Molecular markers of eventual chronic diseases of aging are higher in young adults of lower socioeconomic status.

Sobering work from Shanahan et al.:  

Significance

The analysis of gene expression in peripheral whole blood of US young adults in their late 30s revealed socioeconomic status-based inequalities in the molecular underpinnings of the most common chronic conditions of aging. Associations involved immune, inflammatory, ribosomal, and metabolic pathways, and extra- and intra-cellular signaling. Body mass index was a plausible, sizable mediator of many associations. Results point to new ways of thinking about how social inequalities “get under the skin” and also call for renewed efforts to prevent chronic conditions of aging decades before diagnoses.

Abstract

Many common chronic diseases of aging are negatively associated with socioeconomic status (SES). This study examines whether inequalities can already be observed in the molecular underpinnings of such diseases in the 30s, before many of them become prevalent. Data come from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a large, nationally representative sample of US subjects who were followed for over two decades beginning in adolescence. We now have transcriptomic data (mRNA-seq) from a random subset of 4,543 of these young adults. SES in the household-of-origin and in young adulthood were examined as covariates of a priori-defined mRNA-based disease signatures and of specific gene transcripts identified de novo. An SES composite from young adulthood predicted many disease signatures, as did income and subjective status. Analyses highlighted SES-based inequalities in immune, inflammatory, ribosomal, and metabolic pathways, several of which play central roles in senescence. Many genes are also involved in transcription, translation, and diverse signaling mechanisms. Average causal-mediated effect models suggest that body mass index plays a key role in accounting for these relationships. Overall, the results reveal inequalities in molecular risk factors for chronic diseases often decades before diagnoses and suggest future directions for social signal transduction models that trace how social circumstances regulate the human genome.

Observing the activity of our prosocial brains

Interesting work from Lockwood et al., open source with nice graphics:  

Highlights

• Prosocial behaviors frequently involve exerting effort 

• Human participants completed an effort-based decision-making task during fMRI 

• The anterior cingulate gyrus represented the effort costs of prosocial acts 

• Ventral tegmental area and ventral insula represented value for oneself

Summary

Prosocial behaviors—actions that benefit others—are central to individual and societal well-being. Although the mechanisms underlying the financial and moral costs of prosocial behaviors are increasingly understood, this work has often ignored a key influence on behavior: effort. Many prosocial acts are effortful, and people are averse to the costs of exerting them. However, how the brain encodes effort costs when actions benefit others is unknown. During fMRI, participants completed a decision-making task where they chose in each trial whether to “work” and exert force (30%–70% of maximum grip strength) or “rest” (no effort) for rewards (2–10 credits). Crucially, on separate trials, they made these decisions either to benefit another person or themselves. We used a combination of multivariate representational similarity analysis and model-based univariate analysis to reveal how the costs of prosocial and self-benefiting efforts are processed. Strikingly, we identified a unique neural signature of effort in the anterior cingulate gyrus (ACCg) for prosocial acts, both when choosing to help others and when exerting force to benefit them. This pattern was absent for self-benefiting behaviors. Moreover, stronger, specific representations of prosocial effort in the ACCg were linked to higher levels of empathy and higher subsequent exerted force to benefit others. In contrast, the ventral tegmental area and ventral insula represented value preferentially when choosing for oneself and not for prosocial acts. These findings advance our understanding of the neural mechanisms of prosocial behavior, highlighting the critical role that effort has in the brain circuits that guide helping others.

A lucid exposition on non-dual awareness by James Low

The ‘Waking Up’ app by Sam Harris has posted a series of lectures by James Low that “makes the esoteric teachings of Dzogchen—a non-dual contemplative tradition from Tibet—profoundly accessible.”   I want to pass on to MindBlog readers the following paragraph made up of small clips of text  I have taken from his lecture #4 “The Field of Experience.” Low’s website points to his lectures, writing, and videos of his lectures.

If you want stability, if you want real peace, you already have that in the nature of awareness. But if you look to manifestation, to patterning of yourself, to thinking you could establish a stable personalty, to live a life in which you were happy all the time, or in which you were your own person, that way madness lies. To find our original face, to find the ground of our primordial being, we need to release our fixation on the dialogic movement of subject and object, and allow ourselves to be the space within which the movement of experience is occurring. Awareness means being aware that we are present without being something as such. This is a great mystery. When we look at phenomena the world, things exist as something. A car is not a cow, an apple is not an orange, compare and contrast, category allocation. That’s how our cognition, our conceptual elaboration functions to give a seemingly enduring structure to identifications. But awareness can’t be caught. It’s not a thing. You can’t pin a tail on the donkey, there is no donkey there. The mind is not an object for itself, it is self luminous awareness, but you can’t catch it. You can never know your mind but you can be your mind. We are awareness and that’s a very important distinction.

