Question 1

Which of the following is an advantage of MEG (magnetoencephalography) over EEG (electroencephalography)?

Accepted Answer

A)  With MEG, current flow can be detected in any orientation.
B)  With MEG, the inverse problem can be avoided.
C)  With MEG, magnetic fields are not distorted by the skull.
D)  With MEG, the temporal resolution is much better. C

Question 2

What role does an isotope play in positron emission tomography (PET)? Include a real or hypothetical example.

Accepted Answer

In positron emission tomography (PET), isotopes play a crucial role as part of the radiotracers used to visualize and measure metabolic processes in the body. These isotopes are special forms of elements that have an unstable nucleus, which emits positrons as it decays to a more stable state. The isotopes used in PET scans are typically positron-emitting radionuclides, such as fluorine-18, carbon-11, nitrogen-13, and oxygen-15.

Here's how the process works:

1. Production of the Isotope: The isotopes used in PET are produced in a cyclotron, which is a type of particle accelerator. They are then attached to biologically active molecules to form a radiotracer. For example, fluorine-18 can be attached to deoxyglucose to create fluorodeoxyglucose (FDG), a compound similar to glucose.

2. Administration of the Radiotracer: The radiotracer is injected into the patient's bloodstream. Because the radiotracer is designed to mimic a natural substance in the body, it travels to the area of interest. For instance, FDG accumulates in cells that use glucose for energy, which includes most cancer cells.

3. Positron Emission: As the isotope decays, it emits positrons. When a positron encounters an electron in the body, they annihilate each other, resulting in the emission of two gamma photons in opposite directions.

4. Detection: The PET scanner detects these gamma photons with a ring of detectors that surround the patient. By capturing many such events, the scanner can map the location of the radiotracer in the body.

5. Image Reconstruction: The data from the detectors are processed by a computer to create cross-sectional images and, if needed, three-dimensional images of the tracer distribution within the body.

6. Analysis: Physicians analyze the PET images to assess the function and metabolism of tissues and organs. Areas with high radiotracer uptake might indicate high metabolic activity, as seen in tumors, inflammation, or infection.

Real Example: A common application of PET is in oncology, where FDG-PET scans are used to detect and monitor cancer. Since cancer cells often have a higher rate of glucose metabolism than normal cells, they accumulate more FDG. This results in brighter spots on the PET images, which can indicate the presence and spread of cancer.

Hypothetical Example: Imagine a new drug designed to target Alzheimer's disease by binding to amyloid plaques in the brain. A PET isotope could be attached to this drug to create a radiotracer. When administered to a patient, the radiotracer would accumulate in areas with amyloid plaques, allowing physicians to visualize the distribution and density of plaques and potentially assess the efficacy of the drug in reducing plaque burden.

In summary, isotopes are essential in PET scans as they provide the means to track biological processes in real-time, offering valuable diagnostic and therapeutic information.

Question 3

How do computational models contribute to our understanding of cognitive neuroscience? Include an example in your answer.

Accepted Answer

Computational models play a crucial role in advancing our understanding of cognitive neuroscience by providing a framework for testing and refining theories about how the brain processes information and generates behavior. These models allow researchers to simulate and manipulate complex cognitive processes, providing insight into how different brain regions interact and how neural networks give rise to cognitive functions.

One example of how computational models contribute to cognitive neuroscience is the study of decision-making processes. Computational models have been used to simulate the neural mechanisms underlying decision-making, helping to identify the specific brain regions and neural circuits involved in this complex cognitive process. By manipulating the parameters of these models, researchers can test different hypotheses about how decision-making works at the neural level, leading to a deeper understanding of the underlying cognitive and neural mechanisms.

Overall, computational models provide a powerful tool for integrating behavioral data, neuroimaging findings, and theoretical concepts, ultimately leading to a more comprehensive understanding of the relationship between brain function and cognitive processes in cognitive neuroscience.

Question 4

Research using ________ models sometimes involves "lesioning" the model to see if it adequately simulates the behavioral deficits observed in neurological patients.

Accepted Answer

A)  symbolic
B)  propositional
C)  neural network
D)  chronometric

Question 5

Some progressive neurological disorders can be caused by viruses like the human immunodeficiency virus (HIV) and the herpes simplex virus.

Accepted Answer

A) True 
 B)False

Question 6

The electrical signal evoked by a class of sensory, motor, or cognitive events, which is observed by averaging multiple EEG traces, is known as a(n)

Accepted Answer

A)  brain response potential.
B)  mean event trace.
C)  event-related potential.
D)  neural activity trace.

