General anesthesia alters time perception by phase shifting the circadian clock

Following general anesthesia, people are often confused about the time of day and experience sleep disruption and fatigue. It has been hypothesized that these symptoms may be caused by general anesthesia affecting the circadian clock. The circadian clock is fundamental to our well-being because it regulates almost all aspects of our daily biochemistry, physiology, and behavior. Here, we investigated the effects of the most common general anesthetic, isoflurane, on time perception and the circadian clock using the honeybee (Apis mellifera) as a model. A 6-h daytime anesthetic systematically altered the time-compensated sun compass orientation of the bees, with a mean anticlockwise shift in vanishing bearing of 87° in the Southern Hemisphere and a clockwise shift in flight direction of 58° in the Northern Hemisphere. Using the same 6-h anesthetic treatment, time-trained bees showed a delay in the start of foraging of 3.3 h, and whole-hive locomotor-activity rhythms were delayed by an average of 4.3 h. We show that these effects are all attributable to a phase delay in the core molecular clockwork. mRNA oscillations of the central clock genes cryptochrome-m and period were delayed by 4.9 and 4.3 h, respectively. However, this effect is dependent on the time of day of administration, as is common for clock effects, and nighttime anesthesia did not shift the clock. Taken together, our results suggest that general anesthesia during the day causes a persistent and marked shift of the clock effectively inducing "jet lag" and causing impaired time perception. Managing this effect in humans is likely to help expedite postoperative recovery.     

Impaired face and body perception in developmental prosopagnosia

Prosopagnosia is a deficit in face recognition in the presence of relatively normal object recognition. Together with older lesion studies, recent brain-imaging results provide evidence for the closely related representations of faces and objects and, more recently, for brain areas sensitive to faces and bodies. This evidence raises the issue of whether developmental prosopagnosics may also have an impairment in encoding bodies. We investigated the first stages of face, body, and object perception in four developmental prosopagnosics by comparing event-related potentials to canonically and upside-down presented stimuli. Normal configural encoding was absent in three of four developmental prosopagnosics for faces at the P1 and for both faces and bodies at the N170 component. Our results demonstrate that prosopagnosics do not have this normal processing routine readily available for faces or bodies. A profound face recognition deficit characteristic of developmental prosopagnosia may not necessarily originate in a category-specific face recognition deficit in the initial stages of development. It may also have its roots in anomalous processing of the configuration, a visual routine that is important for other stimuli besides faces. Faces and bodies trigger configuration-based visual strategies that are crucial in initial stages of stimulus encoding but also serve to bootstrap the acquisition of more feature-based visual skills that progressively build up in the course of development.     

The importance of race,gender, and religion in naturalization adjudication in the United States

This study presents an empirical investigation of naturalization adjudication in the United States using new administrative data on naturalization applications decided by the US Citizenship and Immigration Services between October 2014 and March 2018. We find significant group disparities in naturalization approvals based on applicants’ race/ethnicity, gender, and religion, controlling for individual applicant characteristics, adjudication years, and variation between field offices. Non-White applicants and Hispanic applicants are less likely to be approved than non-Hispanic White applicants, male applicants are less likely to be approved than female applicants, and applicants from Muslim-majority countries are less likely to be approved than applicants from other countries. In addition, race/ethnicity, gender, and religion interact to produce a certain group hierarchy in naturalization approvals. For example, the probability of approval for Black males is 5 percentage points smaller than that of White females. The probability of approval for Blacks from Muslim-majority countries is 9 percentage points smaller than that of Whites from other countries. The probability of approval for females from Muslim-majority countries is 6 percentage points smaller than that of females from other countries. This study contributes to our understanding of the nature of inequalities present in agency decision-making in the naturalization process.

