The Physics in Psychology. Jonathan Flynn

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Leslie Atkinson
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1 The Physics in Psychology Jonathan Flynn

2 Wilhelm Wundt August 16, August 31, 1920

3 Freud & Jung 6 May September 26 July June

4 Behaviorism September 14, 1849 February 27, 1936 August 31, 1874 August 9, 1949

5 Gestalt

6 Cognitive Psychology

7 Cognitive Neuroscience

8 How Do We Study the Brain?

9 Neuron

10 Brain

11 Methods Microscopy CAT Scan PET Scan MRI MEG EEG

12 Microscopy

13 Microscopy Golgi and the neuron doctrine Pros Cons Detailed analysis of the structure of single or small groups of neurons Subject must be dead Dynamic activity can only be inferred from sample

14 Electron Microscope

15 Computed Axial Tomography

16 CAT Scan Theory existed since early 1900s, but not applied until widespread adoption of computers Body tissue is differentially permeable to X-Rays Tomography is done by moving the X-Ray source and film in opposite directions, creating a visible focal plane A large series of these X-ray images are taken along an axis and stitched together with computers

17 CAT Scan Pros Cons High spatial resolution Relatively cheap 3 dimensional images Moderate radiation dose Poor contrast resolution - relies on contrast agents

Positron Emission Tomography Detects pairs of gamma rays emitted by decay of a tracer attached to biologically active molecule Tracer is a short lived

18 Positron Emission Tomography Detects pairs of gamma rays emitted by decay of a tracer attached to biologically active molecule Tracer is a short lived isotope that undergoes beta decay Positron is emitted, and collides with local electron Gamma rays hit scintillators, detected by photomultiplier tubes

19 PET

20 PET Pros Cons Tracers can be used track metabolic pathways Easily used with CAT scans and MRIs Needs a local cyclotron to make radionucleides, and special labs for radiopharmaceuticals Lower spatial resolution

21 MRI Structural.gif

22 MRI Nuclei with non-zero spin can be aligned Once aligned, they knocked out of alignment by an EMF burst. When the EMF burst is ended, an oscillating magnetic field is produced from nuclei This produces a small current in a receiver array A computer applies a 2D or 3D Fourier transform

23 MRI

24 MRI gnetacademy/mri/page3.html

25 MRI Pros Cons Detailed dynamic 3D image Good with soft tissue No radiation Can record dynamic activity Expensive Strong magnets are difficult to work with Only moderate temporal resolution Blood flow is does not have a one to one

26 Low Power MRI Only requires 46 microteslas, with one second 30 millisecond pre-polarization burst Primed with burst, uses super conducting quantum interference devices (SQUIDS) to detect the weak signal. Low spatial resolution, but research is improving it. Can be coupled with MEGs

27 Low Power MRI

28 Electro/Magneto Encephalography Ions in the brain produce magnetic and electric fields Potentiometers and SQUIDs are used to detect these fields Source localization runs into inverse problem

29 Inverse Problem Infinite number of solutions Techniques to overcome Estimation and successive refinement Correlations Beam forming Dipole model localization

30 Magnetoencephalography Pros Cons High temporal and spatial (with qualifications) resolution Can be paired with MRI Measures electrical activity Needs a magnetically shielded room Can only measure at the cortical level Expensive Inverse problem

31 Electroencephalography Measures potential on the scalp First used in ESP studies Pros Cons Cheap! High temporal resolution Inverse problem Mid to Low spatial resolution Skull and scalp alter electric fields

32 Sources Rugg, M.; Coles, M. (1995). Electrophysiology of mind: Event-related brain potentials and cognition. New York, NY, US: Oxford University Press, xii, 220 pp. Radiological Society of America (2008). Positron Emission Tomography Computed Tomography. Morton, H. (1994). The Story of Psychology. Anchor Publishing Coyne, K. (2008). MRI: A Guided Tour. Thanks to the wikimedia foundation for their collection of media under the creative commons copyright law.

33 Thank You for Listening

Nuclear Medicine RADIOPHARMACEUTICAL CHEMISTRY

Nuclear Medicine RADIOPHARMACEUTICAL CHEMISTRY An alpha particle consists of two protons and two neutrons Common alpha-particle emitters Radon-222 gas in the environment Uranium-234 and -238) in the environment