scholarly journals Localization and Associative Strength of Acid Polysaccharides in Coccoliths of <i>Pleurochrysis haptonemofera</i> (Haptophyta) Predicted from Their Extractability from Partially Decalcified Coccoliths

2013 ◽  
Vol 03 (01) ◽  
pp. 48-54 ◽  
Author(s):  
Yasutaka Hirokawa ◽  
Satoru Matsuzuka ◽  
Sho Itayama ◽  
Tatsuya Uchida ◽  
Shoko Fujiwara ◽  
...  
Keyword(s):  
Associative Strength ◽  
Pleurochrysis Haptonemofera

scholarly journals Dissociating Representations of Time and Number in Reinforcement-Rate Learning by Deletion of the GluA1 AMPA Receptor Subunit in Mice

2021 ◽  
Vol 32 (2) ◽  
pp. 204-217
Author(s):  
Joseph M. Austen ◽  
Corran Pickering ◽  
Rolf Sprengel ◽  
David J. Sanderson
Keyword(s):  
Associative Strength ◽  
Ampa Receptor ◽  
Reinforcement Rate ◽  
Statistical Properties ◽  
Temporal Information ◽  
Receptor Subunit ◽  
Male And Female ◽  
Female Mice ◽  
Ampa Receptor Subunit ◽  
Numeric Information

Theories of learning differ in whether they assume that learning reflects the strength of an association between memories or symbolic encoding of the statistical properties of events. We provide novel evidence for symbolic encoding of informational variables by demonstrating that sensitivity to time and number in learning is dissociable. Whereas responding in normal mice was dependent on reinforcement rate, responding in mice that lacked the GluA1 AMPA receptor subunit was insensitive to reinforcement rate and, instead, dependent on the number of times a cue had been paired with reinforcement. This suggests that GluA1 is necessary for weighting numeric information by temporal information in order to calculate reinforcement rate. Sample sizes per genotype varied between seven and 23 across six experiments and consisted of both male and female mice. The results provide evidence for explicit encoding of variables by animals rather than implicit encoding via variations in associative strength.

scholarly journals The effects of stimulus distribution form during trace conditioning

2018 ◽  
Vol 72 (2) ◽  
pp. 285-297 ◽  
Author(s):  
Charlotte Bonardi ◽  
Dómhnall J Jennings
Keyword(s):  
Associative Strength ◽  
Auditory Stimulus ◽  
Trace Conditioning ◽  
Response Rates ◽  
Second Phase ◽  
Fixed Duration ◽  
Trace Interval ◽  
Delay Conditioning ◽  
Performance Effect ◽  
Distribution Form

Three experiments examined the effect of distribution form of the trace interval on trace conditioning. In Experiments 1 and 2, two groups of rats were conditioned to a fixed-duration conditioned stimulus (CS) in a trace interval procedure; rats in Group Fix received a fixed-duration trace interval, whereas for rats in Group Var the trace interval was of variable duration. Responding during the CS was higher in Group Var than in Group Fix, whereas during the trace interval this difference in responding reversed—Group Fix showed higher response rates than Group Var. Experiment 3 examined whether the greater response rate observed during the CS in Group Var was due to a performance effect or the acquisition of greater associative strength by the CS. Following trace conditioning, the rats from Experiment 1 underwent a second phase of delay conditioning with the same CS; a 5-s auditory stimulus was presented in compound with the last 5 s of the 15-s CS, and the unconditioned stimulus (US) was delivered at the offset of the CSs. On test with the auditory stimulus alone, subjects in Group Var showed lower response rates during the auditory stimulus than subjects in Group Fix. We interpreted these findings as evidence that the superior responding in Group Var during the CS was a result of it acquiring greater associative strength than in Group Fix.

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