Naturalization—the acquisition of US citizenship—grants immigrants a host of new rights, privileges, and opportunities. It also protects them from deportation, which the US Supreme Court has recognized as “a drastic measure” that can constitute “the equivalent of banishment or exile” (1). Because of its critical importance in shaping the life chances and outcomes for immigrants and their family members, a large body of research exists on naturalization in the United States. This literature has focused on such issues as who is willing to naturalize and why, barriers to seeking naturalization, and the impact of obtaining citizenship on the social, economic, and political integration of immigrants (2–5). However, we still know relatively little about government determinations of who is approved or denied once a naturalization application is submitted to the US Citizenship and Immigration Services (USCIS). This lack of knowledge represents an important gap in our understanding of the naturalization process given that not all immigrants who seek naturalization are granted citizenship. In 2015, for example, 9.4% of nonmilitary applications resulted in denial, which increased to 10.3% in 2016 (6).^* Behind these statistics are tens of thousands of individuals. For example, in 2015, 75,117 total applications were denied naturalization, which increased to 85,364 in 2016 (6).Yet, the agency decision-making component of the naturalization process has escaped public and scholarly scrutiny largely because of a lack of publicly available data. This study draws on new administrative data obtained from the USCIS through a Freedom of Information Act (FOIA) litigation to examine whether there are group disparities by race/ethnicity, gender, and religion in the likelihood of approval among nonmilitary applications.^† Race/ethnicity and gender are two principal axes of inequality in many aspects of American life (7). Of immediate relevance to this study, race/ethnicity and gender have long served as enduring bases of exclusion for citizenship in the United States (8–11). For example, the first US citizenship statute, the Naturalization Act of 1790, limited naturalization to “free White” persons (12). In 1870, the law was amended to grant naturalization rights to persons of “African nativity and … descent” but continued to deny the right to all other groups of non-Whites. Racial restrictions were lifted for selected groups in the 20th century (12). Beginning in 1855 and for decades thereafter, a married woman’s citizenship status followed that of her husband’s (13). Among other things, this meant that an American woman who married a noncitizen could lose her US citizenship, and an immigrant woman could not become a US citizen unless her noncitizen husband naturalized (14, 15). It was not until 1952 that Congress legally prohibited denials of naturalization on the basis of race, sex, or marital status (9).Religion has also functioned as an important axis of inequality in the history and politics of American citizenship. In particular, the treatment of Muslims or individuals perceived as Muslim warrants special scrutiny. Until 1944, judges in naturalization cases generally treated Islam as defining an ethno-racial identity, and Muslims were presumed to be non-White, rendering them ineligible for naturalization (16). In contrast, Christianity functioned as a hallmark of Whiteness, and the presumption of non-Whiteness against Muslims could be overcome only if the presiding judge could be persuaded that they were bona fide Christians. This judicial interpretation was eventually invalidated, but Muslims have faced renewed challenges to attaining US citizenship in the post-9/11 era. For example, in 2008, USCIS created a clandestine program known as the Controlled Application Review and Resolution Program (CARRP) for the purposes of identifying, screening, and adjudicating applications for immigrant benefits—including naturalization—from individuals considered a “national security concern” (17). Class-action litigation challenging CARRP has revealed that it disproportionately and unjustifiably affects Muslims and individuals from Muslim-majority countries (18).Formal legal restrictions based on race/ethnicity, gender, and religion no longer govern eligibility for naturalization in the United States. Moreover, Congress has established a uniform rule of naturalization as required by the US Constitution (19). Nonetheless—or perhaps especially given this context—whether and to what extent de facto agency decision-making results in disparities along these axes remains an important unanswered question. Research on contemporary immigration enforcement suggests that facially neutral immigration laws continue to create or reproduce systems of social stratification. For example, studies have long documented how the purportedly color-blind US immigration enforcement regime subjugates Latinos and other racialized communities of color (20, 21). Golash-Boza and Hondagneu-Sotelo have described the modern deportation regime in the United States as a “gendered racial removal program” that disproportionately targets working-class men from Latin America and the Caribbean (22). Hernández has shown how contemporary immigration detention practices function as “institutionalized racism” against immigrants of color and Muslim immigrants (23).Furthermore, studies of intersectionality suggest that these social categories do not operate in isolation to produce social stratification (24, 25). Instead, they work in overlapping and mutually constitutive ways to generate complex social inequalities (26). For example, a growing number of studies highlight the importance of understanding how American racism and Islamophobia generate a “racial-religious hierarchy” (27), one that subjects Muslims to combined effects of both racial and religious prejudice (28). According to Corbin, the prevailing narrative is that “terrorists are always (brown) Muslims … [but] … white people are never terrorists” (29). Other scholars have emphasized the importance of examining oppression or marginalization stemming from intersectionality of Muslim and gender identities (30–32). Studies shows that Muslim women have experienced unique forms of post-9/11 discrimination owing to their wearing of hijab, which visibly marks them as dual threats—as a group assumed to support “misogyny and antifeminist values that are viewed as inherently un-American” (33) and “sympathetic to the enemy, presumptively disloyal, and forever foreign” (34).The foregoing discussion of existing research suggests that race/ethnicity, gender, and religious identities (and their intersections) of naturalization applicants may play an important role in producing similar social hierarchies in naturalization adjudication outcomes as those identified in extant research on immigration enforcement and studies of intersectionality. The replication of such social hierarchies in the naturalization adjudication context is especially likely if USCIS operates in practice primarily as a vetting agency focused on immigration enforcement and national security priorities rather than as a benefits agency that serves integration needs of immigrant communities (35).A brief overview of the naturalization process and requirements is in order to set the context for our empirical analysis. As shown in SI Appendix, Fig. S1, an aspiring noncitizen begins the process by filing an application called Form N-400 with one of the USCIS field offices located throughout the United States (SI Appendix, Fig. S2). High application fees prevent many low-income immigrants from filing even if they desire naturalization (3). The detailed information solicited on the N-400 form and its length (∼20 pages) reflects increasing agency concerns about the integrity of the naturalization process (19). To be eligible to naturalize, in most cases, a noncitizen must have been a lawful permanent resident for a specified period of time, be of at least 18 y old, demonstrate a required knowledge of English and of US history and government, and be of “good moral character” (36). Once an application is filed, USCIS conducts an investigation of the applicant, including a criminal background check. USCIS will also conduct an interview during which an immigration officer will administer an oral examination that tests the applicant’s English literacy and civics knowledge. Failure to satisfy all of these requirements will result in the application being denied.^‡ For some noncitizens, denial means exclusion from the benefits of citizenship, while for others, denial can have more devastating consequences, including removal from the United States (19). The stakes are thus extraordinarily high for individual applicants and their families.     

