1. Evolutionary Underpininnings of Neurobiology
A brief intro to Evolution

2. Bodies change over time: Evidence for evolution
  Charles Darwin ( ):  1859 book: Origin of Species
Argued species originated from other species and eventually become distinct from their ancestors
 Thus: many animals have common, but very distant, ancestors
Evidence from domesticated plants and animals
  breeding programs;  hybrid plants, purebred dogs, cats, etc.
   Great similarity in body parts across animals:  paws, arms, etc.
 embryology: most embryos look HIGHLY similar
   Fossil records:

3. Natural Selection: Darwin’s 5 major premises:
Members of particular species have characteristics that vary
  Some of these variable characteristics are passed on from parents to siblings
  Some of these variable characteristics aid survival
  Species produce more offspring than survive to become adults
Characteristics that aid survival will become more common across generations, those that impede survival will die out.

4. Heritability
Heritability = percentage of variation in a characteristic that can be attributed to genetic factors
Identical twins versus fraternal twins
Intelligence about 50%
60-90% heritability for schizophrenia
40-50% for personality characteristics
90% for height
Appears about ½ of differences in behavioral characteristics are due to heritability
Rest must be due to environment
or interaction of genes and environment

5. Heritability
Vulnerability: genes contribute to predispositon for disorder
Must exceed required threshold to elicit disorder
Diathesis stress model
Takes both genetic predisposition AND stress to elicit certain mental disorders such as schizophrenia
Why is this such an important concept for Psychology????

6. Methods in Neuroscience
Chapter 4
(yes, we skipped- we will be back!)

7. Research, Theory and Science
Relies on EMPIRICAL DATA as a means of acquiring knowledge
Relies on SCIENTIFIC METHOD
Hypothesis testing and theories
Operational definitions
Systematic observations
Common sense and folklore may or may not be “true”
Science differs from folklore and tradition because it uses empirical method

8. Science (and thus neuroscience) is Tentative
Conclusions based on current information
New information always being acquired
This creates a problem: what was true yesterday is probably not true today, and what is true today is probably not true tomorrow!
Science is evolving, rapidly changing, and ambiguous
Relies on theories:
Integrative interpretation of diverse observations
Attempt to explain some phenomenon
Based on evidence
Conclusions pulled together logically
Explains current facts
Suggests new hypotheses and experiments to constantly test and refine the theory

9. Methods of Research Rules for conducting research Two main methods:
Scientific
Ethical
Technical
Two main methods:
Correlational
Experimental method
Sub-areas and combinations of these, as well

10. Correlational method NON experimental
looking at relation between two variables:
Effect of X on Y
Correlation DOES NOT IMPLY CAUSATION
Values of -1.0 to 0 to +1.0
Closer to 1.0 is stronger relationship
If value is close to 0, little relationship
Positive correlation: 0 to 1.0
Negative correlation: 0 to -1.0

11. Experimental Method Allows us to conclude causation
Uses general experimental method
hypothesis to test
uses INDEPENDENT and DEPENDENT variables

12. Conducting an Experiment
Need independent and dependent variables
Variable = any characteristic or condition which is subject to change
Independent variable: what the experimenter manipulates or changes
Dependent variable: what the experimenter measures, what was changed by the I.V.
Experimenter manipulates IV, measures DV
The WAY that the IV is manipulated is important:
assumes using a random sample
control for extraneous (extra or outside) variables
use systematic observations

13. Types of Groups of IV Experimental group: Control group:
Gets the actual treatment
May have several levels of treatment
Control group:
does not get the “treatment”, but otherwise equal to the experimental group
Placebo Group:
a control group
“thinks” they got the treatment

14. Many Research Techniques in Neuroscience
Correlational studies:
No random assignment to groups
Linking or relating A to B
Intaking high levels of caffeine during pregnancy is related to lower birth weight babies
Causal studies:
Random assignment
Researcher manipulates independent variable
Methamphetamine alters autoreceptors of the neuron in rats
Does it make a difference?
To researchers: All data are important
Must be careful in our conclusions: Don’t conclude causality where there isn’t any!!!!

