ERP, FMRI, EEG, post-mortem examination

suggest a similar 90 minute rhythm continue, drawing waking hours. He called this basic rest activity cycle. This is characterised by a period of alertness, followed by physiological fatigue. This happens within a 90 minute cycle. This happens multiple times a day. Research suggests Myah and focus for 90 minutes and near the end. This results in a lot of concentration, fatigue and hunger.

found the best performing vionlinists well, those who practised three sessions during the course of the day each session to be in 90 minutes and then a break.

Compares bilingual brains to non-bilingual brains that were matched controls. Found a larger parietal cortex in the brain of the people who are bilingual

external cues that may affect or regulate biological rhythms, such as light on the sleep, wake cycle

Studied a group of 12 people who agreed to live in a dark cave for three weeks. They would go to sleep when the clocks said 11:45 pm and rise at 7:45 am over the time the researchers gradually spread the clock up without their knowledge, so 24 hours became 22. None of the participants comfortably adjusted to this, suggesting the existence of a strong, free running. Circadian rhythm cannot easily be overridden by changes in external environment.

It has poor spatial resolution (spatial resolution allows psychologists to discriminate between the brain regions), they only detect activity in superficial regions of the brain they are unable to provide information of what is happening in deeper regions of the brain, so this technology is limited.

Are biological rhythms in which a pattern or behaviour occurs or Ray occurs approximately every 24 hours. It is set and reset by environmental light levels

They captured dynamic brain activity as opposed to post-mortem examination, which purely shows physiological , it is advantageous to investigating brain activity in humans, rather than generalising from animals. This improves the validity and ethical reasons., They produce images that have high spatial resolution, They offer a more objective and reliable measure of psychological processes than is possible with other studies

Decide when humansanimals should be asleep and awake. light provides primary input to the system as an external cue for sleeping or waking. I first detects light and then send messages to SCN it, then uses this information to coordinate the activity of the circadian system. The sleep wake cycle is not only determined by circadian rhythm alone, but also the homoeostasis. When someone has been awake for long, it tells them sleep is needed because of energy contribution. This is the highest in the evenings.

It involves the analysing of a persons brain following the death. Individuals subjective to them all those who have a rare disorder, unusual mental processes or behaviour. damaged areas within the brain are examined after death to correlate structural abnormalities/damage on behaviour. They may also be compared with Neurotypical brains.

They are expensive compared to neuroimaging techniques. This reduces the sample size which negatively affects the validity., As it measures changes in blood flow in the brain, it is not a direct measure of neural activity in particular areas of the brain, They have poor temporal resolution because there is about a five second delay of image showed, Critics argued that they overlook the network of nature of the brain activity as it only focuses on localised areas in the brain. They claim communication among different regions, is the most critical way of mental functions.

EEGs have high temporal resolution, meaning that researchers can accurately measure particular tasks or activities with the brain activity associated with it, EEGs are much cheaper than FMRIs. So results are more likely to be externally valid and have larger sample sizes.

When generalising there are problems as they are animal studies. Additionally, in DeCoursey study, ethical issues are criticised. Animals were exposed to considerate harm and risk when returned to their natural habitat, whether we learn from this investigation such as these justify the ethical issues. Regardless, we cannot be certain the results from animals are completely externally valid. We can’t strongly support the role of SCN as an endogenous peacemaker, Campbell and Murphy study has yet been replicated. Others are critical of the manner in which the study was conducted. They suggest that may have been some limited light exposure to the participants eyes, which is a major confounding variable. Suggesting results may not be entirely valid so we cannot strongly support the role of light as an exogenous zeitgber via the skin, There are only exceptional circumstances where endogenous peacemakers are free, running and unaffected by exogenous zeitgebers influence. Like total isolation studies, e.g. Siffer’s are extremely rare and could be judged as lacking validity for this reason in real life, peacemakers and zeitgerbs interact, and it may make little sense to separate the two for the purpose of research

The evidence of plasticity can all be used as support for plasticity.These studies suggest that the brain changes and adapts functionally and structurally as a result of experience, supporting the theory of plasticity., Prolonged drug use has been shown to result in poorer cognitive functioning as well as an increased risk of dementia later in life. Also, 60-80% of amputees have been known to develop phantom limb syndrome - the continued experience of sensations in the missing limb as if it were still there. These sensations are usually unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss. This suggests that neural plasticity continues throughout the lifespan

