They are involved in olfaction, the perception of odors.[15] Cingulate gyrus – The cingulate gyrus is located above the corpus callosum and is usually considered to be part of the limbic system. The different parts of the cingulate gyrus have different functions, and are involved with affect, visceromotor control, response selection, skeletomotor control, visuospatial processing, and in memory access.[16] A part of the cingulate gyrus is the anterior cingulate cortex, that is thought to play a central role in attention[17] and behaviorally demanding cognitive tasks.[18] It may be particularly important with regard to conscious, subjective emotional awareness. This region of the brain may also play an important role in the initiation of motivated behavior.[18] The subgenual cingulate is more active during both experimentally induced sadness and during depressive episodes.[19]