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

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Accession:105507
"... 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."
Reference:
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):
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Epilepsy;
Implementer(s): Lytton, William [billl at neurosim.downstate.edu];
: $Id: misc.mod,v 1.15 2006/03/06 18:51:58 billl Exp $
COMMENT
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.

    file_exist(filename)
        - 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.

ENDCOMMENT
                           
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
    SUFFIX nothing
}

VERBATIM
#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>
ENDVERBATIM

:* FUNCTION file_exist()
FUNCTION file_exist() {
VERBATIM
    /* 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;
    }
ENDVERBATIM
}

:* PROCEDURE sassign()
PROCEDURE sassign() {
VERBATIM
    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");
        return; 
    }
    
    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);

    pclose(pipein);
    errno = 0;
ENDVERBATIM
}

:* PROCEDURE dassign() 
PROCEDURE dassign() {
VERBATIM
    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");
        return; 
    }

    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,"%s=%g\n",strname,num);
    fprintf(outfile,"system(\"rm dassign\")\n");

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

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

:* FUNCTION prtime()
FUNCTION prtime () {
VERBATIM
  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; 
  PRTIME=clock();
  _lprtime = prt;
ENDVERBATIM
}

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

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

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

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

:* PROCEDURE spitchar
VERBATIM
static char *pmlc;
ENDVERBATIM

PROCEDURE mymalloc(sz) {
VERBATIM
{ 
  size_t x,y;
  x=(size_t)_lsz;
  pmlc=(char *)malloc(x);
  printf("Did %ld: %x\n",x,pmlc);
  y=(unsigned int)_lsz-1;
  pmlc[y]=(char)97;
  printf("WRITE/READ 'a': "); 
  printf("%c\n",pmlc[y]);
  if (ifarg(2)) free(pmlc); else printf("Use unmalloc() to free memory\n");
}
ENDVERBATIM
}

PROCEDURE unmalloc() {
VERBATIM
  free(pmlc);
ENDVERBATIM
}

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

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