Question

CAN YOU PLEASE ANSWER ALL QUESTION AND PLEASE ANSWER AS SOON AS POSSIBLE THANK YOU

1. Behavioral activity is prone to a lot of variation; would Open field and Inhibitory Avoidance be valuable Primary and only endpoint measures? Explain why?

2. Lesions of the amygdala made after a delay from training result in partial retention of fear motivated Inhibitory avoidance task. On the other hand, pharmacological manipulations of the amygdala immediately after training abolished the strength of inhibitory avoidance learning. What conclusion can you draw from these observations? Explain why?

Answer 1

1. The Open Field Maze is one of the most widely used platforms in animal behavioral studies. A number of important conventional and ethological parameters can be collected and analyzed during the performance of the OFM. These data allow the researcher to measure behaviors ranging from overall locomotor activity to anxiety-related emotional behaviors. However, use of OFM is not without its shortcomings. One confounding issue is the wide range of static variables that can be manipulated during any testing session. Examples include time, lighting conditions and novel object inclusion. Variability in experimental protocol setup and design, which are essential to support a broad-spectrum of applications, can make it difficult to compare studies. When subject variability, such as different background or transgenic mouse lines and drug treatments are included, the difficulty in test comparisons can increase even more. Despite these issues, the OFM remains one of the most widely applied techniques in rodent behavioral research.

ehavior has proved to be a convenient experimental variable in screening because it is noninvasive and because alterations in many physiologic systems can be reflected in changes in behavior. The functional observational battery is a systematic neurologic examination for rodents involving a neurologic examination with numerous behavioral measures. It provides more extensive behavioral measures than the mouse ethogram.

2. Although the lateral and basal nuclei of the amygdala are believed to be essential for the acquisition of Pavlovian fear conditioning, studies using post-training manipulations of the amygdala in the inhibitory avoidance learning paradigm have recently called this view into question. Researchers used the GABA_A agonist muscimol to functionally inactivate these nuclei immediately after single-trial Pavlovian fear conditioning or single-trial inhibitory avoidance learning. Immediate post-training infusions of muscimol had no effect on Pavlovian conditioning but produced a dose-dependent effect on inhibitory avoidance. However, pre-training infusions dose-dependently disrupted Pavlovian conditioning. The findings indicated that the amygdala plays an essential role in the acquisition of Pavlovian fear conditioning and contributes to the modulation of memory consolidation of inhibitory avoidance but not of Pavlovian fear conditioning.

Although a considerable amount of progress has been made in understanding the neural basis of fear conditioning, the exact role of the amygdala still remains controversial (Cahill et al., 1999; Fanselow and LeDoux, 1999). Results of studies using Pavlovian fear conditioning paradigms have suggested that essential aspects of fear learning take place in the amygdala, whereas studies based on inhibitory avoidance learning argue that the amygdala modulates the consolidation of fear memories in other brain areas. Because lesions of the amygdala generally abolish the expression of conditioned freezing (but seeMaren, 1999), proponents of this latter view have argued that unambiguous conclusions cannot be drawn about the role of the amygdala in fear memory consolidation using permanent lesions (Cahill et al., 1999). Furthermore, because pharmacological manipulations of the amygdala immediately after training modulate the strength of inhibitory avoidance learning (McGaugh et al., 1995; Cahill and McGaugh, 1998;Packard and Teather, 1998), it has been argued that learning impairments observed in studies using pre-training infusions of drugs such as muscimol and AP-5 do not necessarily indicate that the amygdala is the site of plasticity underlying fear learning