New findings in a long-standing debate
Researchers study the function of the hippocampus at a
cellular level
(July 28, 2015) Are
the same regions and even the same cells of the brain area called hippocampus
involved in encoding and retrieving memories or are different areas of this
structure engaged? This question has kept neuroscientists busy for a long time.
Researchers at the Mercator Research Group "Structure of Memory" at
RUB have now found out that the same brain cells exhibit activity in both
processes. They have published their results in the journal
"Hippocampus".
Hippocampus: the key
to memory
In the course of their project, Dr Nozomu Nakamura and Prof
Dr Magdalena Sauvage from the work group "Functional Architecture of
Memory" (FAM) focused on the brain region hippocampus. This seahorse-like
structure plays a crucial role in the formation of long-term memories and later
in retrieving of memory contents. This has been demonstrated in patients with
amnesia or in elderly people in which cases damage to this structure correlates
to severe memory deficits.
Encoding and
retrieving memories
For their studies with rats, researchers adapted a
standardised word-based memory test for humans, using however scents instead of
words. The researchers hid small treats in sand-filled cups. In addition, each
cup also contained a different scent, such as thyme or coriander which could be
smelled by the rats when searching for the treats. Each training unit consisted
of three phases. During the learning phase, researchers presented several
scents to the animals. A pause followed, and subsequently a recognition phase.
In the latter, the animals were presented the scents from the learning phase as
well as other smells. The animals demonstrated that they recognised a scent
from the learning phase by running to the back wall of their cage, where they
were rewarded with food for the correct response. If, on the other hand, they
recognised that a scent had not been presented during the learning phase, they
demonstrated it by digging in the sand with their front paws.