A preliminary study of single prolonged stress influence acoustic startle reflex and prepulse inhibition in rats / 中华行为医学与脑科学杂志

ObjectiveTo explore the deficits of acoustic startle reflex (ASR) and prepulse inhibition (PPI) of acoustic startle reflex in single prolonged stress rats.MethodsSixty Sprague Dawley rats were randomly divided into control 1,7,14 d groups and stress 1,7,14 d groups.All stressed rats received single prolonged stress while all control rats were left in their home cage.Behavioral changes in these rats were analyzed in ASR and PPI paradigm.ASR and PPI were carried out on day 2,8,15,respectively.ResultsThere were no differences of ASR and PPI among control 1,7,14 d groups (P ＞ 0.05).ASR of stress 1 d group ( (92.49 ± 31.54) g) was higher than that of control 1 d group((64.48 ± 17.95)g,P＜0.05) while PPI of stress 1 d group((28.60 ±29.02)％) was lower than that of control 1 d group( (41.60 ± 15.10)％,P ＜ 0.05 ).There were no differences of ASR between control 7 d group and stress 7 d group,control 14 d group and stress 14 d group (P＞ 0.05 ).Compared with control 7 d group ( (41.30 ± 12.79) ％ ),PPI in stress 7 d group ( ( 17.95 ± 31.79) ％ ) was reduced (P ＜ 0.05 ).Compared with control 14 d group ( (41.16 ± 12.25 ) ％ ),PPI in stress 14 d group( ( 13.71 ± 32.48) ％ ) was reduced (P ＜ 0.05).ConclusionEffects of stress on ASR in rats increased in early period,while the impaired PPI may last for a long time.

Establishment of delay-trace conditioning procedure of classical eyeblink conditioning in Kunming mice and analysis of behavioral characteristic parameters / 中华行为医学与脑科学杂志

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.

Lesions of the medial prefrontal cortex of guinea pig inhibit acoustic startle reflex / 中华行为医学与脑科学杂志

Objective To observe and analyze the role of different subfields of medial prefrontal cortex (mPFC) in the expression course of startle reflex.Methods 24 healthy male British kind of albino guinea pigs were randomly divided into 4 groups:anterior cingulated cortex lesion ( n =6) and sham-lesion ( n =6) ( Experiment 1 ) ; prelimbic cortex lesion/joint lesion of prelimbic cortex and anterior cingulated cortex(n=6) and sham-lesion ( n =6) ( Experiment 2 ).The animals were injected lidocaine ( lesion ) or physiological saline ( sham-lesion ).Each group received paired training of conditioned stimulus( CS,a tone) and unconditioned stimulus (US,a air puff),to observe the acoustic startle reflex(ASR) change of these groups.Results As the results of experiment 1 suggested,SR rate did not change significantly after anterior cingulated cortex lesion ( time effect:F =15.421,P =0.098 ; group effect:F =14.753,P =0.084).As the results of experiment 2 suggested,SR rate did not change significantly after prelimbic cortex lesion ( time effect:F =14.975,P =0.178 ; group effect:F =18.643,P =0.089).When prelimbic cortex and anterior cingulated cortex were lesioned at the same time,SR rate declined significantly and didn ' t recover with the following training ( group effect:F =67.743,P =0.009 ).ConclusionLesions of the prelimbic cortex and anterior cingulated cortex in mPFC cause the significantly decline of acoustic startle reflex( ASR),which don' t recover with the following training.This study indicates that mPFC involves in the regulation of ASR,but the regulation mechanism needs to be discussed.