What type of cells are in the dentate gyrus?
The principal cell type of the dentate gyrus is the granule cell (Figs. 4 and 5). The dentate granule cell has an elliptical cell body with a width of approximately 10 μm and a height of 18 μm (Claiborne et al., 1990).
What is the dentate gyrus made up of?
The dentate gyrus, like the hippocampus, consists of three distinct layers: an outer molecular layer, a middle granule cell layer, and an inner polymorphic layer. (In the hippocampus the outer layer is the molecular layer, the middle layer is the pyramidal layer, and the inner layer the stratum oriens).
How many granule cells does the cerebellum have?
The human brain contains approximately 60 billion cerebellar granule cells1, which outnumber all other brain neurons combined.
What is the molecular layer of the dentate gyrus?
The dentate gyrus has three distinct layers (molecular layer, granule cell layer and polymorphic layer). The molecular layer is relatively cell free and is occupied by the dendrites of the dentate granule cells. The granular layer is the principal layer, and comprises mainly granule cells closely packed together.
What are granule cells?
Granule cells are the smallest and most numerous type of neurons in the brain. They are involved in functions ranging from processing visual and motor information to learning and memory. Brain Bytes showcase essential facts about neuroscience.
What are dentate granule cells?
Dentate gyrus granule cells receive excitatory neuron input from the entorhinal cortex and send excitatory output to the hippocampal CA3 region via the mossy fibers. Thus, new neurons are generated and functionally integrated throughout life.
Are granule cells inhibitory?
The granule cells are the only intrinsic excitatory neurons, the other four neuron types (Purkinje, basket, stellate, and Golgi) involved in computation are all inhibitory and target deep cerebellar nuclei, soma of Purkinje cells, and dendrites of Purkinje and granule cells, respectively.
How many types of granules are there?
Neutrophils have two types of granules; primary (azurophilic) granules (found in young cells) and secondary (specific) granules (which are found in more mature cells).
Is the dentate gyrus part of the hippocampus?
The dentate gyrus is found in the temporal lobe, adjacent to the hippocampus. There is not a consensus, however, on how to anatomically demarcate the hippocampus and its neighboring regions, and some sources consider the dentate gyrus to be part of the hippocampus.
Which cells are most important for navigation memory?
By establishing spatial context, place cells play a role in completing memory patterns. Furthermore, place cells are able to maintain a spatial representation of one location while recalling the neural map of a separate location, effectively differentiating between present experience and past memory.
What are the three layers of the dentate gyrus?
The dentate gyrus has three distinct layers (molecular layer, granule cell layer and polymorphic layer). The molecular layer is relatively cell free and is occupied by the dendrites of the dentate granule cells. The granular layer is the principal layer, and comprises mainly granule cells closely packed together.
Where are granule cells located in the dentate gyrus?
Granule cells (that use glutamate) are excitatory, whereas the dentate pyramidal basket cell is the primary inhibitory interneuron found in the dentate gyrus. They are most commonly located in the border between the polymorphic and granule cell layer.
Where are mossy fibers located in the dentate gyrus?
The granule layer is between the overlying molecular layer and the underlying hilus (polymorphic layer). The granule cells of the granule layer project their axons known as mossy fibers to make excitatory synapses on the dendrites of CA3 pyramidal neurons.
Is the dentate gyrus part of the trisynaptic circuit?
The trisynaptic circuit consists of excitatory cells (mostly stellate cells) in layer II of the entorhinal cortex, projecting to the granule cell layer of the dentate gyrus via the perforant path. The dentate gyrus receives no direct inputs from other cortical structures.