Papers by Alfonso Caramazza
Nature Communications, Jun 7, 2023
bioRxiv (Cold Spring Harbor Laboratory), Jun 1, 2023
Human visual experience of objects comprises a combination of different visual features, such as ... more Human visual experience of objects comprises a combination of different visual features, such as their color, position, and shape. Spatial attention is thought to play a role in creating a coherent perceptual experience, integrating visual information coming from a given location, but the mechanisms underlying this process are not entirely understood. Deficits of spatial attention in which this integration process does not occur normally, such as neglect, can provide insights regarding the mechanisms of spatial attention in visual object recognition. In this study, we describe a series of experiments conducted with an individual with neglect, XX. XX presents characteristic lack of awareness of the left side of individual objects, evidenced by poor object and face recognition, and impaired word reading. However, he exhibits intact recognition of color within the boundaries of the same objects he fails to recognize. Furthermore, he can also report the orientation and location of a colored region on the neglected left side despite lack of awareness of the shape of the region. To our knowledge, selective lack of awareness of shape despite intact processing of basic visual features in the same spatial location has not been reported previously. XX's performance raises intriguing questions and challenges about the role of spatial attention in the formation of coherent object percepts and visual awareness. .
Neuropsychology and cognition, 1991
Neuropsychologia, Nov 1, 2021
Although a great deal is known about the early sensory and the later, perceptual, stages of visua... more Although a great deal is known about the early sensory and the later, perceptual, stages of visual processing, far less is known about the nature of intermediate representational units and reference frames. Progress in understanding intermediate levels of representations in vision is hindered by the complexity and interactions between multiple levels of representation in the visual system, making it difficult to isolate and study the nature of one particular level. Nature occasionally provides the opportunity to peer inside complex systems by isolating components of a system through accidental damage or genetic modification of neural components. We have recently reported the case of a young woman who perceives 2D bounded regions of space as if they were plane-rotated by 90, 180 or 270 degrees around their center, mirrored across their own axes, or both. This suggested that an intermediate stage of processing consists in representing mutually exclusive 2D bounded regions extracted from the retinal image in their own "shape-centered" perceptual frame. We proposed to refer to this level of representation as "intermediate shape-centered representation" (ISCR). Here, we used Davida's pattern of errors across 9 experiments as a tool for specifying in greater detail the geometrical properties of the reference frame in which elongated and/or symmetrical shapes are represented at the level of the ISCR. The nature of Davida's errors in these experiments suggests that ISCRs are represented in reference frames composed of orthogonal axes aligned and centered onto the most elongated segment of elongated shapes and, for symmetrical shapes deprived of a straight segment, aligned to their axis of symmetry, and centered on their centroid.
Journal of Vision, Sep 1, 2015
Visual information is transformed from early sensory formats into increasingly abstract represent... more Visual information is transformed from early sensory formats into increasingly abstract representations of its content. We probed this abstraction by exploring the convergence in the neural responses to pictures of objects and their spoken names, taking a broad look at several major semantic divisions between object categories. Our aim was to explore which neural regions show reliable responses that are specific to visual pictures, specific to auditory words, or common between these two modalities, using a data-driven clustering approach. Using fMRI, we measured neural response patterns to objects from 18 broad semantic categories, presented as both pictures and auditory words, in 16 participants. We used a clustering technique to group together voxels by their response profile similarity over these 18 categories, in a way that is agnostic to where the voxels are located and whether they reflect responses from the visual or auditory modality. They key advantage of this procedure is that it simultaneously discovers common and unique structure across both modalities without presupposing any regional boundaries in advance. This analysis identified several regions with similar neural profiles to pictures and words (parahippocampal, transverse occipital sulcus, retrosplenial cortex), which primarily had a response preference for inanimate categories of objects. In contrast, other neural regions were only reliably modulated by pictorial stimuli (lateral occipital, fusiform), and these regions primarily had a response preference to pictures of animate entities. Taken together, these results demonstrate a surprising and currently unexplained link between the neural organization of broad object domains and activations by different modalities. Meeting abstract presented at VSS 2015.
