Changes

Within the lumen of the midbrain lies the cerebral aqueduct which acts as a simple passage between the spinal cord and the third and fourth ventricles.

Within the lumen of the midbrain lies the cerebral aqueduct which acts as a simple passage between the spinal cord and the third and fourth ventricles.

===Colliculi===

===Colliculi===

The tectum (roof) has four [[#Colliculi|colliculi]], two rostral and two caudal. The caudal colliculi are widely spaced and are joined by a substancial commissure. The caudal colliculi act as integration centres for auditory pathways. The caudal colliculi also have a further connection to the thalamus via the 'ipselateral medial geniculate body'. This body is effectively a swelling of the thalamus.  

The tectum (roof) has four [[#Colliculi|colliculi]], two rostral and two caudal.  

 

 

The caudal colliculi are widely spaced and are joined by a substancial commissure. The caudal colliculi act as integration centres for auditory pathways. The caudal colliculi also have a further connection to the thalamus via the 'ipselateral medial geniculate body'. This body is effectively a swelling of the thalamus.  

Cranial nerves III and IV have their nuculi within the midbrain.

The rostral colliculi are placed closer together in comparison to the caudal. The rostral colliculi are also joined to the thalamus, but by the 'lateral geniculate bodies' rather than the medial. The rostral colliculi help to integrate the visual pathways and also are involved in somatic reflexes that are caused by visual cues. The rostral colliculi have also been suggested to be involved in spatial integration.

==Structure and Function==

==Structure and Function==