| Abstract | Anxiety is an increasingly widespread mental health issue affecting a significant portion of the United States population. Further research in the field of mental health is beneficial to understanding the mechanisms that drive anxiety, and to discovering novel, therapeutic interventions. Using a rodent model to conduct this research is practical due to the similarities between the rat brain and human brain. We examined anxiety- and fear-related responses in both male and female subjects that are subjected to either unpredictable or predictable threat; unpredictable threats generate a state of anxiety, and predictable threats produce fear. Threat predictability was manipulated by administration of temporally inconsistent, or temporally consistent foot shocks in an operant chamber. Equal numbers of males and females were included within each group and the rats were randomly assigned to either the temporally consistent or temporally inconsistent footshock condition. Animals were tested over the course of three days; Day 1 is the contextual conditioning test day wherein the animal is exposed to the novel environment and the initial presentation of the foot shocks. Day 2 is the memory test day, where animals are returned to the test chamber, but no shock is given; Day 3. Day 3 is the reinstatement test where the animal is placed back into the chamber and one footshock is administered. Anxiety and fear were assessed by measuring rearing (anxiety-related) and freezing (fear-related) behaviors in the test chamber on each test day. Treatment and sex differences in anxiety and fear were generated by varying threat predictability. These results will provide insights into the role of potential sex differences in anxiety and fear-related behaviors. |
