The region of brain that is important for facial recognition is called the

Electrical Brain Stimulation Studies on Face Perception

A special role of the right fusiform gyrus for face recognition was also confirmed by a study applying electrical brain stimulation in patients with intracranial electrodes implanted in the ventral temporal cortex, a larger brain area containing the fusiform gyrus. Such electrodes are sometimes implanted in patients with intractable epilepsy in order to localize the source of their seizures. Vinitha Rangarajan from Stanford University and colleagues investigated face perception in five patients with electrodes implanted in the right ventral temporal cortex and five patients implanted with electrodes in the left ventral temporal cortex.93 First, face-sensitive electrode sites were determined by recording the signal obtained from the electrode while the patients viewed pictures of faces. Face-sensitive sites were found in both the right and left fusiform gyrus. In a second step, face-sensitive electrode sites were stimulated while the patients viewed pictures of faces and other stimuli. Patients were asked to report their conscious experience of the face stimuli—e.g., whether they experienced any perceptual effects or changes of the stimuli. Here, a striking hemispheric asymmetry was observed: Only stimulation of electrode sites in the right fusiform gyrus led to changes in the conscious perception of faces, while stimulation of left-sided electrodes only affected visual experience of non-face stimuli. Therefore, Rangarajan and colleagues concluded that this clear functional dissociation between the left and the right fusiform gyrus indicated dominance of the right fusiform gyrus for conscious perception of faces. Interestingly, in a follow-up study, Rangarajan reported a reversed pattern in two patients with atypical language lateralization and left-handedness, concluding that the functional architecture of the ventral temporal cortex might be linked to handedness and language lateralization.94 This idea assumed that when the right hemisphere is language-dominant, the left might in turn be dominant for face perception, at least in some individuals.

Area V4

The cortex of the lingual and fusiform gyri seems to play an important role in color perception, since lesions of this region cause achromatopsia (Meadows, 1974; Damasio et al., 1980; Rizzo et al., 1992; for review Zeki, 1990b), and functional imaging as well as electrophysiological observations demonstrate activation by color (Lueck et al., 1989; Corbetta et al., 1991; Zeki et al., 1991; Gulyás and Roland, 1991, 1994; Allison et al., 1993; Sakai et al., 1995; Sereno et al., 1995) and shape (Corbetta et al., 1991). Thus, this region has been suggested to be the human correlate of the monkey V4, which is populated by color-, space-, and shape-responsive neurons (Desimone and Schein, 1987; Desimone and Ungerleider, 1989; Zeki, 1990b; Schiller and Lee, 1991; Heywood et al., 1992; Walsh et al., 1993; De Yoe et al., 1994). Presently, however, it is controversially discussed whether this human V4 in the fusiform gyrus represents the equivalent of the monkey V4 (Meadows, 1974; Walsh et al., 1993; Zeki, 1993; Ungerleider and Haxby, 1994; Heywood et al., 1995).

The putative human V4 is located on the posterior part of the fusiform gyrus and abuts the rostral border of the putative human VP (Sereno et al., 1995). The position and extent as well as the architecture of the area peristriata magnopyramidalis of Braak (1977) make this pigmentoarchitectonically well-defined cortical region to a candidate for human V4. V4 contains large pyramidal cells in layers III and V, and shows an intense COX staining. Both criteria allow a delineation of this area from VP (Clarke, 1994a). The myelin density is well above average in human and monkey V4 (Zilles and Clarke, 1997).

A ventral area V4v – separable from V4 – has been identified by using fMRI (Sereno et al., 1995) or fMRI in combination with cytoarchitectonic maps (Wilms et al., 2010). This area adjoins the ventral half of the anterior border of VP (Figure 23.27). This border represents the vertical meridian, whereas the horizontal meridian is found at the anterior border of V4v. Human V4v contains the upper visual field as in monkeys with a non-mirror image representation of the visual field.

