EEG - Electroencephalography Neuroanatomy and Physiology Questions and Answers

Question 1

The primary generators of the electrical potentials recorded by scalp EEG are:

Accepted Answer

Postsynaptic potentials of pyramidal cells in the cerebral cortex

Answer

Action potentials from deep cortical neurons

Answer

Electrical activity from glial cells and astrocytes

Answer

Axonal currents from white matter tracts

Question 2

A patient undergoing an EEG displays rhythmic 8-13 Hz activity over the occipital regions that attenuates with eye-opening. This activity is primarily modulated by which subcortical structure?

Accepted Answer

Thalamus

Answer

Hippocampus

Answer

Basal Ganglia

Answer

Cerebellum

Question 3

During a recording, an epileptiform discharge characterized by a sharp wave followed by a slow wave is observed. The slow wave component is physiologically understood to represent:

Accepted Answer

A prolonged afterhyperpolarization and inhibitory postsynaptic potentials (IPSPs)

Answer

A secondary burst of excitatory postsynaptic potentials (EPSPs)

Answer

The summation of multiple action potentials

Answer

Artifact from patient movement following the sharp wave

Question 4

An EEG electrode placed at C3, according to the International 10-20 System, primarily records activity from which cortical region?

Accepted Answer

The primary motor and somatosensory cortex (Brodmann areas 4, 1, 2, 3)

Answer

The primary visual cortex (Brodmann area 17)

Answer

The primary auditory cortex (Brodmann areas 41, 42)

Answer

The prefrontal cortex (Brodmann areas 9, 10)

Question 5

Which of the following best describes the neurophysiological basis for why a minimum cortical area of approximately 6-20 cm² must be synchronously activated to generate a detectable scalp EEG signal?

Accepted Answer

The filtering effect of the skull and scalp, which attenuates small or asynchronous signals

Answer

The high electrical impedance of the cerebrospinal fluid

Answer

The requirement for bilateral hemispheric involvement for any recordable potential

Answer

The specific firing frequency of pyramidal neurons

Question 6

The synchronization of cortical neurons necessary to produce normal resting rhythms and abnormal discharges like generalized spike-and-wave is heavily dependent on the integrity of:

Accepted Answer

Corticothalamic circuits

Answer

Corpus callosum pathways

Answer

Corticospinal tracts

Answer

The fornix and limbic pathways