Significant impacts of the COVID-19 pandemic on race/ethnic differences in US mortality

The coronavirus 2019 (COVID-19) pandemic triggered global declines in life expectancy. The United States was hit particularly hard among high-income countries. Early data from the United States showed that these losses varied greatly by race/ethnicity in 2020, with Hispanic and Black Americans suffering much larger losses in life expectancy compared with White people. We add to this research by examining trends in lifespan inequality, average years of life lost, and the contribution of specific causes of death and ages to race/ethnic life-expectancy disparities in the United States from 2010 to 2020. We find that life expectancy in 2020 fell more for Hispanic and Black males (4.5 and 3.6 y, respectively) compared with White males (1.5 y). These drops nearly eliminated the previous life-expectancy advantage for the Hispanic compared with the White population, while dramatically increasing the already large gap in life expectancy between Black and White people. While the drops in life expectancy for the Hispanic population were largely attributable to official COVID-19 deaths, Black Americans saw increases in cardiovascular diseases and “deaths of despair” over this period. In 2020, lifespan inequality increased slightly for Hispanic and White populations but decreased for Black people, reflecting the younger age pattern of COVID-19 deaths for Hispanic people. Overall, the mortality burden of the COVID-19 pandemic hit race/ethnic minorities particularly hard in the United States, underscoring the importance of the social determinants of health during a public health crisis.

