model of DCN pyramidal neuron
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from __future__ import print_function
#!/usr/bin/python
#
# utilities for NEURON, in Python
# Module neuron for cnmodel
import numpy as np
import numpy.ma as ma # masked array
import re, sys, gc, collections
import neuron
_mechtype_cache = None
def all_mechanism_types():
"""Return a dictionary of all available mechanism types.
Each dictionary key is the name of a mechanism and each value is
another dictionary containing information about the mechanism::
mechanism_types = {
'mech_name1': {
'point_process': bool,
'artificial_cell': bool,
'netcon_target': bool,
'has_netevent': bool,
'internal_type': int,
'globals': {name:size, ...},
'parameters': {name:size, ...},
'assigned': {name:size, ...},
'state': {name:size, ...},
},
'mech_name2': {...},
'mech_name3': {...},
...
}
* point_process: False for distributed mechanisms, True for point
processes and artificial cells.
* artificial_cell: True for artificial cells, False otherwise
* netcon_target: True if the mechanism can receive NetCon events
* has_netevent: True if the mechanism can emit NetCon events
* internal_type: Integer specifying the NEURON internal type index of
the mechanism
* globals: dict of the name and vector size of the mechanism's global
variables
* parameters: dict of the name and vector size of the mechanism's
parameter variables
* assigned: dict of the name and vector size of the mechanism's
assigned variables
* state: dict of the name and vector size of the mechanism's state
variables
Note: The returned data structure is cached; do not modify it.
For more information on global, parameter, assigned, and state
variables see:
http://www.neuron.yale.edu/neuron/static/docs/help/neuron/nmodl/nmodl.html
"""
global _mechtype_cache
if _mechtype_cache is None:
_mechtype_cache = collections.OrderedDict()
mname = neuron.h.ref("")
# Iterate over two mechanism types (distributed, point/artificial)
for i in [0, 1]:
mt = neuron.h.MechanismType(i)
nmech = int(mt.count())
# Iterate over all mechanisms of this type
for j in range(nmech):
mt.select(j)
mt.selected(mname)
# General mechanism properties
name = mname[0] # convert hoc string ptr to python str
desc = {
"point_process": bool(i),
"netcon_target": bool(mt.is_netcon_target(j)),
"has_netevent": bool(mt.has_net_event(j)),
"artificial_cell": bool(mt.is_artificial(j)),
"internal_type": int(mt.internal_type()),
}
# Collect information about 4 different types of variables
for k, ptype in [
(-1, "globals"),
(1, "parameters"),
(2, "assigned"),
(3, "state"),
]:
desc[ptype] = {} # collections.OrderedDict()
ms = neuron.h.MechanismStandard(name, k)
for l in range(int(ms.count())):
psize = ms.name(mname, l)
pname = mname[0] # parameter name
desc[ptype][pname] = int(psize)
# Assemble everything in one place
_mechtype_cache[name] = desc
return _mechtype_cache
def reset(raiseError=True):
"""Introspect the NEURON kernel to verify that no objects are left over
from previous simulation runs.
"""
# Release objects held by an internal buffer
# See https://www.neuron.yale.edu/phpBB/viewtopic.php?f=2&t=3221
neuron.h.Vector().size()
# Make sure nothing is hanging around in an old exception or because of
# reference cycles
# sys.exc_clear()
gc.collect(2)
neuron.h.Vector().size()
numsec = 0
remaining = []
n = len(list(neuron.h.allsec()))
if n > 0:
remaining.append((n, "Section"))
n = len(neuron.h.List("NetCon"))
if n > 0:
remaining.append((n, "NetCon"))
# No point processes or artificial cells left
for name, typ in all_mechanism_types().items():
if typ["artificial_cell"] or typ["point_process"]:
n = len(neuron.h.List(name))
if n > 0:
remaining.append((n, name))
if (
len(remaining) > 0 and raiseError
): # note that not raising the error leads to memory leak
msg = "Cannot reset--old objects have not been cleared: %s" % ", ".join(
["%d %s" % rem for rem in remaining]
)
raise RuntimeError(msg)
def custom_init(v_init=-60.0):
"""
Perform a custom initialization of the current model/section.
