ABSTRACT
ObjectiveTo investigate the characteristic parameters and variation of acoustic startle reflex (ASR) and conditioning response (CR)during the acquisition of delay-trace eyeblink conditioning.Methods15healthy Kunming mice were randomly divided into 3 groups:single-task DEBC group ( n =5 ) ; single-task TEBC group ( n =5) ; dual delay/trace group ( n =5).Three groups received paired training of tone conditioned stimulus(CS)in different audio frequency (TEBC groups:2KHz; DEBC group:1KHz) and a 100 ms comeal oxygenpuff unconditioned stimulus(US).Then observed the characteristic parameters of ASR and CR.ResultsAfter pairing training for 10 days,ASR rate( ASR％ ) of single-task groups ( 10th day (38.00 ± 8.64) ％ and (38.55 ±12.41 ) ％ respectively,time effect:F =4.574,P =0.008 ; group effect:F =2.021,P =0.193 ) and dual delaytrace group ( 10th day (47.95 ± 14.23 ) ％ and (62.01 ± 9.03 ) ％ respectively,time effect:F =5,547 P =0.013 ;group effect:F =0.738,P =0.415) changed significantly with the following training but between single-task groups or dual delay-trace group.CR rate ( CR％ ) of single-task groups ( 10th day were (45.4 ± 5.39) ％ and (65.6 ± 6.77) ％ respectively,time effect:F =9.558,P =0.000 ; group effect:F =5.117,P =0.054 ) and dual delay/trace group ( 10th day (57.66 ± 4.34) ％ and (77.35 ± 7.36) ％ respectively,time effect:F =7.750,P =0.002 ;group effect:F=1.449,P=0.263 ) showed obvious change with the following training but between singletask groups or dual delay-trace group.Peak amplitude of single-task DEBC group ( time effect F =2.679,P =0.017 ) and dual delay-trace group ( F=3.452,P=0.034 ) had increased significantly with the following training.Peak latency showed no obvious change.ConclusionDual delay-trace conditioning procedure of classical eyeblink conditioning and single-task can be successfully established in Kunming mice.Although there are some variations,those can be controled and be weaken effect of them by taking targeted measures.
ABSTRACT
The hippocampus plays a critical role during the consolidation of trace eyeblink conditioned responses (CRs). However, the role of its related structure such as dentate gyms (DG) remains unclear. The present study was aimed at monitoring the activity of single granule cell in the DG during the consolidation of trace eyeblink CRs, and elucidating the possible role of DG during this hippocampus-dependent task. Guinea pigs (n=8) were trained on a trace eyeblink conditioning paradigm using a 200-ms tone conditioned stimulus (CS), a 200-ms corneal airpuff unconditioned stimulus (US) and a 600-ms trace interval. Controls consisted of pseudo- conditioned guinea pigs (n=8). Extracellular single unit recordings in vivo were performed in the DG of learner animals during the consolidation of trace eyeblink CRs. The results revealed that all the trace-conditioned animals acquired the trace eyeblink CRs over 14 training days, however, none of the pseudo-conditioned animals did. Furthermore, 23 of 40 single granule cells in the DG of learner animals exhibited heterogeneous activity patterns during the consolidation of trace eyeblink CRs such as increases in activities to the tone CS, trace interval or airpuff US. The results suggested that the DG might participate in the neural circuit important for the consolidation of trace eyeblink CRs, and that the granule cells might encode different information during the consolidation of trace eyeblink CRs.