Homo sapiens seem to be unique in our ability to communicate symbolically through language. While individual language is learned the ability to recognize the individual phonemes of any language is present in humans at birth, and areas of the left hemisphere of the brain specifically involved with language show asymmetries even before birth, and muscle movements are needed for this to occur.
Language areas primarily of the left cerebral cortex (the left hemisphere is generally dominant for language even in left handed individuals). Paul Broca (1824 to 1880) and Karl Wernicke (1848 to 1905) described patients with specific acquired language disorders called aphasia’s; the two major areas associated with language bare their names.
Broca’s area (left inferior frontal gyrus), area 44, and 43 is involved with the motor production of language; an individual with Broca’s aphasia can no longer speak language normally but can understand what is said.
Wernicke’s area (left superior temporal gyrus, Area 22), is an area associated with the ability to understand spoken language. and an individual with Wernicke’s aphasia’s cannot understand language but can speak fluently, however no longer understands words as they are meaningless.
Written language is an acquired skill but must be trained neurologically, but not every person is literate. Even though reading and writing are taught, the left hemisphere is designed to abstract the rules of written language. There are areas in the brain that underlie the ability to write and read abstracts. Any damage to area (39 or 40 in the left hemisphere or dominant parietal lobe causes a “biological caused illiteracy” in a person who could read a write previously. What is lost is not the ability to see words, but the ability to “map meaning” to a word.
Important: Language helps organize sensory experience. It is fairly complex with mapped meaning to words in our brains, but once we do, it is fairly difficult to lose the meaning unless the brain is damaged. Though in part has a lot to do with words consisting of an internal manipulation of meaning. The role of the brain in spoken or written language is very complex, and can become habitual and controlled by the extrapyramidal motor system.
Broca’s and Wernicke’s area can lose plasticity later in life. Language is the highest order of cognition associated with our species, and it plays a fundamental role in our engagement with the world. Spoken and written language communicates facts and helps organize “SENSORY EXPERIENCE.” Communication can help us express our inner most thoughts and experiences with others.
The cerebellum is a major part of the motor system and functions are one of the main parts of cognitive function, and in cognitive behaviour as well. There are over a 100 billion neurons in the human brain and half are packed into the cerebellum. The major function of the cerebellum is a role in the maintenance of the equilibrium and posture, and regulated timing of the motor movement, especially learned skilled movements and the correction of errors in ongoing movement.
In the organization of the cerebellum are two hemispheres, an outer cortex and an mantle of grey matter and underlying white matter and nuclei. The cerebellar hemispheres are covered by a layer of cortex which can be divided into lobes by deep fissures. The surface area of the cerebellar is about 75% of the cerebral cortex. Different areas of the cerebellum are of different ages phylogenetically. The cerebral cortical organization is different from the cerebral cortex in major ways. There are no Brodman areas in the cerebral cortex. The cerebral cortex is made up of 3 layers throughout; (1) a surface or molecular layer,
(2) Purkinje cell layer, named after the anatomist and physiologist, Johannes Perkinje,
(3) Then a granule cell layer. The Perkinje cells are the only ones to project out of the cerebellar cortex. We could not walk or play without the projections of the cerebellar cortex. The cerebellum receives input from area 4 via the pons, the extrapyramidal motor system and sensory input (for example: the propioceptive input from the spinal chord). Like the extrapyramidal system, the cerebellum has no direct projections to the spinal chord, as it exerts it’s influence on motor behaviour by feedback to the other motor systems. The cerebellum plays a critically important role in the coordination of the learned skilled movements. Essentially the firing patterns of the cerebellar Perkinje neurons become synchronized as we learn from motor skills. These neural circuits are reinforced with practice. From learning to walk from playing basketball, golf, piano, and dancing, any movement that improves with practice involves the cerebellum.
These are the three systems that allow us to make motor muscle movement with timing, space, practiced exact muscle patterns that are necessary for 1 tiny movement. The pryamidal system, is the direct and indirect cortispinal pathways. There is a extrapyramidal system of complication, plus the cerebellum system which is an incredible system.
Please do any further homework about these systems on youtube.
Written by CD Hogarth
