Language and developmental plasticity after perinatal stroke.

The mature human brain is lateralized for language, with the left hemisphere (LH) primarily responsible for sentence processing and the right hemisphere (RH) primarily responsible for processing suprasegmental aspects of language such as vocal emotion. However, it has long been hypothesized that in early life there is plasticity for language, allowing young children to acquire language in other cortical regions when LH areas are damaged. If true, what are the constraints on functional reorganization? Which areas of the brain can acquire language, and what happens to the functions these regions ordinarily perform? We address these questions by examining long-term outcomes in adolescents and young adults who, as infants, had a perinatal arterial ischemic stroke to the LH areas ordinarily subserving sentence processing. We compared them with their healthy age-matched siblings. All participants were tested on a battery of behavioral and functional imaging tasks. While stroke participants were impaired in some nonlinguistic cognitive abilities, their processing of sentences and of vocal emotion was normal and equal to that of their healthy siblings. In almost all, these abilities have both developed in the healthy RH. Our results provide insights into the remarkable ability of the young brain to reorganize language. Reorganization is highly constrained, with sentence processing almost always in the RH frontotemporal regions homotopic to their location in the healthy brain. This activation is somewhat segregated from RH emotion processing, suggesting that the two functions perform best when each has its own neural territory.

"Dividing the labor": Lexical verbs and the linguistic encoding of physical support in 2- to 4.5-year-old children.

Infants reason about support configurations (e.g., teddy bear on table) and young children talk about a variety of support relations, including support-from-below (e.g., apple on table) and many other types (e.g., Band-Aid on leg, picture on wall). Given this wide variation in support types, we asked whether early differentiation of the semantic space of support may play a key role in helping children to learn spatial language in this domain. Previous research has shown such differentiation with 20-month-olds mapping the basic locative construction (BE on) to support-from-below (cube on top of box), but not to a mechanical support configuration (cube on side of box via adhesion). Older children and adults show the same differentiation, with preferential mapping of BE on to support-from-below and lexical verbs to mechanical support. We further explored the development of this differentiation by testing how children aged 2 to 4.5 years map lexical verbs to a wide variety of support configurations. In Experiment 1, using an intermodal preferential pointing paradigm, we found that 2- to 3.5-year-olds map a lexical verb phrase ("sticks to") to mechanical support via adhesion. In Experiments 2 and 3, we expanded the range of mechanical support relations and used production and forced-choice tasks to ask whether 2- to 4.5-year-olds also encode mechanical relations using lexical verbs. We found that they do. These findings suggest continuity between infancy and childhood in the way that children use spatial language to differentially map to support-from-below versus mechanical support and raise new questions about how mechanical support language develops.

Developmental changes in neural lateralization for visual-spatial function: Evidence from a line-bisection task.

Studies of hemispheric specialization have traditionally cast the left hemisphere as specialized for language and the right hemisphere for spatial function. Much of the supporting evidence for this separation of function comes from studies of healthy adults and those who have sustained lesions to the right or left hemisphere. However, we know little about the developmental origins of lateralization. Recent evidence suggests that the young brain represents language bilaterally, with 4-6-year-olds activating the left-hemisphere regions known to support language in adults as well as homotopic regions in the right hemisphere. This bilateral pattern changes over development, converging on left-hemispheric activation in late childhood. In the present study, we ask whether this same developmental trajectory is observed in a spatial task that is strongly right-lateralized in adults-the line bisection (or "Landmark") task. We examined fMRI activation among children ages 5-11 years as they were asked to judge which end of a bisected vertical line was longer. We found that young children showed bilateral activation, with activation in the same areas of the right hemisphere as has been shown among adults, as well as in the left hemisphere homotopic regions. By age 10, activation was right-lateralized. This strongly resembles the developmental trajectory for language, moving from bilateral to lateralized activation. We discuss potential underlying mechanisms and suggest that understanding the development of lateralization for a range of cognitive functions can play a crucial role in understanding general principles of how and why the brain comes to lateralize certain functions.

