Fear level and rats’ open-field activity and defecation

The effect of Pavlovian CS+ and CS- on exploratory behavior

“…A strong negative relationship was found between the amount of defecation (emotional arousal) and the number of squares entered (-.82), and a positive correlation (+.62) was found between the amount of defecation and the percentage of freezing time. DISCUSSION Freezing and defecation are frequently used indicators of fear (Aitken, 1970;Livesey & Egger, 1970), and, within the present study, a strong positive correlation was found between freezing and defecation. Further, both fear indices were negatively correlated with activity.…”

Mapping Open-Field Behavior in Rats: Applicability Across Sexes

“…In other strains (F strain and MNR strain), the effect was not found, either. Aitken's (1970) results of estrus effect, using the Long-Evans strain, were also not as clear as expected. Therefore, the failure to find a clear estrus effect in the present study was not necessarily an uncommon result.…”

“…A troublesome problem arises when one tests open-field behavior of female rats. Researchers have found that female rats show increased ambulation and decreased defecation at estrus (Burke & Broadhurst, 1966;Aitken, 1970). Despite such evidence, however, many studies using OFT have not controlled the estrus effect.…”

A note on Lester’s theory of exploratory behavior

“…Specifically, rats with moderate defecation scores should ambulate more than rats with either low or high defecation scores. Aitken (1970) failed to find curvilinearity under similar circumstances, and a simple check also fails to reveal it in the present case. Tbe 22 male rats were divided into four groups on the basis of their ordered total defecation scores to make up low, moderate, and high scoring groups.…”

“…But Aitken (1970) and Kumar (1970) have failed to find support for Lester's theory, and, more importantly, Sheldon (1970) has reported results which are directly incompatible with it. In this connection, some aspects of the resuIts of a simple open-field study (actually part of a larger experiment) are reported here, since they are also at odds with the theory.…”