Tonic-clonic transitions in a seizure simulation (Lytton and Omurtag 2007)

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"... The authors have ... computationally manageable networks of moderate size consisting of 1,000 to 3,000 neurons with multiple intrinsic and synaptic properties. Experiments on these simulations demonstrated the presence of epileptiform behavior in the form of repetitive high-intensity population events (clonic behavior) or latch-up with near maximal activity (tonic behavior). ... Several simulations revealed the importance of random coincident inputs to shift a network from a low-activation to a high-activation epileptiform state. Finally, a simulated anticonvulsant acting on excitability tended to preferentially decrease tonic activity."
1 . Lytton WW, Omurtag A (2007) Tonic-clonic transitions in computer simulation. J Clin Neurophysiol 24:175-81 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism:
Cell Type(s):
Gap Junctions:
Simulation Environment: NEURON;
Model Concept(s): Epilepsy;
Implementer(s): Lytton, William [billl at];
: $Id: misc.mod,v 1.15 2006/03/06 18:51:58 billl Exp $
Misc. routines:
sassign() // assign a string from system
dassign()// assign a double
nokill() // chatch SIGHUP
prtime() // gives date/time
fspitchar(c,file) // sends single char to a file
spitchar(c)       // sends single char to stdout: eg c=1 => ^A
file_exist(file) // returns 1 if filename exists
hocgetc(file) // get single char from a file

  Note that with a SUFFIX equal to "nothing" these functions do not
have a suffix in hoc.  Thus to call sassign() in hoc use simply type
"sassign()" <- without the quotes.

        - returns 1 if filename exists

    sassign()  (string assign, written by Bill Lytton)
        - This routine is used to set a string in Hoc to something that has
          been returned by a system call.  sassign("name","shell_call ...")
          will produce a file called "sassign" in the cwd that will contain
          a hoc call that sets string 'name' to the result of shell_call 
          which should be a string.
    dassign()  (double assign, written and used by Bill Lytton)
        - This routine is used to set a variable in Hoc to something that has
          been returned by a system call.  sassign("name","shell_call ...")
          will produce a file called "dassign" in the cwd that will contain
          a hoc call that sets variable 'name' to the result of shell_call 
          which should be a number.


    SUFFIX nothing

#include <unistd.h>     /* F_OK     */
#include <errno.h>      /* errno    */
#include <signal.h>
#include <sys/types.h>         /* MUST REMEMBER THIS */
#include <time.h>
#include <stdio.h>
#include <limits.h>

:* FUNCTION file_exist()
FUNCTION file_exist() {
    /* Returns TRUE if file exists, if file not exist the need to reset
       errno else will get a nrnoc error.  Seems to be a problem even
       if I don't include <errno.h> */

    char *gargstr(), *filename;

    filename = gargstr(1);

    if (*filename && !access(filename, F_OK)) {
        _lfile_exist = 1;

    } else {
        /* Errno set to 2 when file not found */
        errno = 0;

        _lfile_exist = 0;

:* PROCEDURE sassign()
PROCEDURE sassign() {
    FILE *pipein;
    char string[BUFSIZ], **strname, *syscall;
    char** hoc_pgargstr();

    strname = hoc_pgargstr(1);
    syscall = gargstr(2);

    if( !(pipein = popen(syscall, "r"))) {
        fprintf(stderr,"System call failed\n");
    if (fgets(string,BUFSIZ,pipein) == NULL) {
        fprintf(stderr,"System call did not return a string\n");
        pclose(pipein); return;

    /*  assign_hoc_str(strname, string, 0); */
    hoc_assign_str(strname, string);

    errno = 0;

:* PROCEDURE dassign() 
PROCEDURE dassign() {
    FILE *pipein, *outfile;
    char *strname, *syscall;
    double num;

    strname = gargstr(1);
    syscall = gargstr(2);

    if ( !(outfile = fopen("dassign","w"))) {
        fprintf(stderr,"Can't open output file dassign\n");

    if( !(pipein = popen(syscall, "r"))) {
        fprintf(stderr,"System call failed\n");
        fclose(outfile); return; 
    if (fscanf(pipein,"%lf",&num) != 1) {
        fprintf(stderr,"System call did not return a number\n");
        fclose(outfile); pclose(pipein); return; 

    fprintf(outfile,"system(\"rm dassign\")\n");

    fclose(outfile); pclose(pipein);
    errno = 0;

:* PROCEDURE nokill() 
: nohup
PROCEDURE nokill() {
  signal(SIGHUP, SIG_IGN);