Area V4

The cortex of the lingual and fusiform gyri seems to play an important role in color perception because lesions of this region cause achromatopsia (Damasio et al., 1980; Meadows, 1974; Rizzo et al., 1992; for review, see Zeki, 1990b), and functional imaging as well as electrophysiological observations demonstrate activation by color (Allison et al., 1993; Corbetta et al., 1991; Gulyás and Roland, 1991, 1994; Lueck et al., 1989; Sakai et al., 1995; Sereno et al., 1995; Zeki et al., 1991) and shape (Corbetta et al., 1991). Thus, this region has been suggested to be the human correlate of the monkey V4, which is populated by color-, space- and shape-responsive neurons (Desimone and Schein, 1987; Desimone and Ungerleider, 1989; De Yoe et al., 1994; Heywood et al., 1992; Schiller and Lee, 1991; Van Essen and Zeki, 1978; Walsh et al., 1993; Zeki, 1990b). Presently, however, it is controversly discussed whether this human V4 in the fusiform gyrus represents the equivalent of the monkey V4 (Heywood et al., 1995; Meadows, 1974; Ungerleider and Haxby, 1994; Walsh et al., 1993; Zeki, 1993).

This putative human V4 is located on the posterior part of the fusiform gyrus and abuts the rostral border of the putative human VP (Sereno et al., 1995). The position and extent as well as the architecture of the area peristriata magnopyramidalis of Braak (1977) make this pigmentoarchitectonicly well-defined cortical region to an architectonic candidate for human V4. An area comparable to V4 has been called V8 by Tootell et al. (1998) (see also Fig. 27.28). V4 contains large pyramidal cells in layers III and V and shows a dark COX staining. Both criteria allow a delineation of this area from VP (Clarke, 1994a). The myelin density is well above average in human and monkey V4 (Zilles and Clarke, 1997).

A ventral area V4v—separable from V4—has been identified by using fMRI (Sereno et al., 1995) and phaseencoded retinal stimulation. This area adjoins the ventral half of the anterior border of VP (Fig. 27.28). This border represents the vertical meridian, whereas the horizontal meridian is found at the anterior border of V4v. Human V4v contains the upper visual field as in monkeys with a non–mirror image representation of the visual field. Architectonic descriptions of this area are presently not available.

Additional color foci were described on the human dorsolateral occipital cortex (Corbetta et al., 1991). Colors as attributes of objects are also represented in a cortical region rostral to V4 (Martin et al., 1995). A face and familiarity recognition area is identifiable medially of this region (Allison et al., 1993, 1994; Clarke et al., 1997; Nakamura et al., 2000) in the posterior temporal part of the fusiform gyrus. This region is also activated by passive viewing of faces (Puce et al., 1995) and by matching of unknown faces (Haxby et al., 1994) in the right hemisphere, but is found more anterior and lateral in the left hemisphere. At least part of this left hemispheric region may be part of a cortical system representing working memory for faces (Haxby et al., 1995).

Expertise Effects in the FFA

Studies have now shown that the fusiform gyrus is recruited for visual objects of expertise (Gauthier, Skudlarski, Gore, & Anderson, 2000; Gauthier, Tarr, Anderson, Skudlarski, & Gore, 1999; Tarr & Gauthier, 2000; Wong, Palmeri, Rogers, Gore, & Gauthier, 2009; but see Op de Beeck, Baker, DiCarlo, & Kanwisher, 2006). For example, when people are trained for thousands of trials to tell apart visually similar nonsense objects (‘greebles’), not only will they become better at this task, but also their performance will start to show signs of increased holistic and configural processing, even for new objects in the category for which they have become visual experts (Gauthier, Williams, Tarr, & Tanaka, 1998). Objects from a category of expertise will also start to evoke greater activity in the FFA (Gauthier et al., 1999; see Figure 1).

Real-world experts also recruit the FFA for the objects of their expertise. As an example, James and James (2013) studied children with an intense interest in Pokémon trading cards at an age where face expertise has not reached its peak. These children show a greater blood-oxygen-level dependent (BOLD) activation in the FFA for Pokémon characters than age-matched controls, but not for Digimon characters found on other types of trading cards. Of course, Pokémon characters have faces, begging the question that FFA is only important for the visual processing of objects of expertise if those objects have faces or face-like qualities. This, however, does not appear to be a necessity. Compared with other children, the experts also show greater FFA activation for so-called Pokémon objects, which do not have faces (in the FFA defined individually, see James & James, 2013, supplementary material). It therefore seems like expertise with a stimulus, and not just its visual appearance, is an important factor.

