Methods for studying the nervous system Flashcards
Why are methods for studying the nervous system important?
“Science only as good as its methods”
Have to be constantly revised
New methods provide new information
What other disciplines does neuroscience use fir their methods?
Physiology, anatomy, biochemistry, psychology, molecular biology
What are the 5 foundation methods of neuroscience?
Dissection Light microscopic (LM) methods Electron microscopic (EM) methods Lesion studies Electrical stimulation
What does the method of dissection involve?
Flemish anatomist, Vesalius (1543), made some of the first accurate drawings of the brain
Latin and Greek names for structures in the CNS originate from this time, e.g. hippocampus= seahorse
How are microscopic features studied in light microscopy?
- Golgi method
- Nissl staining
- Myelin staining
What is the Golgi method in light microscopy?
Silver stain that stains cell bodies and dendrites
What is Nissl staining in light microscopy?
For labelling cell bodies (soma of neurons, shape and collection of cell bodies)
What is Myelin staining in light microscopy?
Myelinated axons (fatty substance in white matter of the brain, surrounds axons)
What can these light microscopic features determine?
The six layers of the human cerebral cortex
How were connections studied in light microscopy?
By cutting/severing axons which form tracts and allowing cells origin to degenerate
When connections are severed in light microscopy what two things degenerate?
Cell bodies
Axons
What is cell body degeneration?
Retrograde degeneration
What is axon degeneration?
Anterograde degeneration (stains used to detect change, usually silver stains)
What are electron microscopes used to examine?
CNS tissue
What did the introduction of electron microscopes allow?
Subcellular elements of neurons can be investigated
Confirmation of existence of synapses and synaptic connections
What are the two types of lesion study?
Observational functional disturbances following experimental lesion in animals
Relate disorders in man to lesions of the CNS e.g. language areas of the brain
What are the problems with lesions studies?
Lesions are seldom specific and compensation may occur
No control over lesions
Nervous system has a capacity to compensate for loss or damage (e.g. when someone has a stroke, some function returns, brain finds an alternative way)
How is electrical stimulation applied to the CNS?
On the tracts or nuclei of the CNS
e.g. stimulation of the motor cortex results in contraction of muscles on the opposite side of the body