Rhythm and Melody in Children and Adolescents after Left or Right Temporal Lobectomy

Rhythm (a pattern of onset times and duration of sounds) and melody (a pattern of sound pitches) were studied in 22 children and adolescents several years after temporal lobectomy for intractable epilepsy. Left and right lobectomy groups discriminated rhythms equally well, but the right lobectomy group was poorer at discriminating melodies. Children and adolescents with right lobectomy, but not those with left temporal lobectomy, had higher melody scores with increasing age. Rhythm but not melody was related to memory for the right lobectomy group. In neither group was melody related to age at onset of non-febrile seizures, time from surgery to music tests, or the linear amount of temporal lobe resection. Pitch and melodic contour show different patterns of lateralization after temporal lobectomy in childhood or adolescence.     

Language localization in cases of left temporal lobe arachnoid cyst: evidence against interhemispheric reorganization

We investigated whether left-hemisphere arachnoid cysts lead to reorganization of the language function using PET. A group analysis demonstrated that patients showed no more right-hemisphere activation than a matched control group. Several patients had clear language localizations in the left hemisphere during language comprehension; none of the patients showed right-hemisphere activation. We conclude that left-hemisphere tissue must suffer considerable compromise before reorganization of language into the right hemisphere becomes necessary. Language activations within the left hemisphere are clearly displaced. This is consistent with mere physical displacement in some patients rather than reorganization within the left hemisphere; in others intrahemispheric reorganization cannot be excluded.     

Reproducibility of fMRI-determined language lateralization in individual subjects

This study investigated within-subject test-retest reproducibility (i.e., reliability) of language lateralization obtained with fMRI. Nine healthy subjects performed the same set of three different language tasks during two fMRI sessions on separate days (verb generation, antonym generation, and picture naming). A fourth task analysis was added in which the three tasks were analyzed conjointly (combined task analysis, CTA). The CTA targets brain areas that are commonly used in different language tasks, aiming more selectively at language-critical structures. The number of active voxels (i.e., robustness) and calculated lateralization index (LI) were compared across sessions, tasks, subjects, and two a priori defined volumes of interest (classical language regions versus whole hemisphere) for a wide range of statistical thresholds. Robustness and reliability strongly varied between task analyses. The CTA was a robust detector of language-related brain activity, in contrast to the single task approaches. The CTA and verb generation task allowed for reliable calculation of the LI. Higher thresholds yielded a clear increase in left lateralization, which was largest when calculated from active voxels in classical language regions.     

Rapid word identification in pure alexia is lexical but not semantic

Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.     

Language disorders as a window on universal grammar: an abstract theory of agreement for IP, DP, and V-PP

A new concept of Agreement (AGR) has been represented as a Formal Feature that can appear in a wide range of different configurations (Chomsky, 1998). A case study from language disorders supports and extends this abstract concept. The child shows no agreement in Inflectional Phrase me can and Determiner Phrase them eyes. We then extend the notion of AGR to include verb-Prepositional Phrase relations, where the child also systematically avoids certain prepositions (go beach). The analysis is supported by intuitional data from compounds (sweep with broom --> broom-swept). We also define a systematic notion of Possible deficit as a premature fixation of functional items which normally require additional Phi-features. The notion of Maximization of Formal Features then emerges as a significant feature of learnability from both a normal and disordered perspective.     

Verb movement in acquisition and aphasia: same problem, different solutions-evidence from Dutch

This paper focuses on verb movement in agrammatism and child language. We present data from a sentence completion experiment with 6 Dutch agrammatic aphasics and 21 Dutch-speaking children. The experiment compares completion of matrix clauses (which require verb movement) and embedded clauses (where such movement is not required) in these two populations. The results reveal a clear asymmetry: Both agrammatics and children do very well with embedded clauses but fail in 50% with the matrix clauses. It is concluded that the problem which both populations are facing is one of verb movement rather than verb inflection. An error analysis of the responses reveals that, although both agrammatics and children try to avoid movement, they apply different strategies to achieve this goal.     

Reconceptualizing the Transitive Inference Ability: A Framework for Existing and Future Research

It has often been claimed that to demonstrate transitive inference is to demonstrate a logical ability, and by implication that transitivity as a property is generally a logical entity. Both claims are considered using a theoretically driven analysis together with consideration of relevant existing experimental research and some newly reported findings. This approach suggests an account of transitivity and transitive inferential reasoning that differs not only from the classic Piagetian account, but also from the information processing account so dominant today. We begin by considering one important issue, that the “logical” definitional criterion can only be approached if individuals are required to demonstrate a capacity for transitive inference that is discriminative in nature. This, together with interpretation of findings from existing transitive tasks, leads to the postulate of a three-component psychological system, with the components relying on perceptual, linguistic, and conceptual subprocesses and sensitivity to simple cues. The framework is testable and accommodates important aspects of classic and modern accounts of “transitive development” that until now have been taken to be mutually exclusive. It also readily accommodates both human and nonhuman research, yet neither a formal logical structure nor memory in any general sense need be assigned the primary role.     

