The anatomical basis of face recognition: The anatomical basis of face recognition: evidence from studies of intact individuals:evidence from studies of intact individuals:

What is the anatomical basis of face recognition in What is the anatomical basis of face recognition in humans?:humans?:

Right hemisphere seems particularly important for face-recognition. Farah (1990): 65% of 81 prosopagnosics had bilateral damage, 29% RH only, 6% LH only.

RH important for configural processing, LH for featural?

Which hemisphere is most Which hemisphere is most important for face important for face recognition?recognition?

Divided-field studies with normal people (Bourne, Vladeanu and Hole, 2008):

Stimuli in extreme left visual field go first to right hemisphere, and vice versa.

Both hemispheres can recognise faces.LH: featural processing.RH: configural processing.

Face type

Normal Blurred

Mean R

T (ms) + 1 SE

700

800

900

1000

1100

1200

LVF-RHRVF-LH

Face type

Mean RT (+ 1 SE) to normal and blurred faces as a function of visual field of presentation.

Complete Eyes only

Mean R

T (ms) + 1 SE

700

750

800

850

900

950

LVF-RHRVF-LH

Face type

Mean RT (+ 1 SE) to complete faces and the eyes only as a function of visual field of presentation.

RH faster than LH with complete faces.

Blurring affects LH more than RH.

Features-only affects RH more than LH.

Bourne and Hole (2003): hemispheric differences in Bourne and Hole (2003): hemispheric differences in processing incomplete faces:processing incomplete faces:

Complete

Eyes missing

Nose missing

Mouth missing

Bars represent the difference between the complete face condition and each experimental condition. The greater the difference the more detrimental the effect of the manipulation.

LH (featural) copes worse with missing features than RH (configural).

Bourne and Hole (2003): hemispheric differences in Bourne and Hole (2003): hemispheric differences in processing incomplete faces:processing incomplete faces:

Tong, Nakayama, Moskowitz, Weinrib and Kanwisher (2000):

fMRI study of fusiform responses to face-like stimuli, eyes, houses and non-face objects.

FFA response similar for cat, cartoon and human faces (with/without eyes);

weaker for schematic faces and eyes alone;

equal for front and profile views, but declining as face rotated away from view;

weakest for non-face objects and houses.

Conclusion: fusiform gyrus responds best to facial configurations plus features - involved in "face" perception/detection.

Schiltz, Dricot, Goebel and Rossion (2010):

fMRI adaptation study of neural responses to composite faces.

Right middle fusiform ("FFA") sensitive to composites - treats them as "new" faces.

Right FFA involved in "holistic" processing.

Lee, Anaki, Grady and Moscovitch (2012):fMRI study of responses to face halves separated in time or space.

Behavioural data: ISI 0 and ISI 200 similar; ISI 800 and Misaligned similar to each other, and worse than ISI 0 and ISI 200.

ISI 800: activated face processing regions (more bilaterally) plus areas involved in attention and working memory (strategic processing?)

ISI 0 and ISI 200: better identification correlated with increased activity in “configural processing” network (R fusiform, middle occipital, bilateral superior temporal, inferior/middle cingulate and frontal cortex).

ISI 800 and Misaligned: better identification correlated with less activity in these regions.

Suggest configural and analytic processing regions oppose each other.

Nakayama et al (2000) PET study:Four visual tasks:

(a) Personally-familiar face recognition.

(b) Unfamiliar-face direction discrimination.

(c) Dot location on scrambled face.

(d) Familiar/unfamiliar scene recognition.

Bilateral occipital cortex and posterior fusiform gyri respond to faces, scrambled faces and scenes: involved in extraction of physical features from complex images.

Right inferior temporal/fusiform gyrus responds selectively to faces (face perception).

Bilateral parahippocampal gyri and parieto-occipital junctions respond selectively to scenes.

Right temporal pole is activated during familiar/unfamiliar face and scene discrimination; probably involved in recognition of familiar objects (memory in general).

Gorno-Tempini and Price (2001) PET/MRI study:Four visual tasks:

(a) Famous face matching.

(b) Non-famous face matching.

(c) Famous building matching.

(d) Non-famous building matching.

Category-specific perceptual processing:

Faces (famous and non-famous) activate fusiform gyrus.

Buildings (famous and non-famous) activate parahippocampal gyrus.

Shared analysis of semantic processing:

Fame (faces or buildings) activates left anterior middle temporal gyrus.

Anatomical location of processes involved in face Anatomical location of processes involved in face recognition (Schweinberger and Burton (2003):recognition (Schweinberger and Burton (2003):

Face recognition

(Fusiform gyrus) N250R

Attribution processes

PIN N400

(Anterior temporal lobe)

Name

(Left temporal lobe)

Integrative device

Semantic information (Anterior medial temporal lobe)

Arousal to familiar face

(Amygdala)

Skin conductance response

Structural encoding N170

(superior temporal sulcus)

Fusiform gyrus

Lingual gyrus

Parahippocampal gyrus

RH LH

Event-related Potential (ERP) studies of face processing Event-related Potential (ERP) studies of face processing (Schweinberger 2003):(Schweinberger 2003):

N170:N170:

Generated from posterior lateral occipitotemporal cortex (superior temporal sulcus).

Larger for faces than most other visual stimuli. Not human face-specific: also produced by car "faces", ape faces, schematic faces and inverted faces.

Unaffected by face familiarity or face priming. i.e., not related to face recognition.

Correlate of structural encoding, identification of face-like configurations?

N250R:N250R:

Strongly right hemisphere. Affected by familiarity of faces, and larger for personally-familiar faces than famous faces. Activity modulated in response to repeated faces (even if diffferent views each time, though strongest with identical images). Probably generated from fusiform gyrus.

Most response from human faces; then ape faces; no response to inverted faces or car "faces".

Correlate of "face recognition units"?

N400:N400:

Anterior medial temporal cortex.

Correlate of "person identity nodes" (post-perceptual response to individuals)?

Barbeau, Taylor, Regis, Marquis, Chauvel and Liegeois-Chauvel (2008):Barbeau, Taylor, Regis, Marquis, Chauvel and Liegeois-Chauvel (2008):Intra-cranial ERP study of time-course of famous face recognition.

Massively distributed processing from 110 -600 msec post-stimulus - at least seven structures involved.

Processing is not "one-way" - frontal areas influence "earlier" stages.

FG - invariant aspects of faces;

STS - changeable aspects.

Perirhinal cortex -signals "familarity".

Temporal structures - recognition.

(Dark blue = periods when recognition

effects were found).

Outstanding questions:Outstanding questions:

How do the hemispheres cooperate during normal face processing?

Are the RH and LH really specialised for configural and featural processing, or are these merely reflections of generalised differences in processing modes? (RH – global, LH – local).

In particular, is featural processing really a mode of face processing, or merely a strategy to cope with odd-looking faces in psychology experiments?