Generative A.I. - more sociopathic than FaceBook and Twitter?

Have a look at this article on how the sociopathic effects of Facebook and Twitter could be dwarfed by what open source generative A.I. could do. I just played with the DALL-E 2 A.I. system that generates an image when you tell it what you want to see. In response to my request to show "Two abyssinian cats sitting in a window looking out at trees" the following spooky and accurate image appeared.

 

New Perspectives on how our Minds Work

I want to pass on to MindBlog readers this link to a lecture I gave this past Friday (10/21/22) to the Univ. of Texas OLLI (Osher Lifelong Learning Institute) UT FORUM group on Oct. 21, 2022. Here is the brief description of the talk:  

Abstract

Recent research shows that much of what we thought we knew about how our minds work is wrong. Rather than rising from our essential natures, our emotional and social realities are mainly invented by each of us. Modern and ancient perspectives allow us to have some insight into what we have made.

Description

This talk offers a description of how our predictive brains work to generate our perceptions, actions, emotions, concepts, language, and social structures. Our experience that a self or "I" inside our heads is responsible for these behaviors is a useful illusion, but there is in fact no homunculus or discrete place inside our heads where “It all comes together.” Starting before we are born diffuse networks of brain cells begin generating actions and perceiving their consequences to build an internal library of sensing and acting correlations that keep us alive and well, a library that is the source of predictions about what we might expect to happen next in our worlds. Insights from both modern neuroscience research and ancient meditative traditions allow us to partially access and sometimes change this archive that manages our behaviors.

Anxiety - What is it, when is it useful, when is it not?

The title of this post is the discussion topic for the Nov. 6 Austin Rainbow Forum, a monthly discussion group of LGBT seniors that first met in Austin Tx in Jan. 2018. I am using this post to pass on links to some optional background reading:

Martin Seligman and learned helplessness versus helpfulness

Eustress - beneficial stress

Bruce McEwen on good and bad stress

Robert Sapolsky on chronic stress

A deeper look into what our bodies are doing during arousal and calm (click on the arrows at bottom left of presentation frame to expand to full screen)

Facebook has no idea where it keeps our personal data.

A fascinating article from Biddle describing the situation that occured when a court ordered Facebook to turn over information it had collected about a lawsuit’s plaintiffs. Facebook...

...has amassed so much data on so many billions of people and organized it so confusingly that full transparency is impossible on a technical level. In the March 2022 hearing, Zarashaw and Steven Elia, a software engineering manager, described Facebook as a data-processing apparatus so complex that it defies understanding from within. The hearing amounted to two high-ranking engineers at one of the most powerful and resource-flush engineering outfits in history describing their product as an unknowable machine.

The special master at times seemed in disbelief, as when he questioned the engineers over whether any documentation existed for a particular Facebook subsystem. “Someone must have a diagram that says this is where this data is stored,” he said, according to the transcript. Zarashaw responded: “We have a somewhat strange engineering culture compared to most where we don’t generate a lot of artifacts during the engineering process. Effectively the code is its own design document often.” He quickly added, “For what it’s worth, this is terrifying to me when I first joined as well.”

The fundamental problem, according to the engineers in the hearing, is that Facebook’s sprawl has made it impossible to know what it consists of anymore; the company never bothered to cultivate institutional knowledge of how each of these component systems works, what they do, or who’s using them. There is no documentation of what happens to your data once it’s uploaded, because that’s just never been something the company does, the two explained. “It is rare for there to exist artifacts and diagrams on how those systems are then used and what data actually flows through them,”

Musical rhythm training improves short-term memory for faces

From Zanto et al:  

Significance

Musical training can improve numerous cognitive functions associated with musical performance. Yet, there is limited evidence that musical training may benefit nonmusical tasks and it is unclear how the brain may enable such a transfer of benefit. To address this, nonmusicians were randomized to receive 8 wk of either musical rhythm training or word search training. Memory for faces was assessed pre- and post-training while electroencephalography data were recorded to assess changes in brain activity. Results showed that only musical rhythm training improved face memory, which was associated with increased activity in the superior parietal region of the brain when encoding and maintaining faces. Thus, musical rhythm training can improve face memory by facilitating how the brain encodes and maintains memories.