Journal of Cognitive Neuroscience, Apr 1, 2021
All it takes is a face to face conversation in a noisy environment to realize that viewing a spea... more All it takes is a face to face conversation in a noisy environment to realize that viewing a speaker's lip movements contributes to speech comprehension. What are the processes underlying the perception and interpretation of visual speech? Brain areas that control speech production are also recruited during lip reading. This finding raises the possibility that lipreading may be supported, at least to some extent, by a covert unconscious imitation of the observed speech movements in the observer's own speech motor system-a motor simulation. However, whether, and if so to what extent motor simulation contributes to visual speech interpretation remains unclear. In two experiments, we found that several participants with congenital facial paralysis were as good at lipreading as the control population and performed these tasks in a way that is qualitatively similar to the controls despite severely reduced or even completely absent lip motor representations. Although it remains an open question whether this conclusion generalizes to other experimental conditions and to typically developed participants, these findings considerably narrow the space of hypothesis for a role of motor simulation in lipreading. Beyond its theoretical significance in the field of speech perception, this finding also calls for a re-examination of the more general hypothesis that motor simulation underlies action perception and interpretation developed in the frameworks of motor simulation and mirror neuron hypotheses. individuals' sensorimotor system, but also their visual, perceptual, cognitive, and social 90 abilities to various extents (Bate et al.,
Journal of Vision, Aug 31, 2017
Visual object recognition is impaired when stimuli are shown upside-down. This phenomenon is know... more Visual object recognition is impaired when stimuli are shown upside-down. This phenomenon is known as the inversion effect, and a substantial body of evidence suggests it is much larger for faces than non-face objects. The large inversion effect for faces has been widely used as key evidence that face processing is special, and hundreds of studies have used it as a tool to investigate face-specific processes. Here we show that large inversion effects are not specific to faces. We developed two car tasks that tap basic object recognition and within-class recognition. Both car tasks generated large inversion effects (~25% on a three-choice format), which were identical to those produced by parallel face tasks. Additional analyses showed that the large car inversion effects did not vary with expertise. Our findings demonstrate that non-face object recognition can depend on processes that are highly orientation-specific, challenging a critical behavioral marker of face-specific processes.
In human occipitotemporal cortex, brain responses to depicted inanimate objects have a largescale... more In human occipitotemporal cortex, brain responses to depicted inanimate objects have a largescale organization by real-world object size. Critically, the size of objects in the world is systematically related to behaviorally-relevant properties: small objects are often grasped and manipulated (e.g., forks), while large objects tend to be less motor-relevant (e.g., tables), though this relationship does not always have to be true (e.g., picture frames and wheelbarrows). To determine how these two dimensions interact, we measured brain activity with functional magnetic resonance imaging while participants viewed a stimulus set of small and large objects with either low or high motor-relevance. The results revealed that the size organization was evident for objects with both low and high motor-relevance; further, a motor-relevance map was also evident across both large and small objects. Targeted contrasts revealed that typical combinations (small motor-relevant vs. large non-motor-relevant) yielded more robust topographies than the atypical covariance contrast (small non-motor-relevant vs. large motorrelevant). In subsequent exploratory analyses, a factor analysis revealed that the construct of motor-relevance was better explained by two underlying factors: one more related to manipulability, and the other to whether an object moves or is stable. The factor related to manipulability better explained responses in lateral small-object preferring regions, while the factor related to object stability (lack of movement) better explained responses in ventromedial large-object preferring regions. Taken together, these results reveal that the structure of neural responses to objects of different sizes further reflect behavior-relevant properties of manipulability and stability, and contribute to a deeper understanding of some of the factors that help the large-scale organization of object representation in high-level visual cortex. .
Neurocase, Feb 1, 2004
The Sensory/Functional Theory, until recently the received explanation of category-specific seman... more The Sensory/Functional Theory, until recently the received explanation of category-specific semantic deficits, has been shown to be at variance with various facts that have emerged about the nature of these deficits. In this context, Rosazza, Imbornone, Zorzi, Farina, Chiavari, and Cappa (2003: The Heterogeneity of Category-Specific Semantic Disorders: Evidence from a New Case. Neurocase, 9, 189-202.) report the case study of a patient, MA, with a purported category-specific semantic deficit for living things compared to nonliving things, and an associated modality-specific impairment that differentially affected visual/perceptual compared to functional/associative knowledge. While acknowledging that the Sensory/Functional Theory cannot account for the existence of category-specific semantic deficits, Rosazza and colleagues (2003) contend that ''.. . the presence of a more severe loss of specific visual rather than functional knowledge could support an interpretation according to the Sensory/Functional Theory'' [sic] (p. 200). Our comments are divided into two parts. First, we point out that there is an asymmetry between evidence and theory: if there is clear evidence that ''disconfirms'' a given theory, evidence that is consistent with the theory cannot be argued to support the theory. Second, we argue that the performance profile of MA could potentially be relevant to other interpretations of category-specific deficits but that theoretical interpretations of the performance profile of patient MA are undermined by a lack of methodological rigor, as well as the generally weak data associated with the case.