This initialization follows the scheme outlined in the
NEURON book, 8.4.2, p 197 for initializing to steady state.
N.B.: For a complex model with dendrites/axons and different channels,
this initialization will not find the steady-state the whole cell,
leading to initial transient currents. In that case, this initialization
should be followed with a 0.1-5 second run (depends on the rates in the
various channel mechanisms) with no current injection or active point
processes to allow the system to settle to a steady- state. Use either
h.svstate or h.batch_save to save states and restore them. Batch is
preferred
Parameters
----------
v_init : float (default: -60 mV)
Voltage to start the initialization process. This should
be close to the expected resting state.
"""
inittime = -1e10
tdt = neuron.h.dt # save current step size
dtstep = 1e9
neuron.h.finitialize(v_init)
neuron.h.t = inittime # set time to large negative value (avoid activating
# point processes, we hope)
tmp = neuron.h.cvode.active() # check state of variable step integrator
if tmp != 0: # turn off CVode variable step integrator if it was active
neuron.h.cvode.active(0) # now just use backward Euler with large step
neuron.h.dt = dtstep
n = 0
while neuron.h.t < -1e9: # Step forward
neuron.h.fadvance()
n += 1
# print('advances: ', n)
if tmp != 0:
neuron.h.cvode.active(1) # restore integrator
neuron.h.t = 0
if neuron.h.cvode.active():
neuron.h.cvode.re_init() # update d(state)/dt and currents
else:
neuron.h.fcurrent() # recalculate currents
neuron.h.frecord_init() # save new state variables
neuron.h.dt = tdt # restore original time step
# routine to convert conductances from nS as given elsewhere
# to mho/cm2 as required by NEURON 1/28/99 P. Manis
# units: nano siemens, soma area in um^2
#
def nstomho(ns, somaarea, refarea=None):
if refarea == None:
return 1e-9 * float(ns) / float(somaarea)
else:
return 1e9 * float(ns) / float(refarea)
def mho2ns(mho, somaarea):
return float(mho) * somaarea / 1e-9
def spherearea(dia):
"""
given diameter in microns, return sphere area in cm2
"""
r = dia * 1e-4 # convert to cm
return 4 * np.pi * r ** 2
def get_sections(h):
"""
go through all the sections and find the names of the sections and all of their
parts (ids). Returns a dict, of sec: [id0, id1...]
"""
secnames = {}
resec = re.compile("(\w+)\[(\d*)\]")
for sec in h.allsec():
g = resec.match(sec.name())
if g.group(1) not in secnames.keys():
secnames[g.group(1)] = [int(g.group(2))]
else:
secnames[g.group(1)].append(int(g.group(2)))
return secnames
def all_objects():
""" Return a dict of all objects known to NEURON.
Keys are 'Section', 'Segment', 'Mechanism', 'Vector', 'PointProcess',
'NetCon', ...
"""
objs = {}
objs["Section"] = list(h.all_sec())
objs["Segment"] = []
for sec in objs["Section"]:
objs["Segment"].extend(list(sec.allseg()))
objs["PointProcess"] = []
for seg in objs["Segment"]:
objs["PointProcess"].extend(list(seg.point_processes()))
return objs
def alpha(alpha=0.1, delay=1, amp=1.0, tdur=50.0, dt=0.010):
tvec = np.arange(0, tdur, dt)
aw = np.zeros(tvec.shape)
i = 0
for t in tvec:
if t > delay:
aw[i] = (
amp * (t - delay) * (1.0 / alpha) * np.exp(-(t - delay) / alpha)
) # alpha waveform time course
else:
aw[i] = 0.0
i += 1
return (aw, tvec)
def syns(
alpha=0.1,
rate=10,
delay=0,
dur=50,
amp=1.0,
dt=0.020,
N=1,
mindur=120,
makewave=True,
):
""" Calculate a poisson train of alpha waves
with mean rate rate, with a delay and duration (in mseco) dt in msec.
