Binocular Rivalry and Visual Awareness in Human Extrastriate Cortex Frank Tong, Ken Nakayama, J. Thomas Vaughan, and Nancy Kanwisher Department of Psychology Harvard University Neuron, Vol , October 1998 Neuron, Vol , October 1998

M E T H O D S B A C K G R O U N D R E S U L T S C O N C L U S I O N Talk Outline

B A C K G R O U N D

Monocular Rivalry Examples

B A C K G R O U N D Binocular Rivalry Brain 2 Stimuli 1 Perception

B A C K G R O U N D Binocular Rivalry Brain 2 Stimuli 1 Perception

B A C K G R O U N D Where is rivalry resolved? LGN First guess: LGN or PVC But, single-unit recordings in monkeys… ??? PVC

B A C K G R O U N D Where is rivalry resolved? FFA = Fusiform Face Area PPA = Parahippocampal Place Area LGN FFA PPA PVC

M E T H O D S

Creating binocular rivalry

M E T H O D S fMRI Scans 1.Localizer Scans 2.Rivalry Scans 3.Non-rivalry Scans Four healthy right-handed human subjects, aged

M E T H O D S 1. Localizer Scans  Alternating house and face stimuli  Locate FFA and PPA

Localizer Scan (In actual experiment, stimuli were presented for 16 second intervals.)

M E T H O D S 1. Localizer Scans  Alternating house and face stimuli  Locate FFA and PPA

M E T H O D S 2. Rivalry Scans  Present single rivalry-causing stimulus  Record timing of subject-reported dominant percept

Rivalry Scan

M E T H O D S 2. Rivalry Scans  Present single rivalry-causing stimulus  Record timing of subject-reported dominant percept

M E T H O D S 3. Non-rivalry Scans  Alternating house and face stimuli  Present stimuli in identical temporal sequence reported during rivalry scans

Non-Rivalry Scan (Stimuli presented in same sequence and duration as reported in rivalry scan.)

M E T H O D S 3. Non-rivalry Scans  Alternating house and face stimuli  Present stimuli in identical temporal sequence reported during rivalry scans

R E S U L T S

FFA = Fusiform Face Area PPA = Parahippocampal Place Area 1. Localizer Scans

R E S U L T S Localizer Scans – Raw Data FFA = Fusiform Face Area PPA = Parahippocampal Place Area

R E S U L T S Rivalry Scans – Raw Data FFA = Fusiform Face Area PPA = Parahippocampal Place Area

R E S U L T S Averaged Transition Data

R E S U L T S Everything together

C O N C L U S I O N

What can we conclude?  FFA & PPA are confirmed.  FFA & PPA activity matches perception.  And back to our original question…

C O N C L U S I O N Upper bound on rivalry resolution FFA = Fusiform Face Area PPA = Parahippocampal Place Area LGN FFA PPA PVC

M E T H O D S B A C K G R O U N D R E S U L T S C O N C L U S I O N Executive Summary Where is rivalry resolved? Chic glasses + fMRI. 3 experiments. FFA & PPA respond the same for rivalry and non-rivalry. Rivalry is resolved before these stages of processing.

Questions?

Picture of cool guy in glasses taken from: parkinsons/diary shtmlbill.innanen.com/ parkinsons/diary shtml

C O N C L U S I O N Binocular Rivalry and Visual Awareness in Human Extrastriate Cortex Frank Tong, Ken Nakayama, J. Thomas Vaughan, and Nancy Kanwisher Department of Psychology Harvard University Neuron, Vol , October 1998 Neuron, Vol , October 1998 Presented by Stan James and Mayumi Koguchi

C O N C L U S I O N Binocular Rivalry and Visual Awareness in Human Extrastriate Cortex Frank Tong, Ken Nakayama, J. Thomas Vaughan, and Nancy Kanwisher Department of Psychology Harvard University Neuron, Vol , October 1998 Neuron, Vol , October 1998 Presented by Stan James and Mayumi Koguchi

M E T H O D S B A C K G R O U N D R E S U L T S C O N C L U S I O N Where is rivalry resolved? Stylish glasses, fMRI FFA & PPA respond the same for rivalry and non. Rivalry is resolved before these stages of processing. Executive Summary

2. Rivalry Scans – Raw Data FFA = Fusiform Face Area PPA = Parahippocampal Place Area

Still not convinced?

Rivalry

Binocular Rivalry Brain 2 Stimuli 1 Perception