The coronavirus 2019 (COVID-19) pandemic has taken an unprecedented toll on mortality around the world. Most high-income countries experienced life-expectancy losses in 2020 (1–4), and many continued to experience declines in 2021 (5). The United States saw its largest drop in life expectancy (1.7 y for females and 2.1 y for males) in recent history (1), with COVID-19 deaths accounting for most of the decline for both females and males (6). Early data showed uneven impacts of the pandemic by race/ethnicity in the United States. The Center for Disease Control and Prevention estimates that between 2019 and 2020, life expectancy decreased by 3 y for the Hispanic population and by 2.9 y for the non-Hispanic Black (henceforth, Black) population, compared with a 1.2-y decline for non-Hispanic White (henceforth, White) people (6). The decrease was largest among Hispanic males (3.7 y), followed by Black males (3.3 y), and was smallest among White females (1.1 y). These findings are consistent with early studies projecting a disproportionate impact of the pandemic on life expectancy among race/ethnic minorities (7). It is important to monitor these disparities, which reflect underlying inequalities that are often magnified during a public health crisis (8). Both direct deaths from COVID-19 infection (9) as well as indirect deaths from other causes likely disproportionately affected race/ethnic minorities during the pandemic because of the social and economic disadvantages of historically marginalized populations in the United States (6, 10).This study provides a comprehensive analysis of mortality changes across racial/ethnic groups in the United States before and during the first year of the pandemic. It contributes to the evidence by 1) analyzing recent trends in life expectancy, average years of life lost (AYLL), and lifespan inequality from 2010 to 2020 separately for Black, Hispanic, and White populations; 2) identifying the ages and causes of death driving recent changes, including deaths from cardiovascular diseases (CVDs), respiratory diseases, infectious and parasitic diseases, “deaths of despair” (i.e., suicide-, drug-, and alcohol-related mortality), cancers, accidents, and COVID-19; and 3) comparing race/ethnic gaps in these outcomes before and during the pandemic.In the years before the pandemic, life expectancy in the United States followed atypical trends of stagnation that have not been observed in most high-income countries (6, 11, 12). These trends have been marked by worsening working-age mortality due to increased drug-related causes of death (13–17), as well as increased deaths from CVD at middle and later ages (18). Life expectancy is consistently higher for the White population relative to the Black population, although the gap between Black and White people narrowed from 5.7 y in 2000 to 3.8 y in 2010, (19). This convergence is partly due to relative improvements in mortality from heart diseases, HIV/AIDS, accidents, and cancer (20, 21). By contrast, the Hispanic population had higher life expectancy than the White population throughout the prepandemic period, attributable to lower mortality from cancer, CVD, diabetes, chronic respiratory diseases, perinatal conditions, as well as deaths of despair. Early evidence suggests that the pandemic has widened the White-Black gap in life expectancy, while reducing the Hispanic advantage (6). However, less is known about which ages and causes of death drove these changes (10).The COVID-19 pandemic has directly and indirectly affected multiple causes of death. For example, delays in treatment may have increased mortality from cancers (22), or avoidance of hospitals for fear of infection may have increased mortality from acute cardiovascular events (23). COVID-19 is also associated with elevated risk of cardiovascular events and diabetes in the months following infection (24, 25). Crucially, the impact of these changes likely varies across race/ethnic groups, due to differences in socioeconomic resources, rates of health insurance, and access to health care (7). Recent findings show that, while COVID-19 death rates were highest in the Hispanic population, Black people experienced exceptionally large increases in mortality from heart disease, diabetes, and external causes of death (10).So far, research on the differential impact of the pandemic on mortality across race/ethnic groups has mainly relied on estimates of overall life expectancy (6, 7, 26, 27) and standardized death rates (10). We extend these previous estimates by examining the ages and specific causes of death contributing to changes in life expectancy by race/ethnicity. While life expectancy is a widely used and important indicator for studying population health and mortality, it is an average measure that conceals population variability and inequality (28–31). Lifespan inequality captures a fundamental type of inequality: variation in length of life (32). Two populations that share the same life expectancy could experience differences in the variation around the timing of death. For instance, a high lifespan inequality measure would suggest that deaths occur within a wider age range, while a low measure of lifespan inequality would suggest a narrower age range. Hence, lifespan inequality, measured as the spread of ages at death in a population (e.g., SD), reflects how predictable length of life is at the individual level, and it underlies how uneven mortality improvements are at the population level (32, 33).Black Americans not only experience shorter life expectancy compared with Hispanic and White people but also have less predictable lifespans, with higher lifespan inequality (34, 35). The impact of the pandemic on US lifespan inequality is currently unknown. Evidence from England and Wales shows that both lifespan inequality and life expectancy decreased during 2020 because mortality was concentrated at older ages (36). However, in the United States, life-expectancy losses during the pandemic have been driven by increases in mortality at both older and working ages (1, 5, 37). Previous studies show that increased midlife death rates increase lifespan inequality (38–40).A complementary indicator to life expectancy is AYLL (41). This refers to the AYLL between birth and an upper age limit, often 95 y, from a synthetic cohort experiencing death rates in a given year throughout their lifespans. For example, if individuals between birth and age 95 live on average 80 y, then there are 15 y of life lost. While other indicators of years of life lost simply add up estimated remaining life expectancies among observed deaths (42, 43), AYLL is comparable across populations and over time, and is not affected by population age structure (44). Unlike life expectancy, this indicator enables researchers to quantify the burden of specific causes of death in a given year in a comparable way between populations (45), which is particularly important when comparing the impact of the pandemic across countries or groups with very different age structures. Conceptualized as such, AYLL represents a useful complement to life expectancy at birth, because it provides a snapshot of the contribution of different causes of death to years lost, rather than only how different causes contribute to changes in life expectancy over time. Using life expectancy, lifespan inequality, and AYLL, we comprehensively quantify the unequal impact of age- and cause-specific mortality before and during the first year of the pandemic across race/ethnic groups in the United States.     

Looking just below the eyes is optimal across face recognition tasks

When viewing a human face, people often look toward the eyes. Maintaining good eye contact carries significant social value and allows for the extraction of information about gaze direction. When identifying faces, humans also look toward the eyes, but it is unclear whether this behavior is solely a byproduct of the socially important eye movement behavior or whether it has functional importance in basic perceptual tasks. Here, we propose that gaze behavior while determining a person’s identity, emotional state, or gender can be explained as an adaptive brain strategy to learn eye movement plans that optimize performance in these evolutionarily important perceptual tasks. We show that humans move their eyes to locations that maximize perceptual performance determining the identity, gender, and emotional state of a face. These optimal fixation points, which differ moderately across tasks, are predicted correctly by a Bayesian ideal observer that integrates information optimally across the face but is constrained by the decrease in resolution and sensitivity from the fovea toward the visual periphery (foveated ideal observer). Neither a model that disregards the foveated nature of the visual system and makes fixations on the local region with maximal information, nor a model that makes center-of-gravity fixations correctly predict human eye movements. Extension of the foveated ideal observer framework to a large database of real-world faces shows that the optimality of these strategies generalizes across the population. These results suggest that the human visual system optimizes face recognition performance through guidance of eye movements not only toward but, more precisely, just below the eyes.     

