Since my owner is not from the field (her background is architecture) I have learned a lot of new from the first lecture. Well, almost everything was new. It was crucial to get the general overview about my structure of brains. I have learned about Broadman’s areas, types of brain cells (which are not only neurons – surprise!), types of neurons and general understanding about how do I work.
So, here are some keynotes.
The brain is a system which could be studied on different levels: as a physical system, chemical system, biological system.
The brain receives information, interprets it, then stores, transforms it, then produces knowledge, and finally gives an output, which is expressed in the control of the body.
The brain has well-structured task-division management. The brain consists of 4 main areas (frontal lobe, pariental lobe, occipital lobe, and temporal lobe), which are subdivided into 52 areas of the brain surface, so-called Broadmanns zones (or Broadmanns areas). These zones have their fixed numbers. Each zone is responsible for a particular kind of tasks. For example, zone number 4 is responsible for movements, 3 – for skin sensors, 17 – for vision, 41- for hearing, 44 and 45 – for language, etc.
The brain consists of two main types of matter: gray and white, approximately in 50/50 proportion. Gray matter is on the top, and white is inside. Gray matter of the brain (cortex) is covered with gyri. Gyri is on top of convolutions, it covers all the surface of the brain. Sulci is inside
Brains could be studied on different levels, from the level of elementary particles (strings), through atomic physics, chemistry, molecular biology, cytology, physiology, anatomy, phycology, sociology, etc.
One of the Pioneers of the brain research was Santiago Ramon Y Cajal (1852 – 1934), who was studying brain cells with a microscope and making hand-drawings of brain cells. He was the first who defined different types of cells.
- unipolar cells (one input/output),
- bipolar cells (two dendrites – for input and output separately),
- multipolar cells,
- pyramidal cells and
- stellate cells.
Gray matter consists of cell bodies, unmyelinated axons, dendrites and glial cells. White matter consists of myelinated axons.
Glia (from “glue”) consists of astrocytes (which are not neurons, but between them), it fills most of the space in the brain that is not occupied by neurons and blood vessels. Glia transports “food” for brains, from blood to cells.
Synapse is a connector for information transfer, it’s a connector between two cells to pass a signal from presynaptic axon to post synaptic. Sygnal goes through synapse only in one direction. Astrocytes – is one type of the glia. Second type is Oligodendrocytes, which wrap around cell for electrical insulation. Axons are surrounded with many layers of oligodendrocytes. This insulation is called myelination, axon covered with oligodendrocytes is a myelinated nerve.
Neuron is an “adding machine”, it adds the input multiplied by synaptic strength. Tens of thousands of inputs comes into one cell. And synaptic connections are changing permanently. This mechanism is called neuroplasticity, and is one of the mechanisms of learning.