5th November 2023

Sensory System, Sensation and Perception

Before we talk about perceptual abnormalities, which is one of the most fascinating aspects of psychiatry, let’s discuss the key concepts of sensation and perception. Although sensation and perception are interrelated processes, they are distinct from one another.

Sensation is the initial stage of receiving information from the external world, which involves sensory receptors receiving information and transmitting it to the brain in the form of neural impulses. Sensation results in raw information from the senses.

Perception, on the other hand, is the process of interpreting the information received by the sensory process at the cortical level. As a result, we interpret and give meaning to the information received. This is an active process that involves constructing a representation of the external world using our own internal templates.

Perception is influenced by a range of factors, such as attention, context, prior experiences, memory, cultural expectations, and pre-existing concepts.

To highlight the difference between sensation and perception, we can look into the example of visual object agnosia. In this condition, an individual may still have intact sensory functions and be able to detect the presence of an object in their visual field (intact sensation), but they are unable to identify or recognise the object or understand its function or meaning (impaired perception).

Sensory system includes: