Hippocampus temporo-septal engram shift model (Lytton 1999)

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Accession:7400
Temporo-septal engram shift model of hippocampal memory. The model posits that memories gradually move along the hippocampus from a temporal encoding site to ever more septal sites from which they are recalled. We propose that the sense of time is encoded by the location of the engram along the temporo-septal axis.
Reference:
1 . Lytton WW, Lipton P (1999) Can the hippocampus tell time? The temporo-septal engram shift model. Neuroreport 10:2301-6 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s):
Channel(s): I Na,t; I K;
Gap Junctions:
Receptor(s): GabaA; AMPA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Pattern Recognition; Temporal Pattern Generation; Spatio-temporal Activity Patterns; Simplified Models;
Implementer(s): Lytton, William [billl at neurosim.downstate.edu];
Search NeuronDB for information about:  GabaA; AMPA; I Na,t; I K;
/
lytton99
README
AMPA.mod
GABAA.mod
kdr.mod
matrix.mod *
naf.mod *
passiv.mod *
pulse.mod *
sinstim.mod *
vecst.mod
vecst.mod.orig
bg.inc *
bg_cvode.inc
boxes.hoc *
declist.hoc *
decvec.hoc *
default.hoc *
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fig1.gif
grvec.hoc
init.hoc
ivl.vecs
labels.hoc
loadr.hoc *
local.hoc
mosinit.hoc
net.hoc
netcon.inc
nrnoc.hoc
ovl.vecs
params.hoc *
params.hoc.SAV *
proc.hoc
run.hoc
simctrl.hoc *
spkts.hoc
syncode.hoc
tmpl.hoc
                            
: $Id: matrix.mod,v 1.25 2000/12/15 20:09:51 billl Exp $

:* COMMENT
COMMENT
NB: only minimal error checking done
NB: no dynamic allocation - eg m1.transpose(m1) will give a wrong result 
NB: matrix and vec sizes must be correct before using: use .resize()

================            USAGE               ================
objref mat
mat = new Vector(rows*cols)
mat.mprintf(M,N)     // print out as M rows and N columns
mat2.transpose(mat)  // transpose of matrix
y.mmult(mat,x)       // y = mat*x
y.spmult(pre,post,mat,x) // y = mat*x using "sparse matrix"
w.spget(pre,post,row,col) // ie pre,post,post,pre!!
wt.mkspcp/chkspcp(pre,post) // copy the indices into integer arrays
mat.outprod(x,y)     // mat = outer product of vectors x and y
mat.mget(i,j,cols)   // i=row#; j=col#
mat.mset(i,j,cols,val)
y.mrow(mat,i,cols)
y.mcol(mat,j,cols)
================================================================
ENDCOMMENT

NEURON {
  SUFFIX nothing
}
 
:* mat.outprod(x,y) // mat = outer product of vectors x and y
VERBATIM
static double outprod(void* vv) {
  int i, j, nx, ny, nz;
  double *x, *y, *z;
  /* this will be the outer product */
  nx = vector_instance_px(vv, &x);
	
  /* these are the two vectors that make it up */
  ny = vector_arg_px(1, &y); // will be number of columns
  nz = vector_arg_px(2, &z); // will be number of rows
  if (nx != ny*nz) {
    hoc_execerror("Vector size mismatch", 0);
  }
  for (i=0;i<ny;i++) {
    for (j=0;j<nz;j++) {
      x[i*nz+j] = y[i]*z[j];
    }
  }
  return nx;
}
ENDVERBATIM
 
:* mmult
VERBATIM
static double mmult(void* vv) {
  int i, j, nx, ny, nz;
  double *x, *y, *z;
  /* x will be the product of matrix y and vec z */
  nx = vector_instance_px(vv, &x);
  ny = vector_arg_px(1, &y);
  nz = vector_arg_px(2, &z);
  if (ny != nx*nz) {
    hoc_execerror("Vector size mismatch", 0);
  }
  for (i=0;i<nx;i++) {
    x[i] = 0.;
    for (j=0;j<nz;j++) {
      x[i] += y[i*nz+j]*z[j];
    }
  }
  return nx;
}
ENDVERBATIM
 
