  This is a follow-up tutorial article of [17] and [16], in this paper, we will
introduce several important cognitive functions of the brain. Brain cognitive
functions are the mental processes that allow us to receive, select, store,
transform, develop, and recover information that we've received from external
stimuli. This process allows us to understand and to relate to the world more
effectively. Cognitive functions are brain-based skills we need to carry out
any task from the simplest to the most complex. They are related with the
mechanisms of how we learn, remember, problem-solve, and pay attention, etc. To
be more specific, in this paper, we will talk about the perception, attention
and memory functions of the human brain. Several other brain cognitive
functions, e.g., arousal, decision making, natural language, motor
coordination, planning, problem solving and thinking, will be added to this
paper in the later versions, respectively. Many of the materials used in this
paper are from wikipedia and several other neuroscience introductory articles,
which will be properly cited in this paper. This is the last of the three
tutorial articles about the brain. The readers are suggested to read this paper
after the previous two tutorial articles on brain structure and functions [17]
as well as the brain basic neural units [16].
