Structure and function in acquired prosopagnosia: Lessons from a series of 10 patients with brain damage

Acquired prosopagnosia varies in both behavioural manifestations and the location and extent of underlying lesions. We studied 10 patients with adult‐onset lesions on a battery of face‐processing tests. Using signal detection methods, we found that discriminative power for the familiarity of famous faces was most reduced by bilateral occipitotemporal lesions that involved the fusiform gyri, and better preserved with unilateral right‐sided lesions. Tests of perception of facial structural configuration showed severe deficits with lesions that included the right fusiform gyrus, whether unilateral or bilateral. This deficit was most consistent for eye configuration, with some patients performing normally for mouth configuration. Patients with anterior temporal lesions had better configuration perception, though at least one patient showed a more subtle failure to integrate configural data from different facial regions. Facial imagery, an index of facial memories, was severely impaired by bilateral lesions that included the right anterior temporal lobe and marginally impaired by fusiform lesions alone; unilateral right fusiform lesions tended to spare imagery for facial features. These findings suggest that (1) prosopagnosia is more severe with bilateral than unilateral lesions, indicating a minor contribution of the left hemisphere to face recognition, (2) perception of facial configuration critically involves the right fusiform gyrus and (3) access to facial memories is most disrupted by bilateral lesions that also include the right anterior temporal lobe. This supports assertions that more apperceptive variants of prosopagnosia are linked to fusiform damage, whereas more associative variants are linked to anterior temporal damage. Next, we found that behavioural indices of covert recognition correlated with measures of overt familiarity, consistent with theories that covert behaviour emerges from the output of damaged neural networks, rather than alternative pathways. Finally, to probe the face specificity of the prosopagnosic defect, we tested recognition of fruits and vegetables: While face specificity was not found in most of our patients, the data of one patient suggested that this may be possible with more focal lesions of the right fusiform gyrus.     

Perceptual functions in prosopagnosia

Some patients with prosopagnosia may have an apperceptive basis to their recognition defect. Perceptual abnormalities have been reported in single cases or small series, but the causal link of such deficits to prosopagnosia is unclear. Our goal was to identify candidate perceptual processes that might contribute to prosopagnosia, by subjecting several prosopagnosic patients to a battery of functions that may be necessary for accurate facial perception. We tested seven prosopagnosic patients. Three had unilateral right occipitotemporal lesions, two had bilateral posterior occipitotemporal lesions, and one had right anterior-to-occipital temporal damage along with a small left temporal lesion. These lesions all included the fusiform face area, in contrast to one patient with bilateral anterior temporal lesions. Most patients had impaired performance on face-matching tests and difficulty with subcategory judgments for non-face objects. The most consistent deficits in patients with lesions involving the fusiform face area were impaired perception of spatial relations in dot patterns and reduced contrast sensitivity in the 4 to 8 cycles deg(-1) range. Patients with bilateral lesions were impaired in saturation discrimination. Luminance discrimination was normal in all but two patients, and spatial resolution was uniformly spared. Curvature and line-orientation discrimination were impaired in only one patient, who also had the most difficulty with more basic-level object recognition. We conclude that deficits in luminance, spatial resolution, curvature, line orientation, and contrast at low spatial frequencies are unlikely to contribute to apperceptive prosopagnosia. More relevant may be contrast sensitivity at higher spatial frequencies and the analysis of object spatial structure. Deficits in these functions may impair perception of subtle variations in object shape, and may be one mechanism by which the recognition defect in prosopagnosia can extend to other classes of object subcategorization.     

Neural systems behind word and concept retrieval

Using both the lesion method and functional imaging (positron emission tomography) in large cohorts of subjects investigated with the same experimental tasks, we tested the following hypotheses: (A) that the retrieval of words which denote concrete entities belonging to distinct conceptual categories depends upon partially segregated regions in higher-order cortices of the left temporal lobe; and (B) that the retrieval of conceptual knowledge pertaining to the same concrete entities also depends on partially segregated regions; however, those regions will be different from those postulated in hypothesis A, and located predominantly in the right hemisphere (the second hypothesis tested only with the lesion method). The analyses provide support for hypothesis A in that several regions outside the classical Broca and Wernicke language areas are involved in name retrieval of concrete entities, and that there is a partial segregation in the temporal lobe with respect to the conceptual category to which the entities belong, and partial support for hypothesis B in that retrieval of conceptual knowledge is partially segregated from name retrieval in the lesion study. Those regions identified here are seen as parts of flexible, multi-component systems serving concept and word retrieval for concrete entities belonging to different conceptual categories. By comparing different approaches the article also addresses a number of method issues that have surfaced in recent studies in this field.     

