This area is involved in episodic short-term memory. In other words, this involves memories of autobiographical events. In people with Alzheimer's these areas break down, and this causes anterograde amnesia. This is the inability to form new episodic memories.
Brodmann Area 26, 29 and 30 are collectively called the retrosplenial cortex. The area is involved in the retrieval of episodic information. Thus, these are autobiographical memories: these memories contain times, places, and emotions, but no knowledge of facts.
Brodmann Area 27 is not located in the cingulate cortex, but is also involved in episodic memory.
The retrosplenial cortex is part of the cingulate cortex. The cingulate cortex is an area in the centre of the brain and forms the lower part of the cortex. From here there exist several connections to the thalamus and hippocampus.
In people with Alzheimer's disease, Brodmann Area 27 is one of the first areas where neurons are lost. This causes these people to have difficulty with short-term memory. Long-term memory is not affected. This is also why people with Alzheimer's often go back in the past and recount many things from their childhood.
Damage to this area is one of the many causes of anterograde amnesia. This is the inability to form new memories. So patients with this condition still have memories from a long time ago, but cannot store new things. There are severe and less severe forms of anterograde amnesia. For example, there are people who can no longer store anything after an accident in which the retrosplenial cortex is damaged. Other people suffer only from forgetfulness.
Author: Myrthe Princen (translated by Melanie Smekal)