Prosopagnosia Emotion recognitionFFA

ProsopagnosiaEvidence from brain injury and genetics

Innate? evidence from developmental psychology

Inversion effectsEvidence from cognitive psychology

Brain imaging and single cell recordingFFA (imaging studies in humans): face specific or not?Infero-temporal cortex in monkeysSingle cells in humans e.g. Quirogaet alFacial emotion recognition

Very similar to the object recognition modelStage 1: Structural encoding.Perceive the face and create a visual 'description' of component features and their configuration.Stage 2: Face recognition units (FRUs).Match visual description of the seen face against stored descriptions of the appearance of familiar faces.Stage 3: Semantic information in the form of person identity nodes (PINs).Access information held in long-term memory concerning the familiar person's occupation, personality, etc.Stage 4: Name retrieval units (NRUs)Access the person's name from the Speech Output Lexicon.

• Benton Face Recognition

• Famous Faces?

ProsopoProsopoαγνωσίααγνωσίαΠροσωποΠροσωποagnosiaagnosia

• Prosopagnosia• Prosopagnosia is extremely rare• Prosopagnosia of vascular origin is due to posterior

cerebral artery infarcts (PCAIs). PCAIs represent 5-10% of all strokes (Brandt et al., 2000)

• The infarct must affect the right side to produce prosopagnosia (e.g. Cals et al., 2002; De Renzi et al., 1994;). Other etiologies include carbon monoxide poisoning, temporal lobectomy, encephalitis, and Alzheimer’s disease.

Right Hemisphere Lesion

Only one case of prosopagnosia has been described with a lesion apparently restricted to the left hemisphere (Mattson et al., 2000).

This is odd, given that neuroimaging studies indicate a left hemisphere role in normal face processing (e.g. Sergeant et al., 1992; Kanwisher et al., 1997).

Of course, a left occipito-temporal lesion may cause subtle face processing deficits that are usually not detected by conventional neuropsychological tests

Patient PH

• De Haan, Young & Newcombe(1987) studied a patient PH who had a closed head injury.

• PH could match unfamiliar faces so he did not have a structural encoding problem(Benton task) and he could recognise names and voices of familiar people so not a person identity impairment.

• Could not make familiarity decisions for faces:• a) Is this face/name familiar or unfamiliar (Y/N)?• ▪faces 18/36names 29/32• b) Which of these two faces/names is familiar (FC)?• ▪faces 65/128names 118/128

Implicit or covert processing in prosopagnosia

• De Haan, et al (1987) found PH implicitly recognised famous faces in matching tasks.

• Given pairs of faces and asked “Are these two faces the same person or different people?”

• PH therefore shows evidence of covert recognition of faces without ‘awareness’.

Physiological Evidence

• Autonomic evidence• Skin conductance responses (SCR) are

different for famous and non-famous faces (Tranel et al. 1995).

• Neurological evidence• Evoked response potentials (ERP) for

prosopagnosic patients are different for famous and non famous faces (Renault et al. 1989).

• Shows that prosopagnosic patients “know” the difference between familiar/unfamiliar faces?

Prosopagnosia- a genetic version?

Gruter et al (2007)From two friends who had face processing problems, they located 7 families and tested many of the membersIt seems to be an dominant mode of transmission

Faces processed holistically?

• Is prosopagnosia a category specific agnosia?• Farah (1990) argued it results from a core visual

disorder affecting holistic processing of visual stimuli.• She argued that disorders of face recognition, object

recognition and word recognition fall on a continuum• Prosopagnosic patients can have difficulty with:• ▪Chairs (Faust, 1955)• ▪Nonsense figures (De Renzi & Spinnler, 1966)• ▪Buildings (Cole & Perez-Cruet, 1964)• ▪Cars (Newcombe, 1979)

McNeil & Warrington (1993) WJ became shepherd Sergent & Signoret (1992): cars

Experts for other faces and things

The Face Inversion Effect (Yin, 1969)

Is it specific to faces? Is it to do with familiarity? Part-whole processing? Something else?

Expertise and Homogeneity: the inversion effect

• Diamond & Carey (1986) proposed a two-factor explanation for the face-inversion effect.

• 1. Familiarity - Expertise • 2. Homogeneity of the Stimulus Class

• (i.e similarity of composition of the exemplars in a class: structural similarity, global rather than local processing?)

• They say that if both the above criterion are met then inversion effects would also occur for non-face stimuli.

• Most classes of animal meet the criterion of homogeneity. That is they share a common configuration. However in general we lack FAMILIARITY with them.

So what if this criterion is met?

• Diamond & Carey (1986) presented upright and inverted pictures of Dogs to dog experts (satisfying the familiarity criterion) and non-experts.

• Significant inversion effect for dog experts.

