![]() ![]() Homeostatic plasticity in neuronal networks: the more things change, the more they stay the same. Correlation among cell morphology, intrinsic electrophysiological properties, and axon targets. Pyramidal neurons in layer 5 of the rat visual cortex. Target-specific differences in somatodendritic morphology of layer V pyramidal neurons in rat motor cortex. The pyramidal neuron of the cerebral cortex: morphological and chemical characteristics of the synaptic inputs. Premature bifurcation of the apical dendritic trunk of vibrissa-responding pyramidal neurones of X-irradiated rat neocortex. Dendritic morphology of CA1 pyramidal neurones from the rat hippocampus: I. Histology of the Nervous System of Man and Vertebrates (Oxford Univ. An overview of its evolutionary development, structural organization and synaptology. Cortex, cognition and the cell: new insights into the pyramidal neuron and prefrontal function. Elaborating simple models of pyramidal-neuron function based on these dendritic-domain-specific properties is a central challenge for the study of cortical function.Įlston, G. At least some forms of modulation affect various dendritic domains and their synaptic inputs in different ways.ĭomain-specific properties in excitatory and inhibitory synaptic inputs, voltage-gated channels, dendritic excitability and neuromodulation all point to a multi-compartment model of pyramidal-neuron function. Neurotransmitters can modulate pyramidal-neuron function. Even single dendritic spikes can result in significant long-term potentiation or long-term depression. This results in forms of coincidence detection that are determined by dendritic structure and excitability.īackpropagating action potentials and dendritic spikes are important signals for the induction of synaptic plasticity. ![]() The coupling of dendritic spikes to axonal action-potential firing probably depends on the pattern of synaptic activation. ![]() Although there is some evidence for dendritic excitability in vivo, much more work is needed in this area.Īctivation of a small fraction of the tens of thousands of excitatory synapses on a pyramidal neuron can probably evoke dendritic spikes, but these events do not always propagate to the soma and the axon. Dendritic excitability is a general property of all pyramidal neurons studied so far, but the details differ between different types of pyramidal neurons. These channels can also support backpropagating action potentials and dendritically initiated spikes. Pyramidal-neuron dendrites contain voltage-gated channels that can influence synaptic integration. Along with variation in dendritic structure and channel distributions, such variability suggests that different pyramidal neurons might carry out specialized functions. The intrinsic firing properties of pyramidal neurons vary considerably. Integration of inhibitory inputs also differs across cellular domains. Inhibitory synapses specifically target the axon, soma or different dendritic domains. Synapses on small-diameter dendrites cause larger local voltage changes, which reduce the effectiveness of synaptic scaling but increase the activation of voltage-gated conductances. Synapses distant from the soma tend to produce less synaptic depolarization, but this might be countered by increasing the conductance of distal synapses or by activating voltage-gated channels in dendrites. Most excitatory synapses onto pyramidal neurons occur on dendritic spines, but the structure of the synapses they receive differs between dendritic domains.ĭendritic integration of synaptic input depends on the dendritic domain that is targeted. Defining the degree to which synapses that carry different kinds of information are segregated onto different dendritic domains remains an important challenge. Synaptic inputs from distinct sources occur onto separate dendritic domains. These include in vivo patch-clamp recording, optical activation and transgenic methods for activating, inactivating or labelling neurons and their connections. This preserved core structure suggests that they have conserved core functions, whereas structural variation in other areas suggests additional functional specialization.Ī number of new methods for studying pyramidal-cell activation and circuitry are available. Pyramidal neurons have basal and apical dendrites, including an apical tuft. ![]()
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