<> Answers Exam 1
Q. 1. 5, 8 or 2, 4, 6, 3, 13, 1, 8, 11, 12
Q.2. b, e ,o, m, l, r, a, s, c
Q.3. There are two basic forces, a concentration force (things move from higher to lower concentrations due to thermal movement) and electrical (opposite charges attract, similar repel).Ý The trapping of large negative proteins inside the cell and positive sodium ions outside, lead potassium and chloride to distribute themselves so that there is an equilibrium. (Focus on potassium--I neglected chloride in describing this).Ý They end up with a concentration force pushing out and an offsetting electrical force pushing in (with the inside negative).Ý That is the equilibrium.Ý If the potassium moves until it ís equal, the negative inside pulls it back in. If it equalizes the electrical force by moving in to offset the negative proteins charge, the concentration force pushes it out. The equilibrium is with the forces equal and opposite.Ý A similar mechanism holds for the sodium and chloride.Ý If the chloride moves to equalize the concentration, it leaves the outside positive and moves back out. If it stays out to offset the electrical force of the sodium, the concentration force pushes it in.Ý So it moves ëtill the forces are equal and opposite--with the outside being positive due to the sodium.Ý Nerve and muscle differ in that their membrane is sensitive to the voltage, changing permeability to sodium (and potassium) in response to voltage changes--thus the action potential as sodium is suddenly allowed to rush in and potassium eventually to leave.Ý In a reflex, a bending or stretch of the nerve ending allows sodium to leak in and make the receptor cell reach threshold and fire. The sensory nerve conducts the resultant action potential into the spinal cord where it activates the motor neuron at a synapse by dumping some neurotransmitter on it which allows sodium to leak in making it reach threshold and fire.Ý It then conducts the action potential out to the muscle, dumping acetylcholine on the muscle leading to an action potential in it and a resultant contraction. In a taxis, a neuron responds to the stimulus and activates the orgainsm to move toward or away from it, using neural firing and synaptic activity as above
Q. 4. 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.Ý Topographic projection-point to point (or spatial) mapping of some aspect of the world onto the brain.Ý Distortion of topographicÝ (more brain area devoted to more sensitive or fine-grained areas of projection).Ý Intensity or strength of stimulus: The frequency of action potentials in a given neuron along with the recruitment of more neurons into the set that are firing.ÝÝ Neurooplasticity--This tells us that the brain ís coding of functions onto specific areas, while it may be genetically encoded, is modifiable (although it might take a long time and great deal of changed input to do it).Ý Cephalization:Ý the evolutionary process that has led to increased size of the front end of the nervous system and increasing control lodged there. Split brain: the demonstration by splitting the corpus callosum, that different functions (language, spatial ability, etc.) are localized to a great extent on different sides of the cerebral cortex.
Q. 5. Tom and Sally can both be right if they have different definitions of what "necessary" means.Ý If it is defined as necessary for life. (i.e. at the level of our need for food/air/fluid/etc.) then Sally is correct--the bulk of the evidence is that it is not life necessary.Ý If however, it is defined as a very strong motivation (sort of at the level of "I really need those new skiis" or above, then Tom can be right.Ý So, it really depends on how it is defined (as do many things!)Ý Sally's view is supported by the that some people sleep very little and animals have been experimentally kept awake via brain operations or in water-pedestal situations for months without dying.Ý Tom's position is supported by the fact that the motivation to sleep is overwhelming, that it is something that occurs in all human beings and most higher animals, and that there are some biological functions that operate differently during sleep.
