Faculty Bibliography

A growing body of evidence suggests that sniffing is not only the mode of delivery for odorant molecules but also contributes to olfactory perception. However, the precise role of sniffing variations remains unknown. The zonation hypothesis suggests that animals use sniffing variations to optimize the deposition of odorant molecules on the most receptive areas of the olfactory epithelium (OE). Sniffing would thus depend on the physicochemical properties of odorants, particularly their sorption. Rojas-Libano and Kay (2012) tested this hypothesis and showed that rats used different sniff strategies when they had to target a high-sorption (HS) molecule or a low-sorption (LS) molecule in a binary mixture. Which sniffing strategy is used by rats when they are confronted to discrimination between two similarly sorbent odorants remains unanswered. Particularly, is sniffing adjusted independently for each odorant according to its sorption properties (analytical processing), or is sniffing adjusted based on the pairing context (synthetic processing)? We tested these hypotheses on rats performing a two-alternative choice discrimination of odorants with similar sorption properties. We recorded sniffing in a non-invasive manner using whole-body plethysmography during the behavioral task. We found that sniffing variations were not only a matter of odorant sorption properties and that the same odorant was sniffed differently depending on the odor pair in which it was presented. These results suggest that rather than being adjusted analytically, sniffing is instead adjusted synthetically and depends on the pair of odorants presented during the discrimination task. Our results show that sniffing is a specific sensorimotor act that depends on complex synthetic processes.

Humans and animals encode and store in memory elapsed intervals as evidenced through their temporal expectancies. However, there are very few experimental studies on long-term memory of duration. The aim of this original study was to examine the consolidation process for duration and its effect on time judgement. In our study, memory of duration was tested in humans with a temporal generalization task. Consolidation was assessed by means of a 15-min nontemporal interference task introduced at different delays after the initial learning of a 4-s standard duration. The results showed that (a) when tested 24 hours after the learning phase, memory of the 4-s duration was disrupted (less precision and lengthening effect) if the interference task was introduced 30-45 min after learning; (b) no disruption was observed when memory was tested immediately after the interference task; and (c) there was a temporal gradient of the disruptive interference effect within the first hour after learning. Overall, these results fulfil the key criteria for the inference of a synaptic/cellular consolidation process and thus demonstrate that, as is the case for other memories, memory of duration undergoes a consolidation process that lasts at least one hour.

Longitudinal imaging studies involve tracking changes in individuals by repeated image acquisition over time. The goal of these studies is to quantify biological shape variability within and across individuals, and also to distinguish between normal and disease populations. However, data variability is influenced by outside sources such as image acquisition, image calibration, human expert judgment, and limited robustness of segmentation and registration algorithms. In this paper, we propose a two-stage method for the statistical analysis of longitudinal shape. In the first stage, we estimate diffeomorphic shape trajectories for each individual that minimize inconsistencies in segmented shapes across time. This is followed by a longitudinal mixed-effects statistical model in the second stage for testing differences in shape trajectories between groups. We apply our method to a longitudinal database from PREDICT-HD and demonstrate our approach reduces unwanted variability for both shape and derived measures, such as volume. This leads to greater statistical power to distinguish differences in shape trajectory between healthy subjects and subjects with a genetic biomarker for Huntington's disease (HD).

The term prediction implies expected outcome in the future, often based on a model and statistical inference. Longitudinal imaging studies offer the possibility to model temporal change trajectories of anatomy across populations of subjects. In the spirit of subject-specific analysis, such normative models can then be used to compare data from new subjects to the norm and to study progression of disease or to predict outcome. This paper follows a statistical inference approach and presents a framework for prediction of future observations based on past measurements and population statistics. We describe prediction in the context of nonlinear mixed effects modeling (NLME) where the full reference population's statistics (estimated fixed effects, variance-covariance of random effects, variance of noise) is used along with the individual's available observations to predict its trajectory. The proposed methodology is generic in regard to application domains. Here, we demonstrate analysis of early infant brain maturation from longitudinal DTI with up to three time points. Growth as observed in DTI-derived scalar invariants is modeled with a parametric function, its parameters being input to NLME population modeling. Trajectories of new subject's data are estimated when using no observation, only the first or the first two time points. Leave-one-out experiments result in statistics on differences between actual and predicted observations. We also simulate a clinical scenario of prediction on multiple categories, where trajectories predicted from multiple models are classified based on maximum likelihood criteria.

Reviews the book, Reading Anna Freud by Nick Midgley (see record 2012-32286-000). Reading Anna Freud is less a work of criticism than a work of orientation, and doubly valuable as such. First, because of the Freud family fame, one sometimes presumes one knows more about them than one really does (indeed, a misplaced presumption of familiarity is at the core of so much of the popular contempt hurled Sigmund's way). Second, orienting yourself to Anna Freud is a way of orienting yourself to child mental health: from how we speak to children and the role of schools in a child's psychological health to developmental psychopathology and the consultation-liaison service. What comes through in Reading Anna Freud is that the core of Freud's success was not just patient, compassionate intellectualism, genes, or an ability to get published, but advocacy. Moreover, you do not need a degree or an internal review board to be an advocate. In fact, it is in this regard that she is most inspiring. Although the book provides a historical and personal orientation, it is intended as an orientation to Freud's intellectual contributions, and Midgely does an excellent job translating her work, some of it nearly a century old, into a language that is still alive, relevant, and enriching.

This article reviews the progression of a research program designed to develop, implement, and study the implementation of "achievable" evidence-based practices (EBPs) in schools. We review challenges encountered and ideas to overcome them to enhance this avenue of research. The article presents two federally funded randomized controlled trials involving comparison of a four-component targeted intervention (Quality Assessment and Improvement, Family Engagement and Empowerment, Modular Evidence-Based Practice, Implementation Support) versus a comparison intervention focused on personal wellness. In both studies, primary aims focused on changes in clinician attitudes and behavior, including the delivery of high-quality EBPs and secondary aims focused on student-level impacts. A number of challenges, many not reported in the literature, are reviewed, and ideas for overcoming them are presented. Given the reality that the majority of youth mental health services are delivered in schools and the potential of school mental health services to provide a continuum of mental health care from promotion to intervention, it is critical that the field consider and address the logistical and methodological challenges associated with implementing and studying EBP implementation by clinicians.