In which one of the following stages are pontogeniculo-occipital (PGO) spikes found in human EEG recordings?

Correct option is A

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Pontogeniculo-occipital (PGO) spikes are high-amplitude waves that originate in the pons, propagate to the lateral geniculate nucleus (LGN) of the thalamus, and then reach the occipital cortex. They are closely associated with REM sleep and are observed in EEG recordings.

• PGO spikes appear immediately before and during REM sleep.
• These spikes precede the onset of rapid eye movements (REMs) and are believed to be involved in dream generation and visual processing during sleep.

1. Option (2) NREM Stage 2: Sleep spindles and K-complexes dominate this stage, but PGO waves are absent.
2. Option (3) Awake Condition: PGO waves do not occur in wakefulness.
3. Option (4) NREM Stage 4: Deep sleep is associated with delta waves, not PGO spikes.

Information Booster

1. Origin of PGO Spikes:

   • Generated in the pons, transmitted through the geniculate body (LGN), and reach the occipital cortex.

2. Function of PGO Spikes:

   • Associated with eye movements during REM sleep.
   • Believed to be involved in visual processing of dreams.
   • May help in memory consolidation and sensory processing during sleep.

3. Neurotransmitters Involved:

   • Acetylcholine (ACh) plays a major role in the initiation of PGO waves and REM sleep.

4. Electrophysiology of PGO Spikes:

   • High-amplitude wave bursts that can be detected in EEG and LFP (local field potential) recordings.

5. PGO Spikes and Dreaming:

   • Increased PGO wave activity correlates with intense dreaming, suggesting a role in the visual aspects of dreams.

6. Disorders Associated with PGO Spikes:

   • Abnormal PGO wave activity has been linked to REM sleep behavior disorder (RBD) and narcolepsy.

7. Experimental Findings:

   • Animal studies (cats, rodents) have shown that lesions in the pons eliminate PGO waves, disrupting REM sleep.