Hyperglycemia alters perception of rectal distention and blunts the rectoanal inhibitory reflex in healthy volunteers

Acute hyperglycemia has been shown to alter gastrointestinal motility. The effects of hyperglycemia on rectal afferent neural and anal sphincter function were studied. Perception of rectal balloon distention, pressure-volume relationships, volumes necessary to induce reflex internal anal sphincter relaxation, resting anal sphincter pressure, and maximal anal sphincter squeeze pressure were measured under basal, hyperglycemic clamp, and euglycemic, hyperinsulinemic clamp conditions in 9 healthy volunteers. Hyperglycemic clamping (258 ± 14 mg/dL) significantly blunted threshold perception and the urge to defecate in response to rectal distention without altering perception of maximally tolerated distention. In contrast, euglycemic, hyperinsulinemic clamping had no effect on perception of rectal distention. Rectal pressure-volume relationships after hyperglycemic clamping were unchanged compared with basal conditions. Hyperglycemic clamping caused a significant increase in the distention necessary to induce the rectoanal inhibitory reflex. This effect was not observed under euglycemic, hyperinsulinemic clamp conditions. Hyperglycemia did not significantly affect resting internal anal sphincter pressure or maximal external anal sphincter squeeze pressure. Acute hyperglycemia but not secondary hyperinsulinemia reduces sensation of rectal distention and blunts the onset of the rectoanal inhibitory reflex, suggesting effects both on visceral afferents projecting to the cortex and intrinsic afferents mediating local reflex activity.     

Oscillatory phase shapes syllable perception

The role of oscillatory phase for perceptual and cognitive processes is being increasingly acknowledged. To date, little is known about the direct role of phase in categorical perception. Here we show in two separate experiments that the identification of ambiguous syllables that can either be perceived as /da/ or /ga/ is biased by the underlying oscillatory phase as measured with EEG and sensory entrainment to rhythmic stimuli. The measured phase difference in which perception is biased toward /da/ or /ga/ exactly matched the different temporal onset delays in natural audiovisual speech between mouth movements and speech sounds, which last 80 ms longer for /ga/ than for /da/. These results indicate the functional relationship between prestimulus phase and syllable identification, and signify that the origin of this phase relationship could lie in exposure and subsequent learning of unique audiovisual temporal onset differences.In spoken language, visual mouth movements naturally precede the production of any speech sound, and therefore serve as a temporal prediction and detection cue for identifying spoken language (1) (but also see ref. 2). Different syllables are characterized by unique visual-to-auditory temporal asynchronies (3, 4). For example, /ga/ has an 80-ms longer delay than /da/, and this difference aids categorical perception of these syllables (4). We propose that neuronal oscillations might carry the information to dissociate these syllables based on temporal differences. Multiple authors have proposed (5–7)—and it has been demonstrated empirically (7–9)—that at the onset of visual mouth movements, ongoing oscillations in auditory cortex align (see refs. 10–12 for nonspeech phase reset), providing a temporal reference frame for the auditory processing of subsequent speech sounds. Consequently, auditory signals fall on different phases of the aligned oscillation depending on the unique visual-to-auditory temporal asynchrony, resulting in a consistent relationship between syllable identity and oscillatory phase.We hypothesized that this consistent “phase–syllable” relationship results in ongoing oscillatory phase biasing syllable perception. More specifically, the phase at which syllable perception is mostly biased should be proportional to the visual-to-auditory temporal asynchrony found in natural speech. A naturally occurring /ga/ has an 80-ms longer visual-to-auditory onset difference than a naturally occurring /da/ (4). Consequently, the phase difference between perception bias toward /da/ and /ga/ should match 80 ms, which can only be established with an oscillation with a period greater than 80 ms, that is, any oscillation under 12.5 Hz. The apparent relevant oscillation range is therefore theta, with periods ranging between 111 and 250 ms (4–9 Hz). This oscillation range has already been proposed as a candidate to encode information, and seems specifically important for speech perception (13, 14).To test this hypothesis of oscillatory phase biasing auditory syllable perception in the absence of visual signals, we presented ambiguous auditory syllables that could be interpreted as /da/ or /ga/ while recording EEG. In a second experiment, we used sensory entrainment (thereby externally enforcing oscillatory patterns) to demonstrate that entrained phase indeed determines whether participants identify the presented ambiguous syllable as being either /da/ or /ga/.     