Question 7

Describe an experiment you could conduct in order to understand the properties of a particular cell's receptive field.

Accepted Answer

The answer of Describe an experiment you could conduct in...

Question 8

Functional connectivity is a measure of functional relatedness between different

Accepted Answer

A)  stimuli.
B)  brain regions.
C)  neurons.
D)  methods.

Question 9

How do transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) differ? Give a real or hypothetical example of an occasion when one of these methods would be preferable to the other. Explain why.

Accepted Answer

The answer of How do transcranial magnetic stimulation (TMS) and...

Question 10

A patient suffering from a progressive neurological disorder is brought to a neurologist for diagnosis. The neurologist notes that the patient's MRI reveals a great deal of cortical atrophy and suspects that the problem may be Alzheimer's disease. Which of the following symptoms, if also discovered, would confirm this diagnosis?

Accepted Answer

A)  tremors and difficulty in initiating movement
B)  double vision
C)  loss of dopaminergic neurons in the basal ganglia
D)  presence of amyloid plaques during postmortem examination of the brain

Question 11

________ is the science of simulating natural cognitive processes on computers.

Accepted Answer

A)  Mental chronometry
B)  Neuropsychology
C)  Artificial intelligence
D)  Cognitive psychology

Question 12

The formation of plaques composed of abnormal amyloid protein in the brain is a characteristic symptom of

Accepted Answer

A)  Alzheimer's disease.
B)  Parkinson's disease.
C)  Huntington's disease.
D)  Korsakoff's disease.

Question 13

The term ________ is used to describe the situation in which group 1 is impaired on task X and unimpaired on task Y and group 2 is impaired on task Y and unimpaired on task X. In contrast, the term ________ is used when group 1 is impaired on task X and unimpaired on task Y and group 2 is unimpaired on both tasks X and Y.

Accepted Answer

A)  single dissociation; double dissociation
B)  double dissociation; single dissociation
C)  double dissociation; triple dissociation
D)  triple dissociation; double dissociation

Question 14

The most frequent cause of stroke is occlusion of the normal passage of blood by a foreign substance, such as an embolus.

Accepted Answer

A) True 
 B)False

Question 15

People are better at identifying a briefly presented letter on a computer screen if the letter is

Accepted Answer

A)  a vowel rather than a consonant.
B)  presented as part of a word.
C)  processed serially.
D)  printed in colored ink.

Question 16

A blockage of the posterior cerebral arteries that resulted in brain damage would most likely cause a deficit in

Accepted Answer

A)  vision.
B)  motor function.
C)  somatosensation.
D)  speech.

Question 17

Functional magnetic resonance imaging (fMRI) is based on a measurement of

Accepted Answer

A)  magnetic fields emanating from the surface of the brain.
B)  the distribution of dye in the arteries and veins of the brain.
C)  virtual lesions following intense magnetic stimulation of the brain.
D)  ratios of oxygenated to deoxygenated hemoglobin in the brain.

Question 18

What can you infer about the responsiveness of two neurons in the visual cortex that lie next to each other in V1?

Accepted Answer

A)  Both cells share a common receptive field.
B)  The cells are sensitive to precisely the same stimulus characteristics.
C)  The receptive fields of these cells are also next to each other.
D)  Both cells have identical baseline activity rates.

Question 19

A magnetic resonance imaging (MRI) image is constructed from signals that are generated by

Accepted Answer

A)  protons being perturbed by the Earth's magnetic field.
B)  protons rebounding to the Earth's magnetic field.
C)  protons being perturbed by the MRI's magnetic field.
D)  protons rebounding to the MRI's magnetic field.

Question 20

The Sternberg paradigm illustrates that when a set of letters held in short-term memory is tested with a recognition task, the time needed to respond to a probe item is

Accepted Answer

A)  unrelated to the number of items in the memory set and is unrelated to whether the probe item was part of the original list.
B)  unrelated to the number of items in the memory set but is affected by whether the probe item was part of the original list.
C)  related by a linear function to the number of items in the memory set, the slope of which is the same regardless of whether the probe item was part of the original list.
D)  related by a linear function to the number of items in the memory set, the slope of which is steeper when the probe item was not part of the original list.

Exam 3: Methods of Cognitive Neuroscience

Which of the following is an advantage of MEG (magnetoencephalography) over EEG (electroencephalography) ?