KEY CONCEPTS Print Section Listen The defining feature of addiction is compulsive, out-of-control drug use, despite negative consequences. Addictive drugs induce pleasurable states or relief from distress, thus motivating repeated…
KEY CONCEPTS Print Section Listen Neurodegenerative diseases, of which Alzheimer disease and Parkinson disease are the most common, are a large and diverse group of neurologic disorders characterized by death…
KEY CONCEPTS Print Section Listen Signal transduction refers to the processes by which signals between cells carried by neurotransmitters, hormones, trophic factors, and cytokines are converted into biochemical signals within…
KEY CONCEPTS Print Section Listen Schizophrenia is characterized by psychotic symptoms such as hallucinations and delusions (often referred to as “positive” symptoms), negative or deficit symptoms such as lack of…
KEY CONCEPTS Print Section Listen Stroke occurs when blood flow to the brain is disrupted and the areas of brain deprived of oxygen die. This can be caused by obstruction…
KEY CONCEPTS Print Section Listen A seizure is caused by the abnormal synchronous firing of large ensembles of neurons. Epilepsy refers to any neurologic disorder that is characterized by recurrent…
KEY CONCEPTS Print Section Listen Executive function, the cognitive control of behavior, depends on the prefrontal cortex, which is extensively developed in higher primates and especially humans. Working memory is…
KEY CONCEPTS Print Section Listen Hormones are signaling molecules that reach their target cells via the bloodstream. The hypothalamus is the key regulator of the endocrine system by releasing hormones…
KEY CONCEPTS Print Section Listen Both sleep and arousal are active processes mediated by specific brain regions and neurotransmitter systems. Sleep can be divided into two phases, nonrapid eye movement…
KEY CONCEPTS Print Section Listen Emotions activate physiologic, cognitive, and behavioral outputs that facilitate adaptive responses to salient external and internal stimuli. A crucial emotion, important in several mental disorders,…