This is bolstered by further evidence. For instance, when compared to novices, chess experts show greater FFA BOLD activity for full-board chess positions (Bilalić, Langner, Ulrich, & Grodd, 2011). Chessboards are complex objects with multiple parts in meaningful spatial relations, yet they look quite distinct from faces. FFA activity in chess experts alone was also sensitive to the disruption of relational information in the chessboards, such as when the boards were turned upside down or the position of the chess pieces was randomized, consistent with the hypothesis that the FFA is important for configural processing of visual objects. As people become greater experts with chess, they will also show increased holistic processing of chessboards (Boggan, Bartlett, & Krawczyk, 2012). Curiously, this increase goes hand in hand with decreased holistic processing for faces (Boggan et al., 2012). This trade-off indicates that face recognition and chess recognition share a common process in people who presumably are experts in both domains (see also McGugin, McKeeff, Tong, & Gauthier, 2011; McKeeff, McGugin, Tong, & Gauthier, 2010).

Functional neuroimaging might be considered a rather crude method for studying neural specificity; in a typical fMRI experiment, BOLD signal within a single voxel is caused by the summed activity of millions of individual neurons. A truly face-specific region in the fusiform cortex might therefore be spatially distinct from a region utilized for objects of expertise, but signals from neurons in these two brain areas could become intermingled in a standard-sized voxel. McGugin, Gatenby, Gore, and Gauthier (2012) sought to explore this possibility by utilizing the greater signal-to-noise ratio of an ultrahigh-field-strength magnet (7 T) to image activity within and around the FFA at a finer spatial resolution. They scanned people with varying degrees of car expertise, measured as the degree to which they could judge whether images (shown outside the scanner) depicted cars from the same make and model.

Consistent with other studies (Gauthier et al., 2000), McGugin, Gatenby, et al. (2012) found that when people viewed cars, the FFA was recruited to an increasing degree with greater levels of car expertise. This is also compatible with the finding that cars are processed holistically by experts (Bukach, Phillips, & Gauthier, 2010) and that holistic processing relies on the FFA. Crucially, this expertise effect was found even in the most face-selective voxels within the FFA (see Figure 1). Expertise effects are found in a highly face-selective patch of cortex, a little over a cubic millimeter in volume, where according to neurophysiology in the monkey brain (Tsao et al., 2006), 97% of the neurons are face-selective. If the single cell recording results generalize to the human brain, this suggests that face-selective neurons also respond to a great degree to other objects of expertise that, like faces, tend to be processed in a holistic manner.

1.30.3.2 Fusiform Face Area

Neuroimaging studies have shown a specific region within the fusiform gyrus that is significantly more active when viewing faces (Sergent, J. and Signoret, J. L., 1992; Haxby, J. V. et al., 1996) compared to other nonface stimuli such as objects (Kanwisher, N. et al., 1997), letter strings (Puce, A. et al., 1996), or houses (Tong, F. et al., 2000). This area has been termed the fusiform face area (FFA) (Kanwisher, N. et al., 1997). Human FFA appears to be topographically homologous to the macaque face patches located in the middle of the STS (Tsao, D. Y. et al., 2003a; 2006). The FFA shows a higher response to upright than inverted faces (Yovel, G. and Kanwisher, N., 2005; but see Epstein, R. A. et al., 2006), suggesting that upright faces are processed holistically in the FFA (see Tanaka, J. W. and Farah, M., 2003, for review). Holistic/configural aspects of face processing may be observed preferentially in the right FFA (Rossion, B. et al., 2000; but see Yovel, G. and Kanwisher, N., 2004). Recently, fMR-adaptation paradigms have elegantly revealed that the FFA contains subpopulations of neurons, which are selectively tuned to face identity (Rotshtein, P. et al., 2005; Loffler, G. et al., 2005).

FFA activation correlates well with successful face processing but not with successful object processing (Grill-Spector, K. et al., 2004). Other experiments have also used bistable phenomena such as binocular rivalry (Tong, F. et al., 1998), and the Rubin face-vase illusion (Hasson, U. et al., 2001; Andrews, T. J. et al., 2002) to show the correlation of FFA activation with different perceptual states.