Dissociable neural systems for recognizing emotions

This study tested the hypothesis that the recognition of emotions would draw upon anatomically separable brain regions, depending on whether the stimuli were static or explicitly conveyed information regarding actions. We investigated the hypothesis in a rare subject with extensive bilateral brain lesions, patient B., by administering tasks that assessed recognition and naming of emotions from visual and verbal stimuli, some of which depicted actions and some of which did not. B. could not recognize any primary emotion other than happiness, when emotions were shown as static images or given as single verbal labels. By contrast, with the notable exception of disgust, he correctly recognized primary emotions from dynamic displays of facial expressions as well as from stories that described actions. Our findings are consistent with the idea that information about actions is processed in occipitoparietal and dorsal frontal cortices, all of which are intact in B.'s brain. Such information subsequently would be linked to knowledge about emotions that depends on structures mapping somatic states, many of which are also intact in B.'s brain. However, one of these somatosensory structures, the insula, is bilaterally damaged, perhaps accounting for B.'s uniformly impaired recognition of disgust (from both static and action stimuli). Other structures that are damaged in B.'s brain, including bilateral inferior and anterior temporal lobe and medial frontal cortices, appear to be critical for linking perception of static stimuli to recognition of emotions. Thus the retrieval of knowledge regarding emotions draws upon widely distributed and partly distinct sets of neural structures, depending on the attributes of the stimulus.     

Varieties of alexia from fusiform, posterior inferior temporal and posterior occipital gyrus lesions

Reading impairments of three alexia patients, two pure alexia and one alexia with agraphia, due to different lesions were examined quantitatively, using Kanji (Japanese morphogram) words, Kana (Japanese phonetic writing) words and Kana nonwords. Kana nonword reading was impaired in all three patients, suggesting that widespread areas in the affected occipital and occipitotemporal cortices were recruited in reading Kana characters (corresponding to European syllables). In addition, the findings in patient 1 (pure alexia for Kanji and Kana from a fusiform and lateral occipital gyri lesion) and patient 2 (pure alexia for Kana from a posterior occipital gyri lesion) suggested that pure alexia could be divided into two types, i.e. ventromedial type in which whole-word reading, together with letter identification, is primarily impaired because of a disconnection of word-form images from early visual analysis, and posterior type in which letter identification is cardinally impaired. Another type of alexia, alexia with agraphia for Kanji from a posterior inferior temporal cortex lesion (patient 3), results from deficient whole-word images of words per se, and thus should be designated "orthographic alexia with agraphia". To account for these impairments, a weighted dual-route hypothesis for reading is suggested.     

成年雄性斑胸草雀高级发声中枢鸣声控制的右侧优势

鸣禽是研究语言功能的动物模型。鸣禽端脑的高级发声中枢(high vocal center, HVC)与人类布洛卡氏区具有功能同源性。利用电损毁与声谱分析相结合的方法, 对成年雄性斑胸草雀两侧HVC分别进行电损毁, 观察HVC控制鸣声的侧别差异。结果表明, 损毁左侧HVC对长鸣和鸣曲的频域和声强特征均无显著性影响。损毁右侧HVC导致长鸣的振幅、调频、幅度调制显著减小(p < 0.05), 鸣曲的振幅、平均频率、峰频率显著减小(p < 0.05)。损毁双侧HVC后均引起鸣曲时域特征的改变, 暗示鸣曲时域特征的编码需要两侧半球鸣唱系统的整合。HVC在控制鸣声频域和声强特征上具有右侧优势, 但对鸣曲时域特征的控制需要两侧HVC的共同参与。     

Whose picture is this? Children's memory for item and source information

Children aged 3½ to 6½ years viewed pictures of common objects presented either once or three times on one of two consecutive days. A different hand puppet was used to present the pictures on each day, providing both perceptual and temporal cues to source. At test, old (studied) and new (non‐studied) pictures were presented for item recognition and source identification. Results showed that both item and source accuracy were higher for older (M = 5; 9 years) than younger children (M = 4; 6 years). Significant interactions between Age and Day of study were found for both item and source accuracy. For younger children, accuracy was higher for pictures studied on Day 1 than Day 2 (significant for source identification but not item recognition), whereas older children showed the opposite pattern: Higher accuracy for Day 2 than Day 1 (significant for item recognition but not source identification). Results are interpreted with respect to proactive interference and response bias. The utility of signal detection theory measures in determining the basis of age differences in performance of source identification is discussed.     