N specifies the number of such independent waveforms to sum """
deadtime = 0.7
if dur + delay < mindur:
tvec = np.arange(0.0, mindur, dt)
else:
tvec = np.arange(0.0, dur + delay, dt)
npts = len(tvec)
ta = np.arange(0.0, 20.0, dt)
aw = ta * alpha * np.exp(-ta / alpha) / alpha # alpha waveform time course
spt = [[]] * N # list of spike times
wave = np.array([]) # waveform
sptime = []
for j in range(0, N):
done = False
t = 0.0
nsp = 0
while not done:
a = np.random.sample(1)
if t < delay:
t = delay
continue
if t >= delay and t <= (delay + dur):
ti = -np.log(a) / (
rate / 1000.0
) # convert to exponential distribution with rate
if ti < deadtime:
continue
t = t + ti # running time
if t > delay + dur:
done = True
continue
if nsp is 0:
sptime = t
nsp = nsp + 1
else:
sptime = np.append(sptime, t)
nsp = nsp + 1
if j is 0:
wavej = np.zeros(len(tvec))
for i in range(0, len(sptime)):
st = int(sptime[i] / dt)
wavej[st] = wavej[st] + 1
spt[j] = sptime
if makewave:
w = np.convolve(wavej, aw / max(aw)) * amp
if len(w) < npts:
w = np.append(w, np.zeros(npts - len(w)))
if len(w) > npts:
w = w[0:npts]
if j is 0:
wave = w
else:
wave = wave + w
return (spt, wave, tvec, N)
def an_syn(
alpha=0.1,
spont=10,
driven=100,
delay=50,
dur=100,
post=20,
amp=0.1,
dt=0.020,
N=1,
makewave=True,
):
# constants for AN:
deadtime = 0.7 # min time between spikes, msec
trise = 0.2 # rise rate, ms
tfall = 0.5 # fall rate, ms
rss = driven / 1000.0 # spikes/millisecond
rr = 3 * rss # transient driven rate
rst = rss
taur = 3 # rapid decay, msec
taust = 10
ton = delay # msec
stim_end = ton + dur
trace_end = stim_end + post
tvec = np.arange(0.0, trace_end, dt) # dt is in msec, so tvec is in milliseconds
ta = np.arange(0.0, 20.0, dt)
aw = ta * alpha * np.exp(-ta / alpha) / alpha # alpha waveform time course
spt = [[]] * N # list of spike times
wave = [[]] * N # waveform
for j in range(0, N): # for each
done = False
sptime = []
qe = 0
nsp = 0
i = int(0)
if spont <= 0:
q = 1e6
else:
q = 1000.0 / spont # q is in msec (spont in spikes/second)
t = 0.0
while not done:
a = np.random.sample(1)
if t < ton:
if spont <= 0:
t = ton
continue
ti = -(np.log(a) / (spont / 1000.0)) # convert to msec
if ti < deadtime: # delete intervals less than deadtime
continue
t = t + ti
if t > ton: # if the interval would step us to the stimulus onset
t = ton # then set to to the stimulus onset
continue
if t >= ton and t < stim_end:
if t > ton:
rise = 1.0 - np.exp(-(t - ton) / trise)
else:
rise = 1.0
ra = rr * np.exp(-(t - ton) / taur)
rs = rst * np.exp(-(t - ton) / taust)
q = rise * (ra + rs + rss)
ti = -np.log(a) / (q + spont / 1000) # random.negexp(1000/q)
if ti < deadtime:
continue
t = t + ti
if t > stim_end: # only include interval if it falls inside window
t = stim_end
continue
if t >= stim_end and t <= trace_end:
if spont <= 0.0:
t = trace_end
continue
if qe is 0: # have not calculated the new qe at end of stimulus
rise = 1.0 - np.exp(-(stim_end - ton) / trise)
ra = rr * np.exp(-(stim_end - ton) / taur)
