Abstract
The estrous cycle is a physiological process modulated by hormonal changes associated, in turn, with alterations of the attraction or sensitivity with which females perceive different sensory stimuli. Auditory stimuli play an important role in the social interaction of several mammals, including their sexual behavior and the mother-young relationship. Since the prefrontal cortex (PFC) and nucleus accumbens (Acc) had been associated with the processing and assignation of the incentive value of stimuli, this study was designed to analyze whether electroencephalographic (EEG) activity in the PFC and Acc was modified during the two antagonist phases of the estrous cycle (proestrus-estrus and diestrus) when female rats heard sound recordings with different types of cries emitted by other rats. EEGs were recorded in eight female virgin Wistar rats, 80-100 days old, bilaterally implanted in the PFC and Acc during an awake-quiet state, in three conditions: when hearing 1) cries of pups; 2) cries of adult male rats; and, 3) cries of adult female rats. The cries were recorded from pups (2-10 days old) and male and female adult rats after gentle prodding by a human hand. Each auditory stimulus (which included vocalizations up to 22 kHz) was randomly played back through a speaker placed near the female rats. Only upon perceiving the cries of male rats did the females in the proestrus-estrous phase show a lower relative power in the 14-30 Hz band in the Acc and an increased inter-prefrontal correlation in the 8-13 Hz band. It is probable that these EEG changes are associated with the lower activation or non-anxious state that the female rat presents specifically during the proestrus-estrous phase in response to the alarm cries of adult male rats.
Highlights
The different reproductive phases of the female rat are associated with hormonal, cognitive, emotional and behavioral changes, as well as variations in sensorial sensitivity
No significant differences were observed between the two estrous phases in the PFC and accumbens nucleus (Acc) when the female rats heard the cries of pups or those of adult female rats
Relative Power (RP) When the females were in the P-E phase, the EEG activity of the Acc was characterized by a decreased RP of the fast frequencies (14 - 30 Hz) in both the left (t = 3.279; p = 0.01351) and right (t = −3.326; p = 0.012) Acc, compared to when they were in the D phase, but only when exposed to the cries of adult male rats (Figure 2)
Summary
The different reproductive phases of the female rat (estrous cycle, pregnancy, and lactation) are associated with hormonal, cognitive, emotional and behavioral changes, as well as variations in sensorial sensitivity. The estrous cycle is a physiological process modulated by hormonal changes associated with alterations in the attraction or sensitivity with which females perceive different sensory stimuli [1,2]. Several studies suggest that in many species the physiological and behavioral output of the auditory system is modulated by hormonal cycles; for example, the perception of behaviorally-relevant auditory signs in mice is affected by hormonal status [8,9]. Subtle changes in auditory perception during the menstrual cycle in women have been suggested [10], especially more acute auditory sensitivity in the periovulatory phase [11,12]. The most pronounced menstrual cycle-related changes in audi-
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call