The effect of emotion-focused orientation at retrieval on emotional memory in young and older adults

This study examines how emotion-focused orientation at retrieval affects memory for emotional versus neutral images in young and older adults. A total of 44 older adults (ages 61–84 years, M=70.00, SD=5.54) and 43 young adults (ages 17–33 years, M=20.58, SD=3.72) were tested on their free recall and forced-choice recognition of images. At retrieval the emotion-focused orientation was manipulated by instructing participants to focus on emotion-related information (i.e., emotional content of images and the emotional reactions evoked by the images). In the control conditions participants were either instructed to focus on visual information or not provided any specific orientation instruction. In free recall but not forced-choice recognition, the emotion-focused orientation increased young adults’ positivity bias and thus wiped out their superior negativity bias. However, the emotion-focused orientation did not affect older adults’ emotional memory. The data suggest that young adults activate and prioritise emotional goals in response to external demand during intentional information processing whereas older adults seem to spontaneously tune themselves to emotional goals.     

Social and emotional functioning following bilateral and unilateral neurosurgical prefrontal cortex lesions

Alterations in emotional and social functioning such as impaired ability to recognize emotions in others, a lack of empathy and poor insight have commonly been reported following prefrontal cortex damage. This study sought to investigate the subtleties of such difficulties in 34 individuals with discrete unilateral and bilateral neurosurgical lesions encroaching on the orbitofrontal, medial, and dorsolateral regions of the prefrontal cortex. A specifically devised self‐ and informant report measure, the social‐emotional questionnaire was used to examine five factors of functioning: emotion recognition; empathy; social conformity; antisocial behaviour; and sociability. There were some specific significant differences between the clinical and control groups' informant‐ratings in certain domains of social and emotional functioning. Individuals with damage involving the orbitofrontal region were reported to display elevated levels of antisocial behaviour. Individuals with bilateral orbitofrontal lesions were rated as showing significantly reduced social and emotional functioning in comparison with individuals with unilateral lesions and controls. In addition, individuals with bilateral lesions had significantly less insight overall regarding their social‐emotional abilities. The right unilateral lesion group showed significantly less insight into their abilities to recognize emotion in others in comparison with the left unilateral group. In conclusion, these results suggest that specific social‐emotional and insight deficits may form separate constellations of impairment. The findings also indicate that marked changes in social and emotional functioning are more likely following bilateral damage, and unilateral lesions do not inevitably lead to impairments.     

Effects of lesions of the central nucleus of the anterior archistriatum on contact call and warble song production in the budgerigar (Melopsittacus undulatus)

We studied the effects of both unilateral and bilateral lesions of the central nucleus of the anterior archistriatum (AAc) on the production of contact calls and warble song in adult male and female budgerigars. Birds were sorted into three experimental groups based on the percentage of AAc destroyed and whether lesions were unilateral or bilateral. The experimental groups were Unilateral Lesion (N = 8), Partial Bilateral Lesion (N = 5), and Bilateral Lesion birds (N = 12). Each group contained both sexes. Unilateral lesions had no demonstrable effects on contact call or warble song production. Bilateral lesions resulted in immediate and permanent disruption of all learned temporal and spectral characteristics of contact calls, although call initiation was not dependent on the AAc. Partial bilateral lesion effects varied with lesion size and location. At least 20-30% sparing of the AAc, including sparing portions of both the dorsal (AAcd) and ventral (AAcv) subdivisions on the same side of the brain, is necessary for production of prelesion contact call patterns. Warble song was absent in birds with complete bilateral destruction. Two birds with large yet incomplete lesions of the AAc sang after surgery, although the warble song of these birds was extremely impoverished and contained only a few of the typical warble song elements. Lesion results indicate that the AAc mediates the production of learned vocal features in male and female budgerigars, with each hemisphere capable of supporting a normal vocal repertoire.     

Unitary vs multiple semantics: PET studies of word and picture processing

In this paper we examine a central issue in cognitive neuroscience: are there separate conceptual representations associated with different input modalities (e.g., Paivio, 1971, 1986; Warrington & Shallice, 1984) or do inputs from different modalities converge on to the same set of representations (e.g., Caramazza, Hillis, Rapp, & Romani, 1990; Lambon Ralph, Graham, Patterson, & Hodges, 1999; Rapp, Hillis, & Caramazza, 1993)? We present an analysis of four PET studies (three semantic categorisation tasks and one lexical decision task), two of which employ words as stimuli and two of which employ pictures. Using conjunction analyses, we found robust semantic activation, common to both input modalities in anterior and medial aspects of the left fusiform gyrus, left parahippocampal and perirhinal cortices, and left inferior frontal gyrus (BA 47). There were modality-specific activations in both temporal poles (words) and occipitotemporal cortices (pictures). We propose that the temporal poles are involved in processing both words and pictures, but their engagement might be primarily determined by the level of specificity at which an object is processed. Activation in posterior temporal regions associated with picture processing most likely reflects intermediate, pre-semantic stages of visual processing. Our data are most consistent with a hierarchically structured, unitary system of semantic representations for both verbal and visual modalities, subserved by anterior regions of the inferior temporal cortex.     