Reperfusion of Specific Brain Regions by Raising Blood Pressure Restores Selective Language Functions in Subacute Stroke

We report a series of six single subject studies examining the effects of pharmacological blood pressure elevation on regional brain perfusion and language function. Previous reports indicate that hypoperfusion of specific brain regions, as delineated by magnetic resonance perfusion weighted imaging (PWI), is associated with disruption of selective lexical functions. On this basis, we hypothesized that reperfusion of the same regions, in the absence of infarct in that region, would restore the associated lexical function. We present five patients with impaired lexical-semantics associated with poor perfusion, but not infarction, of Brodmann's area 22 (BA 22), and one patient with impaired lexical-semantics and a superimposed deficit in retrieving the phonological representations of words, associated with poor perfusion Brodmann's area 37 (BA 37) as well as BA 22. Each patient was treated with induced blood pressure elevation to increase perfusion of the ischemic and dysfunctional tissue. Daily testing of naming and comprehension, with stimulus sets matched for frequency, familiarity, and length, showed improved lexical-semantics in the patients who showed reperfusion of BA 22 and improved oral naming (but not lexical-semantics) in the patient who showed reperfusion of BA 37. These cases illustrate that loss of function with hypoperfusion of a circumscribed area of the brain, and recovery of the same function with improved perfusion of that brain region, can reveal brain/language relationships prior to reorganization after brain injury.     

Right hemisphere semantic processing of visual words in an aphasic patient: an fMRI study

This study was designed to identify the neural network supporting the semantic processing of visual words in a patient with large-scale damage to left-hemisphere (LH) language structures. Patient GP, and a control subject, RT, performed semantic and orthographic tasks while brain-activation patterns were recorded using functional magnetic resonance imaging. In RT, the semantic-orthographic comparison activated LH perisylvian and extrasylvian temporal regions comparable to the network of areas activated by non-brain-damaged subjects in other neuroimaging studies of semantic discrimination. In GP, the same comparison activated homologous right-hemisphere regions, demonstrating the ability of the right hemisphere to subserve visual lexicosemantic processes. The results are discussed within the context of the normal right hemisphere's capacity for semantic processing of visual words. Examining results from functional neuroimaging studies on recovery in the context of innate hemispheric abilities may enable reconciliation of disparate claims about mechanisms supporting recovery from aphasia.     

Recency effects for meaning and form in word selection

Three experiments examined the contribution of phonological availability in selecting words as predicted by interactive activation models of word production. Homophonous words such as week and weak permitted a word's phonological form to be activated on priming trials without selection of its meaning or lemma. Recent production of a homophone failed to significantly increase production of its twin as a sentence completion. However, speakers were significantly more likely to complete a sentence with a recently read or generated unambiguous word. This increase in response probability was unaffected by word frequency. The results constrain the degree to which experience and phonological availability may affect word selection in spoken language production.     

Controversies about CP: a comparison of language acquisition and language impairments in Broca's aphasia

In both language acquisition research and the study of language impairments in Broca's aphasia there is an ongoing debate whether or not phrase-structure representations contain the Complementizer Phrase (CP) layer. To shed some light on this debate, I will provide data on German child language and on German agrammatic Broca's aphasia. Analyses of subordinate clauses, wh-questions, and verb placement indicate that early child grammars do not generate the CP layer yet, whereas the ability to project the CP layer is retained in agrammatism.     

LF-interpretability and language development: a study of verbal and nominal features in Greek normally developing and SLI children

This paper includes (i) a comparison of the developmental pattern of certain morphosyntactic features in normally developing (ND) Greek children with similar data from a group of children with specific language impairment and (ii) a new analysis of the differences found. The analysis is based on a minimalist notion of LF interpretability. Depending on the feature-specification of lexical items (i.e., [+/- interpretable] at LF), a different route of development follows. In addition, phonological salience of both interpretable and noninterpretable features is argued to play an important role in an account of crosslinguistic differences in both normal and exceptional development.     

Grammatical Encoding in Aphasia: Evidence from a “Processing Prosthesis”

Agrammatic aphasia is characterized by severely reduced grammatical structure in spoken and written language, often accompanied by apparent insensitivity to grammatical structure in comprehension. Does agrammatism represent loss of linguistic competence or rather performance factors such as memory or resource limitations? A considerable body of evidence supports the latter hypothesis in the domain of comprehension. Here we present the first strong evidence for the performance hypothesis in the domain of production: an augmentative communication system that markedly increases the grammatical structure of agrammatic speech while providing no linguistic information, functioning merely to reduce on-line processing demands. Copyright 2000 Academic Press and Unisys Corporation.     

Arrows of time in infancy: the representation of temporal-causal invariances

Many transformations that take place over time can only occur in one temporal direction, and adults are highly sensitive to the differences between forward and backward presentations of such events. In seven experiments using two selective-looking paradigms, 4- and 8-month-olds were shown forward and backward videotapes of events involving the effects of gravity on liquids and solid objects and of the separation of whole objects into pieces. Four-month-olds showed a significant preference for the forward version of liquid pouring from a beaker to a glass. Eight-month-olds looked longer at the forward versions of this and four other gravity-related events but showed no directional preferences for the separation events. Several experiments indicate that longer looking at the forward versions of the gravity stimuli is not a product of attraction to specific perceptual features of the stimuli. A model based on the development of representations of types of events is presented and evaluated.     

