Visual boundary cues suffice to anchor place and grid cells in virtual reality.

The hippocampal formation contains neurons responsive to an animal's current location and orientation, which together provide the organism with a neural map of space.1,2,3 Spatially tuned neurons rely on external landmark cues and internally generated movement information to estimate position.4,5 An important class of landmark cue are the boundaries delimiting an environment, which can define place cell field position6,7 and stabilize grid cell firing.8 However, the precise nature of the sensory information used to detect boundaries remains unknown. We used 2-dimensional virtual reality (VR)9 to show that visual cues from elevated walls surrounding the environment are both sufficient and necessary to stabilize place and grid cell responses in VR, when only visual and self-motion cues are available. By contrast, flat boundaries formed by the edges of a textured floor did not stabilize place and grid cells, indicating only specific forms of visual boundary stabilize hippocampal spatial firing. Unstable grid cells retain internally coherent, hexagonally arranged firing fields, but these fields "drift" with respect to the virtual environment over periods >5 s. Optic flow from a virtual floor does not slow drift dynamics, emphasizing the importance of boundary-related visual information. Surprisingly, place fields are more stable close to boundaries even with floor and wall cues removed, suggesting invisible boundaries are inferred using the motion of a discrete, separate cue (a beacon signaling reward location). Subsets of place cells show allocentric directional tuning toward the beacon, with strength of tuning correlating with place field stability when boundaries are removed.

Environment geometry alters subiculum boundary vector cell receptive fields in adulthood and early development.

Boundaries to movement form a specific class of landmark information used for navigation: Boundary Vector Cells (BVCs) are neurons which encode an animal's location as a vector displacement from boundaries. Here we characterise the prevalence and spatial tuning of subiculum BVCs in adult and developing male rats, and investigate the relationship between BVC spatial firing and boundary geometry. BVC directional tunings align with environment walls in squares, but are uniformly distributed in circles, demonstrating that environmental geometry alters BVC receptive fields. Inserted barriers uncover both excitatory and inhibitory components to BVC receptive fields, demonstrating that inhibitory inputs contribute to BVC field formation. During post-natal development, subiculum BVCs mature slowly, contrasting with the earlier maturation of boundary-responsive cells in upstream Entorhinal Cortex. However, Subiculum and Entorhinal BVC receptive fields are altered by boundary geometry as early as tested, suggesting this is an inherent feature of the hippocampal representation of space.

Ethnic differences in respiratory disease for Native Hawaiians and Pacific Islanders: Analysis of mediation processes in two community samples.

OBJECTIVE: The prevalence of asthma and chronic obstructive pulmonary disorder (COPD) is elevated for Native Hawaiians but the basis for this differential is not well understood. We analyze data on asthma and COPD in two samples including Native Hawaiians Pacific Islanders, and Filipinos to determine how ethnicity is related to respiratory disease outcomes. METHODS: We analyzed the 2016 and 2018 Behavioral Risk Factor Surveillance Survey (BRFSS), a telephone survey of participants ages 18 and over in the State of Hawaii. Criterion variables were a diagnosis of asthma or COPD by a health professional. Structural equation modeling tested how five hypothesized risk factors (cigarette smoking, e-cigarette use, second-hand smoke exposure, obesity, and financial stress) mediated the ethnic differential in the likelihood of disease. Age, sex, and education were included as covariates. RESULTS: Structural modeling with 2016 data showed that Native Hawaiian ethnicity was related to higher levels of the five risk factors and each risk factor was related to a higher likelihood of respiratory disease. Indirect effects were statistically significant in almost all cases, with direct effects to asthma and COPD also observed. Mediation effects through comparable pathways were also noted for Pacific Islanders and Filipinos. These findings were replicated with data from the 2018 survey. CONCLUSIONS: Native Hawaiian and Pacific Islander ethnicity is associated with greater exposure to five risk factors and this accounts in part for the ethnic differential in respiratory disease outcomes. The results support a social-ecological model of health disparities in this population. Implications of the findings for preventive interventions are discussed.