Shindigs,brunches, and rodeos: The neural basis of event words

Events (e.g., “running” or “eating”) constitute a basic type within human cognition and human language. We asked whether thinking about events, as compared to other conceptual categories, depends on partially independent neural circuits. Indirect evidence for this hypothesis comes from previous studies showing elevated posterior temporal responses to verbs, which typically label events. Neural responses to verbs could, however, be driven either by their grammatical or by their semantic properties. In the present experiment, we separated the effects of grammatical class (verb vs. noun) and semantic category (event vs. object) by measuring neural responses to event nouns (e.g., “the hurricane”). Participants rated the semantic relatedness of event nouns, as well as of two categories of object nouns—animals (e.g., “the alligator”) and plants (e.g., “the acorn”)—and three categories of verbs—manner of motion (e.g., “to roll”), emission (e.g., “to sparkle”), and perception (e.g., “to gaze”). As has previously been observed, we found larger responses to verbs than to object nouns in the left posterior middle (LMTG) and superior (LSTG) temporal gyri. Crucially, we also found that the LMTG responds more to event than to object nouns. These data suggest that part of the posterior lateral temporal response to verbs is driven by their semantic properties. By contrast, a more superior region, at the junction of the temporal and parietal cortices, responded more to verbs than to all nouns, irrespective of their semantic category. We concluded that the neural mechanisms engaged when thinking about event and object categories are partially dissociable.     

The Underlying Architecture of the Creative Worlds of Children: Young Persons from the UK and China Unwittingly Generate More Concepts that Violate Ontological Category Structure Than Do Older Adults During an Exemplar‐Generation Task

Is our cognition the underlying architecture of the recurrent and pan‐cultural imaginative ideas of children and adolescents? Recent cross‐cultural studies show that children and adolescents recall proportionally more creative, counterintuitive concepts than older adults. One outstanding concern is that cultural transmission is also constrained by how concepts emerge into culture. Hence, a broad sample of age demographics in UK and China (10–58 years; N = 90) participated in an exemplar‐generation task where participants assembled statements exemplifying conceptual categories of positive and negative emotion, imagery, humor, and inferential potential. Multiple regression analysis considering counterintuitiveness and age revealed young persons generated significantly more imaginative, counterintuitive ideas than older adults, in both UK and China groups. This cross‐cultural support for an underlying cognitive architecture of human creativity builds on Ward's (1994) research on structured imagination.     

The distributed human neural system for face perception

Face perception, perhaps the most highly developed visual skill in humans, is mediated by a distributed neural system in humans that is comprised of multiple, bilateral regions. We propose a model for the organization of this system that emphasizes a distinction between the representation of invariant and changeable aspects of faces. The representation of invariant aspects of faces underlies the recognition of individuals, whereas the representation of changeable aspects of faces, such as eye gaze, expression, and lip movement, underlies the perception of information that facilitates social communication. The model is also hierarchical insofar as it is divided into a core system and an extended system. The core system is comprised of occipitotemporal regions in extrastriate visual cortex that mediate the visual analysis of faces. In the core system, the representation of invariant aspects is mediated more by the face-responsive region in the fusiform gyrus, whereas the representation of changeable aspects is mediated more by the face-responsive region in the superior temporal sulcus. The extended system is comprised of regions from neural systems for other cognitive functions that can be recruited to act in concert with the regions in the core system to extract meaning from faces.     

Neural correlates of temporal auditory processing in developmental dyslexia during German vowel length discrimination: an fMRI study

This fMRI study investigated phonological vs. auditory temporal processing in developmental dyslexia by means of a German vowel length discrimination paradigm (Groth, Lachmann, Riecker, Muthmann, & Steinbrink, 2011). Behavioral and fMRI data were collected from dyslexics and controls while performing same-different judgments of vowel duration in two experimental conditions. In the temporal, but not in the phonological condition, hemodynamic brain activation was observed bilaterally within the anterior insular cortices in both groups and within the left inferior frontal gyrus (IFG) in controls, indicating that the left IFG and the anterior insular cortices are part of a neural network involved in temporal auditory processing. Group subtraction analyses did not demonstrate significant effects. However, in a subgroup analysis, participants performing low in the temporal condition (all dyslexic) showed decreased activation of the insular cortices and the left IFG, suggesting that this processing network might form the neural basis of temporal auditory processing deficits in dyslexia.     

