mental Time Travel Questionnaire were administered to assess future thinking in HCM and age-matched controls. RESULTS: HCM presented with a deficit in forming new memories (anterograde amnesia) and recalling events from before the onset of neurological impairment (retrograde amnesia). HCM's autobiographical memory impairments are characterized by a paucity of memories from Recent Life. In comparison with controls, two features of his future thoughts are apparent: Reduced episodic future thinking and outdated content of his episodic future thoughts. CONCLUSIONS: This article suggests neuropsychologists should look beyond popular conceptualizations of the past-future relation in amnesia via focussing on reduced future thinking. Investigating both the quantity and quality of future thoughts produced by amnesic patients may lead to developments in understanding the complex nature of future thinking disorders resulting from memory impairments. PRACTITIONER POINTS: We highlight the clinical importance of examining the content of future thoughts in amnesic patients, rather than only its quantitative reduction. We propose an explanation of how quantitative and qualitative aspects of future thinking could be affected by amnesia. This could provide a useful approach to understand clinical cases of impaired prospection. LIMITATIONS: Systematic group investigations are required to fully examine our hypothesis. Although the current study utilized typical future thinking measures, these may be limited and we highlight the need to develop clinically relevant measures of prospection.

Thymic Origin Neuroendocrine Carcinoma Metastasizing to the Orbit in an Otherwise Asymptomatic Patient.

A 39-year-old man without a significant medical history developed headaches, OS swelling, and limited left-sided ocular motility. An ultrasound of the left orbit and head MRI revealed a retro-orbital mass. A partial left anterior orbitotomy with partial resection was performed, and histopathologic examination of the resected tumor portion was suggestive of a neuroendocrine carcinoma. A large, anterior mediastinal mass was found on chest imaging, and the patient was diagnosed with a primary thymic neuroendocrine tumor. To the authors' knowledge, this is the first report of an otherwise healthy patient presenting with the mass effects of a thymic neuroendocrine carcinoma metastasis to the orbital tissues before detection of the primary thymic malignancy.

Implausible future events in a confabulating patient with an anterior communicating artery aneurysm.

Patient MW, a known confabulator, and healthy age-matched controls produced past and future events. Events were judged on emotional valence and plausibility characteristics. No differences in valence were found between MW and controls, although a positive emotional bias toward the future was observed. Strikingly, MW produced confabulations about future events that were significantly more implausible than those produced by healthy controls whereas MW and healthy controls produced past events comparable in plausibility. A neurocognitive explanation is offered based on differences between remembering and imagining. Possible implications of this single case in relation to confabulation and mental time travel are discussed.

On second thoughts: Testing the underlying mechanisms of spontaneous future thought.

The human capacity to imagine possible future events unintentionally, with minimal cognitive effort, is termed spontaneous future thought (SFT). This paper addresses an important theoretical question for cognitive science: What are the possible cognitive mechanisms underlying such SFT experiences? We contrasted three hypotheses present in the literature: the online construction hypothesis, the recasting hypothesis, and the memories of future thoughts hypothesis. Study 1 (N = 41) used novel subjective ratings which challenged the recasting mechanism: SFTs were mostly rated as dissimilar to autobiographical memories, suggesting they are not simply past experiences 'recast' as future events. Study 2 (N = 90) used a novel experimental paradigm, comparing effects of voluntary episodic future constructions and non-personal narratives upon subsequent spontaneous thought sampling. Results suggested that voluntary future constructions remain accessible to spontaneous retrieval, supporting the memories of future thoughts hypothesis. This finding, and other data presented across the two studies, still indicates a role for online construction processes in SFT, but further empirical work is needed to clarify how and when constructive processes are engaged in SFT. Taken together, these two studies represent initial efforts to elucidate the mechanisms underlying SFT, providing the first proof-of-principle that deliberately envisioned future events can reappear, without intention, in consciousness at some later time, and further supporting the dual process account of future thinking. These methods and findings provide a firm basis for subsequent experimental and longitudinal research on SFT.

The process of replication target selection in psychology: what to consider?

Increased execution of replication studies contributes to the effort to restore credibility of empirical research. However, a second generation of problems arises: the number of potential replication targets is at a serious mismatch with available resources. Given limited resources, replication target selection should be well-justified, systematic and transparently communicated. At present the discussion on what to consider when selecting a replication target is limited to theoretical discussion, self-reported justifications and a few formalized suggestions. In this Registered Report, we proposed a study involving the scientific community to create a list of considerations for consultation when selecting a replication target in psychology. We employed a modified Delphi approach. First, we constructed a preliminary list of considerations. Second, we surveyed psychologists who previously selected a replication target with regards to their considerations. Third, we incorporated the results into the preliminary list of considerations and sent the updated list to a group of individuals knowledgeable about concerns regarding replication target selection. Over the course of several rounds, we established consensus regarding what to consider when selecting a replication target. The resulting checklist can be used for transparently communicating the rationale for selecting studies for replication.