Dynamic faces speed up the onset of auditory cortical spiking responses during vocal detection

How low-level sensory areas help mediate the detection and discrimination advantages of integrating faces and voices is the subject of intense debate. To gain insights, we investigated the role of the auditory cortex in face/voice integration in macaque monkeys performing a vocal-detection task. Behaviorally, subjects were slower to detect vocalizations as the signal-to-noise ratio decreased, but seeing mouth movements associated with vocalizations sped up detection. Paralleling this behavioral relationship, as the signal to noise ratio decreased, the onset of spiking responses were delayed and magnitudes were decreased. However, when mouth motion accompanied the vocalization, these responses were uniformly faster. Conversely, and at odds with previous assumptions regarding the neural basis of face/voice integration, changes in the magnitude of neural responses were not related consistently to audiovisual behavior. Taken together, our data reveal that facilitation of spike latency is a means by which the auditory cortex partially mediates the reaction time benefits of combining faces and voices.In noisy environments, the audiovisual nature of speech is a tremendous benefit to sensory processing. While holding a conversation in a large social setting, your brain must deftly detect when a person is saying something, who is saying it, and discriminate what she is saying. To make the task easier, our brains do not rely entirely on the person’s voice but also take advantage of the speaker’s mouth movements. This visual motion provides spatial and temporal cues (1, 2) that readily integrate with the voice, enhancing both detection (3–10) and discrimination (11–15). How the brain mediates the behavioral benefits achieved by integrating signals from different modalities is the subject of intense debate and investigation (16). For face/voice integration, traditional models emphasize the role of association areas embedded in the temporal, frontal, and parietal lobes (17). Although these regions certainly play important roles, numerous recent studies demonstrate that they are not the sole regions for multisensory convergence (18, 19). The auditory cortex, in particular, has many sources of visual input, and an increasing number of studies in both humans and nonhuman primates demonstrate that dynamic faces influence auditory cortical activity (20).However, the relationship between multisensory behavioral performance and neural activity in the auditory cortex remains unknown for two reasons. First, methodologies typically used to study the auditory cortex in humans are unable to resolve neural activity at the level of action potentials. Second, regardless of the areas explored, none of the face/voice neurophysiological studies in monkeys to date, including auditory cortical studies (21–24) and studies of association areas (25–27), have required monkeys to perform a multisensory task. All these physiological studies demonstrated that neural activity in response to faces combined with voices is integrative, exhibiting both enhanced and suppressed changes in the magnitude of response when multisensory conditions are compared with unisensory ones. It is presumed that such changes in firing rate mediate behavioral benefits (e.g., faster reaction times, better accuracy) of multisensory signals, but it is possible that integrative neural responses—particularly in the auditory cortex—are epiphenomenal.In this study, we combined an audiovisual vocal-detection task with auditory cortical physiology in macaque monkeys. When detecting voices alone, our data show that the signal-to-noise ratio (SNR) systematically influences behavioral performance; the same systematic effects are observed in the magnitude and latency of spiking activity. The addition of a dynamic face leads to audiovisual neural responses that are faster than auditory-only responses—dynamic faces speed up the latency of auditory cortical spiking activity. Surprisingly, the addition of dynamic faces does not systematically change the magnitude or variability of the firing rate. These data suggest that visual influences have a role in facilitating response latency in the auditory cortex during audiovisual vocal detection. Facial motion speeds up the spiking responses of the auditory cortex but has no systematic influence on firing rate magnitudes.     

Attention-driven discrete sampling of motion perception

In movies or on TV, a wheel can seem to rotate backwards, due to the temporal subsampling inherent in the recording process (the wagon wheel illusion). Surprisingly, this effect has also been reported under continuous light, suggesting that our visual system, too, might sample motion in discrete "snapshots." Recently, these results and their interpretation have been challenged. Here, we investigate the continuous wagon wheel illusion as a form of bistable percept. We observe a strong temporal frequency dependence: the illusion is maximal at alternation rates around 10 Hz but shows no spatial frequency dependence. We introduce an objective method, based on unbalanced counterphase gratings, for measuring this phenomenon and demonstrate that the effect critically depends on attention: the continuous wagon wheel illusion was almost abolished in the absence of focused attention. A motion-energy model, coupled with attention-dependent temporal subsampling of the perceptual stream at rates between 10 and 20 Hz, can quantitatively account for the observed data.     

Conversations about race in Black and White US families: Before and after George Floyd’s death

Research has shown that Black parents are more likely than White parents to have conversations about race with their children, but few studies have directly compared the frequency and content of these conversations and how they change in response to national events. Here we examine such conversations in the United States before and after the killing of George Floyd. Black parents had conversations more often than White parents, and they had more frequent conversations post-Floyd. White parents remained mostly unchanged and, if anything, were less likely to talk about being White and more likely to send colorblind messages. Black parents were also more worried than White parents—both that their children would experience racial bias and that their children would perpetrate racial bias, a finding that held both pre- and post-Floyd. Thus, even in the midst of a national moment on race, White parents remained relatively silent and unconcerned about the topic.

Mom, I love you. I love you. Tell my kids I love them. I’m dead. I can’t breathe.

