Numerous invertebrates have contributed to our understanding of the biology of learning
and memory. In most cases, learning performance is documented for groups of
individuals, and nearly always based on a single, typically binary, behavioural metric
for a conditioned response. This is unfortunate for several reasons. Foremost, it has
become increasingly apparent that invertebrates exhibit inter-individual differences in
many aspects of their behaviour, and also that the conditioned response probability for
an animal group does not adequately represent the behaviour of individuals in classical
conditioning. Furthermore, a binary response character cannot yield a graded score
for each individual. We also hypothesise that due to the complexity of a conditioned
response, a single metric need not reveal an individual’s full learning potential. In this
paper, we report individual learning scores for freely moving adult male crickets (Gryllus
bimaculatus) based on a multi-factorial analysis of a conditioned response. First, in an
absolute conditioning paradigm, we video-tracked the odour responses of animals that,
in previous training, received either odour plus reward (sugar water), reward alone, or
odour alone to identify behavioural predictors of a conditioned response. Measures of
these predictors were then analysed using binary regression analysis to construct a
variety of mathematical models that give a probability for each individual that it exhibited
a conditioned response (Presp). Using standard procedures to compare model accuracy,
we identified the strongest model which could reliably discriminate between the different
odour responses. Finally, in a differential appetitive olfactory paradigm, we employed
the model after training to calculate the Presp of animals to a conditioned, and to
an unconditioned odour, and from the difference a learning index for each animal.
Comparing the results from our multi-factor model with a single metric analysis (head
bobbing in response to a conditioned odour), revealed advantageous aspects of the
model. A broad distribution of model-learning scores, with modes at low and high values,
support the notion of a high degree of variation in learning capacity, which we discuss.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:84330 |
| Date | 27 March 2023 |
| Creators | Borstel, Kim J., Stevenson, Paul A. |
| Publisher | Frontiers Research Foundation |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 1662-5153, 741439 |
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