Chapter 2, The Brain Flashcards
What do the levels of analysis refer to?
Levels of analysis refer to the idea that a topic can be studied in a number of different ways, with each approach contributing its own dimension to our understanding.
What does a Neuron do?
They create and transmit information about what we experience and know.
What was Camilo Golgi known for?
He developed staining techniques that allowed fewer than 1% of the brain cells to be stained with silver nitrate so they stood out from the rest of the tissue.
What two techniques did Roman y Cajal use to investigate the nerve net?
- First, he used the Golgi staining technique to stain some cells in a slice of brain tissue.
- Second, he studied tissue from newborn animals due to the density of cells in their brains as compared to the density of adult brains.
What did Cajal discover from his investigation?
That the nerve net was not continuous but was instead made up of individual units connected together. these individual units he called neurons.
What was Cajal’s discovery crucial to?
his discovery was the central piece of the neuron doctrine.
What was the neuron doctrine?
it was the idea that individual cells transmit signals to the nervous system, and that these cells are not continuous with other cells as proposed by the nerve net theory.
What are the basic parts of the neuron?
- the cell body is the center of the nerve, and it contains mechanisms to keep the cell alive.
- Dendrites function as the branches of the cell body that receives signals from other neurons.
- The axon which is also known as the nerve fibers are usually long processes that transmit signals to other neurons
What other conclusions did Cajal make about neurons?
- He found that each neuron has small gaps between the end of one neuron and the dendrites or cell body of another neuron, it is called a synapses
- He found that neurons connect to specific neurons, this forms groups of interconnected neurons that together form a neural circuit.
- In addition to neurons in the brain, Cajal also found specialized neurons used to pick up information in the environment.
What is the mV value of a neuron’s resting potential compared to the outside?
-70 mV
What is a nerve impulse?
A stimulated nerve
When a nerve impulse is transmitted down the axon what is the charge of the axon compared to the outside?
+40 mV
How does the neuron return to resting potential?
as the impulse continues along the axon the charge reverses course and starts to become negative again until resting potential is reached.
What is an action potential and how long does it last?
it is the nerve impulse (+40mV) and last about one millisecond
What happens when the signal reaches the synapses?
Neurotransmitters are released making it possible for the signal to cross the gap to another neuron.
What affects the rate of a nerve firing?
The environmental stimuli
What is a nerve firing?
the number of action potentials that travel down the axon per second
What did Edgar Adrian state about nerve impulses?
“if the nerve impulses are crowded together the sensation is intense, if they are separated by long intervals the sensation is correspondingly feeble.”
What did Edgar Adrian do?
Measured a single neuron
What possibility did Edgar Adrian rule out?
he ruled out that action potentials have different heights and shapes when measured and stated that all action potentials have basically the same height and shape.
What does the principle of neural representation state?
That everything is based on representation in the person’s nervous system
When researchers began recording the neurons in areas outside the primary visual area what did they find?
- Many neurons at higher levels of the visual system fire to complex stimuli like geometrical patterns and faces
- A specific stimulus causes neural firing that is distributed across many areas of the cortex
