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The Central Nervous System

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Presentation on theme: "The Central Nervous System"— Presentation transcript:

1 The Central Nervous System
Year 12 Psychology Unit 3 – The Conscious Self Area of Study 1: Mind, Brain and Body Chapter 4 (pages 177 to 270) PART 4 – Brain Research Methods & Ethics

2 Ethical Principles (in Brain Research)
Standards that guide individuals to identify good, desirable, or acceptable conduct. Australian Psychological society has a code of ethics. Also a National statement on ethical conduct on human research (2007).

3 Ethical Principles (in Brain Research)
Integrity: did this procedure/research genuinely show the potential to advance our understanding of the brain? Respect for persons: were the welfare, rights, cultural heritage etc of the participants respected? Beneficence: did the benefits of this procedure outweigh the potential risks? Justification: is the use of this particular participant justified, do they represent the norm, will others benefit from the generalisation of these results?

4 Ethical Principles (in Brain Research)
Participants’ Rights Ethics Committees (HREC) Informed consent. Withdrawal rights. Deception. Debriefing. Confidentiality. Ensure study meets national guidelines. Ensure researchers are adequately qualified. Monitor progress. Handle complaints. Ensure accountability of researcher.

5 Ethical Considerations
Ethics: the standards that guide individuals to identify good, desirable or acceptable conduct. A code of ethics provides guidelines which must be followed when working with people & animals in a research situation. Responsibilities of the researcher: Consider the ethical issues involved (ensure no psychological or physical harm is done to participants). Balance the welfare of the participants with the benefit (if any) of the findings. Maintain professional conduct at all times. Respect participants’ rights as individuals.

6 Ethical Considerations: Participants’ Rights
Confidentiality: Participants have a right to privacy, so any details of their involvement in a study can’t be mentioned in a way that the person’s identity will be known. An exception is if they have given written consent to have their name mentioned. Informed Consent: Participants must consent to being part of the study, by completing a consent form. If the participant is unable to consent (e.g. child, animal, intellectually disabled) then the researcher must obtain consent from the person who is legally responsible for the participant & inform them of the nature of the study.

7 Ethical Considerations: Participants’ Rights
Voluntary Participation: The researcher must ensure that the participants’ involvement is voluntary. Participants must not be placed under any pressure to take part in a study. Withdrawal Rights: The researcher must inform the participants of the nature of the study and let them know they are free to leave at any point in the study. They can decline to participate and withdraw at anytime, without giving a reason.

8 Ethical Considerations: Participants’ Rights
Deception in Research: Sometimes, giving participants too much information about the study may influence their behaviour during the experiment and affect the results. This may result in the subject not knowing the true nature of the experiment. The researcher must inform them of the true nature at the end of the experiment and try to extinguish any negative effects. Debriefing: The researcher must provide an opportunity for the subjects to obtain information about the research. They must be informed of the purpose of the research at the end of the investigation. The researcher must also correct any mistaken attitudes or beliefs the subjects may have about the research.

9 Ethical Considerations: Animals in Research
Researchers must ensure they minimise the discomfort, illness & pain of animals. Animal research is still considered justified in some cases and there are advantages & disadvantages for using them in research. NOT ETHICAL!

10 Also Unethical… And Just Plain MEAN!

11 And Just When You Thought It Couldn’t Get Any Worse…

12 But It’s Okay, They Get Revenge…

13 Why Use Animals in Research?
Some studies cannot be conducted on humans due to the risk of psychological or physical harm. Bodily systems and nervous system are very similar in humans and many animals. Practical advantages: aging, breeding. Animal behaviour can be controlled easily, their environment can be controlled, thus extraneous variables are easily controlled. Expectations are not a factor in most animal research.

14 THE FOLLOWING SLIDES ARE NOT ON THE CURRENT 2013-2016 STUDY DESIGN

15 Brain Research Methods
Early studies of the brain were limited by the lack of technology and focussed mainly on structure. As scientific technology has evolved, we have learned more about the function of the brain. Direct Brain Stimulation: uses a device that emits a weak electric current to activate or disrupt normal neuronal activity in a specific brain area. Neuroimaging: captures detailed images of the living brain as people do various tasks. Structural Neuroimaging: show structure and anatomy (CT, MRI). Functional neuroimaging: show images of the brain ‘at work (PET, SPECT, fMRI).

16 Direct Brain Stimulation: Electrical Stimulation (ESB)
Pioneered by Wilder Penfield. An electrode delivers a precise, regulated electric current to the brain, stimulating a specific area. If stimulation initiates a behavioural response, then that specific area of the brain controls or is involved in that response. Extremely invasive – usually only conducted when other surgery is already necessary.

17 Direct Brain Stimulation: Transcranial Magnetic Stimulation (TMS)
Delivers a magnetic field pulse through the skull, stimulating the neurons closest to the point of entry. Only effects neurons to a depth of 2 – 3cm. Good for establishing how different brain regions control different functions. Allows for simulated brain damage. Long term effects of repeated exposure are unclear. Side effects can include localised pain or headaches.

18 Computerised Tomography (CT)
Computer enhanced brain ‘slice’ (cross-section) created from X-rays taken at different angles. Extremely useful for identifying precise location and extent of damage or abnormalities. Can reveal the effects of strokes, tumors, injuries and other brain disorders. Does not provide information about brain activity.

19 Magnetic Resonance Imaging (MRI)
Similar to CT but instead of an X-ray, harmless radio frequencies are used to vibrate atoms in the neurons of the brain. Amount of vibration is detected & analysed by computer. Used to detect and display extremely small changes in the brain. E.g. can distinguish between cancerous non-cancerous brain cells. Shows only brain structure, not function.

20 Positron Emission Tomography (PET)
Examines brain function when performing different tasks (active areas ‘light up’): Prior to scan, patient consumes a sugar-like substance containing a harmless radioactive element. When substance enters bloodstream it travels to the brain. As particular parts of brain are activated, substance emits radiation which is detected by the PET scanner. Due to radioactive element, regular use should be avoided.

21 Single Photon Emission Computed Tomography (SPECT)
Similar to PET. Radioactive tracer lasts longer. Not as detailed as PET. Can be combined with CT (below) to increase picture resolution; can also combine with MRI (above). Much cheaper than PET.

22 Functional Magnetic Resonance Imaging (fMRI)
Activity: 4.29 Functional Magnetic Resonance Imaging (fMRI) Technique is based on standard MRI: Measures subtle changes in blood oxygen levels in the functioning brain. When a brain area is active, there is increased blood flow to that area, as more oxygen is required by the active, functioning neurons. Computer analyses blood oxygen levels and creates an image with colour variations similar to those seen on the PET and SPECT.


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