When orthography is not enough: the effect of lexical stress in lexical decision.

Three lexical decision experiments were carried out in Italian, in order to verify if stress dominance (the most frequent stress type) and consistency (the proportion and number of existent words sharing orthographic ending and stress pattern) had an effect on polysyllabic word recognition. Two factors were manipulated: whether the target word carried stress on the penultimate (dominant; graNIta, seNIle 'slush, senile') or on the antepenultimate (non-dominant) syllable (MISsile, BIbita 'missile, drink'), and whether the stress neighborhood was consistent (graNIta, MISsile) or inconsistent (seNIle, BIbita) with the word\u2019s stress pattern. In Experiment 1 words were mixed with nonwords sharing the word endings, which made words and nonwords more similar to each other. In Experiment 2 words and nonwords were presented in lists blocked for stress pattern. In Experiment 3 we used a new set of nonwords, which included endings with (stress) ambiguous neighborhoods and/or with low number of neighbors, and which were overall less similar to words. In all three experiments there was an advantage for words with penultimate (dominant) stress, and no main effect of stress neighborhood. However, the dominant stress advantage decreased in Experiments 2 and 3. Finally, in Experiment 4 the same materials used in Experiment 1 were also used in a reading aloud task, showing a significant consistency effect, but no dominant stress advantage. The influence of stress information in Italian word recognition is discussed

Neural codes for one’s own position and direction in a real-world “vista” environment

Humans, like animals, rely on an accurate knowledge of one’s spatial position and facing direction to keep orientated in the surrounding space. Although previous neuroimaging studies demonstrated that scene-selective regions (the parahippocampal place area or PPA, the occipital place area or OPA and the retrosplenial complex or RSC), and the hippocampus (HC) are implicated in coding position and facing direction within small-(room-sized) and large-scale navigational environments, little is known about how these regions represent these spatial quantities in a large open-field environment. Here, we used functional magnetic resonance imaging (fMRI) in humans to explore the neural codes of these navigationally-relevant information while participants viewed images which varied for position and facing direction within a familiar, real-world circular square. We observed neural adaptation for repeated directions in the HC, even if no navigational task was required. Further, we found that the amount of knowledge of the environment interacts with the PPA selectivity in encoding positions: individuals who needed more time to memorize positions in the square during a preliminary training task showed less neural attenuation in this scene-selective region. We also observed adaptation effects, which reflect the real distances between consecutive positions, in scene-selective regions but not in the HC. When examining the multi-voxel patterns of activity we observed that scene-responsive regions and the HC encoded both spatial information and that the RSC classification accuracy for positions was higher in individuals scoring higher to a self-reported questionnaire of spatial abilities. Our findings provide new insight into how the human brain represents a real, large-scale “vista” space, demonstrating the presence of neural codes for position and direction in both scene-selective and hippocampal regions, and revealing the existence, in the former regions, of a map-like spatial representation reflecting real-world distance between consecutive positions

Age-related effects on spatial memory across viewpoint changes relative to different reference frames

Remembering object positions across different views is a fundamental competence for acting and moving appropriately in a large-scale space. Behavioural and neurological changes in elderly subjects suggest that the spatial representations of the environment might decline compared to young participants. However, no data are available on the use of different reference frames within topographical space in aging. Here we investigated the use of allocentric and egocentric frames in aging, by asking young and older participants to encode the location of a target in a virtual room relative either to stable features of the room (allocentric environment-based frame), or to an unstable objects set (allocentric objects-based frame), or to the viewer's viewpoint (egocentric frame). After a viewpoint change of 0$,^{circ}$ (absent), 45$,^{circ}$ (small) or 135$,^{circ}$ (large), participants judged whether the target was in the same spatial position as before relative to one of the three frames. Results revealed a different susceptibility to viewpoint changes in older than young participants. Importantly, we detected a worst performance, in terms of reaction times, for older than young participants in the allocentric frames. The deficit was more marked for the environment-based frame, for which a lower sensitivity was revealed as well as a worst performance even when no viewpoint change occurred. Our data provide new evidence of a greater vulnerability of the allocentric, in particular environment-based, spatial coding with aging, in line with the retrogenesis theory according to which cognitive changes in aging reverse the sequence of acquisition in mental development

Caloric vestibular stimulation reduces pain and somatoparaphrenia in a severe chronic central post-stroke pain patient: a case study

Central post-stroke pain is a neuropathic syndrome characterized by intolerable contralesional pain and, in rare cases, somatic delusions. To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain. Resting-state functional magnetic resonance imaging was used to assess the neurological effects of this treatment. Following vestibular stimulation we observed impressive improvements in motor skills, pain, and somatic delusions. In the functional connectivity study before the vestibular stimulation, we observed differences in the patient's left thalamus functional connectivity, with respect to the thalamus connectivity of a control group (N = 20), in the bilateral cingulate cortex and left insula. After the caloric stimulation, the left thalamus functional connectivity with these regions, which are known to be involved in the cortical response to pain, disappeared as in the control group. The beneficial use of vestibular stimulation in the reduction of pain and somatic delusion in a CPSP patient is now documented by behavioral and imaging data. This evidence can be applied to theoretical models of pain and body delusions