15. Techniques include Cell work: Study brain cells or slices
Examine the effects of various manipulations on individual cells
Might grow a new cell, examine changes in that cell, try a drug or toxin on that cell
Measuring brain activity in live organisms:
Scans of functioning brains
Implanting measurement tools and measuring
Animal models: Models for human functioning
Post-mortem examination

16. Studying Cells: Staining and imaging neurons
Golgi stain method:
Randomly stains neurons against a background
Allow you to see emerging patterns
Myelin and Nissl stains:
Stain taken up by fatty myelin that insulates axon
Nissl stains allows identification of cell bodies
Stain helps identify neural pathways
Autoradiography:
Makes neurons stand out
Also shows which ones are active
Can correlate this with behavior of the animal
Immunocytochemistry
Allows specific antibodies to attach to a dye
Allows identification of receptors, neurotransmitters and enzymes

17. Light and Electron Microscopy
Electron microscope:
Passes beam of electrons through thin slice of brain tissue onto photo plate
Different parts of tissue block or pass electrons at different degrees
Electrons produce image based on this variance
Scanning electron microscope:
Beam of electrons causes specimen to emit electrons itself
These are captured by photo plate
Not as great of magnification, but image is 3-D

18. Measuring Brain Activity
Electroencephalography or EEG
Hans Berger, 1929
Recorded from two electrodes on scalp over area of interest
Electronic amplifier detects combined electrical activity of all neurons between these two neurons
Can graph activity
Terrific temporal resolution: 1 millisecond recording
Spatial resolution is poor

19. Measuring Brain Activity
Why use?
Detecting changes in brain patterns or arousal
Can average several readings to obtain evoked potential
Signal – background noise
Gives better estimation of patterns
Often used for detecting
Epilepsy
Narcolepsy
Sleep disorders
General arousal patterns

20. Stereotaxic techniques: Invasive Techniques
Stereotaxic device:
Allows precise positioning in brain of electrode or other device
Holds head in position
3-D: height x depth x width
Use stereotaxic atlas to find locations
Brain atlas!
Several kinds of things might be put into brain
Cannula
Electrodes
Measure activity, deliver drugs

21. Stereotaxic techniques:
Several kinds of measures
Electrophysiology
Electrodialysis
Fast scan cyclic voltammetry:
Optogenetic techniques: Light activation!
Placed into neurons
Genetically introducing sensors
Ablation and Lesioning
Ablate and lesion = damaging precise areas of brain
Alter specific area to determine function
Examine behavioral effects
Examine pathways
Practical and Research tool: Transcranial Magnetic Stimulation: TMS
All allow measurement of brain electrical and chemical changes

22. Brain Imaging CT or CAT scan: Computed tomography X ray scanning
Produces series of x rays taken from different angles
Combined using computer to create series of 2-d horizontal cross sessions or slices
Presented as series to make 3-D

23. Brain Scanning: MRI Magnetic Resonance Imaging or MRI
Measures radio-frequency waves emitted by hydrogen atoms when they are subjected to strong magnetic field
Extremely fast
Can scan very small areas clearly

24. Brain Scanning: PET PET: Positron Emission Tomography
Involves injecting radioactive substance (radioactive 2-DG) into bloodstream
Is taken up by parts of brain according to how active each area is
Can use other radioactive tracers to mark bloodflow, oxygen uptake
Requires lots of training and access to cyclotron
Cyclotron supplies radioactive substances
Provides estimates of brain activity and changes in brain activity

25. Brain Scanning: fMRI fMRI: functional magnetic resonance imaging
Measures brain activation by detecting increase in oxygen levels in active neural structures
Can be used as individual is engaging in a behavior or cognitive task
Can see changes as behavior changes
Important: don’t have to ablate or lesion to determine function
Allows use of live human and animal subjects

26. Studying heritability and genetics
Family studies:
Determine how strongly a characteristic is shared across family members
Quantify
Correlate degree of heritability
Adoption studies
Compare adopted and biological children
Compare behavior in adoptive vs biological family
Twin studies
Identical vs. fraternal twins
Concordance rate: frequency with which relatives are alike in characteristics

27. Genetic Engineering Genetic engineering: Knockout technique:
Manipulation of organism’s genes or their functioning
Knockout technique:
Nonfunctioning mutation is introduced into isolated gene
Altered gene is transferred into embryo
Antisense RNA procedure:
Blocks participation of messenger RNA in protein construction

28. Genetic Engineering Gene Transfer: Transgenic animal:
Gene is inserted into an animal’s cells
Transgenic animal:
Gene is inserted into animal embryo
Embryo now has that trait
Genetic Engineering
Manipulate genes to turn on/off different traits
Goal is to be of therapeutic use

29. Research Ethics Regulatory Problems: Ethical dilemmas Animal research:
IACUC: Institutional animal care and use committee
5 federal agencies have federal guidelines
NIH human subjects use
Problems:
Plagiarism
Fabrication of data
Ethical dilemmas
Gene therapy
Stem cell therapy