Sample questions from the Cognitive Neuroscience Written Entrance Exam
- What is the use
of brain-imaging to study questions that cognitive science
is investigating, e.g., the development of language and thought,
the nature of cultural differences, and the origin of individual
variation in competence?
- Biophysical
approaches to study the release of a neurotransmitter from
a presynaptic terminal.
- Linguists have
developed sophisticated models of grammar. Imagine that the
grammar of language X is known. Discuss how it relates to
psycholinguistic models of how X is acquired, produced and
perceived.
- A
simple electric model of an excitable membrane incorporating
passive and active properties.
- Consider the advantages
and disadvantages of individual case studies and group studies,
for drawing inferences about theories of the organisation
of brain processes underlying cognitive disorders manifest
in EITHER (i) adult neuropsychological patients or (ii) children
with cognitive developmental disabilities.
-
The role of neurotrophins in the peripheral and central nervous
system.
- Briefly describe
an experiment to investigate whether, at birth, the functional
properties of the cortex in human infants are organized like
those of adults.
-
The formation of topographic maps during neuronal development.
- Briefly discuss
the main advantages and disadvantages of current brain imaging
techniques.
-
The use of molecular biology techniques to perturb neuronal
functions.>
- How would you
design EITHER a functional imaging or a neuropsychology study
to obtain theoretically useful information on one of the following:
(i) category specificity in semantic memory (ii) apraxia (iii)
the phonological route in reading (iv) apperceptive agnosia
- Discuss
the different ways in which sensory information can be encoded.
- Briefly describe
the physical basis of EEG recording.
-
Describe different types of associative memory networks.
- People suffering
from motor neuron disease or spinal cord injury would benefit
from a technology that would utilize brain signals to control
external devices, such as a joystick. Suppose that you have
access to neuronal activity recorded at 100 electrodes, implanted
chronically in the hand/arm region of primary motor cortex.
Describe how you would "decode" this neural activity to control
an external device in realtime.
-
Information processing in the central nervous system may involve
different time-scale. Discuss.
-
Compare the roles of sodium, potassium, and calcium conductances
in controlling neuronal excitability.
-
Biophysical aspects of protein folding.
-
What is the most significant advance in biology in the last
20 years? Justify your choice.
-
Processes that can produce short and long term changes in
synaptic efficacy.
-
An example of sensory transduction at peripheral sensory organs.
-
Experimental approach you would use to characterize a novel
neurotransmitter receptor.
-
Different mechanisms used by the cells to transduce signals
from outside to inside.
-
Describe biophysical and/or molecular biology methods used
to study basic properties of voltage-activated membrane ionic
channels.
-
Discuss how voltage-activated membrane currents can influence
the release of a neurotransmitter.
-
Discuss the application of the stochastic theory to the analysis
of single channel data and/or synaptic release data.
-
Discuss the derivation of the Hodgkin-Huxley model to interpret
the action potential of a nerve cell.
-
Discuss the possible role of calcium ions in synaptic plasticity.
-
Discuss experimental methods (biophysical or genetic) for
the study of protein-protein interactions.
-
Discuss intracellular protein trafficking: signals and proteins
involved.
-
Discuss the molecular basis of growth factors activity.
-
Discuss how the human genome project is being carried out
and its advantages and disadvantages.
-
Describe one or more examples of how to employ molecular biology
techniques to study Biophysics and Neuroscience.
-
Describe one or more optical methods used to investigate physiological
processes in the nervous system.
-
Describe examples of intracellular mechanisms for signal transduction
of membrane receptor activation.
-
Describe the main biophysical mechanisms of chemical synaptic
transmission and the experimental methods to study them.
-
Discuss the mechanisms of transcriptional activation in mammalian
cells.
- Briefly describe
the most important principles of the anatomical organization
of the cerebral cortex.
- Discuss the proposal
that different mechanisms of synaptic plasticity (LTP, LTD)
are involved in experience-dependent modifications of sensory
cortical circuity.
- Illustrate the
techniques and experiments necessary to demonstrate that a
factor has a neurotrophic action.
- Discuss the role
of spontaneous electrical activity in the development of functional
connectivity.
- You have access
to every methodological tool. Design an experiment to test
possible regenerative properties of CNS neurons.
- Using a 100 x
100 geometric array of microelectrodes (10,000 electrodes),
you can record neuronal activity in 1 ms time bins from some
region of cerebral cortex believed to be involved with sensory
processing. Thus you have available a spatially-temporally
distributed record of activity. Invent analytical methods
to compare the total pattern of activity when different sensory
stimuli are delivered to the subject. Make neat sketches to
illustrate your plan. Explain what each analytical method
might be able to tell you about cortical sensory processing.
- A magazine carries
the headlines "Every Man Will Be A Genius." In the
article, scientists state that, very soon, they will have
the technology to store very large quantities of information
on silicone microchips and implant these chips in the human
brain. For example, the contents of an entire encyclopedia
could be put into the brain. (a) How is information stored
by the brain different from information stored by a silicone
chip? How is it the same? (b) What are the major challenges
the scientists must face? For example, to what part of the
brain should they connect the chip? How should they transfer
information from the chip to the brain, and vice versa?
- Imagine having
to take over as commander of an isolated Czarist outpost in
the Caucasus. The only way to communicate any message, from
military reports to letters by your men to their families,
is to dispatch one of the men - and they are very few - either
through dangerous Circassian-held territory, or via a long
detour through the safer Ossetian wastelands. You can expect
very few replacements for those who fail to return, and serious
damage if they are intercepted. Use your imagination to complete
and quantify this description with the definition of a cost
function, dependent on parameters like the probabilities of
the messenger(s) being caught and of the outpost being attacked
and overrun. On this basis sketch an optimal strategy or schedule
for using your communication channels.
- Forget Guido d'Arezzo.
Devise an original notation for Western music, and briefly
discuss its virtues and flaws as a coding system.
- Are the different
uses of the term "working memory" compatible? Which of them
has/have proved most fruitful for explaining (a) neuropsychological
phenomena and (b) phenomena derived from other empirical methods?
- The Web is now
thought to include some 800 million units (documents), whose
local connectivity (number of links per document) follows
a power law distribution: roughly 1/100 documents have more
than 10 links, 1/14,000 more than 100 links, 1/2,000,000 more
than 1,000 links. The "informational diameter" of the Web
(mean shortest number of links to follow in order to go from
one document to another) has been recently estimated to be
19. On the other hand, the human Cortex has been estimated
to include some 8 billion units (pyramidal cells) whose local
connectivity follows a unimodal distribution, peaked at, say,
40,000. Assuming half of these connections to be really local
and half long-range, and both random, produce a back-of-the-envelope
estimate of the informational diameter of the Cortex.
- As a solitary
lighthouse watch on the Fair Isle, you have devised an efficient
system to broadcast lyrics and ballads to poetry-avid seafarers:
you apply a red, blue or yellow filter (or no filter) at every
sweep of the light (3 per minute). Please tell us the code
you have used, and how long it took you to broadcast William
Wordsworth's "She Dwelt Among the Untrodden Ways" (351 characters
including blank spaces).
- An axonal fiber
branches and contacts a given postsynaptic cell at n synaptic
release sites, each of which has an independent probability
p of actually releasing a single vescicle of neurotransmitter
after a presynaptic spike. The fiber carries spikes with a
certain constant probability q per msec (a Poisson process
of mean rate 1000 x q Hertz). If the postsynaptic signal decays
away with time constant T, in which situation would you regard
the variability of the signal as mainly spatial rather than
temporal in nature? What if n=100, p=0.1, q=0.01, T=10 msec
?