Development of bilateral parietal activation for complex visual-spatial function: Evidence from a visual-spatial construction task.

The neural representation of visual-spatial functions has traditionally been ascribed to the right hemisphere, but little is known about these representations in children, including whether and how lateralization of function changes over the course of development. Some studies suggest bilateral activation early in life that develops toward right-lateralization in adulthood, while others find evidence of right-hemispheric dominance in both children and adults. We used a complex visual-spatial construction task to examine the nature of lateralization and its developmental time course in children ages 5-11 years. Participants were shown two puzzle pieces and were asked whether the pieces could fit together to make a square; responses required either mental translation of the pieces (Translation condition) or both mental translation and rotation of the pieces (Rotation condition). Both conditions were compared to a matched Luminance control condition that was similar in terms of visual content and difficulty but required no spatial analysis. Group and single-subject analyses revealed that the Rotation and Translation conditions elicited strongly bilateral activation in the same parietal and occipital locations as have been previously found for adults. These findings show that visual-spatial construction consistently elicits robust bilateral activation from age 5 through adulthood. This challenges the idea that spatial functions are all right-lateralized, either during early development or in adulthood. More generally, these findings provide insights into the developmental course of lateralization across different spatial skills and how this may be influenced by the computational requirements of the particular functions involved.

Spatial language difficulties reflect the structure of intact spatial representation: Evidence from high-functioning autism.

Previous studies have shown that the basic properties of the visual representation of space are reflected in spatial language. This close relationship between linguistic and non-linguistic spatial systems has been observed both in typical development and in some developmental disorders. Here we provide novel evidence for structural parallels along with a degree of autonomy between these two systems among individuals with Autism Spectrum Disorder, a developmental disorder with uneven cognitive and linguistic profiles. In four experiments, we investigated language and memory for locations organized around an axis-based reference system. Crucially, we also recorded participants' eye movements during the tasks in order to provide new insights into the online processes underlying spatial thinking. Twenty-three intellectually high-functioning individuals with autism (HFA) and 23 typically developing controls (TD), all native speakers of Norwegian matched on chronological age and cognitive abilities, participated in the studies. The results revealed a well-preserved axial reference system in HFA and weakness in the representation of direction within the axis, which was especially evident in spatial language. Performance on the non-linguistic tasks did not differ between HFA and control participants, and we observed clear structural parallels between spatial language and spatial representation in both groups. However, there were some subtle differences in the use of spatial language in HFA compared to TD, suggesting that despite the structural parallels, some aspects of spatial language in HFA deviated from the typical pattern. These findings provide novel insights into the prominence of the axial reference systems in non-linguistic spatial representations and spatial language, as well as the possibility that the two systems are, to some degree, autonomous.

Declarative memory and skill-related knowledge: Evidence from a case study of amnesia and implications for theories of memory.

Theoretical and empirical studies of memory have long been framed by a distinction between declarative and non-declarative memory. We question the sharpness of the distinction by reporting evidence from amnesic L.S.J., who despite retrograde memory losses in declarative knowledge domains, shows sparing of declarative knowledge related to premorbid skill (e.g., playing an instrument). We previously showed that L.S.J. had severe losses of retrograde declarative knowledge across areas of premorbid expertise (e.g., artists of famous works) and everyday knowledge (e.g., company names for logos). Here we present evidence that L.S.J. has sparing of what we call skill-related declarative knowledge, in four domains in which she had premorbid skill (art, music, aviation, driving). L.S.J.'s pattern of loss and sparing raises questions about the strict separation between classically-defined memory types and aligns with a recent proposal by Stanley and Krakauer [2013. Motor skill depends on knowledge of facts. Frontiers in Human Neuroscience, 7,1-11].

The necessity of the medial temporal lobe for statistical learning.

