Prefrontal and tegmental electrical activity during olfactory stimulation in virgin and lactating rats.
This study was designed to analyze if the electroencephalographic (EEG) activity of the medial prefrontal cortex (mPFC) and the ventral tegmental area (VTA) was modified throughout various reproductive stages of female rats exposed to pup-associated or non-associated odors. Simultaneous EEG recordings were obtained from right and left mPFC and VTA in adult female rats during the smelling of nest bedding and female bedding under three reproductive states: proestrus-estrus (P-E), diestrus (D) and lactation (L). Absolute (AP) and relative (RP) powers of three EEG band frequencies, and interhemispheric correlation (r) of EEG activity were calculated and compared among conditions. During the awake-quiet condition, RP of the 12-21 Hz band was significantly higher in the right and left mPFC as well as in the right VTA of lactating rats as compared to P-E rats. During the smelling of nest bedding, the RP of the 8-11 Hz in the mPFC became increased while that of the 6-7 and 12-21 Hz decreased in the three reproductive stages. In the VTA, this phenomenon was mainly observed in lactating rats. Only the RP of the lower frequencies (6-7 and 8-11 Hz bands) was higher in the right mPFC and in the left and right VTA, respectively, of the lactating rats with respect to P-E rats, while that of the 12-21 Hz band was lower in lactating as compared to P-E rats. Moreover, the interprefrontal correlation of the lower-frequency bands was higher in relation to smelling of nest bedding in diestrus and lactating rats, whereas during the smelling of female bedding the correlation of the 6-7 Hz band was increased only in the diestrus rats as compared to P-E rats. These data indicate that EEG activity recording is a sensitive tool to study the functionality of the mPFC and VTA during different reproductive states and suggest the possible participation of these structures in the processing of olfactory stimuli associated to pups to modulate the motivational and performance processes, crucial for the expression of maternal behavior.
Hernandez-Gonzalez
Marisela
M
Instituto de Neurociencias, Universidad de Guadalajara, Rayo 2611, Colonia Jardines del Bosque, C.P. 44520, Guadalajara, Jalisco, Mexico. mariselh@udgserv.cencar.udg.mx
Prieto-Beracoechea
Carlos
C
Navarro-Meza
Monica
M
Ramos-Guevara
Juan Pablo
JP
Reyes-Cortes
Ruth
R
Guevara
Miguel Angel
MA
D000818:Animals; D004298:Dopamine / Q000502:physiology; D004569:Electroencephalography; D004594:Electrophysiology; D030762:Estrous Cycle / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D007774:Lactation / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D025341:Principal Component Analysis; D051381:Rats; D012098:Reproduction / Q000502:physiology; D012741:Sexual Maturation / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013681:Tegmentum Mesencephali / Q000502:physiology*
D004298:Dopamine