Reading segments is not reading words: Comment on Kawamoto et al. (2014)

Word production involves computing the sound of a word from its concept or visually presented form. To perform such process multiple operations are required, including lexical access, word form encoding, and articulation. With regard to articulation, a critical issue is understanding which is the minimal planning unit (henceforth MPU) to address articulatory programs and start motor implementation. Kawamoto and colleagues (2014, QJEP) have recently proposed that the MPU consists in the word initial segment. The segment as MPU hypothesis is winsome, but it is difficult to substantiate. In this commentary, we argue that, in addition to some methodological concerns, at least three issues may challenge this hypothesis. A first challenge to the segment as MPU hypothesis is how to reconcile it with the typical articulatory behavior shown by readers. A second issue questioning the generalizability of the segment as MPU hypothesis is the phonetic realization of stress in polysyllabic words, which in many languages constitute a great part of the lexicon. A third issue deals with the opacity of the orthography-to-phonology mapping. Overall, our observations suggest that the segment as MPU hypothesis is more an exceptional behavior than the behavior usually occurring at the phonology-to-phonetics interface of the reading system. We show that several findings suggest that the phonology-to-phonetics interface adopts units larger than the segment. The latter proposal can account for a bulk of phenomena such as those related to orthography-to-phonology opacity, stress assignment, and co-articulation

Stress assignment in reading Italian: Friendship outweighs dominance

Stress assignment to polysyllabic words is the only aspect of the pronunciation of written Italian that cannot be predicted by rule. It could be a function of stress dominance in the language or of stress neighbourhood (i.e., the number of words sharing ending and stress pattern). Two experiments investigated stress assignment in Italian adult and most importantly young readers. Word frequency and number of stress friends influenced reading times and accuracy, outweighing any effect of stress dominance. In the presence of a majority of stress friends, the reading of low-frequency words was only affected by stress neighbourhood. The effects were the same in fourth graders and adult readers. It is argued that distributional information based on the number of stress friends - rather than stress dominance - is the most effective factor in assigning stress to words in reading

Stress affects articulation planning in reading aloud.

Three experiments of pseudoword reading assessed whether stress assignment affects reading aloud at the level of articulation planning. In experiment 1 (immediate reading) both stimulus length (in syllables) and stress type affected reading latency and accuracy. Italian pseudowords were named faster and more accurately when they were assigned stress on the antepenultimate than on the penultimate syllable. In experiment 2 (delayed reading) reading aloud of the same stimuli was not affected by length but was still affected by stress type, with shorter latencies for pseudowords stressed on the antepenultimate syllable. Experiment 3 replicated the results of the first two experiments with new materials and with a tightly controlled procedure. These results indicate that stress assignment exerts an effect in a processing component where articulation is planned as articulation can not start until stress is assigned. Our results also suggest that, in reading aloud, the minimal planning unit for articulation is smaller than the whole stimulus, including the first syllable up to the stressed unit

Stress assignment in reading Italian polysyllabic pseudowords.

In four naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects naming speed. Experiments 1 and 2 tested how readers assign stress to pseudowords. The results showed that participants assign stress on the basis of the pseudowords\u27 stress neighborhood, but only when this orthographic/phonological information is widely represented in the lexicon. Experiments 3 and 4 tested the naming speed of pseudowords with different stress patterns. Participants were faster in reading pseudowords with antepenultimate than with penultimate stress. The effect was not driven by distributional information, but it was related to the stage of articulation planning. Overall, the experiments showed that, under certain conditions, readers assign stress using orthographic/phonological distributional information. However, the distributional information does not speed up pseudoword naming, which is affected by stress computation at the level of the articulation planning of the stimulus. It is claimed that models of reading aloud and speech production should be merged at the level of phonological encoding, when segmental and metrical information are assembled and articulation is planned

Stress in Context: Morpho-Syntactic Properties Affect Lexical Stress Assignment in Reading Aloud

Recent findings from English and Russian have shown that grammatical category plays a key role in stress assignment. In these languages, some grammatical categories have a typical stress pattern and this information is used by readers. However, whether readers are sensitive to smaller distributional differences and other morpho-syntactic properties (e.g., gender, number, person) remains unclear. We addressed this issue in word and non-word reading in Italian, a language in which: (1) nouns and verbs differ in the proportion of words with a dominant stress pattern; (2) information specified by words sharing morpho-syntactic properties may contrast with other sources of information, such as stress neighborhood. Both aspects were addressed in two experiments in which context words were used to induce the desired morpho-syntactic properties. Experiment 1 showed that the relatively different proportions of stress patterns between grammatical categories do not affect stress processing in word reading. In contrast, Experiment 2 showed that information specified by words sharing morpho-syntactic properties outweighs stress neighborhood in non-word reading. Thus, while general information specified by grammatical categories may not be used by Italian readers, stress neighbors with morpho-syntactic properties congruent with those of the target stimulus have a primary role in stress assignment. These results underscore the importance of expanding investigations of stress assignment beyond single words, as current models of single-word reading seem unable to account for our results