meaning. Most language production and processing occur in the left hemisphere while the majority of the emotional processing and production of emotion in speech occurs in the right hemisphere. Persons with schizophrenia usually have difficulty processing prosody. These patients also show a remarkable increase in lateralization towards the right hemisphere of both emotionally and non-emotional prosody rich speech. Also, a decrease in right-handedness led to an increase in the right hemisphere lateralization. This right hemisphere lateralization extends beyond prosody to many of aspects of language and speech processing in schizophrenic patients. Complementarity specialization The two hemispheres have a complementary specialization for control of different aspects of emotion. a) Left hemisphere primarily process "positive" emotions and right hemisphere primarily process "negative" emotions. A large portion of regions primarily in the right hemisphere are activated during aversive classical conditioning. While this theory seems to hold true for some emotions, this theory is generally considered outdated; however a few examples exist. For example, a study found that when subjects were primed with positive stimuli before hearing a consonant, the left hemisphere was more active than the right hemisphere. In contrast, when subjects were primed with a negative stimulus, the right hemisphere was more active than the left hemisphere. b) Other divisions of specialization The amygdala plays a role in the conscious awareness of emotion (feelings) resulting in perception of feeling, but experiments suggest the left and right amygdala have distinct roles in conscious and unconscious processing of emotion. The right amygdala plays a role in the nonconscious processing of emotion while the left amygdala was involved in the processing of conscious emotions. These results were obtained from studies that masked conditioning stimuli. Stimuli were presented over a very short period of time such that subjects were not consciously aware of the stimuli but were still able to show physiological changes. Damage to the left hemisphere in patients results in a marked increase in depression. Valence asymmetry may be due to more cholinergic and dopaminergic on the left hemisphere and the right hemisphere being more noradrenergic. Patients with right hemisphere damage had reduced arousal response to painful stimuli. Homeostatic basis This model provides a neuroanatomical basis for emotional control and processing. The peripheral autonomic nervous system is not symmetrical. Afferent nerves in the parasympathetic and sympathetic systems of the autonomic nervous system differently innervate various organs that maintain homeostasis such as the heart and