Toward a cultural neuropsychology: An alternative view and a preliminary model

Any integrated theory of mind and behavior must address the dynamic interaction between neurobiological and sociocultural systems as possible causes for human action. Newer findings within the behavioral neurosciences have pointed to the brain's exceptional plasticity and flexibility and suggest that one's surroundings, including one's cultural environment, may directly influence the way the human nervous system becomes organized. In this paper, a preliminary connectionist model of culture-brain interaction is proposed in an effort to illustrate the possible contribution of cultural factors to the development of the individual human brain.     

Mapping from Sound to Meaning: Reduced Lexical Activation in Broca''s Aphasics

Recent studies of lexical access in Broca's aphasics suggest that lexical activation levels are reduced in these patients. The present study compared the performance of Broca's aphasics with that of normal subjects in an auditory semantic priming paradigm. Lexical decision times were measured in response to word targets preceded by an intact semantically related prime word ("cat"-"dog"), by a related prime in which one segment was acoustically altered to produce a poorer phonetic exemplar ("c*at"-"dog"), and by a semantically unrelated prime ("ring"-"dog"). The effects of the locus of the acoustic distortion within the prime word (initial or final position) and the presence of potential lexical competitors ("cat" --> /gaet/versus "coat" --> "goat") were examined. In normal subjects, the acoustic manipulations produce a small, short-lived reduction in semantic facilitation irrespective of the position of the distortion in the prime word or the presence of a voiced lexical competitor. In contrast, Broca's aphasics showed a large and lasting reduction in priming in response to word-initial acoustic distortions, but only a weak effect of word-final distortions on priming. In both phonetic positions, the effect of distortion was greater for prime words with a lexical competitor. These findings are compatible with the claim that Broca's aphasics have reduced lexical activation levels, which may result in a disruption of the bottom-up access of words on the basis of acoustic input as well as increased vulnerability to competition between acoustically similar lexical items.     

Time course of frequency effects in spoken-word recognition: evidence from eye movements

In two experiments, eye movements were monitored as participants followed spoken instructions to click on and move pictures with a computer mouse. In Experiment 1, a referent picture (e.g., the picture of a bench) was presented along with three pictures, two of which had names that shared the same initial phonemes as the name of the referent (e.g., bed and bell). Participants were more likely to fixate the picture with the higher frequency name (bed) than the picture with the lower frequency name (bell). In Experiment 2, referent pictures were presented with three unrelated distractors. Fixation latencies to referents with high-frequency names were shorter than those to referents with low-frequency names. The proportion of fixations to the referents and distractors were analyzed in 33-ms time slices to provide fine-grained information about the time course of frequency effects. These analyses established that frequency affects the earliest moments of lexical access and rule out a late-acting, decision-bias locus for frequency. Simulations using models in which frequency operates on resting-activation levels, on connection strengths, and as a postactivation decision bias provided further constraints on the locus of frequency effects.     

Hemispheric asymmetry in lexical decisions: the effects of grammatical class and imageability

It has been suggested that neural systems for lexical processing of nouns and verbs are anatomically distinct. The aim of the present study was to investigate if brain asymmetry for the processing of these two grammatical classes is also different. Neurologically intact adults performed a lateralized lexical decision task with grammatically unambiguous words of high, medium, and low degrees of imagery. For error scores a right visual field (RVF) advantage and an overall effect of imageability were obtained. For latency scores grammatical class and imageability modified visual field differences: in the noun class a RVF advantage was obtained only for low imagery nouns, while for the verbs the RVF advantage was present for both medium and low imagery verbs. These results suggest that the participation of right hemisphere neural systems in the processing of verbs is more limited than in the processing of nouns.     

Reliability in Dream Research: A Methodological Note

The coefficients of internal consistency and retest reliability had been rarely investigated within the methodology of dream content analysis. Analyzing a dream series of elderly, healthy persons obtained from weekly telephone interviews, the internal consistency of a series of 20 dreams and retests after 4 or 22 weeks, respectively, had been computed. The findings indicate that dream recall and dream length are quite stable, but dream characteristics such as bizarreness and emotional tone underlie large intraindividual fluctuations. In order to obtain reliable measures for these variables which will be important for correlational studies, including waking-life trait measures, one has to obtain as many dreams as possible (about 20) in a very short time period. Further research is needed to extend the present findings to diary dreams and laboratory dreams.     

Tense and syntactic processes in agrammatic speech

This study focuses on inflectional errors in a group of eight, English-speaking people with agrammatism. Subjects were required to provide inflected verbs in declarative sentences and construct negative sentences. The errors made by these speakers are considered in terms of whether they resemble the errors made by children at the Optional Infinitive Stage. Results confirm that the errors differ from those made by children and that a different explanation is required. Explanations offered by Borer and Rohrbacher (1997) and by Friedmann and Grodzinsky (2000) are discussed but are considered inadequate to deal with our data. It is proposed that agrammatic speakers have problems with the implementation of grammar and particularly with syntactic processes such as feature-checking.