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Appears in Collections:Psychology Journal Articles
Peer Review Status: Refereed
Title: The effects of arousal on apical amplification and conscious state
Author(s): Phillips, William
Larkum, Matthew E
Harley, Carolyn W
Silverstein, Steven M
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Keywords: apical amplification
conscious state
context-sensitive modulation
hyperpolarization-activated currents
Issue Date: 11-Sep-2016
Citation: Phillips W, Larkum ME, Harley CW & Silverstein SM (2016) The effects of arousal on apical amplification and conscious state, Neuroscience of Consciousness.
Abstract: Neocortical pyramidal cells can integrate two classes of input separately and use one to modulate response to the other. Their tuft dendrites are electrotonically separated from basal dendrites and soma by the apical dendrite, and apical hyperpolarization-activated currents (Ih) further isolate subthreshold integration of tuft inputs. When apical depolarization exceeds a threshold, however, it can enhance response to the basal inputs that specify the cell’s selective sensitivity. This process is referred to as apical amplification (AA). We review evidence suggesting that, by regulating Ihin the apical compartments, adrenergic arousal controls the coupling between apical and somatic integration zones thus modifying cognitive capabilities closely associated with consciousness. Evidence relating AA to schizophrenia, sleep, and anesthesia is reviewed, and we assess theories that emphasize the relevance of AA to consciousness. Implications for theories of neocortical computation that emphasize context-sensitive modulation are summarized. We conclude that the findings concerning AA and its regulation by arousal offer a new perspective on states of consciousness, the function and evolution of neocortex, and psychopathology. Many issues worthy of closer examination arise.
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Rights: © The Author 2016. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact

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