Serrated gyrus: what it is and what functions it performs in the brain

Our cerebral cortex is a complex structure, extremely developed, which allows us to carry out and coordinate the different functions and actions that can carry out our organism, both physically and mentally and both at the level of perception and of action.

But this structure is not homogeneous: different brain areas specialize in different functions, with certain parts of the brain being more relevant for certain mental processes. An example of this is the serrated gyrus, of great importance in the formation of memories, which we are going to talk about throughout this article.

• Related article: "Parts of the human brain (and functions)"

What is the dentate gyrus?

We call dentate gyrus a gyrus of the cerebral cortex located in the inferior part of the temporal lobe of the brain, being part of one of the oldest regions phylogenetically speaking of the cortex (the archicortex). It limits among other structures with the corpus callosum (although it is separated from it thanks to the gray indusium), the entorhinal cortex, he hippocampus and the cingulate gyrus.

This small brain region is part of the hippocampal formation, connecting it with the cortex, and is mainly made up of gray matter (somata and unmyelinated axons). In fact, it is considered that this turn can be considered a modified and partially separated part of the hippocampus itself during neurodevelopment.

So this part of the cortex has an important role in regards to the memory capacity of the human being, acting as a bridge between the entorhinal cortex (which in turn is considered a bridge between the hippocampus and the rest of the cortex) and hippocampus. This structure acts, receives afferents from the first and sends information to the rest of the hippocampal formation, passing through the perforating pathway through the dentate gyrus. However, its connections with the entorhinal cortex do not allow information to be returned through the same channel. It will be other structures that send the information back to the entorhinal cortex so that it can distribute it to other parts of the cortex.

The toothed turn has the particularity of being mainly made up of granule cells, which at their axonal endings end up transforming into mossy fibers that synapse exclusively with the Ammon field of the hippocampus. In addition, these cells are one of the few that can generate new neurons throughout the entire life cycle, in certain types of mammals (it is not yet clear if it also occurs in humans).

functions

The functions of the dentate gyrus, as mentioned above, are largely derived from its role as a connection between entorhinal cortex and hippocampus. Thus, one of its main roles is to transmit information to this last structure in order to be able to process it.

The dentate gyrus thus plays an important role in the formation of memories, based on episodic memory. It is also of great importance at the level of navigation and spatial memory, this being the structure that allows us to distinguish between similar environments.

also exercises a role in memory consolidation and retrieval, something that merits the aforementioned when participating in the recognition of similar locations.

Since the hippocampal formation is also part of the limbic system, it is suspected that the dentate gyrus also plays a role in the integration into memories of the emotions aroused by the experience. Likewise, the existence of variations in this area has been observed in the presence of emotional disturbances such as stress or anxiety, as well as depression.

• Related article: "Types of memory: how does the human brain store memories?"

The birth of neurons in adults

Traditionally, it has always been said that the formation of new neurons occurred only in the early years. of life and that once in adulthood we had approximately the same neurons for life until these they died. However, over time it has been discovered that in some mammals, although not at a general level, some areas of the brain continue to produce small numbers of new neurons throughout the life life cycle.

One of the points in which this neurogenesis has been detected is the dentate gyrus. said birth has been associated with task learning and spatial learning, which in turn appear to enhance the birth of new neurons. However, studies in this regard do not finish demonstrating that neurogenesis generates an improvement in these capacities, finding contradictory results (although this could be due to the need to develop strong synapses between the new neurons). More research is needed in this area,

It has also been observed that the environment is of great importance in the formation of new neurons: stress or cholinergic lesions decrease the ability to generate new neurons, while stimulation power. The observation of alterations in neurogenesis in this area is one of the main reasons that have led us to think in the implication of the dentate gyrus in the management of emotions, whether said alteration of neurogenesis causes or consequence.

Bibliographic references

• Nieto-Escámez, F.A.; Moreno-Montoya, M. (2011). Neurogenesis in the dentate gyrus of the hippocampus: implications for learning and memory in the adult brain. Arch. Neuroscience., 16 (4): 193-199.
• Andersen, P.; Morris, R.; Amaral, D.; Bliss, T. & O'Keefe, J. (2006). The hippocampus book. 1st Edition. OOP. USES.
• Clark, D.L.; Boutros, N.N. and Mendez, M.F. (2012). The brain and behavior: neuroanatomy for psychologists. 2nd edition. The Modern Handbook. Mexico.