Sexual arousal though they are generally considered secondary in role to the other three. Erotic stimuli which can result in sexual arousal can include conversation, reading, films or images, or a smell or setting, any of which can generate erotic thoughts and memories in a person. Given the right context, these may lead to the person desiring physical contact, including kissing, cuddling, and petting of an erogenous zone. This may in turn make the person desire direct sexual stimulation of the breasts, nipples, buttocks and/or genitals, and further sexual activity. Erotic stimuli may originate from a source unrelated to the object of
Arousal activity within the ARAS is regulated by neurons that release the neurotransmitters acetylcholine, norepinephrine, dopamine, histamine, and serotonin. Activation of these neurons produces an increase in cortical activity and subsequently alertness. Arousal is important in regulating consciousness, attention, alertness, and information processing. It is crucial for motivating certain behaviours, such as mobility, the pursuit of nutrition, the fight-or-flight response and sexual activity (the arousal phase of Masters and Johnson's human sexual response cycle). It is also important in emotion and has been included in theories such as the James-Lange theory of emotion. According to Hans Eysenck, differences in baseline arousal