Recruiting different population ratios in V1 using MotionClouds' orientation components

InViBe's Journal Club - https://intranet.int.univ-amu.fr/fr/invibe/journalclub

• (sep 26th) Laurent : introduction http://blog.invibe.net/files/2016-09-26_Perrinet16journalClub/2016-09-26_Perrinet16journalClub.slides.html
• (oct 3rd) Frédo : Origin and Function of Tuning Diversity in Macaque Visual Cortex by Robbe L.T. Goris, Eero P. Simoncelli, J. Anthony Movshon - http://www.sciencedirect.com/science/article/pii/S0896627315008752
• (oct 10th) : free slot (IRM?)
• (oct 17th) : Ivo
• (oct 24th and 31st) : break
• (nov 7th) Christopher : psychophysics

See http://motionclouds.invibe.net/posts/orientation.html

Re-compile this presentation using http://blog.invibe.net/files/2016-09-26_Perrinet16journalClub/2016-09-26_Perrinet16journalClub.ipynb

• a new serie of JCs:
• 2 available slots

manipulating the bandwidth in MotionClouds

import numpy as np
import MotionClouds as mc
fx, fy, ft = mc.get_grids(mc.N_X, mc.N_Y, mc.N_frame)

name = 'balaV1'

N_X = fx.shape[0]
width = 29.7*256/1050
sf_0 = 4.*width/N_X
B_V = 2.5     # BW temporal frequency (speed plane thickness)
B_sf = sf_0   # BW spatial frequency
theta = 0.0   # Central orientation
B_theta_low, B_theta_high = np.pi/32, 2*np.pi 
B_V = 0.5
seed=12234565

mc1 = mc.envelope_gabor(fx, fy, ft, V_X=0., V_Y=0., B_V=B_V, sf_0=sf_0, B_sf=B_sf, theta=theta, B_theta=B_theta_low)

import numpy as np
import MotionClouds as mc
mc.figpath = figpath
fx, fy, ft = mc.get_grids(mc.N_X, mc.N_Y, mc.N_frame)

name = 'balaV1'

N_X = fx.shape[0]
width = 29.7*256/1050
sf_0 = 4.*width/N_X
B_V = 2.5     # BW temporal frequency (speed plane thickness)
B_sf = sf_0   # BW spatial frequency
theta = 0.0   # Central orientation
B_theta_low, B_theta_high = np.pi/32, 2*np.pi 
B_V = 0.5
seed=12234565

mc1 = mc.envelope_gabor(fx, fy, ft, V_X=0., V_Y=0., B_V=B_V, sf_0=sf_0, B_sf=B_sf, theta=theta, B_theta=B_theta_low)
name_ = name + '_1'
mc.figures(mc1, name_, seed=seed)
mc.in_show_video(name_, figpath=figpath)

mc2 = mc.envelope_gabor(fx, fy, ft, V_X=0., V_Y=0., B_V=B_V, sf_0=sf_0, B_sf=B_sf, theta=theta, B_theta=B_theta_high)
name_ = name + '_2'
mc.figures(mc2, name_, seed=seed)
mc.in_show_video(name_, figpath=figpath)

• Basic effect: whenever one changes bandwidth either you detect the mean orientation or not

Loi de Von Mises (loi normale circulaire) telle que $f(\theta+\pi) = f(\theta)$ définie par :

$$ f(\theta) \propto e^{\kappa{cos(2(\theta - m))}} $$

Par analogie avec la déviation standard d'une loi Gaussienne, on définit $\kappa = \frac {1}{\sigma^{2}}$.

def envelope(th, theta, B_theta):
    if B_theta==np.inf:
        env = np.ones_like(th) 
    elif B_theta==0:
        env = np.zeros_like(th)
        env[np.argmin(th < theta)] = 1.
    else:
        env = np.exp((np.cos(2*(th-theta))-1)/4/B_theta**2)
    return env/env.max()        

N_theta = 12
bins = 180
th = np.linspace(0, np.pi, bins, endpoint=False)
fig, axs = plt.subplots(1, 2, figsize=(fig_width, fig_width/phi/2))
for i, B_theta_ in enumerate([np.pi/12, np.pi/4]):#[0, np.pi/64, np.pi/32, np.pi/16, np.pi/8, np.pi/4, np.pi/2, np.inf]:
    for theta, color in zip(np.linspace(0, np.pi, N_theta, endpoint=False), 
                            [plt.cm.hsv(h) for h in np.linspace(0, 1, N_theta)]):
        axs[i].plot(th*180/np.pi, envelope(th, theta, B_theta_), alpha=.6, color=color, lw=3)
        axs[i].fill_between(th*180/np.pi, 0, envelope(th, theta, B_theta_), alpha=.1, color=color)
    axs[i].set_xlim([0, 180])
    axs[i].set_ylim([0, 1.1])
    axs[i].set_xticks(np.linspace(0, 180, 5, endpoint=True) )#to specify number of tick…
for ax in axs:
    for item in ([ax.title, ax.xaxis.label, ax.yaxis.label] +
                 ax.get_xticklabels() + ax.get_yticklabels()):
        item.set_fontsize(fontsize)