—George Floyd

As George Floyd lay dying on the street in Minneapolis, Minnesota on May 25, 2020, the knee of police officer Derek Chauvin on his neck, he called out for his mother and children.For Black Americans, such violence is inherently familial and has been since the beginning of the United States when Africans were forced into slavery. Today, systemic racism remains a core aspect of the Black American experience (1), reinforcing racial inequality across major sectors of life, from education and employment to housing and health (2–5). Consequentially, Black parents frequently have “the talk” with their children, seeking to prepare them to experience and combat the biases that could one day kill them (6–8).White Americans are not only less likely to be harmed by systemic racism than Black Americans, they are often advantaged by it (9, 10). In contrast to Black parents, White parents are less likely to talk with their children about race (11, 12), and when they do, despite decades of research documenting the pitfalls of colorblindness (13–15), they often tell their children that race is inconsequential, a privilege Black parents do not feel they can afford (12, 16).Sampling nearly 1,000 parents—half recruited shortly before Floyd’s death and half recruited shortly after—we provide here a rare window into how Black and White parents in the United States talk about race and racism (see 17, 18). Other studies suggest that White parents mostly do not (19, 20). Our research goes further by systematically comparing the socialization practices of Black and White parents both before and after George Floyd’s death, a death that was followed by one of the largest racial justice movements in United States history.Table 1.Parent and child demographics

Prior knowledge of illumination for 3D perception in the human brain

In perceiving 3D shape from ambiguous shading patterns, humans use the prior knowledge that the light is located above their head and slightly to the left. Although this observation has fascinated scientists and artists for a long time, the neural basis of this “light from above left” preference for the interpretation of 3D shape remains largely unexplored. Combining behavioral and functional MRI measurements coupled with multivoxel pattern analysis, we show that activations in early visual areas predict best the light source direction irrespective of the perceived shape, but activations in higher occipitotemporal and parietal areas predict better the perceived 3D shape irrespective of the light direction. These findings demonstrate that illumination is processed earlier than the representation of 3D shape in the visual system. In contrast to previous suggestions, we propose that prior knowledge about illumination is processed in a bottom-up manner and influences the interpretation of 3D structure at higher stages of processing.     

Fiscal scarcity and the inevitability of bedside budget balancing

Until recently, generous third-party reimbursements enabled physicians to pursue each patient's interests with little regard to costs. Conscious rationing was required only episodically as some particular commodity, eg, transplant organs, was too scarce to meet demand, or as some patients lacked basic access to the health care system. Cost containment and the economic reorganization of medicine introduce a new sort of scarcity, requiring a different sort of rationing. "Fiscal scarcity," the general contraction of health care dollars, means that because every medical decision has its cost, every decision is now subject to scrutiny for its economic as well as its medical wisdom. Therefore, every detail of medicine is an allocation problem. Many observers argue that physicians can nevertheless avoid directly trading patients' interests against economic considerations: through "efficiency protocols" that eliminate marginal benefits, through turning economic rationing decisions over to outside parties, through avoiding cost constraints until society has established a just health care allocation system. This article shows that none of these proposals permits the physician to escape cost-cutting at the bedside.     

Shared neural codes for visual and semantic information about familiar faces in a common representational space

Processes evoked by seeing a personally familiar face encompass recognition of visual appearance and activation of social and person knowledge. Whereas visual appearance is the same for all viewers, social and person knowledge may be more idiosyncratic. Using between-subject multivariate decoding of hyperaligned functional magnetic resonance imaging data, we investigated whether representations of personally familiar faces in different parts of the distributed neural system for face perception are shared across individuals who know the same people. We found that the identities of both personally familiar and merely visually familiar faces were decoded accurately across brains in the core system for visual processing, but only the identities of personally familiar faces could be decoded across brains in the extended system for processing nonvisual information associated with faces. Our results show that personal interactions with the same individuals lead to shared neural representations of both the seen and unseen features that distinguish their identities.

Face recognition is essential for effective social interactions. When we see a familiar face, we spontaneously retrieve person knowledge and the position occupied by that familiar individual in our social network. This information sets us up for the most appropriate behavior with that specific individual. The importance of familiar faces for social interactions is reflected in the way the human brain processes these stimuli. Familiar faces are processed in a prioritized way with faster detection even in suboptimal conditions (1, 2). Familiarity associated with faces warps their visual representation (3) and can result in a more homogenous representation across the visual field in areas with retinotopic organization (4). Recognition of familiar faces entails processing not only their visual appearance but also retrieval of person knowledge and an emotional response (5–10). Different parts of the distributed neural system for face perception contribute to these processes (5, 10, 11). The core system for face perception processes visual appearance, resulting in view-invariant representations of identity in anterior temporal and inferior frontal face areas (12–14). The extended system for face perception plays a role in extracting semantic information from faces as well as emotional responses (5, 11, 15, 16).Here, we investigated the neural codes for high-level visual and semantic information about personally familiar faces. Specifically, we asked whether these codes are supported by a common set of basis functions that are shared across people who are personally familiar with the same individuals. We measured patterns of brain activity with functional magnetic resonance imaging (fMRI) while participants viewed images of personally familiar faces and faces of strangers who were only visually familiar. We used hyperalignment to derive a set of basis functions that align brain response patterns in a common, high-dimensional information space (17–19). Hyperalignment transformation parameters were based on participants’ brain activity measured while watching The Grand Budapest Hotel (20), an engaging comedy-drama with rich characterizations of several individuals. We found that these basis functions capture shared representations of visual appearance in the core system for both personally familiar faces and visually familiar faces of strangers. Surprisingly, we also found basis functions that capture shared representations of personally familiar others, but not visually familiar strangers, in extended system areas that are associated with representation of person knowledge, theory of mind, and emotion. Importantly, these basis functions are derived from brain responses to the movie and are, thus, not specific to the familiar individuals whose faces were the experimental stimuli. These results show that the face processing system encodes both visual and nonvisual high-level semantic information about personally familiar others in a neural information space that is not specific to a given set of faces and that is shared across brains.     

