Transcript METHODS OF STUDYING THE NERVOUS SYSTEM

METHODS OF STUDYING
THE NERVOUS SYSTEM
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Outline
1. Methods of Visualizing the Living Human Brain
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a. Contrast X-rays
b. Computerized Axial Tomography
c. Magnetic Resonance Imaging
d. Positron Emission Tomography
e. Functional MRI
2. Scalp Electroencephalography
3. Invasive Physiological and Pharmacological Methods
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a. Stereotaxic Surgery
b. Lesion Methods
c. Electrical Stimulation
d. Pharmacological Methods
CT scan of a man struck by
lightning – basal ganglia damage
PET Scan of Normal (left) and
Alzheimer's Disease (right) Brains
Intracellular unit recording
Extracellular Unit recording
Routes of administration
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Intragastric (IG)
Intraperitoneal (IP)
Intravenous (IV)
Subcutaneous (SC)
Intramuscular (IM)
Many drugs cannot pass the blood-brain
barrier
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Microinjection
6-hydroxydopamine (6-OHDA)
Measuring the Chemical
Activity of the Brain:
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2-deoxyglucose autoradiography
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radioactive 2-DG is injected
animal performs the behavior of interest
animal is immediately killed
its brain is removed and sliced
the slices are coated with a photographic emulsion
After a few days in the dark
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areas of the brain that were particularly active
show up as dark spots of radioactivity
in vivo cerebral microdialysis
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measurement of specific neurotransmitters
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in living/behaving animals
Immunocytochemistry
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Finds Neurotransmitters and Receptors
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Takes advantage of the immune reaction.
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Antibodies attempt to destroy foreign substances
(antigens)
Often by attaching themselves to the antigen.
Antibodies for peptide neurotransmitters and
receptors have been created by cell biologists.
The antibodies are labeled with a dye or
radioactive element and then used to identify
specific neuroproteins in slices of brain tissue
Crayfish brain stained with anti-serotonin
antibody
Localization of postsynaptic proteins in a
cultured neuron by immunocytochemistry.
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Antibodies to the NMDA
receptor are labeled
Yellow.
Glutamate acts at
NMDA receptors
The NMDA receptors
are concentrated in the
yellow patches along
the dendrites.
In situ hybridization
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locates peptides and proteins in the brain
All peptides and proteins (including enzymes)
are synthesized according to information
contained on the chromosomes.
mRNA carries the code for a protein of
peptide from the DNA in the nucleus to the
ribosomes.
In situ hybridization
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labeled hybrid RNA strands with a base
sequence complementary (opposite) to the
mRNA for synthesizing the target
neuroprotein are created
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The labeled RNA will attract its complementary
mRNA
The hybrid RNA binds to the complementary
mRNA in the target cells
This tells us where the protein or peptide that
we are interested in is being produced.
Labeled neurons in the hypothalamus – The tissue was
exposed to labeled RNA that binds with mRNA for the
synthesis of vasopressin (a peptide).
BEHAVIORAL RESEARCH METHODS
OF BIOPSYCHOLOGY
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Outline
1. Neuropsychological Testing
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2. Paradigms of Animal Behavior
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a. General Tests: The WAIS
b. lateralization of Language
c. Specific Tests of Memory
d. Specific Tests of Frontal Lobe Function
a. Analysis of Species-Common Behaviors
b. Traditional Conditioning Paradigms
c. Seminatural Animal Learning Paradigms
3. Conclusion: Converging Operations
WAIS
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Most neuropsychological assessments begin with the
Wechsler Adult Intelligence Scale (WAIS)
It has 11 subtests
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6 comprise the verbal scale (e.g., digit span, information,
similarities)
5 comprise the performance scale (e.g., block design,
object assembly)
The information subtest and the digit span test
are memory tests that comprise part of the WAIS
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however, these are notoriously bad measures of memory.