Social behaviors in animals are dependent on their ability to detect different types of signals. These signals regulate social behaviors in animals and play key role in human social relations, too. Psychological disorders such as schizophrenia and autism show deficiencies in olfactory processing. Furthermore, olfactory system plays roles in degenerative disease. In this book the effects of olfactory stimulation on the neural activation in areas and structures such as basal forebrain and amygdala were studied to verify which part of these brain areas are activated during the process of olfactory stimuli, either pheromones or odors. The book contains an introduction, materials and methods, expression patterns of different immediate early genes in olfactory bulbs (main and accessory), and also in the basal forebrain and amygdala of rats exposed to pheromones or odors. In addition, the excitatory/inhibitory types of activated neurons were studied by combined In Situ Hybridization with immunocytochemistry. Reading of this book is suggested to neuroscience students, psychologist and professionals who are interested in cognitive functions such as memory, and social communication.