Monkey visual behavior falls into the uncanny valley

Very realistic human-looking robots or computer avatars tend to elicit negative feelings in human observers. This phenomenon is known as the “uncanny valley” response. It is hypothesized that this uncanny feeling is because the realistic synthetic characters elicit the concept of “human,” but fail to live up to it. That is, this failure generates feelings of unease due to character traits falling outside the expected spectrum of everyday social experience. These unsettling emotions are thought to have an evolutionary origin, but tests of this hypothesis have not been forthcoming. To bridge this gap, we presented monkeys with unrealistic and realistic synthetic monkey faces, as well as real monkey faces, and measured whether they preferred looking at one type versus the others (using looking time as a measure of preference). To our surprise, monkey visual behavior fell into the uncanny valley: They looked longer at real faces and unrealistic synthetic faces than at realistic synthetic faces.     

An anterior temporal face patch in human cortex, predicted by macaque maps

Increasing evidence suggests that primate visual cortex has a specialized architecture for processing discrete object categories such as faces. Human fMRI studies have described a localized region in the fusiform gyrus [the fusiform face area (FFA)] that responds selectively to faces. In contrast, in nonhuman primates, electrophysiological and fMRI studies have instead revealed 2 apparently analogous regions of face representation: the posterior temporal face patch (PTFP) and the anterior temporal face patch (ATFP). An earlier study suggested that human FFA is homologous to the PTFP in macaque. However, in humans, no obvious homologue of the macaque ATFP has been demonstrated. Here, we used fMRI to map face-selective sites in both humans and macaques, based on equivalent stimuli in a quantitative topographic comparison. This fMRI evidence suggests that such a face-selective area exists in human anterior inferotemporal cortex, comprising the apparent homologue of the fMRI-defined ATFP in macaques.     

Gonadectomy alters myosin heavy chain composition in isolated cardiac myocytes

A total of 95 patients with Graves’ disease (GD) and 105 normal healthy controls were enrolled in this study to determine how a single site polymorphism of the transporter associated with antigen processing 1 (TAP1) gene contributes to the pathogenesis of GD. The polymorphism was detected using polymerase chain reaction (PCR)-based restriction analysis. Associations between GD and the two-site polymorphisms of the TAP1 gene at codons 333 and 637 were evaluated. No significant differences were revealed comparing GD patients and normal individuals for the distributions of genotypes and allelic variants at codon 333 (p=0.253 and p=0.891, respectively). By contrast, the distributions for the AA homozygote at codon 637 were reduced and those for the GA heterozygote were increased comparing the two groups (p<0.0001). The allelic analysis also demonstrated lower A and higher G allele frequencies (p=0.0008; OR=2.745, 95% CI=1.482-5.085) comparing the GD patients with the normal healthy controls. This shows that the single-site polymorphism of the TAP1 gene at codon 637 may be an indicator for predicting development of GD.     

Multimodel assessment of water scarcity under climate change

Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. Here we use a large ensemble of global hydrological models (GHMs) forced by five global climate models and the latest greenhouse-gas concentration scenarios (Representative Concentration Pathways) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that a global warming of 2 °C above present (approximately 2.7 °C above preindustrial) will confront an additional approximate 15% of the global population with a severe decrease in water resources and will increase the number of people living under absolute water scarcity (<500 m³ per capita per year) by another 40% (according to some models, more than 100%) compared with the effect of population growth alone. For some indicators of moderate impacts, the steepest increase is seen between the present day and 2 °C, whereas indicators of very severe impacts increase unabated beyond 2 °C. At the same time, the study highlights large uncertainties associated with these estimates, with both global climate models and GHMs contributing to the spread. GHM uncertainty is particularly dominant in many regions affected by declining water resources, suggesting a high potential for improved water resource projections through hydrological model development.