Chapter 2 Flashcards
Describe the idea of levels of analysis.
Levels of analysis refers 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.
How did early brain researchers describe the brain in terms of a nerve net? How does the idea of individual neurons differ from the idea of a nerve net?
A nerve net was visualized like a highway system in which one street connects directly to another but without stop signs or traffic lights. It provided a complex pathway for conducting signals uninterrupted through the network.
Individual neurons don’t connect and therefore make the idea of a giant network of roads impossible.
Describe the research that led Cajal to propose the neuron doctrine.
First, he used the Golgi stain, which stained only some of the cells in a slice of brain tissue. Second, he decided to study tissue from the brains of newborn animals, because the density of cells in the newborn brain is small compared with the density in the adult brain. This allowed him to see the individual neurons and disprove the nerve net theory.
Describe the structure of a neuron. Describe the synapse and neural circuits.
The cell body is the metabolic center of the neuron; it contains mechanisms to keep the cell alive. The function of dendrites that branch out from the cell body is to receive signals from other neurons. Axons are usually long processes that transmit signals to other neurons.
How are action potentials recorded from a neuron? What do these signals look like, and what is the relation between action potentials and stimulus intensity?
Adrian recorded electrical signals from single neurons using microelectrodes—small shafts of hollow glass filled with a conductive salt solution that can pick up electrical signals at the electrode tip and conduct these signals back to a recording device. Modern physiologists use metal microelectrodes.
Signals are all similar in height and shape, making them ideal for traveling long distances without losing intensity.
How has the question of how different perceptions can be represented by neurons been answered? Consider both research involving recording from single neurons and ideas about sensory coding.
A series of papers by David Hubel and Thorsten Wiesel, which would
win them the Nobel Prize in 1981, answered this question. Different neurons fire depending on circumstance; for example some vision-based sensory neurons fire upon seeing certain shapes while others don’t.
How is neural representation for memory different from neural representation for perception? How is it similar?
The neural firing associated with experiencing a perception is associated with what is happening as a stimulus is present. Firing associated with memory is associated with information about the past that has been stored in the brain.
What is localization of function? Describe how localization has been demonstrated by neuropsychology and recording from neurons. Be sure you understand the principle of double dissociations.
Localization of function—specific functions are served by specific areas of the brain.
Localization has been demonstrated by neuropsychology through the study of specific parts of the brain and by brain damage, such a people with damage to certain brain areas. Double dissociations are injuries to the brain where one part is damaged but the other isn’t so that while A is functional, B is not or vice versa.
Describe the basic principles behind functional magnetic resonance imaging.
It plays an important role in understanding the physiology behind cognition, especially localized functions of the brain.
Describe brain-imaging evidence for localization of function.
Describe experiments that involved looking at still pictures and that involved looking at movies. What does each type of experiment tell us about localization of function?
Brain imaging is able to spot where brain activity occurs. Psychologists can then track where brain activity occurs to a certain image or event. Movies have a broad range of images, giving psychologists a good range of material to work with. Each type of experiment tells us which parts of the brain activate when presented with which images.
