Package topo :: Package sheet :: Module saccade :: Class SaccadeController

Class SaccadeController

                        object --+                    
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 param.parameterized.Parameterized --+                
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        base.simulation.EventProcessor --+            
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                            object --+   |            
                                     |   |            
base.sheetcoords.SheetCoordinateSystem --+            
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                          base.sheet.Sheet --+        
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               base.projection.ProjectionSheet --+    
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                                   base.cf.CFSheet --+
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                                                    SaccadeController

Sheet that decodes activity on CFProjections into a saccade command.

This class accepts CF-projected input and computes its activity like a normal CFSheet, then decodes that activity into a saccade amplitude and direction as would be specified by activity in the superior colliculi. The X dimension of activity corresponds to amplitude, the Y dimension to direction. The activity is decoded to a single (x,y) point according to the parameter decode_method.

From this (x,y) point an (amplitude,direction) pair, specified in degrees, is computed using the parameters amplitude_scale and direction scale. That pair is then sent out on the 'Saccade' output port.

NOTE: Non-linear mappings for saccade commands, as in Ottes, et al (below), are assumed to be provided using the coord_mapperg parameter of the incoming CFProjection.

References: Ottes, van Gisbergen, Egglermont. 1986. Visuomotor fields of the superior colliculus: a quantitative model. Vision Research; 26(6): 857-73.

Nested Classes

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Inherited from param.parameterized.Parameterized: __metaclass__

Instance Methods

[hide private]

activate(self)
Collect activity from each projection, combine it to calculate the activity for this sheet, and send the result out.

source code

Inherited from base.cf.CFSheet: release_unit_view, update_unit_view

Inherited from base.projection.ProjectionSheet: __init__, input_event, learn, override_plasticity_state, present_input, process_current_time, projections, restore_plasticity_state

Inherited from base.projection.ProjectionSheet (private): _dest_connect, _grouped_in_projections, _port_match

Inherited from base.sheet.Sheet: activity_len, release_sheet_view, row_col_sheetcoords, sheet_cols, sheet_offset, sheet_rows, state_pop, state_push

Inherited from base.sheet.Sheet (private): _get_density

Inherited from base.simulation.EventProcessor: script_repr, send_output, start

Inherited from base.simulation.EventProcessor (private): _src_connect

Inherited from param.parameterized.Parameterized: __getstate__, __repr__, __setstate__, __str__, debug, defaults, force_new_dynamic_value, get_param_values, get_value_generator, inspect_value, message, print_param_values, set_dynamic_time_fn, verbose, warning

Inherited from param.parameterized.Parameterized (private): _check_params, _instantiate_param, _set_name, _setup_params

Inherited from base.sheetcoords.SheetCoordinateSystem: closest_cell_center, matrix2sheet, matrixidx2sheet, sheet2matrix, sheet2matrixidx, sheetcoordinates_of_matrixidx

Inherited from object: __delattr__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __setattr__

Class Methods

[hide private]

Inherited from param.parameterized.Parameterized: params, print_param_defaults

Class Variables

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amplitude_scale = param.Number(default= 120, doc= ...
Scale factor for saccade command amplitude, expressed in degrees per unit of sheet.

direction_scale = param.Number(default= 180, doc= ...
Scale factor for saccade command direction, expressed in degrees per unit of sheet.

decode_fn = param.Callable(default= activity_centroid, instant...
The function for extracting a single point from sheet activity.

command_mapper = param.ClassSelector(CoordinateMapperFn, defau...
A CoordinateMapperFn that will be applied to the command vector extracted from the sheet activity.

src_ports = ['Activity', 'Saccade']
list() -> new list list(sequence) -> new list initialized from sequence's items

Inherited from base.cf.CFSheet: measure_maps, precedence

Inherited from base.projection.ProjectionSheet: apply_output_fn, dest_ports, divisive_constant, mask, multiplicative_constant, output_fn

Inherited from base.sheet.Sheet: layout_location, nominal_bounds, nominal_density, plastic

Inherited from param.parameterized.Parameterized: name, print_level

Properties

[hide private]

Inherited from base.sheet.Sheet: density

Inherited from base.sheetcoords.SheetCoordinateSystem: shape, xdensity, ydensity

Inherited from object: __class__

Method Details

[hide private]

activate(self)

source code

Collect activity from each projection, combine it to calculate the activity for this sheet, and send the result out.

Subclasses may override this method to whatever it means to calculate activity in that subclass.

Overrides: base.projection.ProjectionSheet.activate: (inherited documentation)

Class Variable Details

[hide private]

amplitude_scale

Scale factor for saccade command amplitude, expressed in degrees per unit of sheet. Indicates how large a saccade is represented by the x-component of the command input.

Value:

param.Number(default= 120, doc= """
        Scale factor for saccade command amplitude, expressed in
        degrees per unit of sheet.  Indicates how large a saccade is
        represented by the x-component of the command input.""")

direction_scale

Scale factor for saccade command direction, expressed in degrees per unit of sheet. Indicates what direction of saccade is represented by the y-component of the command input.

Value:

param.Number(default= 180, doc= """
        Scale factor for saccade command direction, expressed in
        degrees per unit of sheet.  Indicates what direction of saccade
        is represented by the y-component of the command input.""")

decode_fn

The function for extracting a single point from sheet activity. Should take a sheet as the first argument, and return (x,y).

Value:

param.Callable(default= activity_centroid, instantiate= False, doc= """
        The function for extracting a single point from sheet activity.
        Should take a sheet as the first argument, and return (x,y).""")

command_mapper

A CoordinateMapperFn that will be applied to the command vector extracted from the sheet activity.

Value:

param.ClassSelector(CoordinateMapperFn, default= IdentityMF(), doc= """
        A CoordinateMapperFn that will be applied to the command vector extracted
        from the sheet activity.""")