Rats in proestrus-estrus present more attention behaviors toward males and exhibit higher prefrontal-parietal EEG synchronization.

According to the different stages of the estrous cycle, female rats exhibit behavioral changes associated with variations in sex hormone levels that affect the functionality of certain brain regions. In this study, we characterized the attention that female rats paid to a sexually-experienced male and the degree of electroencephalographic (EEG) activation and coupling between the medial prefrontal and posterior parietal cortices during antagonistic phases of the estrous cycle (proestrus-estrus vs. diestrous). The degree of attention paid to the stimulus was measured by the number of nose pokes performed while the rats were in a sexual incentive motivation box. EEGs were recorded in two conditions: a) awake-quiet state with no male rat present; and b) awake-quiet state in the presence of a male. Only during proestrus-estrus did the females show lower latency with a higher frequency and duration of nose pokes. In both cortices, the receptive females presented higher absolute power in all EEG bands recorded in the presence of the male, regardless of the phase of the estrous cycle. They also had greater EEG coupling between the medial prefrontal and posterior parietal cortices of the left hemisphere in all EEG bands regardless of the presence of a male. The higher synchronization between prefronto-parietal areas could be associated with the greater attention paid to, and adequate processing of, the sexual stimuli emitted by the male. Hence, it is probable that manifesting the proceptivity and receptivity behaviors characteristic of the proestrus-estrus phase requires a higher functional coupling between the prefrontal and parietal cortices.

Male rats exhibit higher prefrontal-parietal EEG synchronization during the sexually-motivated state.

Sexual motivation (SM) is a physiological state generated by the adequate processing of sexually-relevant stimuli. Induction and maintenance of this state requires the coordinated functioning of various cortical and subcortical areas. The medial prefrontal (mPFC, the prelimbic area in rats) and posterior parietal cortices (pPC) form an attentional network involved in processing incentive stimuli. Given that the sexual incentive stimuli emitted by a receptive female are highly relevant for the male rat, it is probable that these cortices interact functionally in processing the sexual stimuli that produce SM. Thus, the objective of this study was to characterize the cortical activation and degree of electroencephalographic coupling (coherence, hEEG) between the mPFC and pPC during a sexually-motivated state in male rats. Only rats that reached this state after 1 intromission prior to EEG recording, presented a higher frequency and duration of nose pokes, and showed higher prefronto-parietal activation and EEG synchronization while close to an inaccessible receptive female. Results show that both cortices are activated and that they are functionally coupled during the processing of sexually-relevant stimuli mainly in the right hemisphere, a key condition for inducing SM. We conclude that the attentional network made up of the prefrontal and parietal cortices participates in the adequate attention to, and processing of, sexual incentive stimuli and, hence, in inducing SM in male rats.

Immobilization of Zn(II) ions from contaminated biomass using ceramic matrices.

This article describes the adsorption of zinc ions from synthetic solutions using residual pine sawdust as an adsorbent and, subsequently, the use of clay ceramic pieces and contaminated biomass as metal immobilizers. The process of adsorption was carried out with a synthetic solution of ZnCl2 in contact with sawdust for a fixed time of 24 h. The mixture was stirred continually. The mixture was then filtered, and the metal ions not adsorbed by the biomass and present in the liquid phase were quantified. The physicochemical characteristics of the sawdust were determined by thermogravimetric and differential thermal analysis, infrared Fourier transform spectroscopy, fluorescence and X-ray diffraction, among others. The adsorption kinetics shows that the equilibrium was reached at 24 h. The most efficient ratio of the amount of biomass and the concentration of Zn(II) was 10 g/L of sawdust and 6.5 × 104 mg/L of metal, which was used to analyse the capacity of metal immobilization in the designed bricks. The values obtained for the apparent porosity, the loss of weight by ignition, the mechanical properties and the efficiency of retention, indicate that these bricks are suitable for use in civil construction.