[1] The MRN extends from the lower part of the dorsal raphe nucleus to an approximate position at the decussation of the superior cerebellar peduncle .

One study found that this raphe–hippocampus pathway plays a critical role in regulating hippocampal activity and likely associated memory consolidation processes.

[4] The serotonergic neurons of the MRN give rise to the majority of the ascending 5-HT projections to the forebrain limbic areas that control emotional behavior.

[clarification needed] These behaviors that are typically seen in rats during stressful situations involved crouching, teeth chattering, piloerection, and micturition.

When the MRN is electrically stimulated, the behavioral response was not only suppressed but there was a counteraction with para-chlorophenylalanine (PCPA), a serotonin synthesis inhibitor.

[12] Animal models indicate that inactivation of serotonergic neurons of the median raphe nucleus induces anxiolysis, suggesting involvement of the MRN in anxiety.

One study found that this raphe–hippocampus pathway plays a critical role in regulation of hippocampal activity and likely associated memory consolidation processes.

Numerous studies reveal that lesions in the MRN continuously caused ongoing theta activity, and when the MRN was injected with pharmacological agents, the neurons displayed inhibited activity or reduced excitatory to drive them to produce theta at short latencies and for long durations.