Neocortex: Difference between revisions
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The '''neocortex''' (literally translated "new coat or layer") is the six-layered outer layer of the [[mammal]]ian [[brain]]. It consists of vertically organised [[cortical column]]s as discovered and described by [[Vernon Mountcastle]]. In higher mammals and primates such as humans the neocortex has adapted a highly folded structure, with bumps (gyri) and valleys (sulci) making up the typical surface appearance of the cortex. This structure of columns is preserved all across the surface of the cortex and it is now believed that only the connectivity patterns and cell density distinguish the function of one area of cortex from another. This is why the cortical [[macrocolumn]], which consists of about 60.000 neurons and about a thousand [[minicolumn]]s in the human cortex, is considered to be the basic 'computing' [[unit]] of the neocortex. The neocortex is considered to be the seat of [[intelligence]], all higher [[brain function]]s such as [[thought]], [[perception]], [[consciousness]], [[memory]], [[problem solving]], [[creativity]] etc. are all considered to be functions of the common [[algorithm]] on which the neocortex operates. it consists of a large number of tightly packed [[neuron]]s with their [[dendrite]]s and [[axon]]s and sitting atop a large amount of long distance axons covered with [[myelin]] that connect the different areas of the neocortex and connects it to the various older parts of the [[brain]]. The first type of [[tissue]] is called the [[grey matter]] and the 'box of cables' below it is called the [[white matter]]. It is believed that the neocortex is organised in a hierarchial structure ie. sensory input comes in and goes through a hierarchy of [[cortical area]]s and the higher up the [[hierarchy]] you go, the more abstract the [[representation]]s of the cortex become. | The '''neocortex''' (literally translated "new coat or layer") is the six-layered outer layer of the [[mammal]]ian [[brain]]. It consists of vertically organised [[cortical column]]s as discovered and described by [[Vernon Mountcastle]]. In higher mammals and primates such as humans the neocortex has adapted a highly folded structure, with bumps ([[gyri]]) and valleys ([[sulci]]) making up the typical surface appearance of the cortex. This structure of columns is preserved all across the surface of the cortex and it is now believed that only the connectivity patterns and cell density distinguish the function of one area of cortex from another. This is why the cortical [[macrocolumn]], which consists of about 60.000 neurons and about a thousand [[minicolumn]]s in the human cortex, is considered to be the basic 'computing' [[unit]] of the neocortex. There are about 20 billion neurons in the human neocortex (throughout postnatal life), and about 30 billion [[glia]] cells (these numbers, and also the percentages of different kinds of glia cells, vary strongly with [[gender]] and also a bit with [[age]]). | ||
The neocortex is considered to be the seat of [[intelligence]], all higher [[brain function]]s such as [[thought]], [[perception]], [[consciousness]], [[memory]], [[problem solving]], [[creativity]] etc. are all considered to be functions of the common [[algorithm]] on which the neocortex operates. it consists of a large number of tightly packed [[neuron]]s with their [[dendrite]]s and [[axon]]s and sitting atop a large amount of long distance axons covered with [[myelin]] that connect the different areas of the neocortex and connects it to the various older parts of the [[brain]]. The first type of [[tissue]] is called the [[grey matter]] and the 'box of cables' below it is called the [[white matter]]. It is believed that the neocortex is organised in a hierarchial structure ie. sensory input comes in and goes through a hierarchy of [[cortical area]]s and the higher up the [[hierarchy]] you go, the more abstract the [[representation]]s of the cortex become. | |||
== Organisation of the cortex == | == Organisation of the cortex == | ||
The cortex consists of six layers, differentiated by the [[ | The cortex consists of six layers, differentiated by the [[cell type]]s and [[connectivity]] patterns that occur within them. | ||
Revision as of 09:42, 29 May 2009
The neocortex (literally translated "new coat or layer") is the six-layered outer layer of the mammalian brain. It consists of vertically organised cortical columns as discovered and described by Vernon Mountcastle. In higher mammals and primates such as humans the neocortex has adapted a highly folded structure, with bumps (gyri) and valleys (sulci) making up the typical surface appearance of the cortex. This structure of columns is preserved all across the surface of the cortex and it is now believed that only the connectivity patterns and cell density distinguish the function of one area of cortex from another. This is why the cortical macrocolumn, which consists of about 60.000 neurons and about a thousand minicolumns in the human cortex, is considered to be the basic 'computing' unit of the neocortex. There are about 20 billion neurons in the human neocortex (throughout postnatal life), and about 30 billion glia cells (these numbers, and also the percentages of different kinds of glia cells, vary strongly with gender and also a bit with age).
The neocortex is considered to be the seat of intelligence, all higher brain functions such as thought, perception, consciousness, memory, problem solving, creativity etc. are all considered to be functions of the common algorithm on which the neocortex operates. it consists of a large number of tightly packed neurons with their dendrites and axons and sitting atop a large amount of long distance axons covered with myelin that connect the different areas of the neocortex and connects it to the various older parts of the brain. The first type of tissue is called the grey matter and the 'box of cables' below it is called the white matter. It is believed that the neocortex is organised in a hierarchial structure ie. sensory input comes in and goes through a hierarchy of cortical areas and the higher up the hierarchy you go, the more abstract the representations of the cortex become.
Organisation of the cortex
The cortex consists of six layers, differentiated by the cell types and connectivity patterns that occur within them.