ABSTRACT
The major function of the neuronal synapse is neurotransmission. This is classically measured by electrophysiology or electrochemistry in neuronal cultures, brain slices, and in vivo live animal brain. The human brain contains billions of neurons and more than 100 trillion synaptic connections that form its neural circuits. The form and function of neurons are extremely variable, ranging from photoreceptors to midbrain dopamine neurons. Postnatal synaptic development in mammalian brain, including humans as discovered by the late Peter Huttenlocher, is characterized by an initial overproduction of synapses followed by a large-scale net synaptic pruning that extends from childhood through adolescence. The majority of morphological studies on synaptic development have measured dendritic spines, the postsynaptic structural component of excitatory synapses. Recent evidence implicates roles for proteolysis in synaptic plasticity and synapse elimination. Autophagy provides an evolutionarily conserved catabolic process to degrade long-lived proteins and dysfunctional or superfluous organelles in the lysosomes of eukaryotic cells.
