Paired turbulence and light effect on calcium increase in Hermissenda (Blackwell 2004)

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The sea slug Hermissenda learns to associate light and hair cell stimulation, but not when the stimuli are temporally uncorrelated...These issues were addressed using a multi-compartmental computer model of phototransduction, calcium dynamics, and ionic currents of the Hermissenda photoreceptor...simulations show that a potassium leak channel, which closes with an increase in calcium, is required to produce both the untrained LLD and the enhanced LLD due to the decrease in voltage dependent potassium currents.
1 . Blackwell KT (2004) Paired turbulence and light do not produce a supralinear calcium increase in Hermissenda. J Comput Neurosci 17:81-99 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Electrogenic pump;
Brain Region(s)/Organism:
Cell Type(s): Hermissenda photoreceptor Type B;
Channel(s): I A; I K,leak; I h; I K,Ca; I Sodium; I Calcium; I Potassium;
Gap Junctions:
Receptor(s): GabaA; GabaB; IP3;
Transmitter(s): Gaba;
Simulation Environment: Chemesis;
Model Concept(s): Temporal Pattern Generation; Invertebrate; Signaling pathways; Calcium dynamics;
Implementer(s): Blackwell, Avrama [avrama at];
Search NeuronDB for information about:  GabaA; GabaB; IP3; I A; I K,leak; I h; I K,Ca; I Sodium; I Calcium; I Potassium; Gaba;

function Vcomp(path, length, radius, RM, CM, RI, Er, Vinit)
str path
float length,radius
float RM,CM, RI, Er, Vinit
float area, xarea, diam

float PI = 3.14159

create  compartment {path}
diam = 2*radius
area = PI*diam*length
xarea = PI*radius*radius
setfield {path} \
		len {length} \
		dia {diam} \
		Em {Er}	\
		initVm {Vinit} \
		Rm {RM/area} \ /* Mohms is passive resistance */
		Cm {CM*area} \ /* nF */
		Ra {RI*length/xarea}

/* commented sections implemented prior to 08/14/02 */
function ellipse_vcomp(path, len, slice, diama, diamb, RM, CM, RI, Er, Vinit)
//function ellipse_vcomp(path, len, slice, rada, radb, RM, CM, RI, Er, Vinit)
str path
float len, diama, diamb
//float len, rada, radb
int slice
float RM,CM, RI, Er, Vinit

int i
float complen = len/slice
//float circum = 2*PI*{sqrt {(rada*rada + radb*radb)/2}}
//float xarea = PI*rada*radb
float circum = PI*{sqrt {(diama*diama + diamb*diamb)/2}}
float xarea = (PI*diama*diamb)/4
float vol = xarea*complen
float SA = circum*complen
for (i=1; i<=slice; i=i+1)
  create compartment {path}[{i}] 
  setfield {path}[{i}] 	\
		len {complen}	\
		dia {(diama+diamb)/2} 	\
		Em {Er}		\
		initVm {Vinit} \
		Rm {RM/SA} 	\
		Cm {CM*SA}	\
		Ra {RI*complen/xarea}
//dia {(rada+radb)/2}     \

for (i=1; i<slice; i=i+1)
  addmsg {path}[{i}] {path}[{i+1}] RAXIAL Ra previous_state
  addmsg {path}[{i+1}] {path}[{i}] AXIAL previous_state