Ethnicity, Coronavirus Disease-Related Stress, and E-cigarette Use and Cigarette Smoking Among Young Adults: A Longitudinal Study.

INTRODUCTION: Research has rarely examined ethnic differences in exposure to coronavirus disease (COVID)-related stress in relation to smoking and e-cigarette use. AIMS AND METHODS: Using pre- and post-COVID data from a sample of predominantly Asian American (AA) and Native Hawaiian and Pacific Islander (NHPI) young adults, this study aimed to test the effects of ethnicity on cigarette smoking and e-cigarette use through exposure to COVID-related stress. Young adults from Hawaii who provided pre-COVID data in or before January 2020 were followed up with in March-May 2021. N = 1907 (mean age = 24.9 [SD = 2.9], 56% women) provided complete data relevant to the current analysis at both waves of data collection. Structural equation modeling was used to test the effects of ethnicity (white, Asian [eg, Japanese, Chinese], Filipino, NHPI, and other) on pre- to post-COVID changes in cigarette and e-cigarette use via effects on COVID-related stress. RESULTS: Relative to Asian young adults, members of all other ethnic groups (NHPI, Filipino, white, and other) indicated greater exposure to COVID-related stress. Higher levels of COVID-related stress were associated with increased dual-use status and increased current e-cigarette and cigarette use frequencies. Higher COVID-related stress mediated the effects of NHPI, Filipino, and other ethnicity on increased dual-use status. CONCLUSIONS: The current data indicate that young adults of vulnerable ethnic groups who experience higher COVID-related stress are at increased risk for dual use of cigarettes and e-cigarettes. IMPLICATIONS: The findings imply that tobacco use prevention and treatment efforts may need to pay increased attention to racial or ethnic groups that have experienced greater adverse impact of the COVID-19 pandemic.

Associations for subgroups of E-cigarette, cigarette, and cannabis use with asthma in a population sample of California adolescents.

Knowledge about the respiratory health consequences of adolescents' use of tobacco products with cannabis remains limited. We studied whether e-cigarettes, combustible cigarettes, and cannabis were independently associated with asthma in a population-based sample of 150,634 public high school students (10th and 12th graders), drawn in a two-stage design to be representative of the state of California in 2019-2020. Measures were obtained for use of e-cigarettes, combustible cigarettes, and cannabis; motives for use (three substances); method of use (for cannabis); ever being diagnosed with asthma; and having an asthma attack in past 12 months. Cross-classification indicated Nonuse for 64% of the sample; 15% Dual E-cigarette/Cannabis Use; 10% Exclusive Cannabis Use; 5% Exclusive E-cigarette Use; and 5% Triple Use. Multinomial logistic regression with a three-level criterion variable, controlling for age, sex, parental education, race/ethnicity, and three types of household use showed that compared with Nonuse, odds of Lifetime Asthma (vs. Never Had) was elevated for Triple Use (AOR = 1.14, CI 1.06-1.24), Dual E-cigarette/Cannabis Use (1.17, 1.12-1.23), Exclusive Cannabis Use (1.17, 1.11-1.23), and Exclusive E-cigarette Use (1.10, 1.02-1.18). Similar results were noted for Recent Asthma. Among persons who had used cannabis, 88% of the Triple group and 74% of the Dual E-cigarette/Cannabis group reported both smoking and vaping cannabis. Thus, co-occurrence of e-cigarette and cannabis use was a common pattern among adolescents in this study, and subgroups of cannabis and e-cigarette use showed similar associations with asthma. Preventive approaches should highlight the health implications of exclusive or combined e-cigarette and cannabis use.

Tests for confounding with cigarette smoking in the association of E-cigarette use with respiratory disorder: 2020 National-Sample Data.