Abstract

Playing a musical instrument engages numerous cognitive abilities, including sensory perception, selective attention, and short-term memory. Mounting evidence indicates that engaging these cognitive functions during musical training will improve performance of these same functions. Yet, it remains unclear the extent these benefits may extend to nonmusical tasks, and what neural mechanisms may enable such transfer. Here, we conducted a preregistered randomized clinical trial where nonmusicians underwent 8 wk of either digital musical rhythm training or word search as control. Only musical rhythm training placed demands on short-term memory, as well as demands on visual perception and selective attention, which are known to facilitate short-term memory. As hypothesized, only the rhythm training group exhibited improved short-term memory on a face recognition task, thereby providing important evidence that musical rhythm training can benefit performance on a nonmusical task. Analysis of electroencephalography data showed that neural activity associated with sensory processing and selective attention were unchanged by training. Rather, rhythm training facilitated neural activity associated with short-term memory encoding, as indexed by an increased P3 of the event-related potential to face stimuli. Moreover, short-term memory maintenance was enhanced, as evidenced by increased two-class (face/scene) decoding accuracy. Activity from both the encoding and maintenance periods each highlight the right superior parietal lobule (SPL) as a source for training-related changes. Together, these results suggest musical rhythm training may improve memory for faces by facilitating activity within the SPL to promote how memories are encoded and maintained, which can be used in a domain-general manner to enhance performance on a nonmusical task.

Sleepless and unhelpful

Simon et al. demonstrate that sleep loss leads to the withdrawal of human helping across individuals, groups, and large-scale societies:

Humans help each other. This fundamental feature of homo sapiens has been one of the most powerful forces sculpting the advent of modern civilizations. But what determines whether humans choose to help one another? Across 3 replicating studies, here, we demonstrate that sleep loss represents one previously unrecognized factor dictating whether humans choose to help each other, observed at 3 different scales (within individuals, across individuals, and across societies). First, at an individual level, 1 night of sleep loss triggers the withdrawal of help from one individual to another. Moreover, fMRI findings revealed that the withdrawal of human helping is associated with deactivation of key nodes within the social cognition brain network that facilitates prosociality. Second, at a group level, ecological night-to-night reductions in sleep across several nights predict corresponding next-day reductions in the choice to help others during day-to-day interactions. Third, at a large-scale national level, we demonstrate that 1 h of lost sleep opportunity, inflicted by the transition to Daylight Saving Time, reduces real-world altruistic helping through the act of donation giving, established through the analysis of over 3 million charitable donations. Therefore, inadequate sleep represents a significant influential force determining whether humans choose to help one another, observable across micro- and macroscopic levels of civilized interaction. The implications of this effect may be non-trivial when considering the essentiality of human helping in the maintenance of cooperative, civil society, combined with the reported decline in sufficient sleep in many first-world nations.

Third-party punishment by preverbal infants

From Kanakogi et al.:

Third-party punishment of antisocial others is unique to humans and seems to be universal across cultures. However, its emergence in ontogeny remains unknown. We developed a participatory cognitive paradigm using gaze-contingency techniques, in which infants can use their gaze to affect agents displayed on a monitor. In this paradigm, fixation on an agent triggers the event of a stone crushing the agent. Throughout five experiments (total N = 120), we show that eight-month-old infants punished antisocial others. Specifically, infants increased their selective looks at the aggressor after watching aggressive interactions. Additionally, three control experiments excluded alternative interpretations of their selective gaze, suggesting that punishment-related decision-making influenced looking behaviour. These findings indicate that a disposition for third-party punishment of antisocial others emerges in early infancy and emphasize the importance of third-party punishment for human cooperation. This behavioural tendency may be a human trait acquired over the course of evolution.

A sleeping touch improves vision.

Interesting work reported by Onuki et al. in the Journal of Neuroscience:   

SIGNIFICANCE STATEMENT

Tactile sensations can bias our visual perception as a form of cross-modal interaction. However, it was reported only in the awake state. Here we show that repetitive directional tactile motion stimulation on the fingertip during slow wave sleep selectively enhanced subsequent visual motion perception. Moreover, the visual improvement was positively associated with sleep slow wave activity. The tactile motion stimulation during slow wave activity increased the activation at the high beta frequency over the occipital electrodes. The visual improvement occurred in agreement with a hand-centered reference frame. These results suggest that our sleeping brain can interpret tactile information based on a hand-centered reference frame, which can cause the sleep-dependent improvement of visual motion detection.