Elsevier eBooks, 2000
Publisher Summary This chapter discusses the aspects of lexical access. The study of aphasia has ... more Publisher Summary This chapter discusses the aspects of lexical access. The study of aphasia has made significant contributions to the understanding of the organization of the lexicon. The contributions have come in several forms and have concerned many aspects of the lexical processing system. At the most general level, the selective deficit or sparing of the semantic, the grammatical, or the phonological (or orthographic) properties of words has been used to inform theories of the architecture of the lexical system. The analysis of aphasic language patterns has also been used to support more specific claims about the processing structure and the organization of the lexical system. The analysis of aphasic language patterns has also been used to support more specific claims about the processing structure and the organization of the lexical system. Modality-specific naming deficits have also been observed for output modalities. There are many reports of patients who are more impaired in producing the spoken than the written name of an object or vice versa. The chapter illustrates a specific phenomenon from the performance of brain-damaged patients to shed light on several issues of current interest in lexical processing.
When we perform a cognitive task, multiple brain regions are engaged. Understanding how these reg... more When we perform a cognitive task, multiple brain regions are engaged. Understanding how these regions interact is a fundamental step to uncover the neural bases of behavior. Most research on the interactions between brain regions has focused on the univariate responses in the regions. However, fine grained patterns of response encode important information, as shown by multivariate pattern analysis. In the present article, we introduce and apply multivariate pattern connectivity (MVPC): a technique to study the dependence between brain regions in humans in terms of the multivariate relations between their patterns of responses. MVPC characterizes the responses in each brain region as trajectories in regionspecific multidimensional spaces, and models the multivariate relationship between these trajectories. Considering the fusiform face area (FFA) as a seed region, we used searchlight-based MVPC to reveal interactions between regions undetected by univariate functional connectivity analyses. MVPC (but not functional connectivity) identified significant interactions between right FFA and the right anterior temporal lobe, the right superior temporal sulcus, and the dorsal visual stream. Additionally, MVPC outperformed univariate connectivity in its ability to explain independent variance in the responses of individual voxels. In the end, MVPC uncovered different connectivity profiles associated with different representational subspaces of FFA: the first principal component of FFA shows differential connectivity with occipital and parietal regions implicated in the processing of low-level properties of faces, while the second and third components show differential connectivity with anterior temporal regions implicated in the processing of invariant representations of face identity.
Routledge eBooks, Sep 3, 2018
ABSTRACT
Cortex, Jun 1, 1976
Routine clinical examinations generally suggest that damage to the frontal area in the left hemis... more Routine clinical examinations generally suggest that damage to the frontal area in the left hemisphere Broca's area disrupts the ability of patients to produce speech much more than their ability to comprehend. Such patients Broca's aphasics often seem to fully understand commands and questions and appear to know what they want to say, yet can only produce short, labored, agrammatic utterances. Like telegrams, these utterances are characterized by the relative omission of bound and unbound grammatical morphemes, or functors, and by a corresponding reliance on content words. This speech pattern and the apparent discrepancy between output and comprehension have been interpreted by some as evidence of preserved language competence in Broca's aphasia (Weigl and Bierwisch, 1970; Lenneberg, 1973; Locke, Caplan and Kellar, 1973). In this view, the patient's tacit knowledge of his language is considered spared, and his agrammatism, simply an economizing measure to circumvent articulatory problems. Evidence that we have recently gained from a metalinguistic paradigm, however, cannot be aligned with this "preserved-competence" notion. On the contrary, the metalinguistic data strongly suggest that the Broca's grammatical knowledge is limited in the same manner as is his production. This point has been underlined in two of our previous reports (Zurif, Caramazza and Myerson, 1972; Zurif and Caramazza, 1976). The present note has a two-fold purpose: to update these findings, primarily by providing a broader empirical context in which to place them, and to permit us a second pass at their theoretical implications. To briefly describe the paradigm itself, data are gathered by asking patients to judge how words in a written sentence "go best together" in that sentence. No vocal output is required of the patients; in fact, precautions are taken to limit even subvocal factors. The patients need indicate their judgments simply by pointing to the words that they feel cluster best within each of the test sentences (Zurif et al., 1972). These judgment-derived word groupings then serve as input matrices for an algorithmic, hierarchical scaling procedure that generates for each sentence separately a graphic description in the form of a phrase structure tree. The more often any two words of a sentence are judged to form a "constituent," the more compact is the node joining these two words. To the extent that these nodes can then be identified in linguistic terms such as