Q. 6. {Dream} Freud: Multiple levels of dream based on the mechanism whereby the dream is generated when the censor (superego) relaxes at night, letting us dream forbidden wishes/impulses in a disguised form. Personality theory: Normally the superego which has internalized rules for our behavior is horrified by the idís demands (which represent our more biological urges) and represses thoughts/impulses arising out of the id. We dream so as to preserve sleep against its being disturbed by these impulses/repressed thoughts, just as we incorporate alarm clocks into dreams, etc. according to Freud, to prevent sleep from being disturbed. Latent dream= underlying wish that is true story of dream. Manifest dream= the dreamed dream--the one you experience in the dream. It is a distorted version of the latend dr., distorted by dreamwork--use of symbols, one element standing for more than one thing, things being moved around in space/time. The remembered dream is what you remember of the manifest dream--thus you doubly protect yourself from knowing the latent dream. Hall's dream series show that we dream overtly (openly) on some nights, then have disguised dream another night! Therefore, it can't be to hide things from ourselves, the cat is out of the bag. (Cartwright showed that we dream about serious issues on our minds--divorce/separation and do so over extended periods of time?multiple nights.) The dreamwork (symbolization/condensation/etc. remain viable--Hall found them-- it is the motivation for doing the dreamwork (hiding as per Freud or creativity of the normal mind when it doesnít have to be logical?sort of artistic freedom! as per Hall) that his work disputes. The regularity of dreaming in REM sleep (Dement/Kleitman) shows that dreams are regular phenomena, not responses to disturbance (from our id impulses trying to break free) that attempt to keep us asleep as Freud thought.
Q.7. 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. This is where physiological and motivational controls come in (along with the regulators that control them) as described by Cannon and modeled by Norbert Weiner. 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 temp. the hypothal. senses the temp. and if it increases or decreases, it (motivationally) makes us uncomfortable so that we seek to heat/cool our selves (motivation to find a comfortable temperature), and physiologically (optional for the answer to this question) it makes us shiver/close blood dist. to periphery so that we conserve and generate heat, or makes us sweat and open peripheral circulation to lose heat (in the case of being too warm). For water, the regulator operates thru the hypothalamus which senses osmotic pressure causing the pituitary to release ADH which acts to promote water reabsorption in the distal kidney.Ý (Again, the physiology is optional for this answer.) It also makes us thirsty so that we find and ingest water. 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.Ý. VMH acts as satiety center. Destroy it and rat gets very fat (but does regulate around a new and much higher set point).Ý LH feeding center (plus tracts that run thru it are general motivational activating system).Ý 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.Ý The main point is that motivation often plays an important regulatory (homeostatic) role in the body
Q. 9. Motivation, at least the primary drives, are built in mechanisms that play a major role in regulating basic bodily states (temperature, food level, water and salt level, oxygen level, etc.) They are not mysterious ³feelings² that arise from nowhere, but rather, are part of our basic regulatory processes that originate for the most part in the hypothalamus. The boy who sought large amounts of salt and died when he couldn¹t find it demonstrates that motivations (in this case, a specific hunger) was directly tied to bodily needs and thus part of the physical/biological world.
Q. 10. It demonstrated the distortion in topographic projection for touch (or a somato-sensory experience). The finger tip had much denser enervation than the back. It makes sense in that it helps show or at least fits with the idea that the distribution of sensitivity correlates with the amount of brain tissue devoted to that part of the body.
Q. 11. Participants were not randomly assigned (assigned based on gender only but could pick type of music), no control group, so not possible to know whether it was a negative effect of rock or a positive effect of classical music. They could stop when they wanted after 15 minutes so they might have been exposed to differing amounts of music which could have caused the effect. Participants self-selected their group which could mean those who chose rock music had worse memory to begin with or vice versa, listening time was not controlled (participants should have been randomly assigned to the two groups and listened to music for the same amount of time).
Q. 12. a) It is the brain (particularly the cerebral cortex and/or limbic system) that is the right organ. (b and c) Evidence includes old localization studies where people stimulated the brain and saw bodily reactions, studies of brain damage (remember Phineas Gage?), brain imaging studies (MRI,PET) such as we viewed in the brainscan lab exercise, the fact that nerve signals take "real time" (as demonstrated in our demos and in the reaction time (ruler) lab shows that they are real physical events.Ý Also and various studies of how sensory modalities project onto the brain (in animals) using electrical stimulation or the elimination (extirpation) of portions of the brain.
Extra Credit. The behavior was catching a tossed ball.