A type of biological rhythm with a duration over 24 hours

For discriminating patience with Alzheimer’s disease from controls

Takes up about 4 to 5% of sleep time. it is light sleep when muscle movement starts to slow down and muscle twitching can happen., Takes up about 45 to 55% of sleep time. Breathing and heart rate slows down and body temperature decrease a bit. , Takes all about 5 to 6% of sleep time. Is where Deep Sleep begins and brain begins to generate slow delta waves, Takes up 12 to 15% of sleep time. It is very deep sleep where there is limited muscle activity and brain produces delta waves, Takes up 20 to 25% of sleep time. Rapid eye-movement happens here brainwave speeds up and dreaming of occurs. Increased heart rate, muscle relaxer, and breathing, is rapid and shallow

they measure electrical activities in the brain. Electrodes are placed on the scalp wall using a school cap and attacked small electrical changes resulting from neuronal activity directly below where they are placed

often used by clinics as a diagnosis tool for an usual or rhythmic patterns of activity. This may include neurological abnormalities. Such as epilepsy, E.G EEGs readings of patients with epilepsy shows spikes of electrical activity.

infradian rhythm

They are used to be able to characterise brain functions at the level of neural processes. Also doctors can use them before surgery as risk assessment and see what is happening in the head

The brains ability to adapt and change its structure and function due to experiences both negative and positive. This is also known as neuroplasticity.

Support from the Study has good application to shift work

Is a positive and negative voltage functions, drawing and EEG that are locked to a cognitive event. They reflect the brain is activity specifically related to a stimulus

Biological rhythms that lasts less than 24 hours (more than one cycle in 24 hours)

Ericsson is supportive evidence for ultradian rhythm as the consistent claim that fatigue is a characteristic of the end of the RAC cycle, which roughly occurs in a 90 minute cycle, stern and McClintock could show evolutionary value as it may have been useful for females to men straight together, and therefore fall pregnant at the same time so newborns could collectively be cared for increasing the survival rate. This supports the importance of endogenous infradian on the menstrual cycle,, A treatment of SAD is phototherapy. This is a light box that stimulates very strong light in the morning and evening. It is due to reset melatonin levels in the people with SAD. This relieve the symptoms in up to 60% of the sufferers. This supports the need of knowing about infradian rhythm is, and therefore the external validity of this theory

he spent time underground to study the effects of his biological rhythms. He was deprived of exposure to natural light and sound. But he had access to food and drink. He also 10 years later we did the study and in each case, his free running biological Ray is on settle down to just beyond the usual 24 hours around 25. He did continue to sleep at a schedule. This suggest natural sleep may be slightly longer than 24 hours, but this is entrained by exogenous zeitgetbers

Internal body clock that regulates up biological rhythms, such as influence on the SCN and pineal gland on the sleep wake cycle

sleep wake cycle

Destroyed, the SCN connections in the brains of 30 chipmunks, who were then returned to their natural habitat, and observed for 80 days. The sleep wake cycle disappeared in the chipmunks, and by the end of the study, a significant proportion had been killed by predators.

bred mutant hamsters with a 20 hour sleep wake cycle. When the SCN cells from the fetal tissue of mutant hamsters were transferred into the brains of normal hamsters, the cycle of the second group defaulted to 20 hours.

when damage to an area of the brain after trauma has happened to function from the damaged area are transferred to an undamaged area

DeCoursey, Ralph, Campbell and Murphy, Burgess provide supporting evidence with that animal studies emphasise the role of the sen in establishing and maintaining the circadian sleep cycle, Using the knowledge of light as an exogenous zeitgerber from the sleep, wake cycle, we can use light exposure to avoid jetlag. Burgess supports this suggesting research is externally valid and potentially important implications for society.

That was poor control in studies and issue with the case study evidence

ultradian rhythm

Study the brains of London, taxi drivers. As a part of their training, they had to take the knowledge which assesses the recall of the city Street and possible roots. What is significantly more volume of Greymatter in posterior hippocampus of the taxi drivers compared to match controls. This part of the brain is known for development of spatial and neurological skills in humans and other animals. The more time on the job, the more different the structure was this is a positive correlation

It is governed by monthly changes in hormone levels which regulate ovulation. This is the time between woman’s first day, the womb lining sheds to the day before her next period. During the cycled, there is rising levels of oestrogen causing ovaries to develop egg. After ovulating levels of progesterone increases, helping the womb lining thicker to ready for pregnancy. If an egg doesn’t occur. It gets absorbed and the lining leaves the body

allows a more detailed examination of abnormal and neurochemical aspects of the brain than would be in non-invasive scanning techniques. E.g. EEGs and FMRIs. An example is they can’t examine deeper regions of the brain like the hippocampus, They have contributed to our understanding of key processes in the brain. E.g. they helped to establish links between language in the broca and Wernicke’s Ariana decades before types of scanning techniques were possible. Therefore, the studies are important for medical knowledge and general hypothesis service studies.