ABSTRACT

Tactile sensations can bias visual perception in the awake state while visual sensitivity is known to be facilitated by sleep. It remains unknown, however, whether the tactile sensation during sleep can bias the visual improvement after sleep. Here, we performed nap experiments in human participants (n = 56, 18 males, 38 females) to demonstrate that repetitive tactile motion stimulation on the fingertip during slow wave sleep selectively enhanced subsequent visual motion detection. The visual improvement was associated with slow wave activity. The high activation at the high beta frequency was found in the occipital electrodes after the tactile motion stimulation during sleep, indicating a visual-tactile cross-modal interaction during sleep. Furthermore, a second experiment (n = 14, 14 females) to examine whether a hand- or head-centered coordination is dominant for the interpretation of tactile motion direction showed that the biasing effect on visual improvement occurs according to the hand-centered coordination. These results suggest that tactile information can be interpreted during sleep, and can induce the selective improvement of post-sleep visual motion detection.

Liberal Democracy versus Christian Democracy

I pass on the opening paragraphs of Thomas Edsall's essay, which offers one of the most succinct summaries I have seen.

Could there soon be an American counterpart to Viktor Orban, the Hungarian prime minister, a right-wing populist who in 2018 declared, “We must demonstrate that there is an alternative to liberal democracy: It is called Christian democracy. And we must show that the liberal elite can be replaced with a Christian democratic elite”?

Liberal democracy, Orban continued,

is liberal, while Christian democracy is, by definition, not liberal: it is, if you like, illiberal. And we can specifically say this in connection with a few important issues — say, three great issues. Liberal democracy is in favor of multiculturalism, while Christian democracy gives priority to Christian culture; this is an illiberal concept. Liberal democracy is pro-immigration, while Christian democracy is anti-immigration; this is again a genuinely illiberal concept. And liberal democracy sides with adaptable family models, while Christian democracy rests on the foundations of the Christian family model; once more, this is an illiberal concept.

Or could there soon be an American counterpart to Giorgia Meloni, another right-wing populist and admirer of Orban, now on course to become the next prime minister of Italy?

Meloni’s platform?

Yes to natural families, no to the L.G.B.T. lobby. Yes to sexual identity, no to gender ideology. Yes to the culture of life, no to the abyss of death. No to the violence of Islam, yes to safer borders. No to mass immigration, yes to work for our people.

I highly recommend reading the rest of Edsall's article on the signals pointing to the vulnerability of the liberal state.

Cognitive and Evolutionary Foundations of Puritanical Morality

MindBlog receives articles for commentary from the Cambridge University Journal of Behavioral and Brain Sciences. I will pass on the following abstract of an article by Fitouchi et. al. Motivated readers can email me to request a copy.

Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: it must emerge from cognitive systems that did not evolve for cooperation (e.g., disgust-based "Purity" concerns). Here, we argue that, despite appearances, puritanical morality is no exception to the cooperative function of moral cognition. It emerges in response to a key feature of cooperation, namely that cooperation is (ultimately) a long-term strategy, requiring (proximately) the self-control of appetites for immediate gratification. Puritanical moralizations condemn behaviors which, although inherently harmless, are perceived as indirectly facilitating uncooperative behaviors, by impairing the self-control required to refrain from cheating. Drinking, drugs, immodest clothing, and unruly music and dance, are condemned as stimulating short-term impulses, thus facilitating uncooperative behaviors (e.g., violence, adultery, free-riding). Overindulgence in harmless bodily pleasures (e.g., masturbation, gluttony) is perceived as making people slave to their urges, thus altering abilities to resist future antisocial temptations. Daily self-discipline, ascetic temperance, and pious ritual observance are perceived as cultivating the self-control required to honor prosocial obligations. We review psychological, historical, and ethnographic evidence supporting this account. We use this theory to explain the fall of puritanism in WEIRD societies, and discuss the cultural evolution of puritanical norms. Explaining puritanical norms does not require adding mechanisms unrelated to cooperation in our models of the moral mind.

Triggers for mother love

A fascinating open source article from Margaret Livingstone carrying forward the famous experiments by Harry Harlow:  

Significance

Harry Harlow found that infant monkeys form strong and lasting attachments to inanimate surrogates, but only if the surrogate is soft; here I report that postpartum monkey mothers can also form strong and lasting attachments to soft inanimate objects. Thus, mother/infant and infant/mother bonds may both be triggered by soft touch.