Associations of e-cigarette use with respiratory disorder have been demonstrated but it has been unclear whether these are confounded by current or previous cigarette smoking. We address this question through studying different time frames for e-cigarette use and respiratory disorders in 2020 BRFSS data (N = 214,945). E-cigarette use and combustible cigarette smoking were classified into four categories: Participant never used either (Nonuse); used e-cigarettes/cigarettes but not in the past 30 days (Former Use), used in past 30 days on some days (Nondaily Use), or used past 30 days on all days (Daily Use). Contrasts for e-cigarette status and cigarette status (with nonuse as reference group) were entered with covariates in logistic regression with asthma or COPD as criterion. Stratified analyses of e-cigarette use were also performed for smokers and nonsmokers. In the total sample, results showed independent positive associations with both lifetime and current asthma for Former, Nondaily, and Daily e-cigarette use (mostly p < .0001) and the three cigarette indices. Significant positive associations with COPD were found for the three e-cigarette indices (p < .0001) and all the cigarette indices. Stratified analyses showed significant associations of e-cigarette use with respiratory disorder among nonsmokers as well as among smokers. We conclude that independent associations for former e-cigarette use (controlling for current/former smoking) and significant associations of e-cigarette use with respiratory disorder among nonsmokers indicate these associations are not confounded with cigarette smoking and suggest reverse causation is implausible. Findings for former use are discussed with reference to possible mechanisms including sensitization effects.

E-cigarette-inclusive smoke-free policies, excise taxes, tobacco 21 and changes in youth e-cigarette use: 2017-2019.

BACKGROUND: We examined whether the implementation of electronic cigarette (e-cigarette) policies at the state level (e-cigarette-inclusive smoke-free (ESF) policies, excise taxes on e-cigarettes and raising tobacco legal purchasing age to 21 years (T21)) affected recent upward trends in youth e-cigarette use. METHODS: Data were from participants from 34 US states who completed the Youth Risk Behavior Survey (YRBS) state surveys in 2017 and 2019 (n=278 271). States were classified as having or not having ESF policies, any e-cigarette excise tax and T21 policies by 1 January 2019. Participants reported ever, past 30-day and frequent (≥20 days) e-cigarette use; past 30-day combustible cigarette smoking; and age, sex and race/ethnicity. Weighted multivariable logistic regression models assessed whether changes in e-cigarette use over time differed by policy status, adjusting for participants' demographics and combustible cigarette smoking. RESULTS: Prevalence of ever and past 30-day youth e-cigarette use in states with ESF policies decreased during 2017-2019, while the prevalence of these measures in states without ESF policies increased. States with T21 policies showed non-significant changes in prevalence of ever and past 30-day youth e-cigarette use, whereas states without T21 policies showed significant increases in ever and past 30-day youth e-cigarette use. States with ESF and T21 policies showed slower increases in youth frequent e-cigarette use. E-cigarette excise taxes were not associated with decreasing prevalence of youth e-cigarette use. CONCLUSIONS: State-level ESF and T21 policies could be effective for limiting growth of youth e-cigarette use despite an overall national increase. Higher e-cigarette excise tax rates may be needed to effectively reduce youth e-cigarette use.

Concurrent Use of E-cigarettes, Combustible Cigarettes, and Marijuana.