Currently, there is debate whether the function of the FFA is truly specific to faces, or whether it instead involves a domain-general operation that could in principle be applied to other stimulus categories. Gauthier and colleagues have argued that the right FFA is an expertise center, responding better to any overtrained visual stimuli, including (but not limited to) faces (Tarr, M. J. and Gauthier, I., 2000). For instance, the FFA is reportedly activated by cars in car experts and by birds in bird experts (Gauthier, I. et al., 2000a). The FFA is also more active when participants become expert at distinguishing computer-generated nonsense shapes known as greebles (Gauthier, I. et al., 1999). These evidence led Tarr M. J. and Gautier I. (2000) to reinterpret the name FFA as the flexible fusiform area. Additional evidence that has challenged the role of FFA in face processing is apparently normal face-related fMRI activation in the FFA in congenital prosopagnosic individuals who are markedly impaired at face processing (Hasson, U. et al., 2003a; Avidan, G. et al., 2005; Behrmann, M. and Avidan, G., 2005).

Early studies of face-selective activation in the cortex have reported that, in addition to the FFA, other cortical areas are selectively active for faces, specifically in the STS and in the inferior and mid-occipital gyri (e.g., Kanwisher, N. et al., 1997; Halgren, E. et al., 1999; Haxby, J. V. et al., 1999; Vaina, L. M. et al., 2001), although in some studies these areas appeared to be less systematically activated (e.g., Kanwisher, N. et al., 1997) or showed a weaker face-selective response (Gauthier, I. et al., 2000b) than did the FFA. Gauthier I. et al. (2000b) termed the face-selective inferior occipital area that falls within the larger LOC region, the occipital face area (OFA).

The ‘Visual Word Form Area’

A region of left ventral temporal cortex, on the fusiform gyrus, is involved in processing the printed forms of words. Evidence that this region plays a role in early visual processing of written words comes from studies using a wide range of techniques. Within less than 200 ms after a stimulus is presented, electrophysiological responses in this region differentiate words from nonlinguistic visual stimuli. Patients with brain damage in this region present with alexia – an inability to read, often with a spared ability to write. Furthermore, metabolic neuroimaging techniques consistently show a role for this region in reading. Whether activity in this region is specific to words is under debate, as is its specific function, although anatomical and functional evidence suggests that it intermediates among lower level visual information and the phonological and semantic processes involved in recognizing visual words. Bilateral ventral temporal cortex has been implicated in many tasks involving perceptual expertise for visual stimuli. Specialization for text in this region may thus be understood as an example of perceptual expertise.

2.8.2 The Fusiform Face Area

Human neuroimaging studies have shown that a region in the fusiform gyrus, called the FFA, responds more strongly to faces than to just about any other category of objects (Kanwisher et al., 1997). This region responds more to human, animal, and cartoon faces than to a variety of nonface stimuli, including hands, bodies, eyes shown alone, back views of heads, flowers, buildings, and inanimate objects (Kanwisher et al., 1997; McCarthy et al., 1997; Schwarzlose et al., 2005; Tong et al., 2000). In a recent study, researchers tried scanning the brains of monkeys to see if they might also have a face-selective area in the ventral temporal cortex, and it turns out that they do too (Tsao et al., 2006). The researchers then recorded the activity of single neurons in this face area and discovered that 97% of the neurons in this region responded more to faces than to other kinds of objects. Moreover, these neurons were very good at telling apart different identities of faces but poor at telling apart different identities of objects, suggesting they may have an important role in recognizing and telling apart different faces. As we will see, this region seems to be important for the conscious perception of faces (Fig. 4.11B–D).

Considerations for Future Research of AUD and EFE Processing

To better understand how occipito-temporal regions, specifically the FG for facial expressions, contribute to difficulties in emotional face processing in AUD, it is critical to recruit large sample sizes to investigate how key brain regions and their neural network interconnectivity are altered. For most studies on AUD, comorbidity should be considered as other substances may contribute to the neural mesocorticolimbic network response to emotion and alcohol cues. AUD not only occurs in conjunction with other abuse of substance, it also shows a high comorbidity with psychiatric disorders, often making it difficult to pinpoint the unique contribution of alcohol addiction to difficulties in emotion processing, specifically facial expressions that uniquely convey human interaction and communication skills.

What part of the temporal lobe controls facial recognition?

What lobe of the brain is most likely involved with facial recognition?

Is the frontal lobe responsible for facial recognition?