• The suggestion is that expertise is critical, not faces per se

Thatcher illusion (face inversion and global processing)

Is there a specific brain area (or areas) for face processing?

• Identity recognition

• FusiformFace Area (FFA)

• Occipital Face Area (OFA)

• Superior temporal Sulcus

• Emotion

• Amygdala

• Insula

FFA and OFA

OFA is in the Lateral Occipital Complex (LOC)

Superior Temporal Sulcus

Gaze direction

FFA and OFA• Role of FFA?• Involved in the recognition of individual faces (Haxby et al 1994;

Sergeant et al 1992). • Lesions of the FFA lead to problems with the identification of

individual faces (prosopagnosia) rather than detection of faces per se

• Role of OFA? • Some (Haxby et al 1999) suggest that the OFA is involved in

simply detecting faces and/or categorical distinctions e.g. gender, age

• Part of LOC• But early visual areas are not typically involved in much

categorical object recognition

Neural network for face processing

Innateness

• present at birth or develop over time (e.g Karmiloff-Smith and neuroconstructivism)

• So, we could ask if faces are special at different stages of development

• 30 mins of birth, infants track moving faces longer than other complex targets (e.g. Easterbrook et al 1999)

• Within days, can distinguish mother’s face (Bushnell et al 1989)

• Look more at attractive than unattractive faces (Langloiset al 1987)

Innate?

Infants track face-like stimuli more than scrambled faces. Goren et al, 1975; Johnson et al, 1991). Can replicate facial emotion (Meltzoff & Moore, 1977)

Preference also evident for patterns reflecting face-like structure.

Thus faces themselves not special (Simion et al, 2002), but some innate structural knowledge (CONSPEC)

Conlern and ConspecPreferences for conspecifics?

• Other animals e.g. birds show a preference for conspecifics at birth

• Morton and Johnson proposed: • At birth, babies have a CONSPEC system – an

innate face-specific system that orients us to faces. • Mediated by subcortical structures (e.g. superior colliculi) • By 2 months, however, face discrimination is a

product of the CONLERN system – a domain general system that allows learning of specific faces through experience.

• ▪ Mediated by cortex

Object recognitionLateral Occip.cortexInferior temporal cortes

Face detection Superior colliculusAmygdalaPulvinar

Face identificationFusiform gyrus

Expressionamygdala

GazeSuperior temporalsulcus

Kanwisher et al, 1999

• the FFA does not respond as strongly to any aspect of animals as it does to human faces/heads

• the FFA showed higher responses for human faces than

• animal heads, whole animals, and animal bodies

• Thus, the FFA responds much more strongly to human faces or heads than to any aspect

Gauthier and Greebles

• Gauthier et al. (2000) suggested that FFA, a region which shows preferential activation for faces, can also be activated while bird and car experts viewed objects in their domain of expertise.

• FFA activation was also found for laboratory created expertise with Greebles (Gauthier et al., 1999).

Gauthier (2000)Bird and car experts. FFA and OFA• Gauthier et al

tested experts at recognising birds (n=8) and cars (n=11)

• Did expert knowledge activate the FFA for these stimuli? Yes…

Single Cell recordings in monkeys

Typical neural responses in the primate inferior temporal cortex:

Single Cell Findings

• 1984 Face cells (typically) do not respond to:• 1.“jumbled” faces• 2.“partial” faces • 3.“single components” of faces (although some

face-component cells have been found)• 4.other “significant” stimuli Face cells (typically) do respond to:• 1.faces anywhere in a large bilateral visual field• 2.faces with “reduced” feature content (e.g, low

contrast) Face cell responses can vary with: facial expression, view-orientation

Quiroga et al(2005)

• 8 patients suffering from epilepsy, all of whom had been temporarily implanted with devices to monitor brain-cell activity as part of their treatment.

• Using a laptop, they presented subjects with a series of one-second snapshots of celebrities, animals, objects and landmark buildings. Each person was shown a total of almost 2,000 pictures; in each sitting they saw about 90 pictures showing roughly a dozen distinct items.

• They had previously shown that neurons in the human medial temporal lobe (MTL) fire selectively to images of faces, animals, objects or scenes (Kreiman et al 2000)

• Here they report on a remarkable subset of MTL neurons that are selectively activated by strikingly different pictures of given individuals, landmarks or objects and in some cases even by letter strings with their names.

Figure 4.29 (a) Location of the hippocampus and some of the other structures that were studied by Quiroga and coworkers (2005)

(a) Monkey brain showing location of the inferotemporal cortex (IT) in the lower part of the temporal lobe. (b) Human brain showing location of the fusiform face area (FFA) in the fusiform gyrus, which is located under the temporal lobe.

Facial Emotion

Ekman faces6 universal emotions▪Happiness▪Surprise▪Fear▪Sadness▪Disgust▪AngerFear and amygdalaDisgust and insula