:* FUNCTION prtime()
FUNCTION prtime () {
  double prt;
  static double PRTIME;
  prt = (clock()-PRTIME)/CLOCKS_PER_SEC;
  // UINT_MAX for 32 bit machine -- see 'man clock'
  if (prt<0) prt += UINT_MAX/CLOCKS_PER_SEC; 
  _lprtime = prt;

:* FUNCTION now ()
FUNCTION now () {
  _lnow = time((time_t*)0);
  _lnow -= (12784) * 24*60*60; // time from the Epoch to 01/01/05

:* PROCEDURE sleepfor ()
PROCEDURE sleepfor (sec) {
  struct timespec ts;
  ts.tv_sec = (time_t)_lsec;
  ts.tv_nsec = (long)0;
  nanosleep(&ts,(struct timespec*)0);

:* PROCEDURE fspitchar
PROCEDURE fspitchar(c) {
  FILE* f, *hoc_obj_file_arg();
  f = hoc_obj_file_arg(2);
  fprintf(f, "%c", (int)_lc);

:* PROCEDURE spitchar
PROCEDURE spitchar(c) {
  printf("%c", (int)_lc);

:* PROCEDURE spitchar
static char *pmlc;

PROCEDURE mymalloc(sz) {
  size_t x,y;
  pmlc=(char *)malloc(x);
  printf("Did %ld: %x\n",x,pmlc);
  y=(unsigned int)_lsz-1;
  printf("WRITE/READ 'a': "); 
  if (ifarg(2)) free(pmlc); else printf("Use unmalloc() to free memory\n");

PROCEDURE unmalloc() {

:* FUNCTION hocgetc
FUNCTION hocgetc() {
  FILE* f, *hoc_obj_file_arg();
  f = hoc_obj_file_arg(1);
  _lhocgetc = (double)getc(f);

Lytton WW, Omurtag A (2007) Tonic-clonic transitions in computer simulation. J Clin Neurophysiol 24:175-81[PubMed]

References and models cited by this paper

References and models that cite this paper

Bush PC, Prince DA, Miller KD (1999) Increased pyramidal excitability and NMDA conductance can explain posttraumatic epileptogenesis without disinhibition: a model. J Neurophysiol 82:1748-58 [Journal] [PubMed]

   Cortical network model of posttraumatic epileptogenesis (Bush et al 1999) [Model]

Dudek FE, Patrylo PR, Wuarin JP (1999) Mechanisms of neuronal synchronization during epileptiform activity. Adv Neurol 79:699-708 [PubMed]

Garcia Dominguez L, Wennberg RA, Gaetz W, Cheyne D, Snead OC, Perez Velazquez JL (2005) Enhanced synchrony in epileptiform activity? Local versus distant phase synchronization in generalized seizures. J Neurosci 25:8077-84 [PubMed]

Hereld M, Stevens RL, Teller J, Drongelen W (2005) Large neural simulations on large parallel computers Int J Bioelectromagn 7:44-46

Lytton WW (2002) From Computer To Brain

Lytton WW (2006) Neural Query System: Data-mining from within the NEURON simulator. Neuroinformatics 4:163-76 [Journal] [PubMed]

   Neural Query System NQS Data-Mining From Within the NEURON Simulator (Lytton 2006) [Model]

Lytton WW, Hellman KM, Sutula TP (1998) Computer models of hippocampal circuit changes of the kindling model of epilepsy. Artif Intell Med 13:81-97 [PubMed]

Lytton WW, Sejnowski TJ (1991) Simulations of cortical pyramidal neurons synchronized by inhibitory interneurons. J Neurophysiol 66:1059-79 [Journal] [PubMed]

Lytton WW, Stewart M (2005) A rule-based firing model for neural networks Int J Bioelectromagn 7:47-50

Lytton WW, Stewart M (2006) Rule-based firing for network simulations. Neurocomputing 69:1160-1164

Meeren HK, Pijn JP, Van Luijtelaar EL, Coenen AM, Lopes da Silva FH (2002) Cortical focus drives widespread corticothalamic networks during spontaneous absence seizures in rats. J Neurosci 22:1480-95 [PubMed]

Migliore M, Cannia C, Lytton WW, Markram H, Hines ML (2006) Parallel Network Simulations with NEURON. J Comp Neurosci 21:110-119 [Journal] [PubMed]

   Parallel network simulations with NEURON (Migliore et al 2006) [Model]

Omurtag A, Knight BW, Sirovich L (2000) On the simulation of large populations of neurons. J Comput Neurosci 8:51-63 [Journal] [PubMed]

