Test #2

Choose and answer ONE question from each of the three sections below.  Your answer for each question should be approximately 1 typed page.  Your goal should be to write a concise, coherent, and original answer that addresses all aspects of the question.  You can use course readings, slides, and other sources to help you compose your answers.  However, you should note all of your sources at the end of each question and observe all conventions about citations and quotations.  Please make sure to ask about any aspects of the question about which your are unclear.  I encourage you to go through several drafts of your answers.  You should submit your completed tests to beachboard by Wednesday 11/11/2009.

Section I:
1.) What is the difference between parvocellular and magnocellular ganglion cells in the retina.  Outline the anatomical differences of parvocellular and magnocellular pathways from the retina to the dorsal and ventral pathways.  Discuss the different information processing roles of the respective pathways.

2.) Discuss the difference between the four types of cells discussed in the primary visual pathway; center-surround, simple, complex, and hypercomplex.  Make sure to discuss their information processing functions in relation to their receptive feild.

3.) What are the dorsal and ventral pathways?  What cognitive functions do each of the pathways facilitate?  What cognitive deficit emerges when damage occurs to the dorsal pathway?  What cognitive deficit emerges when damage occurs to the dorsal pathway?

4.) Outline the two different views in the mental imagery debate.  Present what you find to be the most convincing evidence cited by Posner in favor of his position.  You should only discuss one or two of the types of evidence in his list.

Section II:

1.) Outline the sequence of events involved in an action potential.  Define an action potential.  Tell me each of the steps (at the dendritic branches, the cell body, and the axion hillock and axion) outlined in lecture leading to an action potential.  You needn't specify the exact details of each mechanism (ex. you don't need to know the particular ions involved, just that ions are involved and how).

2.) What are the three main classes of neurons.  What functional role does each sort of neuron play in cognition?

3.) What is the significance of neuronal action potentials in cognition?  What aspect of connectionist models corresponds to an action potential?

Section III:

1.) How do connectionist networks represent input and output?  Define local verses distributed representations and discuss their relationship to one another. You should provide me with a one or two line definition of a connectionist system.

2.) What are the strengths of connectionism?  What do the adherents of connectionism cite as reasons for adopting their architecture? You should provide me with a one or two line definition of a connectionist system.

3.) What are the two general classes of learning algorithms for connectionist systems?  Make sure you thoroughly characterize each one. You should provide me with a one or two line definition of a connectionist system.