A point of view.

Perspective pieces are scholarly reviews of fundamental concepts or prevalent ideas in a field. These are usually essays that present a personal point of view critiquing widespread notions pertaining to a field
((Frontiers in group. Frontiers in Neuroscience [Accessed Feb 18, 2015] Available from http://www.frontiersin.org/Neuroscience/articletype))
(( Sage Publications.  Manuscript Submission Guidelines [Accessed Feb 18, 2015] Available from http://www.uk.sagepub.com/msg/hsr.htm#ARTICLETYPES))
((Nature Publications. Author Resources [Accessed Feb 18, 2015] Avaialable from http://www.nature.com/authors/author_resources/article_types.html))

A perspective piece can be a review of a single concept or a few related concepts. These are considered as secondary literature and are usually short articles, around 2000 words
((Sage Publications.  Manuscript Submission Guidelines [Accessed Feb 18, 2015] Available from http://www.uk.sagepub.com/msg/hsr.htm#ARTICLETYPES)).