Distinct dendritic regions receive synaptic input from different sources. The pattern of dendritic arborization is critical because it determines the synaptic input field of the dendrite. Synapses are the major sites of information input into neurons. Cortical pyramidal neurons are organized into six layers and neurons from each layer have characteristic dendrite branching patterns, coincident with their functional roles ( Spruston, 2008). Most of the pyramidal neurons in the cortex and hippocampus have a characteristic pyramidal morphology with distinct large apical and shorter basolateral dendrites that originate from the apex and base of the soma respectively, each with multiple branches. The structure and arborization of dendrites has a profound impact on the processing of neuronal information.
Synapses represent major sites of information input into neurons. Dendrites bear synapses, both excitatory and inhibitory (Figure 1). The presence of voltage gated sodium channels allows the propagation of action potentials along the length of the axon to the presynaptic terminals, thus promoting neurotransmitter release. Dendritic Structure and FunctionĪxons harbor presynaptic terminals that contain neurotransmitter bearing vesicles. Finally, we will discuss the current challenges in the field. In addition, we will review the consequences of aberrations in dendritic arborization in disease. In this review, we will focus on some of the more recent studies that have provided critical insights into the molecular and cellular mechanisms that control neuronal morphology, with particular reference to dendrites of pyramidal neurons in the hippocampus and cortex. The majority of our understandings of the cellular and molecular mechanisms that control neuronal morphology have come from studies on the pyramidal neurons, which represent the vast majority of excitatory neurons in the hippocampus and cortex. Most neurons have several dendrites that represent the information input centers of the neuron and single axons that represent the information output centers. Neurons are highly specialized and polarized cells that have morphologically distinct regions optimized for their functional roles.
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