EEG Neuroanatomy and Physiology 4

Question 1

Which cortical layer contains the large pyramidal neurons (Betz cells) that give rise to corticospinal tract fibers?

Accepted Answer

Layer V

Answer

Layer V (internal pyramidal layer) contains Betz cells, the large pyramidal neurons projecting to the spinal cord via the corticospinal tract.

Question 2

The thalamocortical relay neurons that synchronize cortical oscillations and contribute to sleep spindles are located in which thalamic nucleus?

Accepted Answer

Reticular nucleus

Answer

The thalamic reticular nucleus (TRN) GABAergic neurons pace sleep spindles by rhythmically inhibiting thalamocortical relay neurons.

Question 3

What property of pyramidal neurons makes them the primary generators of scalp-recorded EEG signals rather than stellate cells?

Accepted Answer

Open-field geometry with parallel dendrites perpendicular to cortical surface

Answer

Pyramidal neurons are arranged in parallel columns perpendicular to the cortical surface, creating open-field dipoles whose extracellular currents summate and propagate to the scalp.

Question 4

During an EEG-recorded absence seizure, the 3 Hz spike-and-wave discharge is generated by abnormal oscillations between the cortex and which structure?

Accepted Answer

Thalamus

Answer

Absence seizures arise from abnormal thalamocortical resonance, with cortical and thalamic circuits entraining at ~3 Hz spike-and-wave frequency.

Question 5

The lateral sulcus (Sylvian fissure) separates the frontal and parietal lobes above from which lobe below?

Accepted Answer

Temporal lobe

Answer

The lateral sulcus separates the frontal and parietal lobes superiorly from the temporal lobe inferiorly.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Neuroanatomy and Physiology 4