The sensory input that we experience is highly patterned, and we are experts at detecting these regularities. Although the extraction of such regularities, or statistical learning (SL), is typically viewed as a cortical process, recent studies have implicated the medial temporal lobe (MTL), including the hippocampus. These studies have employed fMRI, leaving open the possibility that the MTL is involved but not necessary for SL. Here, we examined this issue in a case study of LSJ, a patient with complete bilateral hippocampal loss and broader MTL damage. In Experiments 1 and 2, LSJ and matched control participants were passively exposed to a continuous sequence of shapes, syllables, scenes, or tones containing temporal regularities in the co-occurrence of items. In a subsequent test phase, the control groups exhibited reliable SL in all conditions, successfully discriminating regularities from recombinations of the same items into novel foil sequences. LSJ, however, exhibited no SL, failing to discriminate regularities from foils. Experiment 3 ruled out more general explanations for this failure, such as inattention during exposure or difficulty following test instructions, by showing that LSJ could discriminate which individual items had been exposed. These findings provide converging support for the importance of the MTL in extracting temporal regularities.

Understanding the mapping between numerical approximation and number words: evidence from Williams syndrome and typical development.

All numerate humans have access to two systems of number representation: an exact system that is argued to be based on language and that supports formal mathematics, and an Approximate Number System (ANS) that is present at birth and appears independent of language. Here we examine the interaction between these two systems by comparing the profiles of people with Williams syndrome (WS) with those of typically developing children between ages 4 and 9 years. WS is a rare genetic deficit marked by fluent and well-structured language together with severe spatial deficits, deficits in formal math, and abnormalities of the parietal cortex, which is thought to subserve the ANS. One of our tasks, requiring approximate number comparison but no number words, revealed that the ANS precision of adolescents with WS was in the range of typically developing 2- to 4-year-olds. Their precision improved with age but never reached the level of typically developing 6- or 9-year-olds. The second task, requiring verbal number estimation using number words, revealed that the estimates produced by adolescents with WS were comparable to those of typically developing 6- and 9-year-olds, i.e. were more advanced than their ANS precision. These results suggest that ANS precision is somewhat separable from the mapping between approximate numerosities and number words, as the former can be severely damaged in a genetic disorder without commensurate impairment in the latter.

A Phone in a Basket Looks Like a Knife in a Cup: Role-Filler Independence in Visual Processing.

When a piece of fruit is in a bowl, and the bowl is on a table, we appreciate not only the individual objects and their features, but also the relations containment and support, which abstract away from the particular objects involved. Independent representation of roles (e.g., containers vs. supporters) and "fillers" of those roles (e.g., bowls vs. cups, tables vs. chairs) is a core principle of language and higher-level reasoning. But does such role-filler independence also arise in automatic visual processing? Here, we show that it does, by exploring a surprising error that such independence can produce. In four experiments, participants saw a stream of images containing different objects arranged in force-dynamic relations-e.g., a phone contained in a basket, a marker resting on a garbage can, or a knife sitting in a cup. Participants had to respond to a single target image (e.g., a phone in a basket) within a stream of distractors presented under time constraints. Surprisingly, even though participants completed this task quickly and accurately, they false-alarmed more often to images matching the target's relational category than to those that did not-even when those images involved completely different objects. In other words, participants searching for a phone in a basket were more likely to mistakenly respond to a knife in a cup than to a marker on a garbage can. Follow-up experiments ruled out strategic responses and also controlled for various confounding image features. We suggest that visual processing represents relations abstractly, in ways that separate roles from fillers.

Tactile localization on digits and hand: structure and development.

