Biopsychology

Hindbrain - continuation of spinal cord into the bottom of the brain. Cerebellum controls movement and motor coordination.

Diencephalon - Thalamus: concered with relaying sensory information from the brainstem to the cortex. Hypothalamus: controls basic functions such as hunger, thirst

Cerebral hemispheres - limbic system involves learning, memory and emotions. basal ganglia motor activities and movement. cerebral cortex planning, problem-solving, language, consciousness and personality

Somatic nervous system: - sensory nerve pathways bring information to the CNS from sensory receptors, dealing with touch, pain pressure                                                                                        - Motor nerve pathways which control bodily movement by carrying instructions towards muscles

Autonomic nervous system: - sympathetic ANS leads to increased arounsal eg in heart rate, blood pressure                                                                                                                                               - parasympathetic ANS leads to decreased arousal

Sensory neurones: convey information about sensory stimuli- vision, touch, taste

Motor neurones: convey instructions for physical operations- muscle movement, digestion

Relay neurons: connect different parts of the central nervous system

Electrical nerve impulses travel from the dendrites along the cell body and the axon to the axon terminals. These action potentials are the basic units of information processing in the nervous sytem and control all aspects of human behaviour.

When an electrical signal reaches the axon terminal, neurotransmitters diffuse across the synapse and attach to post-synaptic receptors on the adjacent neuron. This triggers an electrical impulse.

Excitatory - make a nerve impulse more likely to be triggered, dopamine or serotonin which produce states of excitement.

Inhibitory - make a nerve impulse less likely to be triggered, GABA calms activity in the nervous system

Thyroid - regulates metabolic rate and protein synthesis 

Adrenal medulla - fight or flight response, increased heart rate, blood pressure

Adrenal cortex - release of glucose and fats for energy 

Testes - male sexual characteristics

Ovaries - female sexual characteristics 

Pineal - sleep wake cycle

ACTH - stimulates release of corticosteroids during fight-flight response

Prolactin - stimulates production of milk from mammary glands 

Growth hormone - cell growth and multiplication 

Vasopressin - regulates water balance

Oxytocin - uterine contractions during childbirth

Hypothalamus activates the adrenal medulla, part of the autonomic nervous system.

Secretes the hormone adrenaline which gets the body ready for fight or flight response. 

Adrenaline leads to the arousal of the sympathetic nervous system and reduced activity in the parasympathetic nervous system. 

Once the threat is over the parasympathetic branch takes control and brings the body back into a balanced state. 

Hypothalamus stimulates the pituitary gland which secretes adrenocorticotropic hormone ACTH.

ACTH stimulates the adrenal glands to produce the hormone corticosteroid.

Adrenal cortex releases stress hormone cortisol which releases stored energy.

Adequate and steady blood sugar levels help person to cope with prolonged stress and helps the body to return to normal.

Motor cortex controls voluntary movements. Both hemispheres have a motor cortex each side which controls muscles on the opposite side of the body. 

Different areas of the motor cortex control different parts of the body and these are in the same sequence as in the body.

Processing of visual information starts when light enters the eye and strikes photoreceptors on the retina. Nerve impulses travel up the optic nerve to the thalamus and are passed on to the visual cortex in the hindbrain. 

Right hemispheres visual cortex processes visual information received by the left eye. 

Processing of auditory information begins in the inner ear's cochlea where sound waves are converted into nerve impulses which travel along the auditory nerve to the brain stem and then to the auditory cortex which recognises the sound and forms an appropriate response. 

Broca's area is considered to be the main centre of speech production. Patients with speech production problems had lesions to this area in their left hemisphere. Broca's area is also involved with performing complex cognitive tasks.

Wernicke's area is also in the left hemisphere and is concerned with speech comprehension. Lesions in this brain area could produce but not understand language. Wernicke's area is divided into the motor region and the sensory area.

Research has found that damage to brains can result in other areas of the brain taking over control of functions that were previously controlled by the part of the brain that is damaged. Severity of brain damage is determined by the amount of damage to the brain rather than the particular area which has been damaged. 

Gender differences have been found with women possessing larger Broca and Wernicke's areas than men, presumably as a result of women's greater use of language. 

SPERRY 

When their right eye was covered and the lights were flashed to the left side of their visual field they claimed not to have seen any lights. 

Participants had seen the lights in both hemispheres but the material presented to the left eye could not be spoken about as the right hemisphere has no language centre and can't speak about what it has seen. It can communicate it by pointing at what they had seen. 

Split brain research patients are rare, findings like Sperry's was based on samples of 2 or 3, and these patients had other neurological problems which may have acted as a confounding variable. It is hard to generalise these findings.

Individuals with high level mathematical skills tend to have superior right hemisphere abilitie, are more likely to be left handed and suffer allergies. This suggests a relationship between brain lateralisation and the immune system.

Plasticity refers to neurological changes as a result of learning and experience. Learning and new experiences cause new neural pathways to strengthen whereas neural pathways which are used infrequently become weak and eventually die.

Phenomenon was shown in a study with London taxi drivers. MRI scans revealed that the posterior portion of the hippocampus was significantly larger than a control group, and size of difference was positively correlated with amount of time spent as a taxi driver.

An effect of brain plasticity which is thought to operate in 2 main ways:

1. Neuronal unmasking, Wall 1977 noticed the brain contained dornant synapses which have no fucntion. When brain damage occurs these activate and take over the neural fucntion that has been lost due to brain damage.

2. Stem cells are unspecialised cells which can become specialised to carry out different types of task.

A brain scanner which measures increased blood flow to brain sites where individuals are asked to perform cognitive tasks. Increased blood flow indicates increased demand for oxygen in that area. fMRI can help build a map of brain localisation.

+ fMRI is non-invasive and doesn't expose the brain to potentially harmful radiation.

- fMRI only measures blood flow and is an objective measure of neural activity in the brain.

Measures electrical activity in the brain using electrodes attached to the scalp and measures how electrical activity in the brain varies over time / in different states.

+ Records brain activity over time and can monitor changes as a person's state changes

+ Medical applications in diagnosing disorders such as Alzheimers

- Only monitor electrical activity in outer layers of the brain and cannot reveal electrical activity in deeper brain sites

Measures small voltages of electrical activity when a stimulus is presented. Stimulus needs to be repeatedly presented to be considered as an ERP.

+ Provide a continuous measure of neural activity in response to a stimulus.

- Only monitor electrical activity in outer layers of the brain.

Brains from dead individuals who displayed cognitive abnormalities when alive can be measured

+ Allow for detailed examinations and measurement of deep brain structures

- Various factors can act as confounding variables and might confuse conclusions

Circadian Rhythms follow a 24 hour cycle, sleep-wake cycle

Circadian rhythms are also influenced by EZ's 'cues' in the environment about what time of day or  night it is. In 1975 Siffre spent 6 months underground in an environment cut off from all EZ's. He organised his time in regular patterns of sleeping and waking but his body had a preference for a 25 hour day.

Occur more than once a day, the cycles of REM and NREM sleep

When asleep we enter the stage NREM, then in the next half hour we descend through stages 2,3 and 4. During REM, pulse, respiration and blood pressure increase but become less regular and EEG's resemble those of the waking state.