OBJECTIVE: Subgroups of adolescent single and dual e-cigarette and cigarette users have been identified, but usage patterns have changed in recent years, and there has been an increase in marijuana use. Research is needed with current data to identify subgroups of use including marijuana and determine their behavioral correlates. METHODS: We cross classified ever and recent use of e-cigarettes, combustible cigarettes, and marijuana among US high school students in the 2019 Youth Risk Behavior Survey (YRBS), providing 8 different groups. Levels of 14 risk and protective factors were compared across groups in general linear models with demographic covariates using omnibus tests, pairwise comparisons, and planned contrasts. Replicability was tested through identical analyses for 2017 YRBS data. RESULTS: The nonuser group was 43.9% of the sample. The most frequent user groups were triple users (ever-use proportion: 16.9%), dual (e-cigarette and marijuana) users (15.8%), and exclusive e-cigarette users (13.2%). For risk profiles on levels of psychosocial variables, the triple-user group was typically elevated above all other groups. Exclusive e-cigarette users were above nonusers in risk profile but below dual users (both cigarettes and marijuana). Results were similar for ever use and recent use. The patterning of results in 2019 YRBS data were closely replicated in 2017 YRBS data. CONCLUSIONS: Co-occurrence of e-cigarette, cigarette, and marijuana use is currently substantial among adolescents and is associated with an elevated psychosocial risk profile. This has implications for both epidemiology and prevention studies. Further research is needed to study prevalence and identify pathways to triple use.

A Cultural Dance Program Improves Hypertension Control and Cardiovascular Disease Risk in Native Hawaiians: A Randomized Controlled Trial.

BACKGROUND: Native Hawaiians have higher hypertension (HTN) and cardiovascular disease (CVD) rates than non-Hispanic whites, calling for culturally responsive interventions to close this gap. PURPOSE: We tested the effects of a 6-month behavioral intervention, a cultural dance program based on hula (the customary dance of Hawai'i), for improving blood pressure (BP) and CVD risk among Native Hawaiians with uncontrolled HTN. METHODS: In a randomized controlled trial, we tested the effects of the hula-based intervention among 263 Native Hawaiians with uncontrolled HTN (systolic ≥ 140 or ≥ 130 mmHg if diabetes) and no CVD at enrollment. All participants received a brief culturally tailored heart health education before random assignment to the hula-based intervention (n = 131) or the education-only waitlist control (n = 132). Intervention received hula lessons and group-based activities for 6 months. Control received only 1-week education through 6 months. RESULTS: Intervention yielded greater reductions in systolic (-15.3 mmHg) and diastolic (-6.4 mmHg) BP than control (-11.8 and -2.6 mmHg, respectively) from baseline to 6 months (p < .05). At 6 months, 43% of intervention participants compared to 21% of controls achieved a HTN stage <130/80 mmHg (p < .001). The 10-year CVD risk reduction was two times greater for the intervention group than the control group based on the Framingham Risk Score calculator. All improvements for intervention participants were maintained at 12 months. CONCLUSIONS: This trial represents one of the few rigorously conducted examinations of an Indigenous practice leveraged for health promotion, with implications for other ethnic populations.

Vector trace cells in the subiculum of the hippocampal formation.

Successfully navigating in physical or semantic space requires a neural representation of allocentric (map-based) vectors to boundaries, objects and goals. Cognitive processes such as path-planning and imagination entail the recall of vector representations, but evidence of neuron-level memory for allocentric vectors has been lacking. Here, we describe a novel neuron type, vector trace cell (VTC), whose firing generates a new vector field when a cue is encountered and a 'trace' version of that field for hours after cue removal. VTCs are concentrated in subiculum, distal to CA1. Compared to non-trace cells, VTCs fire at further distances from cues and exhibit earlier-going shifts in preferred theta phase in response to newly introduced cues, which demonstrates a theta-linked neural substrate for memory encoding. VTCs suggest a vector-based model of computing spatial relationships between an agent and multiple spatial objects, or between different objects, freed from the constraints of direct perception of those objects.

E-cigarette use and respiratory disorders: an integrative review of converging evidence from epidemiological and laboratory studies.