EEG decoding of semantic category reveals distributed representations for single concepts

Achieving a clearer picture of categorial distinctions in the brain is essential for our understanding of the conceptual lexicon, but much more fine-grained investigations are required in order for this evidence to contribute to lexical research. Here we present a collection of advanced data-mining techniques that allows the category of individual concepts to be decoded from single trials of EEG data. Neural activity was recorded while participants silently named images of mammals and tools, and category could be detected in single trials with an accuracy well above chance, both when considering data from single participants, and when group-training across participants. By aggregating across all trials, single concepts could be correctly assigned to their category with an accuracy of 98%. The pattern of classifications made by the algorithm confirmed that the neural patterns identified are due to conceptual category, and not any of a series of processing-related confounds. The time intervals, frequency bands and scalp locations that proved most informative for prediction permit physiological interpretation: the widespread activation shortly after appearance of the stimulus (from 100 ms) is consistent both with accounts of multi-pass processing, and distributed representations of categories. These methods provide an alternative to fMRI for fine-grained, large-scale investigations of the conceptual lexicon.     

Pyramidal parent training using behavioral skills training: Training caregivers in the use of a differential reinforcement procedure

Six caregivers participated in a research study in which behavioral skills training (BST) was used within a pyramidal training model to train a differential reinforcement of an alternative behavior (DRA) procedure. Physical prompting was utilized to obtain correct responses across the identified alternative behavior. The caregivers were split into two tiers, comprised of three caregivers each. The experimenter trained tier‐one caregivers, who then trained tier‐two caregivers after meeting a predetermined mastery criterion. A multiple baseline design across participants research design was used to evaluate the effectiveness of correct implementation of the DRA procedure, demonstrating experimental control across participants. During baseline, caregivers did not implement DRA correctly. Following training, tier‐one and tier‐two caregivers demonstrated correct implementation of the DRA and prompting procedure. Intervention score was (M = 96%), from a baseline score of (M = 34.6%), for tier‐one participants. Intervention score was (M = 96.6%), from a baseline score of (M = 33%), for tier‐two participants. A follow‐up maintenance probe demonstrated correct implementation of the DRA procedure with prompting across both tiers of trained caregivers.     

Impaired auditory recognition memory in amnesic patients with medial temporal lobe lesions

Two tests of auditory recognition memory were given to four patients with bilateral hippocampal damage (H+) and three patients with large medial temporal lobe lesions and additional variable damage to lateral temporal cortex (MTL+). When single stimuli were presented, performance was normal across delays as long as 30 sec, presumably because information could be maintained in working memory through rehearsal. When lists of 10 stimuli were presented, performance was impaired after a 5-min delay. Patients with MTL+ lesions performed marginally worse than patients with H+ lesions, consistent with findings for recognition memory in other modalities. The findings show that auditory recognition, like recognition memory in other sensory modalities, is dependent on the medial temporal lobe.     

Group and Leadership Effects on Social Anxiety Experienced During an Exercise Class1

This study examined the effects of the group environment and group leadership style on social anxiety experienced by participants (N= 90) in a 40‐min step aerobics class. In a 2±2 factorial design, group environment (enriched/bland) was manipulated, along with the fitness instructor's leadership style (enriched/bland). Participants in the enriched group condition had significantly higher social anxiety (M= 15.1) than did those in the bland group condition (M= 12.0, p < 0.05). Also, participants tended to have less social anxiety when the instructor used an enriched leadership style (M= 12.4) than when she used a bland leadership style (M= 14.8, p= 0. 08). Discussion focuses on aspects of the social environment that can affect social anxiety during group exercise classes.     

How age affects memory task performance in clinically normal hearing persons

The main objective of this study is to investigate memory task performance in different age groups, irrespective of hearing status. Data are collected on a short-term memory task (WAIS-III Digit Span forward) and two working memory tasks (WAIS-III Digit Span backward and the Reading Span Test). The tasks are administered to young (20–30 years, n = 56), middle-aged (50–60 years, n = 47), and older participants (70–80 years, n = 16) with normal hearing thresholds. All participants have passed a cognitive screening task (Montreal Cognitive Assessment (MoCA)). Young participants perform significantly better than middle-aged participants, while middle-aged and older participants perform similarly on the three memory tasks. Our data show that older clinically normal hearing persons perform equally well on the memory tasks as middle-aged persons. However, even under optimal conditions of preserved sensory processing, changes in memory performance occur. Based on our data, these changes set in before middle age.