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Record W7133045822

A Discriminating Memory: Learning and Chemosensation in C. elegans

2022· dissertation· W7133045822 on OpenAlexaff
Daniel M. Merritt

Bibliographic record

VenueTSpace · 2022
Typedissertation
Language
FieldBiochemistry, Genetics and Molecular Biology
TopicGenetics, Aging, and Longevity in Model Organisms
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsSensory systemOlfactionCaenorhabditis elegansSensory cueMechanosensationDesensitization (medicine)Stimulus modalitySensory neuron
DOInot available

Abstract

fetched live from OpenAlex

Animals receive information about the external world through their senses, which feed this information into the nervous system where it’s processed, stored, and subsequently influences behaviour. In this work, I describe both how the first steps of chemosensory processing occur in the sensory neurons of the nematode Caenorhabditis elegans, and how the information provided by this chemosensory input, in conjunction with previous sensory information and the internal satiety state of the animal, act to modulate subsequent behaviour. In the first part of this work, I provide an analysis of the phenomenon of Kamin Blocking in C. elegans, in which past learning about sensory cues can modulate the ability of subsequent cues to form memories, and offer a molecular analysis of Kamin Blocking in the worm which challenges a common interpretation of it in mammals. In the second part of this work, I focus on the very initial steps occurring during chemosensation in C. elegans chemosensory neurons, and find that discrimination between different olfactory stimuli which are sensed within the same neuron relies on β-arrestin mediated desensitization of ligand-bound receptors. I provide a model for how desensitization acts to enable intraneuronal olfactory discrimination in the paradigm being tested, offering a resolution to a longstanding question in the field, and test several predictions of this model. In sum, the research presented in this work describes both the earliest mechanisms of chemosensory biology in the worm, and examines how chemosensation acts to create memories and modulate subsequent behaviour. By exploiting the simplicity and genetic tractability of C. elegans, the research described here deepens our understanding of the mechanisms underlying (and linking) the most fundamental aspects of sensation and learning in animals.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.004
Threshold uncertainty score0.007

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.010
GPT teacher head0.307
Teacher spread0.297 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2022
Admission routes1
Has abstractyes

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