Pyramidal Cell

The spontaneous electrical activity of the brain can be measured by electroencephalography (EEG), a technique that has been widely employed to study neurotoxic effects of chemicals both in humans and in experimental animals. EEG waves represent summated synaptic potentials generated by the pyramidal cells of the cerebral cortex (Misra 1992). These potentials are the responses of cortical cells to rhythmical changes arising from thalamic nuclei. The signals recorded can be separated into frequency bands—faster waves exceeding 13 Hz, and slower ones below 4 Hz. 

The neurons from which NTs are released number more than 7 billion in the human brain. Each (Fig. 1.2) consists of a cell body, the soma or perikaryon, with one major cytoplasmic process termed the axon, which projects variable distances to other neurons, e.g. from a cortical pyramidal cell to adjacent cortical neurons, or to striatal neurons or to spinal cord motoneurons. Thus by giving off a number of branches from its axon one neuron can influence a number of others. All neurons, except primary sensory neurons with cell bodies in the spinal dorsal root ganglia, have a number of other, generally shorter, projections running much shorter distances among neighbouring neurons like the branches of a tree. These processes are the dendrites. Their... 

Cortical p5ramidal cells Cortical pyramidal cells... 

Hippocampal pyramidal cells Hippocampal p5ramidal cells... 

Cole, AE and Nicoll, RA (1984) Characterization of a slow cholinergic post synaptic potential recorded in vitro from rat hippocampal pyramidal cells. J. Physiol. 352 173-188. 

Nearly all mechanistic studies of LTP have been carried out in the CAl region of hippocampal slices, where Schaffer collateral/commissural fibres make monosynaptic contacts with the dendrites of CAl pyramidal cells. It is generally accepted that the... 

It is equally well known that if a neuron dies, or is destroyed, then any other neuron, which had been innervated by it, gradually becomes supersensitive to the NT it released. In the case of degenerating pyramidal cells this would be glutamate, the excitatory NT. Not surprisingly, undercutting the cortex in animals to produce a deafferentation of some of its neurons not only renders them more likely to show epileptic-like discharges but neurons in hippocampal slices from kindled rats and human focal cortex show supersensitivity to the excitatory amino acids. Such supersensitivity could make some neurons so easily activated that they become epileptic . 

These are intraneuronal cytoplasmic lesions found predominantly in large pyramidal cells, again, mostly within the hippocampus and frontal temperal cortex, and while they... 

It appears that the voltage waves recorded in the EEG represent the summation of synaptic potentials in the apical dendrites of pyramidal cells in the cortex. These cells generate sufficient extracellular current for it to reach, and be recorded from, the cranium and scalp. Although these waves originate from the cortex rather than the SCN, the distinctive REM and non-REM phases of sleep still remain after destruction of the SCN but they then occur randomly over the 24-h cycle. This is a further indication that the SCN is at least partly responsible for setting the overall circadian rhythm of the sleep cycle. 

Somatosensory cortical, pyramidal cells die at a very high rate with chronic administration. It seems to me that the involvement of dopamine in that is... 

COMMENT We feel that it is due to the formation of 5,6-DHT in the eortex. These cells are indeed innervated by serotonin cells and, as a matter of fact, we have an experiment that is being published in Brain Research where we show that if we injeet 5,6-DHT into the ventricles, we ean produce exactly the same type of degeneration in the pyramidal cells, due to the formation of the 5,6 from the 5-hydroxytryptamine. We are exploring the possibility of it being another catecholamine in addition to dopamine, so I think both of those may be helpful in answering your question. 

Ameri A. Effects of the Aconitum alkaloid songorine on synaptic transmission and paired-pulse facilitation of CA1 pyramidal cells in rat hippocampal slices. Br J Pharmacol 1998 125 461—468. 

The corticospinal tracts originate in the cerebral cortex. Neurons of the primary motor cortex are referred to as pyramidal cells. Most of these neurons axons descend directly to the alpha motor neurons in the spinal cord. In... 

Haas, H. L. Greene, R. W. (1984). Adenosine enhances afterhyperpolarization and accommodation in hippocampal pyramidal cells. Iflugers Arch. 402, 244-7. 

Sprouse, J. S. Aghajanian, G. K. (1988). Responses of hippocampal pyramidal cells to putative serotonin 5-HTia and 5-HTib agonists a comparative study with dorsal raphe neurons. Neuropsychopharmacology 27, 707 15. 

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