Biology 3330, 3rd Midterm 2011
Name_________________
1. (4pts) What kind of experiments did Lashley perform using rats and what did these
experiments tell us about memory?
b.
What part of the brain is required for the consolidation of long-term memories (although
memories do not reside there)?
2. (7 pts) High-frequency activity at synapses on hippocampal and cortical neurons can result in
LTP.
a) Fill in the boxes below to explain the mechanisms that underlie LTP in the hippocampus.
3.
Experience-dependent plasticity is observed in the electrosensory cerebellum of skates. This
plasticity enables skates to cancel the expected reafference that results from their ventilatory
movements (gilling).
a) (7 pts) Using the diagram below, describe the processes that underlie long-term depression
at parallel fiber synapses. That is, what biochemical events result from reafferent and
motor corollary discharge inputs to the neuron?
b) The memory (negative image of the expected reafferent effects) persists for many hours.
Explain how the mechanism of LTD generation can account for the longevity of this
memory.
4. ( ) Emotion:
a) Describe 2 prominent behavioral abnormalities that characterize the Kluver-Bucy
syndrome.
b) These behavioral effects are associated with damage primarily to what brain structure?
c) This structure is believed to be important for establishing memories of what type of
information? Briefly describe electrophysiological and lesion evidence that supports this
hypothesis.
5. (5pts) The cortical areas labeled above are most active, as measured by fMRI, during which of the
following behaviors ? (Place the appropriate letter in each blank below).
____ During generating speech; also known as Broca’s area.
____ When listening to (and understanding) speech; Wernicke’s area.
____ When reading (seeing) words.
____ When seeing complex images, such as faces.
_____ When thinking of a verb that is appropriate for a particular noun.
6. (6 pts) In a crime investigation, 2 witnesses are asked whether they saw the suspect commit the
crime. Witness #1 testifies affirmatively, however witness #2 denies seeing the suspect commit the
crime. Confusion ensues when witness #1 testifies that witness #2 was indeed at the crime scene and
witnessed the crime.
a) In an effort to solve this mystery, you do some investigating and find that witness #2 had his
corpus callosum severed to relieve epilepsy. Using your knowledge of neurobiology, provide a
plausible explanation of why the statements of the 2 witnesses are discrepant.
b) What method of questioning could you use to prove that witness #2 did indeed see the suspect
commit the crime?
7. (7 pts) Cite 2 lines of experimental evidence suggesting that hippocampal ‘place cells’ do not
code exclusively for place.
b) Present experimental evidence (describe one experiment and its findings ) that supports the
‘Relational Hypothesis’ of hippocampal ‘place cell’ function. Explain this hypothesis.
8. ( 6pts ) Label each below with respect to the type of memory represented and the brain structures
involved.
Memory types: D=Declarative
W=Working P=Procedural
Brain structures: TL=Temporal lobe and cortex ST=Striatum LIP: Lateral Intraparietal
____ ____
Rehearsing a phone number
____ ____ Memory of names of places, facts events
____ ____ Riding a bike
____ ____ Memory of maze arms visited recently
____ ____ Associating a bell with the end of class
____ ____ Motor error memory associated with a planned saccade (delayed saccade task)
9. ( 8 pts). From your knowledge of developmental plasticity in the visual system, explain what
experimental conditions (manipulations of visual experience) during the sensitive period (first 2
months after birth) result in the ocular dominance characteristics of visual cortical neurons that is
shown below:
Experiment 1
Experiment 2
Left
Right
Left
Equal
Right
Equal
Left
Equal
Number of cells
Normal
Right
Ocular dominance
b) Explain what these results suggest with regard to the factors that are important in producing
binocular cells in the visual cortex.
c) Would you expect ocular dominance bands in the Lateral Geniculate N. to be normal in these
experimental conditions? Explain your answer in the context of what is required for development of
normal ocular dominance bands (and functionality) in the LGN.
10 . ( 9 pts) Mechanism of associative conditioning (learning) of the gill-withdrawal reflex in
Aplysia: Fill in the diagram (right) with the appropriate letter (left).
