Biology:Beevor's axiom
Beevor's Axiom is the idea that the brain does not know muscles, only movements. In other words, the brain registers the movements that muscles combine to make, not the individual muscles that are making the movements. Hence, this is why one can sign their name (albeit poorly) with their foot. Beevor's Axiom was coined by Dr. Charles Edward Beevor, an English neurologist. Dr. Beevor presented Beevor's Axiom in a series of four lectures from June 3, 1903 to July 4, 1903 before the Royal College of Physicians of London as part of the Croonian Lectures. His experiments showed that when an area of the cortex was stimulated, the body responded with a movement, not just a single muscle. Dr. Beevor concluded that “only co-ordinated movements are represented in the excitable cortex” [1]
In relation to Beevor's Axiom, it has been found that the brain encodes sequences, such as playing the piano, signing our name, wiping off a counter, and chopping vegetables, and once encoded and practiced, it takes less brain activity to perform them. This supports Beevor's Axiom, because the brain can recall movements easier than it can learn them.[2]
Beevor's Axiom is only partially true, however. Most behavior of muscles is encoded in the primary motor cortex (M1) and separated by muscle group. In an effort to understand the encoding in the M1, researchers observed commands of monkeys. Muscle cells changed firing rate according to the direction of the arm movements. Each neuron has one direction that elicits the greatest response.[3] Some M1 neurons encode muscle contractions, while others react to particular movements, regardless of the muscles used to perform them. The key characteristic of the primary motor cortex is its dynamic nature; the M1 changes based on experience. The supplementary motor area (SMA) plays a key role in initiating motion sequences. The premotor cortex (PMA) plays a key role when motor sequences are guided by external events. They map behaviors as opposed to the M1 which maps specific movements.[4] This could cause in issue in brain–computer interface research. If a researcher tries to excite only a muscle, it might be impossible without expecting a full movement.[5]
References
- ↑ Beevor CE (Jul 1903). "The Croonian Lectures ON MUSCULAR MOVEMENTS AND THEIR REPRESENTATION IN THE CENTRAL NERVOUS SYSTEM: Delivered before the Royal College of Physicians of London". Br Med J 2 (2218): 12–6. doi:10.1136/bmj.2.2218.12. PMID 20760993.
- ↑ Penhune Virginia B (2013). "Neural encoding of movement sequences in the human brain". Trends in Cognitive Sciences 17 (10): 487–489. doi:10.1016/j.tics.2013.08.008. PMID 23973185.
- ↑ "On the relations between the direction of two-dimensional arm movements and cell discharge in primate motor cortex". J Neurosci 2 (11): 1527–37. Nov 1982. doi:10.1523/JNEUROSCI.02-11-01527.1982. PMID 7143039.
- ↑ Rathelot J.A.; Strick P.L (2006). "Muscle representation in the macaque motor cortex: An anatomical perspective". Proceedings of the National Academy of Sciences 103 (21): 8257–8262. doi:10.1073/pnas.0602933103. PMID 16702556. Bibcode: 2006PNAS..103.8257R.
- ↑ Vidal JJ (1973). "Toward direct brain-computer communication". Annu Rev Biophys Bioeng 2 (1): 157–80. doi:10.1146/annurev.bb.02.060173.001105. PMID 4583653.
External links
- Medical glossary entry at hemmeapproach.com
- Rijntjes M (February 2006). "Mechanisms of recovery in stroke patients with hemiparesis or aphasia: new insights, old questions and the meaning of therapies". Curr. Opin. Neurol. 19 (1): 76–83. doi:10.1097/01.wco.0000203886.28068.38. PMID 16415681.
- "The discovery of encephalic arteries. From Johann Jacob Wepfer to Charles Foix". Cerebrovasc. Dis. 20 (6): 427–32. 2005. doi:10.1159/000088980. PMID 16230846. http://content.karger.com/produktedb/produkte.asp?DOI=CED2005020006427&typ=pdf.
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