Synthesizing the effects of mental simulation on behavior change: Systematic review and multilevel meta-analysis.

Mental simulation of future scenarios is hypothesized to affect future behavior, but a large and inconsistent literature means it is unclear whether, and under what conditions, mental simulation can change people's behavior. A meta-analysis was conducted to synthesize the effects of mental simulation on behavior and examine under what conditions mental simulation works best. An inclusive systematic database search identified 123 (N = 5,685) effect sizes comparing mental simulation to a control group. After applying a multilevel random effects model, a statistically-reliable positive effect of Hedges' g = 0.49, 95% CI [0.37; 0.62] was found, which was significantly different than zero. Using a taxonomy to identify different subtypes of mental simulation (along two dimensions, class [process, performance, outcome] and purpose [whether an inferior, standard, superior version of that behavior is simulated]), it was found that superior simulations garnered more reliable beneficial effects than inferior simulations. These findings have implications for integrating theories of how mental simulations change behavior, how mental simulations are classified, and may help guide professionals seeking evidence-based and cost-effective methods of changing behavior.

Ecology of speciation in the genus Bacillus.

Microbial ecologists and systematists are challenged to discover the early ecological changes that drive the splitting of one bacterial population into two ecologically distinct populations. We have aimed to identify newly divergent lineages ("ecotypes") bearing the dynamic properties attributed to species, with the rationale that discovering their ecological differences would reveal the ecological dimensions of speciation. To this end, we have sampled bacteria from the Bacillus subtilis-Bacillus licheniformis clade from sites differing in solar exposure and soil texture within a Death Valley canyon. Within this clade, we hypothesized ecotype demarcations based on DNA sequence diversity, through analysis of the clade's evolutionary history by Ecotype Simulation (ES) and AdaptML. Ecotypes so demarcated were found to be significantly different in their associations with solar exposure and soil texture, suggesting that these and covarying environmental parameters are among the dimensions of ecological divergence for newly divergent Bacillus ecotypes. Fatty acid composition appeared to contribute to ecotype differences in temperature adaptation, since those ecotypes with more warm-adapting fatty acids were isolated more frequently from sites with greater solar exposure. The recognized species and subspecies of the B. subtilis-B. licheniformis clade were found to be nearly identical to the ecotypes demarcated by ES, with a few exceptions where a recognized taxon is split at most into three putative ecotypes. Nevertheless, the taxa recognized do not appear to encompass the full ecological diversity of the B. subtilis-B. licheniformis clade: ES and AdaptML identified several newly discovered clades as ecotypes that are distinct from any recognized taxon.

Characteristics of Waveform Shape in Parkinson's Disease Detected with Scalp Electroencephalography.

Neural activity in the ß frequency range (13-30 Hz) is excessively synchronized in Parkinson's disease (PD). Previous work using invasive intracranial recordings and non-invasive scalp electroencephalography (EEG) has shown that correlations between ß phase and broad-band γ (>50 Hz) amplitude [i.e., phase amplitude coupling (PAC)] are elevated in PD, perhaps a reflection of this synchrony. Recently, it has also been shown, in invasive human recordings, that non-sinusoidal features of ß oscillation shape also characterize PD. Here, we show that these features of ß waveform shape also distinguish PD patients on and off medication using non-invasive recordings in a dataset of 15 PD patients with resting scalp EEG. Specifically, ß oscillations over sensorimotor electrodes in PD patients off medication had greater sharpness asymmetry and steepness asymmetry than on medication (sign rank, p < 0.02, corrected). We also showed that ß oscillations over sensorimotor cortex most often had a canonical shape, and that using this prototypical shape as an inclusion criteria increased the effect size of our findings. Together, our findings suggest that novel ways of measuring ß synchrony that incorporate waveform shape could improve detection of PD pathophysiology in non-invasive recordings. Moreover, they motivate the consideration of waveform shape in future EEG studies.

Brain Oscillations and the Importance of Waveform Shape.

Oscillations are a prevalent feature of brain recordings. They are believed to play key roles in neural communication and computation. Current analysis methods for studying neural oscillations often implicitly assume that the oscillations are sinusoidal. While these approaches have proven fruitful, we show here that there are numerous instances in which neural oscillations are nonsinusoidal. We highlight approaches to characterize nonsinusoidal features and account for them in traditional spectral analysis. Instead of being a nuisance, we discuss how these nonsinusoidal features may provide crucial and so far overlooked physiological information related to neural communication, computation, and cognition.