:* ST[PO].spltp(pr,po,wt,ST[PRE])
VERBATIM
static double spltp(void* vv) {
  int ii, jj, nstpr, nstpo, nw, npr, npo, flag, cnt;
  double *stpr, *stpo, *w, *pr, *po;
  extern double hoc_call_func(Symbol*, int narg);

  char func[4] = "ltp";
  Symbol* s = hoc_lookup(func);
  if (! s) { hoc_execerror("Can't find ltp() func", 0); }
  nstpo = vector_instance_px(vv, &stpo);
  npr = vector_arg_px(1, &pr);
  npo = vector_arg_px(2, &po);
  nw = vector_arg_px(3, &w);
  nstpr = vector_arg_px(4, &stpr);
  for (ii=0,jj=0,cnt=0;ii<nstpo;ii++) {
    if (stpo[ii]==1.0) { /* connections to these will be changed */ 
      for (;po[jj]<ii;jj++) ; /* move forward till find a po */
      for (;po[jj]==ii;jj++) { /* move through these po's */
	if (stpr[(int)pr[jj]]==1.) { /*  did the presyn spike? */
	  cnt++; hoc_pushx(1.0);
	} else { 
	  cnt--; hoc_pushx(-1.0);
	}
        hoc_pushx(w[jj]);
        w[jj]=hoc_call_func(s, 2);
      }
    }
  }
  return cnt;
}
ENDVERBATIM
 
VERBATIM
/* Maintain a parallel vector of ints to avoid the slowness of repeated casts in spmult */
static int *pr_int;
static int *po_int;
static int cpfl=0;
ENDVERBATIM

:* wt.mkspcp(pr,po)
VERBATIM
static double mkspcp(void* vv) {
  int j, nw, npr, npo;
  double *w, *pr, *po;
  if (! ifarg(1)) { 
    cpfl=0; 
    if (po_int!=NULL) free(po_int); 
    if (pr_int!=NULL) free(pr_int);
    po_int=(int *)NULL; pr_int=(int *)NULL; 
    return 0;
  }
  nw = vector_instance_px(vv, &w);
  npr = vector_arg_px(1, &pr);
  npo = vector_arg_px(2, &po);
  pr_int=(int *)ecalloc(nw, sizeof(int));
  po_int=(int *)ecalloc(nw, sizeof(int));
  for (j=0;j<nw;j++) {
    po_int[j]=(int)po[j];
    pr_int[j]=(int)pr[j];
  }
  cpfl=nw;
  return cpfl;
}
ENDVERBATIM

:* wt.chkspcp(pr,po)
VERBATIM
static double chkspcp(void* vv) {
  int j, nw, npr, npo, flag;
  double *w, *pr, *po;
  nw = vector_instance_px(vv, &w);
  npr = vector_arg_px(1, &pr);
  npo = vector_arg_px(2, &po);
  flag=1;
  if (po_int==NULL || pr_int==NULL) { cpfl=0; return 0; }
  if (cpfl!=nw) { flag=0;
  } else for (j=0;j<nw;j++) {
    if (po_int[j]!=(int)po[j] || pr_int[j]!=(int)pr[j]) {flag=0; continue;}
  }
  if (flag==0) {
    cpfl=0; free(po_int); free(pr_int); 
    po_int=(int *)NULL; pr_int=(int *)NULL; 
  }
  return flag;
}
ENDVERBATIM

:* y.spmult(pr,po,wt,x[,flag])
: y=W*x, y will be the product of matrix w with pre/post indices and vec x
: optional flag (5th arg present) - do not clear dest vector initially
VERBATIM
static double spmult(void* vv) {
  int i, j, nx, ny, nw, npr, npo, flag;
  double *x, *y, *w, *pr, *po, xx;
  ny = vector_instance_px(vv, &y);
  npr = vector_arg_px(1, &pr);
  npo = vector_arg_px(2, &po);
  nw = vector_arg_px(3, &w);
  nx = vector_arg_px(4, &x);
  if (ifarg(5)) {flag=1;} else {flag=0;}
  if (nw!=npr || nw!=npo) {
    hoc_execerror("Sparse mat must have 3 identical size vecs for pre/post/wt", 0); 
  }
  if (flag==0) for (i=0;i<ny;i++) y[i] = 0.; // clear dest vec
  if (cpfl==0) {
    for (j=0;j<nw;j++) y[(int)po[j]] += (x[(int)pr[j]]*w[j]);
  } else if (cpfl!=nw) { hoc_execerror("cpfl!=nw in spmult", 0); } else {
    for (j=0;j<nw;j++) if (x[pr_int[j]]!=0) { y[po_int[j]] += ((x[pr_int[j]])*w[j]); }
  }
  return nx;
}
ENDVERBATIM
 

