Psychogenics: Conditioned Avoidance Response Essay


Briefly describe the interpretation of the following:

Q1. a. Head twitch test

b. Condition Avoidance test

c. Novel object recognition test

d. Catalepsy test
Q2. What did you find most challenging or interesting?


1. a. Head twitch test:

The head twitch response is rapid side to side head movement, which occurs in rats, which activates serotonin 5 HT2A receptor. CP-809,101 was tested for both agonist and antagonist activity on the mice in the head twitch model, to determine its functional activity for 5HT2A receptor. Rats administered with CP-809,101 and with other 5HT2A agonist. CP-809,101 failed to show head twitch activity, resulted that it lacks 5HT2A agonist like response. But when CP-809,101 activity was compared with risperidone, which is used to antagonise the (-) DOI induced head twitch response, then CP-809,101 resulted in significant antagonist like activity.

b. Conditioned avoidance responding:

In this test, a foot shock is delivered, in which subjects are trained in the task, to avoid the delivery of the mild foot shock, rather than escaped after the start of the shock. Antipsyhotic drug weakens the ability to avoid shock, but does not affect the escape response. CP-809,10, administered in rats and its activity was compared with other anti-psychotic drugs such as haloperidol, resperidone, ziprasidone and clozapine.CP-809,101 administration resulted in dose dependent inhibition of the CAR, the order of potencies for inhibiting CAR was found to be haloperidol> resperidone> ziprasidone> CP-809,101> clozapine.

c. Novel object recognition test:

This test is done for recognition of memory. Rat are exposed to two or more objects and gets to explore them. One of these object is replaced and if memory is functioning normally then, rat takes more time in exploring the novel object than explored one. In this study, CP-809,101 and positive control methylphenidate were administered in trained rats, CP-809,101 showed high memory response in rats, but at high doses it showed sedative effect rather than improved memory response.

d. Catalepsy test:

Catalepsy test is done by bar test. In this, mouse is placed on the bar oriented panel and which is 1 inch above ground. If rats remains immobile for more than 20 seconds than it is cataleptic. CP-809,101 does not induce catalepsy, when it is compared other with antipsychotic drugs, clozapine was only failed to produce catalepsy.

2. The most challenging part was analyse the test and its result and how they affect the psychotic activity. The interesting part is to read about these tests and how they are conducted on the rats. I think handling the rats can be challenging as well as interesting.


1. Noldus.
2. Schizophrenia & Mania – Conditioned Avoidance Response. Psychogenics.

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