Localization of tactile stimuli to the hand and digits is fundamental to somatosensory perception. However, little is known about the development or genetic bases of this ability in humans. We examined tactile localization in normally developing children, adolescents, and adults and in people with Williams syndrome (WS), a genetic disorder resulting in a wide range of severe visual-spatial deficits. Normally developing 4-year-olds made large stimulus-localization errors, sometimes across digits, but nevertheless their errors revealed a structured internal representation of the hand. In normally developing individuals, errors became exponentially smaller over age, reaching the adult level by adolescence. In contrast, people with WS showed large localization errors regardless of age and a significant proportion of cross-digit errors, a profile similar to that of normally developing 4-year-olds. Thus, tactile localization reflects internal organization of the hand even early in normal development, undergoes substantial development in normal children, and is susceptible to developmental, but not organizational, impairment under genetic deficit.

Consequences of severe visual-spatial deficits for reading acquisition: evidence from Williams syndrome.

To further understand the nature of the visual-spatial representations required for successful acquisition of written language skills, we investigated the written language abilities of two individuals with Williams syndrome (WS) a developmental genetic disorder in which the presence of severe visual-spatial developmental delays and deficits has been well established. Using a case study approach, we examined the relationship between reading achievement and general cognitive ability, phonological skills, and visual-spatial skills for the two individuals. We found that, despite the strong similarity between the two individuals in terms of their verbal and non-verbal cognitive abilities and their phonological abilities (as well as chronological age and educational opportunities), their reading and spelling abilities differed by more than 5 grade levels. We present evidence that the difference in written language performance was likely to be due to differences in the severity and nature of their visual-spatial impairment. Moreover, we show that specific difficulty processing the orientation of visual stimuli is related to the reading difficulties of one of the two individuals. These results underscore the contribution of visual-spatial abilities to the reading acquisition process and identify WS as a potential source of valuable information regarding the role of visual-spatial processing in reading development.

Impaired geometric reorientation caused by genetic defect.

The capacity to reorient in one's environment is a fundamental part of the spatial cognitive systems of both humans and nonhuman species. Abundant literature has shown that human adults and toddlers, rats, chicks, and fish accomplish reorientation through the construction and use of geometric representations of surrounding layouts, including the lengths of surfaces and their intersection. Does the development of this reorientation system rely on specific genes and their action in brain development? We tested reorientation in individuals who have Williams syndrome (WS), a genetic disorder that results in abnormalities of hippocampal and parietal areas of the brain known to be involved in reorientation. We found that in a rectangular chamber devoid of surface feature information, WS individuals do not use the geometry of the chamber to reorient, failing to find a hidden object. The failure among people with WS cannot be explained by more general deficits in visual-spatial working memory, as the same individuals performed at ceiling in a similar task in which they were not disoriented. We also found that performance among people with WS improves in a rectangular chamber with one blue wall, suggesting that some individuals with WS can use the blue wall feature to locate the hidden object. These results show that the geometric system used for reorientation in humans can be selectively damaged by specific genetic and neural abnormalities in humans.

Where word and world meet: Language and vision share an abstract representation of symmetry.

Symmetry is ubiquitous in nature, in logic and mathematics, and in perception, language, and thought. Although humans are exquisitely sensitive to visual symmetry (e.g., of a butterfly), symmetry in natural language goes beyond visuospatial properties: many words point to abstract concepts with symmetrical content (e.g., equal, marry). For example, if Mark marries Bill, then Bill marries Mark. In both cases (vision and language), symmetry may be formally characterized as invariance under transformation. Is this a coincidence, or is there some deeper psychological resemblance? Here we asked whether representations of symmetry correspond across language and vision. To do so, we developed a novel cross-modal matching paradigm. On each trial, participants observed a visual stimulus (either symmetrical or nonsymmetrical) and had to choose between a symmetrical and nonsymmetrical English predicate unrelated to the stimulus (e.g., "negotiate" vs. "propose"). In a first study with visual events (symmetrical collision or asymmetrical launch), participants reliably chose the predicate matching the event's symmetry. A second study showed that this "language-vision correspondence" generalized to objects and was weakened when the stimuli's binary nature was made less apparent (i.e., for one object, rather than two inward-facing objects). A final study showed the same effect when nonsigners guessed English translations of signs from American Sign Language, which expresses many symmetrical concepts spatially. Taken together, our findings support the existence of an abstract representation of symmetry which humans access via both perceptual and linguistic means. More broadly, this work sheds light on the rich, structured nature of the language-cognition interface. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Genes, language, and the nature of scientific explanations: the case of Williams syndrome.