Neuron, Jul 1, 2020
Two Forms of Knowledge Representations in the Human Brain Highlights d Blind and sighted individu... more Two Forms of Knowledge Representations in the Human Brain Highlights d Blind and sighted individuals perform object-colorknowledge tasks partially similarly d Dorsal anterior temporal lobe represents object-color knowledge in both groups d The visual cortex represents object-color knowledge in only the sighted group d There are two types of knowledge representation for concepts with sensory referents
Cerebral Cortex, Sep 24, 2016
Neural responses to visually presented objects have a large-scale spatial organization across the... more Neural responses to visually presented objects have a large-scale spatial organization across the cortex, related to the dimensions of animacy and object size. Most proposals about the origins of this organization point to the influence of differential connectivity with other cortical regions as the key organizing force that drives distinctions in object-responsive cortex. To explore this possibility, we used resting-state functional connectivity to examine the relationship between stimulus-evoked organization of objects, and distinctions in functional network architecture. Using a data-driven analysis, we found evidence for three distinct whole-brain resting-state networks that route through object-responsive cortex, and these naturally manifest the tripartite structure of the stimulus-evoked organization. However, object-responsive regions were also highly correlated with each other at rest. Together, these results point to a nested network architecture, with a local interconnected network across object-responsive cortex and distinctive subnetworks that specifically route these key object distinctions to distinct long-range regions. Broadly, these results point to the viability that long-range connections are a driving force of the large-scale organization of object-responsive cortex.
Psychological Science, Mar 1, 2008
Word-order rules impose major constraints on linguistic behavior. For example, adjectives appear ... more Word-order rules impose major constraints on linguistic behavior. For example, adjectives appear before nouns in English, and after nouns in French. This means that constraints on word order must be language-specific properties upheld on-line by the language system. Despite the importance of these rules, little is known about how they operate. We report an influence of word order on the activation of phonological representations. Participants were presented with colored objects and asked to name either the colors or the objects; the phonological similarity between the object and color names was manipulated. French speakers showed a phonological congruency effect in color naming, but not in object naming. English participants yielded the opposite pattern: a phonological effect in object naming, but not in color naming. Differences in the typical order of nouns and adjectives in French and English provide a plausible account for this cross-linguistic contrast. More generally, these results provide direct evidence for the operation of word-order constraints during language production.
Brain and Language, 1983
Fort Hm.urd Veterans' Administration Medic,crl Center A case study is reported of an aphasic pati... more Fort Hm.urd Veterans' Administration Medic,crl Center A case study is reported of an aphasic patient with fluent speech and markedly superior comprehension of written vs. spoken words. Results of extensive testing supported the hypothesis that the patient suffers from a phonological processing deficit that affects performance in all tasks that require the generation of a phonological code. This selective deficit is interpreted as the underlying cause of diverse symptoms such as asyntactic comprehension of written sentences. the commission of spelling errors in writing, and the production of literal paraphasias and neologisms in spontaneous speech. Alternative possibilities for the classification of this patient are discussed. The syndrome of "pure word-deafness" is a relatively rare language disorder that has received considerable attention from neurologists and neuropsychologists. The dominant feature of this disorder is the occurrence of a severe comprehension disorder for spoken words with relatively intact abilities in all other areas (Hemphill & Stengel, 1940; Lichtheim, 1885; Liepmann, 1898). The pure word-deaf patient is expected to read, to write, and to speak without difficulty except when these functions depend on the processing of spoken language (i.e., repetition and writing from dictation would be expected to be impaired). A review of the reported cases, however, reveals that this clean dissociation of language The research reported here was supported by NIH (NINCDS) Grants NS.
The MIT Press eBooks, Sep 18, 2009
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Papers by Alfonso Caramazza