BACKGROUND: Use of electronic cigarettes (e-cigarettes) is prevalent among adolescents and young adults, but there has been limited knowledge about health consequences in human populations. We conduct a systematic review and meta-analysis of results on respiratory disorders from studies of general-population samples and consider the mapping of these results to findings about biological processes linked to e-cigarettes in controlled laboratory studies. METHOD: We conducted a literature search and meta-analysis of epidemiological studies on the association of e-cigarette use with asthma and with COPD. We discuss findings from laboratory studies about effects of e-cigarettes on four biological processes: cytotoxicity, oxidative stress/inflammation, susceptibility to infection and genetic expression. RESULTS: Epidemiological studies, both cross-sectional and longitudinal, show a significant association of e-cigarette use with asthma and COPD, controlling for cigarette smoking and other covariates. For asthma (n=15 studies), the pooled adjusted odds ratio (aOR) was 1.39 (95% CI 1.28-1.51); for COPD (n=9 studies) the aOR was 1.49 (95% CI 1.36-1.65). Laboratory studies consistently show an effect of e-cigarettes on biological processes related to respiratory harm and susceptibility to illness, with e-cigarette conditions differing significantly from clean-air controls, although sometimes less than for cigarettes. CONCLUSIONS: The evidence from epidemiological studies meets established criteria for consistency, strength of effect, temporality, and in some cases a dose-response gradient. Biological plausibility is indicated by evidence from multiple laboratory studies. We conclude that e-cigarette use has consequences for asthma and COPD, which is of concern for respirology and public health.

E-Cigarette Use Associated With Asthma Independent of Cigarette Smoking and Marijuana in a 2017 National Sample of Adolescents.

PURPOSE: Knowledge about the health consequences of e-cigarette use in adolescence remains limited. Available studies of asthma among adolescents are based on data collected five or more years ago, and evidence from more recent generations of e-cigarette products is needed. METHODS: We analyzed data from the 2017 Youth Risk Behavior Survey, a cross-sectional study with a representative U.S. national sample of high school students. Multivariable analyses tested for associations of ever and 30-day e-cigarette use with asthma controlling for cigarette smoking, marijuana use, demographics, and obesity. RESULTS: A significant association with asthma was found for ever use of e-cigarettes, adjusted odds ratio (AOR) = 1.15 (confidence interval [CI], 1.02-1.30; p = .02) and for currently using e-cigarettes, AOR = 1.30 (CI, 1.10-1.53; p = .002). Also related to asthma were current cigarette smoking, AOR = 1.24 (CI, 1.03-1.51; p = .03) and obesity, AOR = 1.48 (CI, 1.30-1.68; p < .0001). E-cigarettes had an additive effect for asthma beyond smoking (p = .03). Differentials in asthma prevalence by race/ethnicity were found, with lower prevalence of asthma for non-Hispanic Asian (p = .02) and Hispanic (p = .03) and higher prevalence for non-Hispanic black (p < .0001) and non-Hispanic multirace (p < .0001) relative to non-Hispanic white populations. CONCLUSIONS: E-cigarette use was significantly associated with asthma in recent data on adolescents, controlling for several disease-relevant covariates. The results are consistent with studies based on previous generations of e-cigarettes and support the significance of e-cigarettes as a continuing public health concern.

Rural mental health service utilization in a Texas telepsychology clinic.

OBJECTIVE: To determine if service utilization behaviors varied with the remoteness of clients served by a telepsychology clinic in a predominantly rural health professional shortage area (HPSA) in Texas. METHODS: Archival data from 290 low-income clients were analyzed to test associations between service utilization behaviors and clients' distance from the nearby access points where they traveled to receive counseling services from remotely located counselors. RESULTS: Distance to access points did not predict differences in service utilization behaviors. However, clients in rural counties traveled farther to receive services than clients in metropolitan areas. Some utilization behaviors varied by demographic variables and depressive symptom severity. CONCLUSIONS: A "hub and spoke" model of telehealth service delivery is an acceptable model for improving access to mental health care services in rural and underserved communities, even for clients who live relatively far from access points. Telehealth providers should consider geographic, socioeconomic, transportation, and health-related barriers to care experienced by clients when implementing services and policies.

Parental Support, Parent-Adolescent Conflict, and Substance Use of Native Hawaiian and Other Pacific Islander Youth: Ethnic Differences in Stress-Buffering and Vulnerability Effects.