Abstract

Previous studies showed that baby monkeys separated from their mothers develop strong and lasting attachments to inanimate surrogate mothers, but only if the surrogate has a soft texture; soft texture is more important for the infant’s attachment than is the provision of milk. Here I report that postpartum female monkeys also form strong and persistent attachments to inanimate surrogate infants, that the template for triggering maternal attachment is also tactile, and that even a brief period of attachment formation can dominate visual and auditory cues indicating a more appropriate target.

Trigger warnings and ‘safety-ism’ don’t work.

Mark Manson does an engaging "Mindf*ck Monday Newsletter from Sept. 7" that I recommend you have a look at. It cites a meta-analysis by Brigland et al. that shows that trigger warning don't work, in some cases they may make things worse. Their abstract:

Trigger warnings, content warnings, or content notes are alerts about upcoming content that may contain themes related to past negative experiences. Advocates claim that warnings help people to emotionally prepare for or completely avoid distressing material. Critics argue that warnings both contribute to a culture of avoidance at odds with evidence-based treatment practices and instill fear about upcoming content. Recently, a body of psychological research has begun to investigate these claims empirically. We present the results of a meta-analysis of all empirical studies on the effects of these warnings. Overall, we found that warnings have no effect on affective responses to negative material nor on educational outcomes (i.e., comprehension). However, warnings reliably increase anticipatory affect. Findings on avoidance were mixed, suggesting either that warnings have no effect on engagement with material, or that they increase engagement with negative material under specific circumstances. Limitations and implications for policy and therapeutic practice are discussed.

Manson also discusses the dying fad of "safety-ism" noted by Jonathan Haidt and Greg Lukianoff in their book "The Coddling of the American Mind," and makes the point that...

The human mind is antifragile—that is, it gains from discomfort and strain. That means to grow stronger, the human mind needs to regularly be confronted with difficult and upsetting experiences to develop stability and serenity for itself.

Neural synchronization predicts marital satisfaction

From Li et al.:  

Significance

Humans establish intimate social and personal relationships with their partners, which enable them to survive, successfully mate, and raise offspring. Here, we examine the neurobiological basis of marital satisfaction in humans using naturalistic, ecologically relevant, interpersonal communicative cues that capture shared neural representations between married couples. We show that in contrast to demographic and personality measures, which are unreliable predictors of marital satisfaction, neural synchronization of brain responses during viewing of naturalistic maritally relevant movies predicted higher levels of marital satisfaction in couples. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction and advance our understanding of human marital bonding.

Abstract

Marital attachment plays an important role in maintaining intimate personal relationships and sustaining psychological well-being. Mate-selection theories suggest that people are more likely to marry someone with a similar personality and social status, yet evidence for the association between personality-based couple similarity measures and marital satisfaction has been inconsistent. A more direct and useful approach for understanding fundamental processes underlying marital satisfaction is to probe similarity of dynamic brain responses to maritally and socially relevant communicative cues, which may better reflect how married couples process information in real time and make sense of their mates and themselves. Here, we investigate shared neural representations based on intersubject synchronization (ISS) of brain responses during free viewing of marital life-related, and nonmarital, object-related movies. Compared to randomly selected pairs of couples, married couples showed significantly higher levels of ISS during viewing of marital movies and ISS between married couples predicted higher levels of marital satisfaction. ISS in the default mode network emerged as a strong predictor of marital satisfaction and canonical correlation analysis revealed a specific relation between ISS in this network and shared communication and egalitarian components of martial satisfaction. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction, reflecting shared values and beliefs. Our study advances foundational knowledge of the neurobiological basis of human pair bonding.

How nature nurtures

MindBlog has passed on a number of articles on how exposure to nature reduces stress (see a sample list below). Here is a further contribution from Sudimac et al., who show amygdala activity decreases as the result of a one-hour walk in nature:

Since living in cities is associated with an increased risk for mental disorders such as anxiety disorders, depression, and schizophrenia, it is essential to understand how exposure to urban and natural environments affects mental health and the brain. It has been shown that the amygdala is more activated during a stress task in urban compared to rural dwellers. However, no study so far has examined the causal effects of natural and urban environments on stress-related brain mechanisms. To address this question, we conducted an intervention study to investigate changes in stress-related brain regions as an effect of a one-hour walk in an urban (busy street) vs. natural environment (forest). Brain activation was measured in 63 healthy participants, before and after the walk, using a fearful faces task and a social stress task. Our findings reveal that amygdala activation decreases after the walk in nature, whereas it remains stable after the walk in an urban environment. These results suggest that going for a walk in nature can have salutogenic effects on stress-related brain regions, and consequently, it may act as a preventive measure against mental strain and potentially disease. Given rapidly increasing urbanization, the present results may influence urban planning to create more accessible green areas and to adapt urban environments in a way that will be beneficial for citizens’ mental health.

