The human brain controls the central nervous system (CNS), by way of the cranial nerves and spinal cord, the peripheral nervous system (PNS) and regulates virtually all human activity.Involuntary, or "lower," actions, such as heart rate, respiration, and digestion, are unconsciously governed by the brain,specifically through the autonomic nervous system. Complex, or "higher," mental activity, such as thought, reason, and abstraction, is consciously controlled.

The human brain is separated by a longitudinal fissure, separating the brain into two distinct cerebral hemispheres by the corpus callosum. The two sides of the brain are similar in appearance, and every structure in each hemisphere is generally mirrored on the other side. Despite these strong similarities, the functions of each cortical hemisphere are different.

Broad generalizations are often made in popular psychology about certain function (eg. logic, creativity) being lateralised, that is, located in the right or left side of the brain. These ideas need to be treated carefully because the popular lateralizations are often distributed across both sides.However, there is some division of mental processing. Probably most fundamental to brain lateralization is the fact that the lateral sulcus is generally longer in the left hemisphere than in the right hemisphere. Researchers have been investigating to what extent areas of the brain are specialized for certain functions. If a specific region of the brain is injured or destroyed, their functions can sometimes be recovered by neighboring brain regions - even opposite hemispheres. This depends more on the age and the damage occurred than anything else.

It is important to note that—while functions are indeed lateralized—these lateralizations are trends and do not apply to every person in every case. Short of having undergone a hemispherectomy (the removal of an entire cerebral hemisphere) there are no "left-brained only" or "right-brained only" people.

LEFT BRAIN FUNCTIONS

uses logic
detail oriented
facts rule
words and language
present and past
math and science
can comprehend
knowing
acknowledges
order/pattern perception
knows object name
reality based
forms strategies
practical
safe


RIGHT BRAIN FUNCTIONS

uses feeling
"big picture" oriented
imagination rules
symbols and images
present and future
philosophy & religion
can "get it" (i.e. meaning)
believes
appreciates
spatial perception
knows object function
fantasy based
presents possibilities
impetuous
risk taking

Source : www.wikipedia.org