TECHNIQUES

Perfusion
Fixation : Destroy autolytic enzymes
Sectioning
- Microtome - 10-80 um thick
  - freezing - quick
  - embedding - paraffin sectioning
Mounting
- albumin
Staining
- Cell Body - Nissl substance
  - RNA and DNA
  - Cresyl violet - most common
- Myelin Stains - axons
- Membrane Stains
  - Golgi-Cox stain (silver)
- Autoradiography
  - Inject radioactive substance.
  - Labeled amino acids taken up by cell.
  - Brain sections coated with sensitive emulsion develop like photograph.

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Tracing Neural Connections

Tracing Efferent Axons

Anterograde labeling
Lectins - stain cells of immune system
Immunocytochemical methods - take advantage of immune reaction

Tracing Afferent Axons

Retrograde labeling methods
Chemical injected into region
Taken up by terminal boutons
Transported to cell body
example; Flurogold

Horseradish peroxidase

Enzyme
Picked up at ends of neuron & transported back to cell.

Tracing Brain Connections

After person dies, the brain is fixed
Dil crystals placed on fiber tract
Travel by diffusion to ends of fibers
Under UV light, it appears flourescent

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Neurochemical Procedures

Three basic ways of locating of neurons that produce chemicals:

Localizing the chemicals
Localizing the enzymes that produce
Localizing the messenger RNA for synthesis

Peptides are localized directly

Autoradiography

Measuring Metabolic Activity

Radioactive 2-deoxyglucose
- Form of glucose - taken up by cell
- High rate activity takes up most
Genetic activity

Neuronal activity - genes turned on

Fos protein staining

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Neuroradiological Procedures (Brain Imaging)

Computerized Axial Tomography (CT Scan)

X-ray emitter & detector
Brain scanned from all angles - circular

Scanning figure

Magnetic Resonance Imaging (MRI Scan)

Doesn't use X-rays
Strong magnetic field
Nuclei emit radio waves
Detects radiation from H molecules

Positron Emission Tomography (PET Scan)

Inject radioactive 2-DG
Decay of radioactive isotopes emit positrons
Detected by PET scanner

SPECT Scan

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Ablation

Doesn't tell function, rather what rest of brain can do in its absence.
Brain areas highly interconnected
Nuclei vs fibers of passage
Bilateral organization
Aspiration
Electrical Lesions
- DC current
- RF lesions
Neurotoxin Lesions
- Kanic acid, Ibotenic acid
- Destroy cell bodies, not fibers of passage
- 6-hydroxy-dopamine
Reversible Lesions
- Cryogenic Lesions
- Other Chemicals

Stereotaxic Surgery

Stereotaxis - Solid Arrangement
Stereotaxic Atlas (Bregma)
Stereotaxic Apparatus

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Electrical Recording

Electrodes

Microelectrodes
Gross electrodes
Surface electrodes

EEG (Electroencephalogram)

Evoked Potentials use macroelectrodes

MEG - magnetoencephalography: measures magnetic fields from brain

Stimulation

Electrical
Chemical

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Terms to Know

perfusion	fixation	sectoning
Nissl substance	Myelin stains	autoradiography
immunocytochemical method	anterograde labeling	retrograde labeling
Flurogold	horseradish peroxidase	CT scan
MRI scan	PET scan	SPECT scan
aspiration	DC lesions	RF lesions

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PHYSIOLOGICAL

NEUROPSYCHOLOGY

NEUROPATHOLOGY

ISSUES

ASSESSMENT STRATEGIES

THE DATA BASE

DECISION STRATEGIES

ASSESSMENT ISSUES

TREATMENT