Multiple regression

In this Techniques article Peter Cahusac explains multiple regression, a much used statistical procedure, but one that is frequently misunderstood or misused. Multiple regression allows the effects of many explanatory (independent) variables on the measured (dependent) variable to be analysed simultaneously for situations when a single explanatory variable fails to account for most of the variation in the dependent variable – a common occurrence

Selective decline in the prevalence of slowly adapting type I mechanoreceptors during development

Merkel nerve endings are identified physiologically as slowly adapting type I mechanoreceptor units. They are important for fine acuity tactile perception. We examined the effect of age on the electrophysiological availability of different types of slowly adapting mechanoreceptor units. Using 6 - 50 week old rats, we observed an obvious decline with age in the probability of recording from St I units of the deep vibrissal nerve. The precipitous decline occurred between ages 6 – 14 weeks and then stabilized. By contrast, the prevalence of St II units, the other type of slowly adapting mechanoreceptor, remained constant over the age range studied. These observations correlate with anatomical findings reported elsewhere

Initial findings of a longitudinal study of wellbeing and mental health among graduate students around the world: The intra-individual impact of a pandemic

This paper explores the impact of the COVID-19 pandemic on the mental health and wellbeing of graduate students at universities and research institutions around the world. In so doing, it assesses the intra-individual effects of pandemic-related restrictions on a key cohort in academia: doctoral candidates. We trace this cohort’s ability to adapt to the pandemic over a two-year period by investigating their quality of mental health, indicators of mental health disorders, and indicators of wellbeing and resilience. A consensual qualitative research methodology was adopted when analyzing data gathered during April 2020 and February 2022. The study uses Ecological Systems Theory as a framework, providing insights into how the COVID-19 pandemic affected the wellbeing and mental health of graduate students in myriad ways. The researchers found that while the pandemic negatively affected cognitive processes, a significant proportion of doctoral candidates exhibited remarkable levels of resistance and reconfiguration resilience and short-term improvements in mental health during the period under investigation. Keywords: Wellbeing, mental health, Consensual Qualitative Research, COVID-19, graduate student

Combined Recording of Mechanically Stimulated Afferent Output and Nerve Terminal Labelling in Mouse Hair Follicle Lanceolate Endings

A novel dissection and recording technique is described for monitoring afferent firing evoked by mechanical displacement of hairs in the mouse pinna. The technique is very cost-effective and easily undertaken with materials commonly found in most electrophysiology laboratories, or easily purchased. The dissection is simple and fast, with the mechanical displacement provided by a generic electroceramic wafer controlled by proprietary software. The same software also records and analyses the electroneurogram output. The recording of the evoked nerve activity is through a commercial differential amplifier connected to fire-polished standard glass microelectrodes. Helpful tips are given for improving the quality of the preparation, the stimulation and the recording conditions to optimize recording quality. The system is suitable for assaying the electrophysiological and optical properties of lanceolate terminals of palisade endings of hair follicles, as well as the outcomes from their pharmacological and/or genetic manipulation. An example of combining electrical recording with mechanical stimulation and labeling with a styryl pyridinium vital dye is given

Who am I? Mothers’ shifting identities, loss and sensemaking after workplace exit

© 2015, © The Author(s) 2015. We analyse mothers’ retrospective accounts of their transition from professional worker to stay-at-home mother using a framework that integrates sensemaking and border theory. The data come from in-depth interviews with former professional and managerial women in London. Continuing struggles to reconcile professional and maternal identities before and after workplace exit illustrate how identity change is integral to workplace exit. The concept of ‘choice’, which takes place at one point in time, obfuscates this drawn-out process. Mothers pay a high cost in lost professional identities, especially in the initial stages after workplace exit. They cope with this loss and the disjuncture of leaving employment by moving back and forth across the border between home and work – a classic action of sensemaking. Subsequent communal sensemaking and community action bolster mothers’ fragile status at home, eventually leading to reconciliation of their loss and finally enabling them to view their exit ‘choice’ as right