In this article, we discuss two experiments of nature and their implications for the sciences of the mind. The first, Williams syndrome, bears on one of cognitive science's holy grails: the possibility of unravelling the causal chain between genes and cognition. We sketch the outline of a general framework to study the relationship between genes and cognition, focusing as our case study on the development of language in individuals with Williams syndrome. Our approach emphasizes the role of three key ingredients: the need to specify a clear level of analysis, the need to provide a theoretical account of the relevant cognitive structure at that level, and the importance of the (typical) developmental process itself. The promise offered by the case of Williams syndrome has also given rise to two strongly conflicting theoretical approaches-modularity and neuroconstructivism-themselves offshoots of a perennial debate between nativism and empiricism. We apply our framework to explore the tension created by these two conflicting perspectives. To this end, we discuss a second experiment of nature, which allows us to compare the two competing perspectives in what comes close to a controlled experimental setting. From this comparison, we conclude that the "meaningful debate assumption", a widespread assumption suggesting that neuroconstructivism and modularity address the same questions and represent genuine theoretical alternatives, rests on a fallacy.

Characterizing the Details of Spatial Construction: Cognitive Constraints and Variability.

Spatial construction-the activity of creating novel spatial arrangements or copying existing ones-is a hallmark of human spatial cognition. Spatial construction abilities predict math and other academic outcomes and are regularly used in IQ testing, but we know little about the cognitive processes that underlie them. In part, this lack of understanding is due to both the complex nature of construction tasks and the tendency to limit measurement to the overall accuracy of the end goal. Using an automated recording and coding system, we examined in detail adults' performance on a block copying task, specifying their step-by-step actions, culminating in all steps in the full construction of the build-path. The results revealed the consistent use of a structured plan that unfolded in an organized way, layer by layer (bottom to top). We also observed that complete layers served as convergence points, where the most agreement among participants occurred, whereas the specific steps taken to achieve each of those layers diverged, or varied, both across and even within individuals. This pattern of convergence and divergence suggests that the layers themselves were serving as the common subgoals across both inter and intraindividual builds of the same model, reflecting cognitive "chunking." This structured use of layers as subgoals was functionally related to better performance among builders. Our findings offer a foundation for further exploration that may yield insights into the development and training of block-construction as well as other complex cognitive-motor skills. In addition, this work offers proof-of-concept for systematic investigation into a wide range of complex action-based cognitive tasks.

Object recognition in Williams syndrome: uneven ventral stream activation.

Williams syndrome (WS) is a genetic disorder associated with severe visuospatial deficits, relatively strong language skills, heightened social interest, and increased attention to faces. On the basis of the visuospatial deficits, this disorder has been characterized primarily as a deficit of the dorsal stream, the occipitoparietal brain regions that subserve visuospatial processing. However, some evidence indicates that this disorder may also affect the development of the ventral stream, the occipitotemporal cortical regions that subserve face and object recognition. The present studies examined ventral stream function in WS, with the hypothesis that faces would produce a relatively more mature pattern of ventral occipitotemporal activation, relative to other objects that are also represented across these visual areas. Using functional magnetic imaging, we compared activation patterns during viewing of human faces, cat faces, houses and shoes in individuals with WS (age 14-27), typically developing 6-9-year-olds (matched approximately on mental age), and typically developing 14-26-year-olds (matched on chronological age). Typically developing individuals exhibited changes in the pattern of activation over age, consistent with previous reports. The ventral stream topography of individuals with WS differed from both control groups, however, reflecting the same level of activation to face stimuli as chronological age matches, but less activation to house stimuli than either mental age or chronological age matches. We discuss the possible causes of this unusual topography and implications for understanding the behavioral profile of people with WS.

