Principles of biological level of analysis: 1. Behaviour can be innate because it is genetically based. 2. Animal research can provide insight into human result. 3. There are biological correlates of behaviour.
Reductionist approach – micro-level of research, which breaks down complex human behaviour into its smallest parts. Neurons Neurotransmission Neurotransmitters are stored in neuron’s terminal buttons Synapse – gap between neurons Reuptake – neurotransmitters after sending the message are either broken down or reabsorbed by terminal buttons Neurotransmitters: 1. Acetylcholine – effect: muscle contraction, and a role in the development of memory in the hippocampus. 2. Dopamine – effect: voluntary movement, learning, and feelings of pleasure. 3. Norepinephrine (noradrenaline) – effect: arousal, alertness, and stimulation of the sympathetic nervous system. 4. Serotonin – sleep, arousal levels, and emotion.
Kasamatsu and Hirai – monks after 48h of not eating, drinking, sleeping started to have hallucinations and the level of serotonin was increased. These higher levels of serotonin activated the parts of the brain called the hypothalamus and the frontal cortex, resulting in hallucinations.
Drugs given to people are not neurotransmitters, but they stimulate or block specific neurotransmitter. Mertinez and Kesner –role of acetylcholine on memory. Rats going through the maze, at the end=food. 1st group= injected scopolamine, which blocks acetylcholine receptor sites, so decreasing available acetylcholine. Effect: slower than the control group. 2nd group= injected physostigmine, which blocks the production of cholinesterase(cleans up the rests of acetylcholine). Effect: quicker than the control group. 3rd group= control group, no injections. Longitudinally – over a long period of time
Localization of brain function Phineas Gage - the man with an iron stick going through his brain Paul Broca – discovered that people with damage in the left frontal lobe were unable to understand and make grammatically complex sentences. Broca’s Aphasia- being unable to speak but able to understand speech (Tan studied by Broca) Carl Warnicke – the left posterior superior temporal gyrus=language comprehension. Warnicke’s patients could produce speech, but could not understand it. Wernicke’s Aphasia - able to produce speech, but could not understand it. Karl Kim and Joy Hirsch – used fMRI to research how the brain processes language in bilingual individuals. 1st group= those who had learned a second language as children. 2 nd group= had learned a second language later in life. People were asked to think about something they had done a day before, first in one language, then in the other. Both groups used the same part of Wernicke’s area, regardless of which language they were thinking in. But their use of Broca’s area differed. 1 st group used the same Broca’s area for both languages. 2 nd group used a larger area of the brain, with the second language activating an area adjacent (sąsiedni, sąsiadujący) to the area activated by the first language. Nucleus accumbens – pleasure centre Robert Heath – by electrically stimulating specific parts of the brain of depressed patients, they would experience pleasure. He let the patients press the buttons themselves to receive pleasure. James Olds – stimulated pleasure centres of rats. Rat was pressing a button to receive pleasure, but to get to the button the rat had to walk across electrified grids. It appears that the electrical activation of the pleasure centre is based mostly on dopamine (a neurotransmitter that promotes desire) and serotonin ( a neurotransmitter that promotes satiety and inhibition).