Neuroanatomy and Physiology Flashcards
6 cards from real EEG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Neuroanatomy and Physiology flashcards as text
The reticular activating system (RAS) primarily influences EEG by:
Answer: Modulating cortical arousal and desynchronization through ascending projections to the thalamus and cortex
The reticular activating system in the brainstem modulates the level of cortical arousal through ascending projections to the thalamus and diffuse cortical projections, switching the EEG between synchronized (sleep) and desynchronized (wake) patterns.
Which neurotransmitter system is most responsible for the generation of REM sleep and its characteristic EEG pattern?
Answer: Cholinergic system from the pedunculopontine and laterodorsal tegmental nuclei
Cholinergic neurons in the brainstem pedunculopontine (PPT) and laterodorsal tegmental (LDT) nuclei are primary drivers of REM sleep, producing the characteristic desynchronized, low-voltage EEG with rapid eye movements and muscle atonia.
In terms of cortical dipole orientation, activity generated on the crown of a gyrus produces:
Answer: A radial dipole oriented perpendicular to the scalp surface, most easily detected by nearby scalp electrodes
Cortical activity on the gyral crown creates a radial dipole (perpendicular to the scalp surface), which is optimally oriented for detection by overlying scalp electrodes, unlike sulcal activity which creates tangential dipoles.
Excitatory postsynaptic potentials (EPSPs) at the apical dendrites of cortical pyramidal neurons produce which electrical field at the scalp?
Answer: A surface-negative potential directly over the active cortex
EPSPs at the apical dendrites create a current sink (negative extracellular field) near the cortical surface, producing a surface-negative potential at the overlying scalp electrode.
The blood-brain barrier's role in EEG is primarily related to:
Answer: Maintaining the ionic environment necessary for proper neuronal electrical activity
The blood-brain barrier maintains the precise ionic composition of the extracellular fluid (particularly Na+, K+, Ca2+, and Cl- concentrations) essential for proper neuronal membrane potentials and synaptic transmission that generate EEG signals.
Beta activity (13-30 Hz) on the normal EEG is typically maximal over which brain region?
Answer: Frontal and central regions
Normal beta activity is most prominent over frontal and central regions, reflecting the activity of frontal cortical networks during alertness and cognitive processing.