Binocular Rivalry and Visual Awareness in Human Extrastriate Cortex

Frank Tong, Ken Nakayama, J. Thomas Vaughan, and Nancy KanwisherDepartment of PsychologyHarvard UniversityNeuron, Vol. 21 753-759, 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

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

M E T H O D S

Creating binocular rivalry

M E T H O D S

fMRI Scans

1. Localizer Scans2. Rivalry Scans3. Non-rivalry Scans

Four healthy right-handed human

subjects, aged 20-39.

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

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

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: http://bill.innanen.com/ parkinsons/diary200110.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 KanwisherDepartment of PsychologyHarvard UniversityNeuron, Vol. 21 753-759, October 1998

Presented by Stan James and Mayumi Koguchistan@wanderingstan.comkoguchischoepf@tiscali.de

C O N C L U S I O NBinocular Rivalry and Visual Awareness in Human Extrastriate Cortex

Frank Tong, Ken Nakayama, J. Thomas Vaughan, and Nancy KanwisherDepartment of PsychologyHarvard UniversityNeuron, Vol. 21 753-759, October 1998

Presented by Stan James and Mayumi Koguchistan@wanderingstan.comkoguchischoepf@tiscali.de

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