Lateralization of brain function

This article is about specialization of function between the left and right hemispheres of the brain. For specialization of brain function generally, see Functional specialization (brain).

Diagram of the human brain.
The human brain is divided into two hemispheres–left and right. Scientists continue to explore how some cognitive functions tend to be dominated by one side or the other; that is, how they are lateralized.
  Right cerebral hemisphere
  Left cerebral hemisphere

The lateralization of brain function (or hemispheric dominance[1][2]/ lateralization[3][4]) is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. The median longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. Although the macrostructure of the two hemispheres appears to be almost identical, different composition of neuronal networks allows for specialized function that is different in each hemisphere.

Lateralization of brain structures is based on general trends expressed in healthy patients; however, there are numerous counterexamples to each generalization. Each human's brain develops differently, leading to unique lateralization in individuals. This is different from specialization, as lateralization refers only to the function of one structure divided between two hemispheres. Specialization is much easier to observe as a trend, since it has a stronger anthropological history.[5]

The best example of an established lateralization is that of Broca's and Wernicke's areas, where both are often found exclusively on the left hemisphere. Function lateralization, such as semantics, intonation, accentuation, and prosody, has since been called into question and largely been found to have a neuronal basis in both hemispheres.[6] Another example is that each hemisphere in the brain tends to represent one side of the body. In the cerebellum, this is the same body side, but in the forebrain this is predominantly the contralateral side.

  1. ^ "Left brain vs. right brain: How does one dominate?". www.medicalnewstoday.com. 24 December 2018. Retrieved 10 January 2023.
  2. ^ "Hemispheric differences and hemispheric dominance (video)". Khan Academy. Retrieved 10 January 2023.
  3. ^ "Localisation of Function in the brain and Hemispheric Lateralisation: motor, somatosensory, visual, auditory and language centres; Broca's and Wernicke's areas, split brain research. Plasticity and Functional Recovery of the brain after trauma". Psychology Hub. Retrieved 10 January 2023.
  4. ^ "Lateralization of Brain Function - Simply Psychology". www.simplypsychology.org. Retrieved 10 January 2023.
  5. ^ Halpern ME, Güntürkün O, Hopkins WD, Rogers LJ (November 2005). "Lateralization of the vertebrate brain: taking the side of model systems". The Journal of Neuroscience. 25 (45): 10351–10357. doi:10.1523/JNEUROSCI.3439-05.2005. PMC 2654579. PMID 16280571.
  6. ^ Riès SK, Dronkers NF, Knight RT (April 2016). "Choosing words: left hemisphere, right hemisphere, or both? Perspective on the lateralization of word retrieval". Annals of the New York Academy of Sciences. 1369 (1): 111–131. Bibcode:2016NYASA1369..111R. doi:10.1111/nyas.12993. PMC 4874870. PMID 26766393.