rs = rst * np.exp(-(stim_end - ton) / taust)
qe = rise * (ra + rs + rss) # calculate the rate at the end
fall = np.exp(-(t - stim_end) / tfall)
q = qe * fall
ti = -np.log(a) / (
q + spont / 1000.0
) # keeps rate from falling below spont rate
if ti < deadtime:
continue
t = t + ti
if t >= trace_end:
done = True
continue
# now add the spike time to the list
if nsp is 0:
sptime = t
nsp = nsp + 1
else:
sptime = np.append(sptime, t)
nsp = nsp + 1
# end of for loop on i
if j is 0:
wavej = np.zeros(len(tvec))
for i in range(0, len(sptime)):
st = int(sptime[i] / dt)
wavej[st] = wavej[st] + 1
spt[j] = sptime
npts = len(tvec)
if makewave:
w = np.convolve(wavej, aw / max(aw)) * amp
wave[j] = w[0:npts]
return (spt, wave, tvec, N)
def findspikes(t, v, thresh):
""" findspikes identifies the times of action potential in the trace v, with the
times in t. An action potential is simply timed at the first point that exceeds
the threshold.
"""
tm = np.array(t)
s0 = (
np.array(v) > thresh
) # np.where(v > thresh) # np.array(v) > thresh # find points above threshold
# print ('v: ', v)
dsp = tm[s0]
if dsp.shape[0] == 1:
dsp = np.array(dsp)
sd = np.append(True, np.diff(dsp) > 1.0) # find first points of spikes
if len(dsp) > 0:
sp = dsp[sd]
else:
sp = []
return sp # list of spike times.
def measure(mode, x, y, x0, x1):
""" return the mean and standard deviation of y in the window x0 to x1
"""
xm = ma.masked_outside(x, x0, x1)
ym = ma.array(y, mask=ma.getmask(xm))
if mode == "mean":
r1 = ma.mean(ym)
r2 = ma.std(ym)
if mode == "max":
r1 = ma.max(ym)
r2 = 0
if mode == "min":
r1 = ma.min(ym)
r2 = 0
if mode == "median":
r1 = ma.median(ym)
r2 = 0
if mode == "p2p": # peak to peak
r1 = ma.ptp(ym)
r2 = 0
return (r1, r2)
def mask(x, xm, x0, x1):
xmask = ma.masked_outside(xm, x0, x1)
xnew = ma.array(x, mask=ma.getmask(xmask))
return xnew.compressed()
def vector_strength(spikes, freq):
"""
Calculate vector strength and related parameters from a spike train, for the specified frequency
:param spikes: Spike train, in msec.
:param freq: Stimulus frequency in Hz
:return: a dictionary containing:
r: vector strength
n: number of spikes
R: Rayleigh coefficient
p: p value (is distribution not flat?)
ph: the circularized spike train over period of the stimulus freq, freq, in radians
d: the "dispersion" computed according to Ashida et al., 2010, etc.
"""
per = 1e3 / freq # convert from Hz to period in msec
ph = 2 * np.pi * np.fmod(spikes, per) / (per) # convert to radians within a cycle
c = np.sum(np.cos(ph)) ** 2
s = np.sum(np.sin(ph)) ** 2
vs = (1.0 / len(ph)) * np.sqrt(c + s) # standard vector strength computation
n = len(spikes)
R = n * vs # Raleigh coefficient
Rp = np.exp(-n * vs * vs) # p value for n > 50 (see Ashida et al. 2010).
d = np.sqrt(2.0 * (1 - vs)) / (2 * np.pi * freq)
return {"r": vs, "n": n, "R": R, "p": Rp, "ph": ph, "d": d}
def isi_cv2(splist, binwidth=1, t0=0, t1=300, tgrace=25):
""" compute the cv and regularity according to Young et al., J. Neurophys, 60: 1, 1988.
