Understanding the psychological aspects of ED requires understanding the connection between the brain and the penis. There are two basic inputs leading to sexual arousal and, therefore, erections. One is physiological and results from direct stimulation of the penis. This reflexogenic input is centered in the sacral regions of the spinal cord and is primarily under parasympathetic nervous system control.

The other is psychological and results from mental experiences in the brain which are transmitted to the penis. This psychogenic input is mediated in the cerebral cortex. The brain is the source of both excitatory and inhibitory influences on erections. The inhibitory pathway is under serotonergic control, while the excitatory pathway is under the influence of the neurotransmitter oxytocin. The medial parietooccipital region of the limbic system has a primarily inhibitory role, such as in the fight-or-flight response. The sexual centers of the brain, particularly the midbrain, hypothalamus, and amygdala respond to gonadal hormones and, thus, are part of the hormonal feedback system that shapes sexual behavior. The reticular activating system has an important triage role through its connections between higher and lower brain structures as they process sexual stimuli.

These connect to one of two coordinating nerve centers along the spinal cord. More simply stated, erections are the result of friction and fantasy. An implication of these two inputs to erectile response is that mental experiences, i.e., thoughts, feelings, memories, and fantasies, have a central role in normal sexual response and are crucial factors in the development of sexual dysfunctions.

Bancroft and Janssen have proposed a dual control model of erectile function that includes both excitatory and inhibitory influences on sexual response, which is similar to the model of CNS control over erections described above. This model emphasizes that higher brain functions (e.g., thoughts and feelings) can impact erectile response positively or negatively. For example, a common manifestation of ED is the man who, while experiencing sexual arousal, becomes anxious about his performance and loses his erection.

The inhibitory influence of sympathetic nervous system arousal on erectile response is the biological basis to many of the psychological origins of ED.

Everhard and colleagues have posited a complex feedback process for sexual arousal that incorporates physiological response, the immediate situation or context, emotional arousal, and cognitive appraisal. This understanding of the neurological control involved in sexual response highlights the interdependence of psychological and physiological aspects of ED.