A few previous MindBlog posts on this topic:

Blue Mind - looking at water improves your health and calm 

Pictures of green spaces make you happier. 

More green space in childhood, fewer psychiatric disorders in adulthood.

Machine learning is translating the languages of animals

Anthes does an article on how machine learning is being used to eavesdrop on naked mole rats, fruit bats, crows and whales — and to communicate back. Some edited clips:

Machine-learning systems, which use algorithms to detect patterns in large collections of data, have excelled at analyzing human language, giving rise to voice assistants that recognize speech, transcription software that converts speech to text and digital tools that translate between human languages.

...this technology can be deployed to decode animal communication, working towards finding a Google Translate for animals, using machine-learning algorithms to identify when squeaking mice are stressed or why fruit bats are shouting. Even more ambitious projects are underway — to create a comprehensive catalog of crow calls, map the syntax of sperm whales and even to build technologies that allow humans to talk back.

...machine-learning algorithms can spot subtle patterns that might elude human listeners...these programs can tell apart the voices of individual animals, distinguish between sounds that animals make in different circumstances and break their vocalizations down into smaller parts, a crucial step in deciphering meaning.

...the technology could also be deployed for the benefit of animals, helping experts monitor the welfare of both wild and domestic fauna. Scientists also said that they hoped that by providing new insight into animal lives, this research might prompt a broader societal shift. Many pointed to the galvanizing effect of the 1970 album “Songs of the Humpback Whale,” which featured recordings of otherworldly whale calls and has been widely credited with helping to spark the global Save the Whales movement...many scientists said they hoped these new, high-tech efforts to understand the vocalizations of whales — and crows and bats and even naked mole rats — will be similarly transformative, providing new ways to connect with and understand the creatures with whom we share the planet.

Lasting improvements in seniors’ working and long-term memory with repetitive neuromodulation

From Grover et al., an open source article in which details of their transcranial alternating current stimulation (tACS) protocols are given:

The development of technologies to protect or enhance memory in older people is an enduring goal of translational medicine. Here we describe repetitive (4-day) transcranial alternating current stimulation (tACS) protocols for the selective, sustainable enhancement of auditory–verbal working memory and long-term memory in 65–88-year-old people. Modulation of synchronous low-frequency, but not high-frequency, activity in parietal cortex preferentially improved working memory on day 3 and day 4 and 1 month after intervention, whereas modulation of synchronous high-frequency, but not low-frequency, activity in prefrontal cortex preferentially improved long-term memory on days 2–4 and 1 month after intervention. The rate of memory improvements over 4 days predicted the size of memory benefits 1 month later. Individuals with lower baseline cognitive function experienced larger, more enduring memory improvements. Our findings demonstrate that the plasticity of the aging brain can be selectively and sustainably exploited using repetitive and highly focalized neuromodulation grounded in spatiospectral parameters of memory-specific cortical circuitry.

The sex of human experimenters influences mouse behaviors and neural responses.

As I was scanning a recent nature neuroscience table of contents, the title of this item elicited an immediate “What the f…..?” reaction, so I had to click on it. I had not been aware that mice are aversive to the scent of male versus female human experimenters. Here is the Georgiou et al. abstract:

We show that the sex of human experimenters affects mouse behaviors and responses following administration of the rapid-acting antidepressant ketamine and its bioactive metabolite (2R,6R)-hydroxynorketamine. Mice showed aversion to the scent of male experimenters, preference for the scent of female experimenters and increased stress susceptibility when handled by male experimenters. This human-male-scent-induced aversion and stress susceptibility was mediated by the activation of corticotropin-releasing factor (CRF) neurons in the entorhinal cortex that project to hippocampal area CA1. Exposure to the scent of male experimenters before ketamine administration activated CA1-projecting entorhinal cortex CRF neurons, and activation of this CRF pathway modulated in vivo and in vitro antidepressant-like effects of ketamine. A better understanding of the specific and quantitative contributions of the sex of human experimenters to study outcomes in rodents may improve replicability between studies and, as we have shown, reveal biological and pharmacological mechanisms.