:* wt.spget(pr,po,row,col) returns weight value
VERBATIM
static double spget(void* vv) {
  int j, nw, npr, npo;
  double *w, *pr, *po, row, col;
  nw = vector_instance_px(vv, &w);
  npr = vector_arg_px(1, &pr);
  npo = vector_arg_px(2, &po);
  row = *getarg(3);
  col = *getarg(4);
  for (j=0;j<nw;j++) if (row==po[j]&&col==pr[j]) break;
  if (j==nw) return 0.; else return w[j];
}
ENDVERBATIM

:* transpose
VERBATIM
static double transpose(void* vv) {
  int i, j, nx, ny, rows, cols;
  double *x, *y;
  /* x will be the transpose of matrix y */
  nx = vector_instance_px(vv, &x);
  ny = vector_arg_px(1, &y);
  rows = (int)*getarg(2);
  cols = (int)*getarg(3);
  if (ny != nx) {
    hoc_execerror("Vector size mismatch", 0);
  }
  for (i=0;i<rows;i++) {
    for (j=0;j<cols;j++) {
      x[j*rows+i] = y[i*cols+j];
    }
  }
  return nx;
}
ENDVERBATIM
 
:* mprintf
VERBATIM
static double mprintf(void* vv) {
  int i, j, nx, rows, cols;
  double *x;
  /* x will be printed out */
  nx = vector_instance_px(vv, &x);
  rows = (int)*getarg(1);
  cols = (int)*getarg(2);
  if (nx != rows*cols) {
    hoc_execerror("Vector size mismatch", 0);
  }
  for (i=0;i<rows;i++) {
    for (j=0;j<cols;j++) {
      printf("%g\t",x[i*cols+j]);
    }
    printf("\n");
  }
  return nx;
}
ENDVERBATIM
 
:* mget(i,j,cols)
VERBATIM
static double mget(void* vv) {
  int i, j, nx, rows, cols;
  double *x;
  nx = vector_instance_px(vv, &x);
  i = (int)*getarg(1);
  j = (int)*getarg(2);
  cols = (int)*getarg(3);
  if (i*cols+j >= nx) {
    hoc_execerror("Indices out of bounds", 0);
  }
  return x[i*cols+j];
}
ENDVERBATIM
 
:* mrow(mat,i,cols)
VERBATIM
static double mrow(void* vv) {
  int i, j, nx, ny, rows, cols;
  double *x, *y;
  nx = vector_instance_px(vv, &x);
  ny = vector_arg_px(1, &y);
  i = (int)*getarg(2);
  cols = (int)*getarg(3);
  if (cols!=nx || i>=ny/cols) {
    hoc_execerror("Indices out of bounds", 0);
  }
  for (j=0;j<nx;j++) { x[j] = y[i*cols+j]; }
  return nx;
}
ENDVERBATIM
 
:* mcol(mat,j,cols)
VERBATIM
static double mcol(void* vv) {
  int i, j, nx, ny, rows, cols;
  double *x, *y;
  nx = vector_instance_px(vv, &x);
  ny = vector_arg_px(1, &y);
  j = (int)*getarg(2);
  cols = (int)*getarg(3);
  if (cols!=ny/nx || j>=cols) {
    hoc_execerror("Indices out of bounds", 0);
  }
  for (i=0;i<nx;i++) { x[i] = y[i*cols+j]; }
  return nx;
}
ENDVERBATIM
 
:* mset(i,j,cols,val)
VERBATIM
static double mset(void* vv) {
  int i, j, nx, rows, cols;
  double *x, val;
  nx = vector_instance_px(vv, &x);
  i = (int)*getarg(1);
  j = (int)*getarg(2);
  cols = (int)*getarg(3);
  val = *getarg(4);
  if (i*cols+j >= nx) {
    hoc_execerror("Indices out of bounds", 0);
  }
  return (x[i*cols+j]=val);
}
ENDVERBATIM
 
:* PROCEDURE install_matrix()
PROCEDURE install_matrix() {
VERBATIM
  /* the list of additional methods */
  install_vector_method("outprod", outprod);
  install_vector_method("mmult", mmult);
  install_vector_method("spmult", spmult);
  install_vector_method("spget", spget);
  install_vector_method("mkspcp", mkspcp);
  install_vector_method("chkspcp", chkspcp);
  install_vector_method("spltp", spltp);
  install_vector_method("transpose", transpose);
  install_vector_method("mprintf", mprintf);
  install_vector_method("mget", mget);
  install_vector_method("mset", mset);
  install_vector_method("mrow", mrow);
  install_vector_method("mcol", mcol);
ENDVERBATIM
}

Lytton WW, Lipton P (1999) Can the hippocampus tell time? The temporo-septal engram shift model. Neuroreport 10:2301-6[PubMed]

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