Figure 1.

Predicted energy use for cerebellar cortex with all cell types firing at their physiological rate. (A) Schematic diagram showing the cell types considered. Note that parallel fibres in reality make en passant (non-terminal) synapses. (B) Cellular distribution of predicted energy use (ATP used per cell). Key: P, Purkinje cell; Go, Golgi cell; s, stellate cell; b, basket cell; g, granule cell; mf mossy fibre; cf, climbing fibre; a, astrocyte; Bg, Bergmann glia. (C) Cellular distribution of energy use, taking density of cells into account (ATP use per class of cell). (D) Energy distribution among subcellular processes (summed over all cell types, weighted by cell densities). Resting potentials account for approximately 42% of the energy use, action potentials 36%, postsynaptic receptors 17%, neurotransmitter recycling (ATP used in glia and on packaging transmitter into vesicles in the releasing cell) 2%, and presynaptic Ca²⁺ entry and vesicle cycling 3%. (E) As D, but including non-signalling energy use, assumed to be 4 μmol ATP per g per min (see text). Housekeeping tasks account for 19% of the energy use, resting potentials 34%, action potentials 29%, postsynaptic receptors 14%, neurotransmitter recycling (ATP used in glia and on packaging transmitter into vesicles in the releasing cell) 2%, and presynaptic Ca²⁺ entry and vesicle cycling 2%.