Sirovich L, Omurtag A, Lubliner K (2006) Dynamics of neural populations: stability and synchrony. Network 17:3-29

Traub RD, Jefferys JG, Whittington MA (1994) Enhanced NMDA conductance can account for epileptiform activity induced by low Mg2+ in the rat hippocampal slice. J Physiol 478 Pt 3:379-93 [PubMed]

Van Drongelen W, Koch H, Marcuccilli C, Pena F, Ramirez JM (2003) Synchrony levels during evoked seizure-like bursts in mouse neocortical slices. J Neurophysiol 90:1571-80 [Journal]

van Drongelen W, Lee HC, Hereld M, Chen Z, Elsen FP, Stevens RL (2005) Emergent epileptiform activity in neural networks with weak excitatory synapses. IEEE Trans Neural Syst Rehabil Eng 13:236-41

Xie X, Lancaster B, Peakman T, Garthwaite J (1995) Interaction of the antiepileptic drug lamotrigine with recombinant rat brain type IIA Na+ channels and with native Na+ channels in rat hippocampal neurones. Pflugers Arch 430:437-46 [PubMed]

Chadderdon GL, Mohan A, Suter BA, Neymotin SA, Kerr CC, Francis JT, Shepherd GM, Lytton WW (2014) Motor cortex microcircuit simulation based on brain activity mapping. Neural Comput 26:1239-62 [Journal] [PubMed]

   Motor cortex microcircuit simulation based on brain activity mapping (Chadderdon et al. 2014) [Model]

Chadderdon GL, Neymotin SA, Kerr CC, Lytton WW (2012) Reinforcement learning of targeted movement in a spiking neuronal model of motor cortex PLoS ONE 2012 7(10):e47251 [Journal]

   Reinforcement learning of targeted movement (Chadderdon et al. 2012) [Model]

Dura-Bernal S, Zhou X, Neymotin SA, Przekwas A, Francis JT, Lytton WW (2015) Cortical Spiking Network Interfaced with Virtual Musculoskeletal Arm and Robotic Arm. Front Neurorobot 9:13 [Journal] [PubMed]

   Cortical model with reinforcement learning drives realistic virtual arm (Dura-Bernal et al 2015) [Model]

Kerr CC, Neymotin SA, Chadderdon GL, Fietkiewicz CT, Francis JT, Lytton WW (2012) Electrostimulation as a prosthesis for repair of information flow in a computer model of neocortex IEEE Transactions on Neural Systems & Rehabilitation Engineering 20(2):153-60 [Journal] [PubMed]

   Prosthetic electrostimulation for information flow repair in a neocortical simulation (Kerr 2012) [Model]

Kerr CC, Van Albada SJ, Neymotin SA, Chadderdon GL, Robinson PA, Lytton WW (2013) Cortical information flow in Parkinson's disease: a composite network-field model. Front Comput Neurosci 7:39:1-14 [Journal] [PubMed]

   Composite spiking network/neural field model of Parkinsons (Kerr et al 2013) [Model]

Lytton WW, Neymotin SA, Hines ML (2008) The virtual slice setup. J Neurosci Methods 171:309-15 [Journal] [PubMed]

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Lytton WW, Neymotin SA, Wester JC, Contreras D (2011) Neocortical simulation for epilepsy surgery guidance: Localization and intervention Computational Surgery and Dual Training

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Neymotin S, Uhlrich DJ, Manning KA, Lytton WW (2008) Data mining of time-domain features from neural extracellular field data Applic. of Comput. Intel. in Bioinf. and Biomed.: Current Trends and Open Problems 151:119-140 [Journal]

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Neymotin SA, Chadderdon GL, Kerr CC, Francis JT, Lytton WW (2013) Reinforcement learning of 2-joint virtual arm reaching in a computer model of sensorimotor cortex Neural Computation 25(12):3263-93 [Journal] [PubMed]

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Neymotin SA, Dura-Bernal S, Lakatos P, Sanger TD, Lytton WW (2016) Multitarget Multiscale Simulation for Pharmacological Treatment of Dystonia in Motor Cortex. Front Pharmacol 7:157 [Journal] [PubMed]

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Neymotin SA, Jacobs KM, Fenton AA, Lytton WW (2011) Synaptic information transfer in computer models of neocortical columns. J Comput Neurosci. 30(1):69-84 [Journal] [PubMed]

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Neymotin SA, Lee H, Park E, Fenton AA, Lytton WW (2011) Emergence of physiological oscillation frequencies in a computer model of neocortex. Front Comput Neurosci 5:19-75 [Journal] [PubMed]

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(30 refs)