Biology subjects

Chang, C.-J.

Publications and source records attributed to Chang, C.-J..

3 recordsLinked to original sources

bioRxiv2018

Acute Food Deprivation Rapidly Modifies Valence-Coding Microcircuits in the Amygdala

In the quest for food, we may expend effort and increase our vulnerability to potential threats. Motivation to seek food is dynamic, varying with homeostatic need. What mechanisms underlie these changes? Basolateral amygdala neurons projecting to the nucleus accumbens (BLA[->]NAc) preferentially encode positive valence, whereas those targeting the centromedial amygdala (BLA[->]CeM) preferentially encode negative valence. Longitudinal in vivo two-photon calcium imaging revealed that BLA[->]NAc neurons were more active, while BLA[->]CeM neurons were less active, following just 1 day of food deprivation. Photostimulating BLA[->]CeM neurons inhibited BLA[->]NAc neurons at baseline, but food deprivation rapidly converted this inhibition into facilitation, supporting a model wherein BLA[->]NAc excitability mediates invigorated food-seeking behavior after deprivation. Indeed, inhibiting BLA[->]NAc reduced motivation for a caloric reinforcer in food deprived animals. Taken together, negative valence overrides positive valence processing in satiety, but changing homeostatic needs alter reward value via a rapid shift in the balance between projection-defined populations of BLA neurons.

neuroscience↗

bioRxiv2017

Collection and Storage of HLA NGS Genotyping Data for the 17th International HLA and Immunogenetics Workshop

For over 50 years, the International HLA and Immunogenetics Workshops (IHIW) have advanced the fields of histocompatibility and immunogenetics (H&I) via community sharing of technology, experience and reagents, and the establishment of ongoing collaborative projects. In the fall of 2017, the 17th IHIW will focus on the application of next generation sequencing (NGS) technologies for clinical and research goals in the H&I fields. NGS technologies have the potential to allow dramatic insights and advances in these fields, but the scope and sheer quantity of data associated with NGS raise challenges for their analysis, collection, exchange and storage. The 17 th IHIW has adopted a centralized approach to these issues, and we have been developing the tools, services and systems to create an effective system for capturing and managing these NGS data. We have worked with NGS platform and software developers to define a set of distinct but equivalent NGS typing reports that record NGS data in a uniform fashion. The 17th IHIW database applies our standards, tools and services to collect, validate and store those structured, multi-platform data in an automated fashion. We are creating community resources to enable exploration of the vast store of curated sequence and allele-name data in the IPD-IMGT/HLA Database, with the goal of creating a long-term community resource that integrates these curated data with new NGS sequence and polymorphism data, for advanced analyses and applications.\n\nAbbreviations

bioinformatics↗

bioRxiv2017

An integral role for timing in interception

Timing is critical for myriad behaviors in dynamic environments. For example, to intercept an object, the brain must compute a reliable estimate of time-to-contact (TTC). Prior work suggests that humans compute TTC using kinematic information such as distance and speed without explicitly relying on temporal cues, just as one would do in a physics classroom using kinematic equations. Considering the inherent uncertainty associated with estimates of speed and distance and the ability of human brain to combine different sources of information, we asked whether humans additionally rely on temporal cues. We found that humans actively integrate speed information with both explicit and implicit timing cues. Analysis of behavior in relation to a Bayesian model revealed that the additional temporal information helps subjects optimize their performance in the presence of measurement uncertainty. These findings suggest that brains timing mechanisms are actively engaged while interacting with dynamic stimuli.

animal behavior and cognition↗