The privileging of 'Support-From-Below' in early spatial language acquisition.

Spatial terms that encode support (e.g., "on", in English) are among the first to be understood by children across languages (e.g., Bloom, 1973; Johnston & Slobin, 1979). Such terms apply to a wide variety of support configurations, including Support-From-Below (SFB; cup on table) and Mechanical Support, such as stamps on envelopes, coats on hooks, etc. Research has yet to delineate infants' semantic space for the term "on" when considering its full range of usage. Do infants initially map "on" to a very broad, highly abstract category - one including cups on tables, stamps on envelopes, etc.? Or do infants begin with a much more restricted interpretation - mapping "on" to certain configurations over others? Much infant cognition research suggests that SFB is an event category that infants learn about early - by five months of age (Baillargeon & DeJong, 2017) - raising the possibility that they may also begin by interpreting the word "on" as referring to configurations like cups on tables, rather than stamps on envelopes. Further, studies examining language production suggests that children and adults map the basic locative expression (BE on, in English) to SFB over Mechanical Support (Landau et al., 2016). We tested the hypothesis that this 'privileging' of SFB in early infant cognition and child and adult language also characterizes infants' language comprehension. Using the Intermodal-Preferential-Looking-Paradigm in combination with infant eye-tracking, 20-month-olds were presented with two support configurations: SFB and Mechanical, Support-Via-Adhesion (henceforth, SVA). Infants preferentially mapped "is on" to SFB (rather than SVA) suggesting that infants differentiate between two quite different kinds of support configurations when mapping spatial language to these two configurations and more so, that SFB is privileged in early language understanding of the English spatial term "on".

How does a blind person see? Developmental change in applying visual verbs to agents with disabilities.

Classic theories emphasize the primacy of first-person sensory experience for learning meanings of words: to know what "see" means, one must be able to use the eyes to perceive. Contrary to this idea, blind adults and children acquire normative meanings of "visual" verbs, e.g., interpreting "see" and "look" to mean with the eyes for sighted agents. Here we ask the flip side of this question: how easily do sighted children acquire the meanings of "visual" verbs as they apply to blind agents? We asked sighted 4-, 6- and 9-year-olds to tell us what part of the body a blind or a sighted agent would use to "see", "look" (and other visual verbs, n = 5), vs. "listen", "smell" (and other non-visual verbs, n = 10). Even the youngest children consistently reported the correct body parts for sighted agents (eyes for "look", ears for "listen"). By contrast, there was striking developmental change in applying "visual" verbs to blind agents. Adults, 9- and 6-year-olds, either extended visual verbs to other modalities for blind agents (e.g., "seeing" with hands or a cane) or stated that the blind agent "cannot" "look" or "see". By contrast, 4-year-olds said that a blind agent would use her eyes to "see", "look", etc., even while explicitly acknowledging that the agent's "eyes don't work". Young children also endorsed "she is looking at the dax" descriptions of photographs where the blind agent had the object in her "line of sight", irrespective of whether she had physical contact with the object. This pattern held for leg-motion verbs ("walk", "run") applied to wheelchair users. The ability to modify verb modality for agents with disabilities undergoes developmental change between 4 and 6. Despite this, we find that 4-year-olds are sensitive to the semantic distinction between active ("look") and stative ("see"), even when applied to blind agents. These results challenge the primacy of first-person sensory experience and highlight the importance of linguistic input and social interaction in the acquisition of verb meaning.

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome.

The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo-spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3- and 4-year-olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k-statistic) showed similar developmental profiles in typically developing 3- and 4-year-old children, but the WS profile differed from either age group. People with WS could track more objects than 3-year-olds, and the same number as 4-year-olds, but they could remember the locations of more static objects than both 3- and 4-year-olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4-year-olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development.