Trial Outcome and Associative Learning Signals in the Monkey Hippocampus

In tasks of associative learning, animals establish new links between unrelated items by using information about trial outcome to strengthen correct/rewarded associations and modify incorrect/unrewarded ones. To study how hippocampal neurons convey information about reward and trial outcome during new associative learning, we recorded hippocampal neurons as monkeys learned novel object-place associations. A large population of hippocampal neurons (50%) signaled trial outcome by differentiating between correct and error trials during the period after the behavioral response. About half these cells increased their activity following correct trials (correct up cells) while the remaining half fired more following error trials (error up cells). Moreover, correct up cells, but not error up cells, conveyed information about learning by increasing their stimulus-selective response properties with behavioral learning. These findings suggest that information about successful trial outcome conveyed by correct up cells may influence new associative learning through changes in the cell's stimulus-selective response properties.National Institutes of Health (U.S.) (NIH grant MH48847)National Institutes of Health (U.S.) (NIH Award DA015644)National Institutes of Health (U.S.) (NIH Award MH59733)National Institutes of Health (U.S.) (NIH grant MH071847)National Institutes of Health (U.S.) (NIH grant DP1 OD003646)Fondation pour la recherche médical

From Odd Encounters to a Prospective Confluence: Dance-Philosophy

This text inquires into the relationship between Western philosophy and Western theatre dance from their odd encounters in modernity to the current affiliations between contemporary choreographic poetics, critical theory and contemporary philosophical thought. The point of departure for the inquiry is a discussion of the three problems that have structured the historically vexed relationship between dance and philosophy: dance’s belated acquisition of the status of an art discipline, the special ontological status of the work of dance, and the limits of dance’s meaning-production set by the theme of bodily movement’s “ephemerality” and “disappearance.” After critically examining the approaches of Alain Badiou and Jacques Rancière in whose philosophies dance is relegated to a metaphor or, even worse, to an ahistorical conduit for a general ontology, the author makes a case for another movement of thought that arises in dance practice and is at the same time philosophical, rooted in Spinoza’s (and Deleuze’s) principle of expression. Demonstrating how choreographers, like Xavier Le Roy and Jonathan Burrows, create by “posing problems,” Cvejić presents a theory of “expressive concepts,” whereby choreography contributes to a philosophical rethinking of the relationship between the body, movement and time. This points to the new prospects of a kind of “dance-philosophy,” in which the epistemic hierarchy is reversed: the stake is no longer in what philosophy could do for dance, but how an experimental, radically pragmatic orientation in dance offers a practical framework for theorizing perception, concept-formation and other philosophical issues

Perceiving Nasal Patency through Mucosal Cooling Rather than Air Temperature or Nasal Resistance

Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive.The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool

Correlates of reward-predictive value in learning-related hippocampal neural activity

Temporal difference learning (TD) is a popular algorithm in machine learning. Two learning signals that are derived from this algorithm, the predictive value and the prediction error, have been shown to explain changes in neural activity and behavior during learning across species. Here, the predictive value signal is used to explain the time course of learning-related changes in the activity of hippocampal neurons in monkeys performing an associative learning task. The TD algorithm serves as the centerpiece of a joint probability model for the learning-related neural activity and the behavioral responses recorded during the task. The neural component of the model consists of spiking neurons that compete and learn the reward-predictive value of task-relevant input signals. The predictive-value signaled by these neurons influences the behavioral response generated by a stochastic decision stage, which constitutes the behavioral component of the model. It is shown that the time course of the changes in neural activity and behavioral performance generated by the model exhibits key features of the experimental data. The results suggest that information about correct associations may be expressed in the hippocampus before it is detected in the behavior of a subject. In this way, the hippocampus may be among the earliest brain areas to express learning and drive the behavioral changes associated with learning. Correlates of reward-predictive value may be expressed in the hippocampus through rate remapping within spatial memory representations, they may represent reward-related aspects of a declarative or explicit relational memory representation of task contingencies, or they may correspond to reward-related components of episodic memory representations. These potential functions are discussed in connection with hippocampal cell assembly sequences and their reverse reactivation during the awake state. The results provide further support for the proposal that neural processes underlying learning may be implementing a temporal difference-like algorithm