Looking back at the rungs of the ladder analogy used to describe the different levels of analysis in psychological research we can see that one of those levels deals with the impact biology has on our mind. When you think of biology you can also think of evolution and when evolution is involved you can surely thank Charles Darwin. Many theories Darwin discovered have implications in the field of psychology.
There are two terms associated with evolution that are a good idea to know, genotype and phenotype. The genotype of an organism is it's genetic code whereas the phenotype is the observable characteristic brought about by the active genotype. Essentially throughout the evolutionary process a genotype will emerge through some means such as mutation which causes a phenotype such as perhaps a longer beak on a bird to develop. Over time the bird with the longer beak lives longer and has more children allowing it to spread it's mutation allowing that phenotype to survive. Evolution is brought about by stresses brought by the environment and success can be measured by the mating success of a subject.
Three major evolutionary achievements for humans that have led to where we are today is out bipedalism, the ability to walk upright and therefore free up our hands, our encephalization, the enlargement of our brains for more complex functions, and the development of language allowing for us to describe the world around us in a more useful way.
Our bodies make use of the nervous system to allow for the input, processing, storage, and output of information much like a computer does. Our nervous system can be broken up into two main parts, the central nervous system which is the brain and the spinal cord and the peripheral nervous system which is the other connections of the body that link our central nervous system (CNS) to the other organs and limbs. The peripheral nervous system (PNS) also tends to take care of automated functions for us such as instinctive reactions.
The brain is part of the CNS and is responsible for pretty much everything we are. The brain is broken up into individual parts which each have their own functions and responsibilities but are all interconnected to some degree and can adapt over time. The brain is divided into two hemispheres separated by the central sulcus which is a deep grove running down the center. The left hemisphere controls the right side of the body and is used in producing and understanding language. The Right hemisphere controls the left side of the brain and is known for it's use in temporal and spatial relationships, analyzing nonverbal information and communicating emotion. Although the two hemispheres of the brain are divided in their functions they are able to communicate with each other via the corpus callosum.
Apart from the two hemispheres the brain is also broken up into multiple lobes. The frontal lobe is responsible for planning, thinking and long term memory as well as many other functions. It is located in the front of the two hemispheres and is connected to the motor cortex. The temporal lobe is mostly responsible for hearing as well as some language and visual processing. The parietal lobe is mostly known for its use in touch and response to internal stimuli. The occipital lobe is mostly for vision and reading comprehension.
Two critical areas of the brain to look at are Broca's and Wernicke's area which is used for language. Broca's area is responsible for maintaining grammatical structure of language whereas Wernicke's area is responsible for maintaing the meaning of words. If damage occurs to either of these areas it is possible that language capabilities will become diminished or non existent.
The hippocampus is another critical area of the brain used for memory and spatial navigation.
The brain is made up of billions of neurons which make trillions of connections. These neurons are responsible for controlling out mind and body. Different types of neurons exist in the brain such as sensory, motor, internuerons and mirror neurons. Sensory neurons are responsible for sensing the world around. Motor neurons are used in reacting to stimuli and moving your body. Interneurons allow for cross talk between neurons and mirror neurons allow for the collective actions a species takes.
Neurons are made up of multiple parts which each has their own tasks to accomplish. The soma (body) is the main processing area of the neuron and also includes the nucleus, damage to this area is fatal for the neuron. Dendrites extend from the soma and receive information from other neurons. The axon carries signals from the neuron and terminal buttons are used with neurotransmitters. Neurons fire in an on off style such as the case with computers known as all or none law and also have a refractory period between firings in which another firing cannot exist. There are two types of communication between neurons, electrical and chemical. Electrical communication is extremely rapid with practically no refractory period. It is useful for reflexes and other quick decisions. Chemical communication makes use of nuerochemicals to make complex thought and other actions. This method has a small refractory period but is good for complex reasoning.
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