## binoc_filter

WMWorking Modelswww.iModel.org/wm

## Overview

This model implements the basic binocular disparity energy (BDE) model of Ohzawa et al. (1998), as well as variations on this model proposed by Chen et al. (2001) and Read et al. (2002).

## Configuring the Model

## Parameters

These parameters set the basic simulation settings:The following phase parameters are common to all BDE models and set up the spatial phase shift between the left and right eyes. Note that in WM, the negative spatial filters are inferred (we do not have explicit parameters for setting the -1s/d or -2s/d pathways).

sscale- spatial resolution (degrees/pixel)tscale- temporal resolution (samples per second)xn- filter x-axis spatial extent (pixels)yn- filter y-axis spatial extent (pixels)tn- duration of the model (sampling units)The next 2 options are implemented for defining the 4 subunit filters in the BDE models. ME models are always in a specific quadrature relationship (+90 deg) by convention, but this can produce incorrect filters for the Read et al. models depending on which type of disparity tuning is being built (ie. TE/TI vs NE/FA).

phase_1- Spatial phase of cosine in Gabor for first left filterphase_shift- Spatial phase shift of right eye RF relative to phase_1The following parameters relate to the last two stages of the BDE model, introducing options for rectification and inhibitory interactions as in the Read et al. models. In particular, 'right_sign' sets the pattern of +'s and -'s that indicate addition or subtraction of each subunit output.

phase_shift_opp- [0,1] -- if 1, use negative phase shift to generate the RF phase for the second pathway (i.e., 2s = 1s - phase_shift)quad_shift_opp- [0,1] -- if 1, use -90 deg quadrature shift instead of +90 (2s to 2d). This is allows a variation on quadrature from the ME models, where the quadrature shift is always +90 degrees (ME model we define 1s to 1d shift as +90, 2s and 2d are then adjusted to give anti-direction RFs)

simp_rect- [0,1] If 1, monocular filter outputs are rectified before summationsimp_thresh- Non-zero threshold to be applied to monocular filter outputs (fraction of filter area)binoc_nonlin- type of nonlinearity for final stage [squaring, halfsq]right_sign- [+,-] add/subtract a given subunit. Symbols represent, in order, subunits 1s 1d 2s 2d## Filters

binoc_filtermodels use a <filter> object that specifies parameters for the spatiotemporal RFs of each monocular subunit. For the BDE_Gabor and BDE_Gabor_DS models as well as the BDE_RPC models, the basic 'Gabor' filter is used. With the BDE_CWQ models, a specific 'Gabor_CWQ' filter type is defined, that includes parameters for the temporal filtering implented in the Chen et al. models.

## Spike Generation

binoc_filtermodels also require a <spike_gen> object that defines the method of spike generation from the final filter output.

## Model Outputs

## Model Components

The spatial filters for each of the four component monocular subunits can be output using the <filter> object'swrite_filteroption. If Poisson spike generation is used, then the output firing probability can be written to a .pl file using thespike_dumpoption in <spike_gen>.## Model Responses

The following response types can be requested:A template .rsp file including these quantities can be downloaded here.

spikes- spike timesbinoc_energy- final stage filter outputbinoc_1- input to final stage from pathway 1binoc_2- input to final stage from pathway 2filter_left_1- output from subunit 1sfilter_left_2- output from subunit 2sfilter_right_1- output from subunit 1dfilter_right_2- output from subunit 2dbinoc_1_pos- summed output from 1s and 1dbinoc_1_neg- summed output from -1s and -1dbinoc_2_pos- summed output from 2s and 2dbinoc_2_neg- summed output from -2s and -2dbinoc_1_pos_sq-binoc_1_possignal squaredbinoc_1_neg_sq-binoc_1_negsignal squaredbinoc_2_pos_sq-binoc_2_possignal squaredbinoc_2_neg_sq-binoc_2_negsignal squared

## Models of This Type