Analysis is limited to isi's starting at or after t0 but before t1, and ending completely
before t1 + tgrace(to avoid end effects). t1 should correspond to the
the end of the stimulus
VERSION using dictionary for cvisi
"""
cvisit = np.arange(0, t1, binwidth) # build time bins
cvisi = {} # isi is dictionary, since each bin may have different length
for i in range(0, len(splist)): # for all the traces
isit = splist[i] # get the spike times for this trial [1:-1]
if len(isit) <= 1: # need 2 spikes to get an interval
continue
isib = np.floor(isit[0:-2] / binwidth) # discreetize
isii = np.diff(splist[i]) # isis.
for j in range(0, len(isib)): # loop over possible start time bins
if (
isit[j] < t0 or isit[j] > t1 or isit[j + 1] > t1 + tgrace
): # start time and interval in the window
continue
if isib[j] in cvisi:
print("spike in bin: %d" % (isib[j]))
cvisi[isib[j]] = np.append(
cvisi[isib[j]], isii[j]
) # and add the isi in that bin
else:
cvisi[isib[j]] = isii[j] # create it
cvm = np.array([]) # set up numpy arrays for mean, std and time for cv analysis
cvs = np.array([])
cvt = np.array([])
for i in cvisi.keys(): # for each entry (possible bin)
c = [cvisi[i]]
s = c.shape
# print c
if len(s) > 1 and s[1] >= 3: # require 3 spikes in a bin for statistics
cvm = np.append(cvm, np.mean(c))
cvs = np.append(cvs, np.std(c))
cvt = np.append(cvt, i * binwidth)
return (cvisit, cvisi, cvt, cvm, cvs)
def isi_cv(splist, binwidth=1, t0=0, t1=300, tgrace=25):
""" compute the cv and regularity according to Young et al., J. Neurophys, 60: 1, 1988.
Analysis is limited to isi's starting at or after t0 but before t1, and ending completely
before t1 + tgrace(to avoid end effects). t1 should correspond to the
the end of the stimulus
Version using a list of numpy arrays for cvisi
"""
cvisit = np.arange(0, t1, binwidth) # build time bins
cvisi = [[]] * len(cvisit)
for i in range(0, len(splist)): # for all the traces
if len(splist[i]) < 2: # need at least 2 spikes
continue
isib = np.floor(
splist[i][0:-2] / binwidth
) # begining spike times for each interval
isii = np.diff(splist[i]) # associated intervals
for j in range(0, len(isib)): # loop over spikes
if (
splist[i][j] < t0 or splist[i][j] > t1 or splist[i][j + 1] > t1 + tgrace
): # start time and interval in the window
continue
cvisi[int(isib[j])] = np.append(
cvisi[int(isib[j])], isii[j]
) # and add the isi in that bin
cvm = np.array([]) # set up numpy arrays for mean, std and time for cv analysis
cvs = np.array([])
cvt = np.array([])
for i in range(0, len(cvisi)): # for each entry (possible bin)
c = cvisi[i]
if len(c) >= 3: # require 3 spikes in a bin for statistics
cvm = np.append(cvm, np.mean(c))
cvs = np.append(cvs, np.std(c))
cvt = np.append(cvt, i * binwidth)
return (cvisit, cvisi, cvt, cvm, cvs)
if __name__ == "__main__":
test = "isicv"
if test == "isicv":
""" this test is not perfect. Given an ISI, we calculate spike times
by drawing from a normal distribution whose standard deviation varies
with time, from 0 (regular) to 1 (irregular). As coded, the standard
