| The mammalian brain consists of billions of neurons that form distinct circuits to collect, process, and transmit information for various functions and behaviors. The information is encoded in neurons by means of action potentials, which are initiated by voltage-gated ion channels located in the axo-somatic region. A variety of ion channels throughout the neuron determine the pattern of action potential firing. Action potentials are propagated to the axon terminals, where, with sufficient depolarization, neurotransmitters are released into the synaptic cleft in order to deliver the information to postsynaptic neurons. These target neurons also contain voltage-gated ion channels, including voltage-gated channels in dendrites, which can influence the spatial and temporal summation of synaptic inputs and changes in synaptic strength via activity-dependent plasticity.;This thesis explores how the excitability of pyramidal neurons contribute to synaptic plasticity and target specificity in the hippocampus, a central region of the brain involved in formation and distribution of new memory. Chapter one describes the current knowledge of hippocampal function, anatomy, and physiology. Chapter two explores how dendritic excitability of CA1 pyramidal neurons contributes to changes in synaptic strength in response to patterned presynaptic activity. Chapter three investigates how intrinsic excitability of subicular pyramidal neurons is related to anatomical distribution and target-specific connectivity. Finally, Chapter four discusses these findings in the context of their significance for neuronal excitability in input and output connections of the hippocampus. |
