Dendriites

Dendrites are highly branched extensions of neurons that receive signals from other neurons or sensory receptors. They play a crucial role in the transmission of electrical and chemical signals within the nervous system. Structurally, dendrites are tree-like projections that increase the surface area of a neuron, allowing it to receive a greater number of synaptic inputs. Unlike axons, which transmit signals away from the cell body, dendrites primarily conduct impulses toward the neuron’s cell body, or soma.

The shape and complexity of dendrites vary depending on the type of neuron and its function. For example, pyramidal neurons in the brain have elongated dendrites that fan out, while Purkinje cells in the cerebellum possess densely branched dendrites that form intricate networks. These variations contribute to the diverse computational capabilities of neural circuits.

Dendrites are not passive receivers of signals; they actively integrate incoming information through a process called dendritic integration. This involves the summation of excitatory and inhibitory postsynaptic potentials, which determine whether a neuron will fire an action potential. Some dendrites also contain voltage-gated ion channels and even miniature synapses, allowing for local processing of signals before they reach the soma.

In pathological conditions, dendrites can exhibit abnormalities. For instance, dendritic spines—small protrusions that receive synaptic inputs—may shrink or grow in neurodegenerative diseases and psychiatric disorders, affecting neural communication. Additionally, dendritic damage or dysfunction has been linked to conditions such as Alzheimer’s disease and schizophrenia.

Research on dendrites continues to advance our understanding of neural plasticity, memory formation, and cognitive functions. Techniques like electron microscopy and advanced imaging have provided detailed insights into their structure and dynamics, highlighting their importance in both healthy and diseased states.