Date of Award


Degree Type


Degree Name

MS Experimental Psychology




Menstrual cycle phase, Gender effects, Hippocampally modulated sensorimotor processes, Eyeblink conditioning, Acoustic startle response


Experimental animal research studies have demonstrated that hormones affect neurological physiology and morphology in areas such as the striatum, hypothalamus, and hippocampus. How the specific effects of estrogen and progesterone are manifested behaviorally in humans, however, is not yet understood. The current study tested sensorimotor responding and simple motor learning in three groups of women - follicular/low hormone, luteal/high hormone, oral contraceptive - and men. Using PPI as an operational measure, this study was designed to expand limited findings which report menstrual cycle phase effects on pre-pulse inhibition (PPI) of the acoustic startle response (ASR), a direct measure of sensorimotor gating. In addition, classical eyeblink conditioning was evaluated using the same subset of groups. This paradigm was included to build on previous work indicating that women demonstrate facilitated conditioned responding as compared to males, and that women taking oral contraceptives acquire conditioned responses at a significantly higher rate than females not currently taking oral contraceptives and males. Using a simple discrimination paradigm, acquisition of conditioned responding to a CS+ tone, which is paired with an airpuff stimulus, versus responding to an explicitly unpaired CS- tone was assessed. ASR testing revealed that there were no differences between sex, menstrual cycle phase, or oral contraceptive use with respect to baseline startle responding and PPI. Assessment of classical eyeblink conditioning revealed significant differences in conditioned eyeblink response acquisition rates between groups. Also, significant sex differences were found in baseline eyeblink responding, and for the percent of conditioned responses (%CR) emitted.