Sci. STKE, 6 April 2004
NEUROBIOLOGY Dendritic Balancing Act
Neurons receive multiple excitatory (E) and inhibitory (I) inputs, which must be integrated to yield the proper level and pattern of neuronal activity (action potentials). A great proportion of the input synapses occur away from the soma (cell body) on dendrites. Liu analyzed the distribution and relative activities of E and I inputs on the dendritic trees of cultured hippocampal neurons. His results suggest that the functional E/I balance in the dendrites is regulated through a feedback mechanism to attain a constant compound synaptic potential (Vs) at the soma. In the cultured hippocampal neurons, larger dendrites (based on diameter) had more synaptic inputs and the functional E/I balance was also constant at a given time in culture. The majority of E inputs were canceled within the dendrite by I inputs before reaching the soma. Treatments that increased Vs changed the E/I balance such that I input was increased. Changes that decreased Vs also predominantly affected I inputs, but such that I inputs were decreased with only a small increase in E inputs. Thus, synaptic activity is dictated by the E/I balance, and this balance is adjusted through a feedback mechanism that alters the amount of I input to maintain a constant somatic activity.
G. Liu, Local structural balance and functional interaction of excitatory and inhibitory synapses in hippocampal dendrites. Nat. Neurosci. 7, 373-379 (2004). [Online Journal]
Citation: Dendritic Balancing Act. Sci. STKE 2004, tw125 (2004).
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