Retina selectivity receptive field size retina v1 v4

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Unformatted text preview: ng” Hypothesis - as signals pass through the “what” pathway, the manifolds for different object “untangle” Retina V1 IT In other words, the purpose of the “what” pathway is to untangle manifolds (for invariant object recognition) pIT IT LGN *How* are object manifolds untangled? retina Selectivity Receptive field size retina V1 V4 IT Hypothesis: in each visual area, the neurons become a little more selective for conjunctions of simpler features and and a little more tolerant for changes in the position and size of those features Until signals reach IT where the neurons become tolerant for changes in the position and size of objects! As for changes in pose, well, we donʼt know ... LGN neurons combine to form orientation-tuned V1 simple cells (selectivity) “LN model” Hubel & Wiesel, 1962 Simple cells combine to form position/polarity invariant complex cells (invariance) “LN-LN cascade” Hubel & Wiesel, 1962 Adelson & Bergen, 1985 V1 neurons combine to form V2 corner detection neurons ARTICLES a 2 b V2 1.0 1 0.5 0 0 –0.5 –1 –2 –2 d V2 24 spikes per s 0 –1.0 2 V2 11 spikes per s –1 e 2 0 1 V2 1 y (°) 1 0 0 –1 –1 16 spikes per s –2 14 spikes per s c2 Figure maps Respo 1 to the are plo 0 stimul hexag –1 locatio –2 to obt 18 spikes per s secon –2 0 2 indica by the V1 Orient 0.5 the 3 for the were r 0 circle. tuned –0.5 V2 ne Anzai, Peng, Van Essen 2007) (b–e 32 spikes per s f V2 To build up an IT population representation that is selective for objects invariant of the details (like position), the visual system implements a little selectivity and invariance in each visual area...
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