1. b c d f e d b d d d

2  5 4 4 c f a b c a c

3.  9 11 10 6 22 16 19 14 13 20

4. “Top-down” refers to the role of expectation, memory and context in perceiving. “Bottom-up” refers to the process of interpreting the sensory data.

5. Freud’s version has an emotionally meaningful underlying story (the latent dream) which is converted into a disguised “manifest” dream that is the dream actually experienced. Hobson’s view is that the generator of dreams is random neural activity that gets “interpreted” or converted into a more meaningful dream….so does not have the two distinct levels and is not necessarily emotionally meaningful. Hall’s view was that sometimes Freud’s version is correct (latent dream converted into manifest dream via dreamwork that disguises it/hides its deep meaning from us and that sometimes we simply dream the latent dream directly—that it’s identical to the manifest dream.

6. This would start with a vehicle with crossed connections (which yields behavior of a phototaxis). For learning, you could build in a “reinforcement” mechanism whereby an an additional photoreceptor with a high threshold fires only when the vehicle is close to the light and when it fires, strengthens the basic crossed connections as in Aplyssia where neurons that fire together wire together as in classical conditioning. Other solutions are also possible but more complex.

7. Thorndike’s Law of Effect states basically that we learn to repeat behaviors that lead to pleasure. Satisfying basic drives (eating when hungry for ex.) leads to pleasure—via activation of brain pleasure centers which were shown by Olds to be very powerful reinforcers of behavior. Putting this together, we learn to repeal behaviors that lead to drive satisfaction, and thus learn to satisfy our basic drives. More primitive animals do it via instincts but our generalized learning mechanism is much more flexible and adaptive to changes in the environment.

8. a) Topographic projection-point to point (or spatial) mapping of some aspect of the world onto the brain. 

b) Cephalization:  the evolutionary process that has led to increased size of the front end of the nervous system and increasing control lodged there.

c) Doctrine of specific nerve energies-which fibers bring info in or which area they bring it to defines what it is--sight, smell, taste, touch, etc.--that is how the brain "knows" the type of stimulation it is receiving. 

d) All or none law: The finding that a neuron ether fires (if it reaches threshold) or doesn’t. There are not different sizes of action potentials within a given neuron.

e) Phrenology was a theory (not based on much empirical evidence!) that many different behaviors or characteristics of a person were localized in distinct mostly cortical brain regions and that if you had a “lot” of some characteristic that brain area would be enlarged and expand that portion of the skull, allowing a person to “read” another person’s behavior and character/personality via feeling their skull. Having less of a given function would lead similarly to reduced brain tissue and a depression in the skull. The importance of this movement was that it set the stage for the later discovery of localization of function.

f) Maslow postulated that our motivations exist in a hierarchy, with primary drives at the bottom, safety and security needs above them and various social and self esteem needs in layers above those. In addition, he argued that you can’t work on one level of need or motive until lower level needs are met—that there is a true hierarchy of needs (with self actualization at the very top).

g) Spatial summation refers to the finding that neurons can act together (firing closely in time) to stimulate a post synaptic neuron that they all connect to. They can add their influence or effects together to make it reach threshold even if they can’t do so acting independently.

9 Background info: [Claude Bernard's view was that the move from water onto land represented a challenge in that the vastness of the ocean provided a fairly constant environment for our cells (temp. food, wastes, salinity, etc.) A major solution for this was to keep our cells surrounded by a constant (temp. food, waste, salinity, etc.) fluid layer. This "mileau interior" did not stay constant because of its vastness, but had to have lots of regulation in order to maintain constant levels of the variables and hunger/eating was part of this.]

Answer: The control system can be viewed as a regulator sensitive to an environmental variable capable of producing an output (physiological and motivational outputs actually) that offsets an input that moves the system away from the set point. Both the physiological regulation and the motivational reg. operate to keep whatever variable is being regulated near the set point. For hunger, the hypothalamus plays a regulatory role with the VMH and the LH housing opposing centers for eating, and stopping eating when the set point (possibly related to blood glucose level) is reached. . VMH acts as satiety center. Destroy it and rat gets very fat (but does regulate around a new and much higher set point).  LH feeding center (plus tracts that run thru it are general motivational activating system).  Destroy cells there and get starvation (and if you also destroy fibers running thru, you destroy much motivated behavior). The system is sensitive to glucose levels and thus regulates hunger/feeding.  The monitoring of the glucose to glycogen (and visa versa) reaction in the liver also contributes to this homeostatic control. Similarly, the ‘fullness” of fat cells is monitored, and via the release of leptin plays a regulatory role as well, making us hungry when the cells are low on fat.

Schacter’s externality theory posits that obese people are less sensitive to bodily (internal) cues for hunger and so are more susceptible to external cues (what’s happening in the environment, how palatable food is, what clocks say, etc. This is a non-homeostatic mechanism.

10. One way would be to set the two motivations “against” each other. (Have a bar at one end of a Skinner box that reinforces with food and at the other with water. Then make rat thirsty and hungry (try to find a maximum for each) and see which one the rat prefers/bar presses for. Another way is to put an electric grid in front of a food dish or a water dish and see how much voltage it takes to just stop the hungry and separately, the thirsty, animal from crossing. The first is best in that it directly pits one against the other and gives a direct measure. The second also works because it pits the two motivations against a common measure (the willingness to accept pain).

11. The experiment is very uncontrolled with many possible confounds. They include, different schedules (days of the week and time of day and class length). It is also not double blind—I know which section and method they are in and they do too. It doesn’t mention obtaining their permission to be in an experiment and the exam output is too close to be a likely significant (non-chance) difference. The judgement of their class discussion quality is very subjective and I have a bias in that I want one of the methods to be better.

12. Empiricists (historically, a British philosophical movement) maintain that all knowledge comes in via the senses; that we are born with a blank slate which has to be filled in by experience. Nativists (historically, a German philosophical movement) maintain that some basic properties of the mind or mental operations have to be innate (built-in) or else we’d not be able to take in and assimilate new knowledge. Some empirical support for the latter position is that when blind people have their vision restored in their teens or adulthood, they can see some things—like the very basic figure-ground distinction that’s the basis for seeing objects in the world. They can’t assimilate much information from visual exposure at first, so the empiricists have their support too, but it’s not that they are a completely blank slate.

e.c. White matter can be measured using DTI or DSI which is a method of tracking water molecules to define the axon fibers in the brain. The increase in white matter integrity was seen in the frontal and parietal lobes. Students who showed that greatest improvement in logic and reasoning showed the greatest change in the connectivity in regions associated with higher level cognition.