Structural imaging of the living human brain represents certain measurement techniques that can display anatomical information of the brain. These measurements techniques include X-ray, Ultrasound, Magnetic Resonance Imaging (MRI), and Computed Tomography (CT). computed Tomography scanning builds up a picture of the brain based on the differential absorptions of X-rays (Laureys & Tononi, 2011). It takes advantage of the fact that X-rays reflect the relative density of the tissue through which they pass (Laureys & Tononi, 2011). It uses computational techniques to provide visual images of the living human brain through passing of the X-rays at different angles. The major challenge of this technique is that repeated or prolonged exposure to ionizing energy could damage the brain tissues.
Magnetic Resonance Imaging generates image contrasts in different ways that represent a variety of the nuclei such as their interaction with electromagnetic fields, density, diffusion or flow, and chemical environment. It visualizes spatial information on macroscopic assembles of atomic nuclei, typically the distribution of 1H nuclei using a clinical scanner (Laureys & Tononi, 2011). It uses the detection of radio frequency signals that are produced by displaced waves in a magnetic field. It is better than other techniques since it does not use radioactive materials, safe and painless. However, it is expensive to use.
In ultrasound, high frequency sound waves that cannot be heard by the human beings are allowed into the body and bounce back. These sounds produce echoes that in turn produce pictures called sonograms, which are used to get the images of the brain. X-ray was used to obtain brain images since 1970s by passing these rays through the living human brain to produce a whole-brain image. Due to its devastating effects, this technique has been abandoned.
Three Principles of Sensorimotor Function
- The Sensorimotor System is Hierarchically organized: from general goals to specific details of action. Information flows downwards as the information in the sensory system flows through the hierarchy (Pinel, 2009).
- Motor Output is guided by sensory Input: the sensory system continually monitors the progress of responses and feed their information back into the sensory circuits (Pinel, 2009).
- Learning changes the nature and locus of sensory motor from conscious control to automatic pilot lower levels (Pinel, 2009).
Pinel J. P. (2009). Biopsychology: MyPsychKit Series. Boston: Allyn and Bacon Publishing.
Laureys L., & Tononi G. (2011). The Neurology of Consciousness: Cognitive Neuroscience And Neuropathology. Waltham, Massachusetts: Academic Press.