deviation never reaches the target value because spikes fall before or
after previous spikes (thus reducing the stdev). Nonetheless, this shows
that the CV calculation works correctly. """
nreps = 500
# cv will be 0 for first 50 msec, 0.5 for next 50 msec, and 1 for next 50 msec
d = [[]] * nreps
isi = 5.0 # mean isi
# we create 100 msec of data where the CV goes from 0 to 1
maxt = 100.0
for i in range(nreps):
for j in range(int(maxt / isi) + 1):
t = float(j) * isi
sd = float(j) / isi
if sd == 0.0:
d[i] = np.append(d[i], t)
else:
d[i] = np.append(d[i], np.random.normal(t, sd, 1))
for j in range(1, 10): # add more intervals at the end
te = t + float(j) * isi
d[i] = np.append(d[i], np.random.normal(te, sd, 1))
d[i] = np.sort(d[i])
# print d[i]
# print diff(d[i])
sh = np.array([])
for i in range(len(d)):
sh = np.append(sh, np.array(d[i]))
(hist, bins) = np.histogram(sh, bins=250, range=(0, 250), new=True)
if len(bins) > len(hist):
bins = bins[0 : len(hist)]
pl.figure(1)
pl.subplot(2, 2, 1)
pl.plot(bins, hist)
(cvisit, cvisi, cvt, cvm, cvs) = isi_cv(
d, binwidth=0.5, t0=0, t1=100, tgrace=25
)
order = np.argsort(cvt)
cvt = cvt[order]
cvs = cvs[order]
cvm = cvm[order]
pl.subplot(2, 2, 2)
pl.plot(cvt, cvm)
pl.hold(True)
pl.plot(cvt, cvs)
pl.subplot(2, 2, 4)
pl.plot(cvt, cvs / cvm)
pl.show()
if test == "measure":
x = np.arange(0, 100, 0.1)
s = np.shape(x)
y = np.random.randn(s[0])
for i in range(0, 4):
print("\ni is : %d" % (i))
x0 = i * 20
x1 = x0 + 20
(r0, r1) = measure("mean", x, y, x0, x1)
print("mean: %f std: %f [0, 20]" % (r0, r1))
(r0, r1) = measure("max", x, y, x0, x1)
print("max: %f std: %f [0, 20]" % (r0, r1))
(r0, r1) = measure("min", x, y, x0, x1)
print("min: %f std: %f [0, 20]" % (r0, r1))
(r0, r1) = measure("median", x, y, x0, x1)
print("median: %f std: %f [0, 20]" % (r0, r1))
(r0, r1) = measure("p2p", x, y, x0, x1)
print("peak to peak: %f std: %f [0, 20]" % (r0, r1))
if test == "an_syn":
(s, w, t, n) = an_syn(N=50, spont=50, driven=150, post=100, makewave=True)
sh = np.array([])
for i in range(len(s)):
sh = np.append(sh, np.array(s[i]))
(hist, bins) = np.histogram(sh, bins=250, range=(0, 250), new=True)
if len(bins) > len(hist):
bins = bins[0 : len(hist)]
import pylab as pl
pl.figure(1)
pl.subplot(2, 2, 1)
pl.plot(bins, hist)
pl.subplot(2, 2, 3)
for i in range(len(w)):
pl.plot(t, w[i])
pl.hold = True
(cvisit, cvisi, cvt, cvm, cvs) = isi_cv(s)
order = np.argsort(cvt)
cvt = cvt[order]
cvs = cvs[order]
cvm = cvm[order]
pl.subplot(2, 2, 2)
pl.plot(cvt, cvs / cvm)
pl.show()
if test == "syns":
(s, w, t, n) = syns(rate=20, delay=0, dur=100.0, N=5, makewave=True)
sh = np.array([])
for i in range(len(s)):
sh = np.append(sh, np.array(s[i]))
(hist, bins) = np.histogram(sh, bins=250, range=(0, 250), new=True)
if len(bins) > len(hist):
bins = bins[0 : len(hist)]
import pylab as pl
pl.figure(1)
pl.subplot(2, 2, 1)
pl.plot(bins, hist)
pl.subplot(2, 2, 3)
pl.plot(t, w)
pl.hold = True
(cvisit, cvisi, cvt, cvm, cvs) = isi_cv(s)
order = np.argsort(cvt)
cvt = cvt[order]
cvs = cvs[order]
cvm = cvm[order]
pl.subplot(2, 2, 2)
pl.plot(cvt, cvs / cvm)
pl.show()