TY - JOUR
T1 - Functional role of spines in the retinal horizontal cell network
AU - Winslow, R. L.
AU - Miller, R. F.
AU - Ogden, T. E.
PY - 1989
Y1 - 1989
N2 - Compartmental models derived from serial electron-microscopic reconstructions of horizontal cell processes entering cone pedicles and rod spherules are used to show that these processes have the morphological and electrical characteristics of dendritic spines. Properties of these spines are incorporated into a distributed model of the horizontal cell network. Expressions relating the magnitude of conductance changes applied at the spine heads to hyperpolarization of cells within the network are derived. Model analyses show that spine properties play a critical role in determining network responses. Specifically, increasing spine stem resistance increases the network input resistance and space constant, hyperpolarizes the resting potential, decreases response to full-field light stimuli, and increases response to small light spots. Increasing spine-stem resistance also decouples potential at the spine head from potential at the cell body. This result suggests that the location of feedback neurotransmitter release sites (e.g., at the spine heads versus the cell body) may have a profound influence on properties of horizontal cell inhibition of cone response. Because of these important functional consequences, structurally realistic models of the horizontal cell network must incorporate spine properties.
AB - Compartmental models derived from serial electron-microscopic reconstructions of horizontal cell processes entering cone pedicles and rod spherules are used to show that these processes have the morphological and electrical characteristics of dendritic spines. Properties of these spines are incorporated into a distributed model of the horizontal cell network. Expressions relating the magnitude of conductance changes applied at the spine heads to hyperpolarization of cells within the network are derived. Model analyses show that spine properties play a critical role in determining network responses. Specifically, increasing spine stem resistance increases the network input resistance and space constant, hyperpolarizes the resting potential, decreases response to full-field light stimuli, and increases response to small light spots. Increasing spine-stem resistance also decouples potential at the spine head from potential at the cell body. This result suggests that the location of feedback neurotransmitter release sites (e.g., at the spine heads versus the cell body) may have a profound influence on properties of horizontal cell inhibition of cone response. Because of these important functional consequences, structurally realistic models of the horizontal cell network must incorporate spine properties.
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U2 - 10.1073/pnas.86.1.387
DO - 10.1073/pnas.86.1.387
M3 - Article
C2 - 2463626
AN - SCOPUS:0024532337
SN - 0027-8424
VL - 86
SP - 387
EP - 391
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 1
ER -