The brain is protected by the skull , suspended in cerebrospinal fluid , and isolated from the bloodstream by the blood–brain barrier . However, the brain is still susceptible to damage , disease , and infection . Damage can be caused by trauma , or a loss of blood supply known as a stroke . The brain is susceptible to degenerative disorders , such as Parkinson's disease , dementias including Alzheimer's disease , and multiple sclerosis . Psychiatric conditions , including schizophrenia and clinical depression , are thought to be associated with brain dysfunctions. The brain can also be the site of tumours , both benign and malignant ; these mostly originate from other sites in the body . The study of the anatomy of the brain is neuroanatomy , while the study of its function is neuroscience . A number of techniques are used to study the brain. Specimens from other animals, which may be examined microscopically , have traditionally provided much information. Medical imaging technologies such as functional neuroimaging , and electroencephalography (EEG) recordings are important in studying the brain. The medical history of people with brain injury has provided insight into the function of each part of the brain.
60% of a dried brain weight is fat, it is no wonder deficiencies in specific kinds of fats can have huge repercussions on intelligence and behaviour.