A. Adenylate cyclase- strongly
activated.
B. Serotonin (5HT) release
U.S. pathway
C.S. pathway
Depolarization
C. Ca+2 influx and binding to
calmodulin.
D. cAMP levels increase.
E. Phosphorylation &Closure of K+
channels.
F. PKA activity increases
G. G protein activation
H.. Increased transmitter release
b.
What further changes must occur to form a stable, long-term memory of this conditioning?
11. ( ) a) As we’ve seen, serotonin generally functions as a neuromodulatory transmitter, and has
diverse functional roles. Fill in the blanks below to show the short-term actions of serotonin
(released in response to licking and grooming) in decreasing stress responses in rats.
b) In addition, the actions of 5 HT can lead to long-term changes in stress responses that persist into
adulthood. Describe 2 additional processes that cause these long-term effects?
12. ( ) Fill in the table below to indicate the EEG pattern (Slow- or Fast-Wave) (High or LowAmplitude) and whether the activity of brainstem modulatory neurons is High or Low.
State
EEG pattern
Frequency Amplitude
Activity of brainstem
modulatory neurons
Awake:
REM sleep:
Non-REM sleep
b) What are 2 additional features of REM sleep that distinguish it from non-REM sleep.
10) 12 pts. Serotonin generally functions as a neuromodulatory transmitter, acting through
metabotropic receptors, and has diverse functional roles. Fill in the blanks below to show
the actions of serotonin in forming associative memories (and sensitization) in Aplysia, and
controlling stress responses in rats.
Increased
PKA activity
5HT released,
binds receptors
and activates G
protein
Associative
memory
Increased
PKA activity
Increased
PKA activity
Modulation of
stress responses
Less ACTH
released by
pituitary
b) In addition to the short-term changes described above, the actions of 5 HT can lead to long-term
memory formation and changes in stress responses that persist into adulthood. For each case,
describe 2 additional processes that cause these long-term effects?
Memory formation, Aplysia:
Stress response, rats:
11. ( 7 pts) Adult plasticity and memory:
the adult nervous system.
In skates, as in many electric fish, plasticity is found in
a) Complete the traces below (Draw the patterns/histograms of activity that would be seen for a
single neuron in the dorsal nucleus of a skate at the times and stimulus conditions shown).
V=ventilation, S=sensory stimulus; for V+S, sensory stimulus is delivered at the start of each
ventilatory cycle that the fish produces. Arrows= start of stimulation and/or ventilation.
Duration of Paired
stimulation (V + S)
0
Ventilation alone
S alone
10 mins
20 mins
S alone
b) What role (function) does the ‘modifiable efference copy’ play?
c) What roles do the granule cells (cerebellar) play in this learning process?
9. (4 pts) Split Brain question: A patient has had a section of the corpus callosum. Subsequently
the patient is tested on the following tasks:
a) The subject is shown a banana in the left visual field. Will he/she be able to verbally describe
this object? Explain your answer (1 sentence).
b) Will this subject be able to select a banana (without seeing it) from a group of other objects?
Which hand must he/she use?
11. (9 pts) Serotonergic systems can also be important in another form of learning- ‘epigenetic
imprinting’. Maternal care of pups in rats is an excellent example of such imprinting; early
experience can greatly “shape” an individual’s ability to respond to stimuli later in life.
a) What is the primary difference between brains of pups raised under high levels of maternal
care (i.e. licking and grooming of pups) and pups raised under low levels of maternal care?
b) As adults, pups raised under high levels of maternal care respond differently to stressful
situation than those raised by mothers that provided little maternal care.
Explain the basis of this long-term difference in stress response with 1-2 sentences and by labeling
the diagram below with the letters on the right.
A. Cortisol release
Tactile stimulation
B. Demethylation
C. Increased transcription &
Glucocorticoid receptor density
Hippocampus
D. cAMP, PKA increase
E. Inhibition
Hypothalamus
Pituitary
Adrenal
Glands
F. Serotonin release
G. Excitation