This research study examined the overall and ethnic-specific effects of parental emotional and instrumental support, parent-adolescent interpersonal conflict, and negative life events (i.e., major life stressors, such as parental job loss or school suspension) on the substance use of Caucasian, Asian-American, Filipino, and Native Hawaiian and other Pacific Islander (NHOPI) youth in Hawai'i. Adolescents (N = 3,561) from 10 public middle/intermediate schools completed paper/pencil surveys, and multiple regression and structural equation models were developed to examine overall and ethnic-specific effects. Parental support was found to buffer against the influence of negative life events on substance use in the overall sample; however, this effect was not observed for either Caucasian or NHOPI youth in ethnic-specific analyses. The impact of parent-adolescent conflict and negative life events on substance use was more pronounced for both Filipino and NHOPI youth. While the study may have had some limitations related to regional specificity and measurement, the findings nonetheless point to the differential effects of risk and protective factors for NHOPI youth, compared with other youth ethnic groups in Hawai'i. Implications of these findings for culturally specific, family-focused prevention research and practice for NHOPI youth are discussed.

Adverse Childhood Experiences and E-Cigarette Use During Young Adulthood.

BACKGROUND AND OBJECTIVES: E-cigarette use among young people is highly prevalent. Individuals exposed to adverse childhood experiences such as childhood maltreatment (CM) may be at particular risk, as CM has been linked to nicotine dependence. Studies testing the association between CM and e-cigarette use are lacking, including research that examines pathways linking CM to e-cigarette use. METHODS: Using a community sample of young adults (N = 208; ages 18-21), we examined the relationship between CM and e-cigarette use and explored the potential role of impulsivity in linking CM to e-cigarette use via a series of structural equation models controlling for demographic characteristics. RESULTS: CM was significantly associated with lifetime e-cigarette use. Furthermore, CM was associated with negative urgency (NU), whereas NU and sensation seeking were significantly related to lifetime e-cigarette use. NU fully mediated the relationship between CM and lifetime e-cigarette use. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Our results suggest that young adults with a history of CM might be vulnerable to e-cigarette use and that NU played a significant role in linking CM to lifetime e-cigarette use. Addressing NU in young adults with a history of CM might be a useful avenue for preventing e-cigarette use in this population. (Am J Addict 2019;28:303-310).

Coordinated Emergence of Hippocampal Replay and Theta Sequences during Post-natal Development.

Hippocampal place cells encode an animal's current position in space during exploration [1]. During sleep, hippocampal network activity recapitulates patterns observed during recent experience: place cells with overlapping spatial fields show a greater tendency to co-fire ("reactivation") [2], and temporally ordered and compressed sequences of place cell firing observed during wakefulness are reinstated ("replay") [3-5]. Reactivation and replay may underlie memory consolidation [6-10]. Compressed sequences of place cell firing also occur during exploration: during each cycle of the theta oscillation, the set of active place cells shifts from those signaling positions behind to those signaling positions ahead of an animal's current location [11, 12]. These "theta sequences" have been linked to spatial planning [13]. Here, we demonstrate that, before weaning (post-natal day [P]21), offline place cell activity associated with sharp-wave ripples (SWRs) reflects predominantly stationary locations in recently visited environments. By contrast, sequential place cell firing, describing extended trajectories through space during exploration (theta sequences) and subsequent rest (replay), emerge gradually after weaning in a coordinated fashion, possibly due to a progressive decrease in the threshold for experience-driven plasticity. Hippocampus-dependent learning and memory emerge late in altricial mammals [14-17], appearing around weaning in rats and slowly maturing thereafter [14,15]. In contrast, spatially localized firing is observed 1 week earlier (with reduced spatial tuning and stability) [18-21]. By examining the development of hippocampal reactivation, replay, and theta sequences, we show that the coordinated maturation of offline consolidation and online sequence generation parallels the late emergence of hippocampal memory in the rat.