Valéria Csépe

Orthographic Depth and Its Impact on Universal Predictors of Reading A Cross-Language Investigation

Alphabetic orthographies differ in the transparency of their letter-sound mappings, with English orthography being less transparent than other alphabetic scripts. The outlier status of English has led scientists to question the generality of findings based on English-language studies. We investigated the role of phonological awareness, memory, vocabulary, rapid naming, and nonverbal intelligence in reading performance across five languages lying at differing positions along a transparency continuum (Finnish, Hungarian, Dutch, Portuguese, and French). Results from a sample of 1,265 children in Grade 2 showed that phonological awareness was the main factor associated with reading performance in each language. However, its impact was modulated by the transparency of the orthography, being stronger in less transparent orthographies. The influence of rapid naming was rather weak and limited to reading and decoding speed. Most predictors of reading performance were relatively universal across these alphabetic languages, although their precise weight varied systematically as a function of script transparency.

Brain responses reveal the learning of foreign language phonemes

Learning to speak a new language requires the formation of recognition patterns for the speech sounds specific to the newly acquired language. The present study demonstrates the dynamic nature of cortical memory representations for phonemes in adults by using the mismatch negativity (MMN) event-related potential. We studied Hungarian and Finnish subjects, dividing the Hungarians into a naive (no knowledge of Finnish) and a fluent (in Finnish) group. We found that the MMN for a contrast between two Finnish phonemes was elicited in the fluent Hungarians but not in the naive Hungarians. This result indicates that the fluent Hungarians developed cortical memory representations for the Finnish phoneme system that enabled them to preattentively categorize phonemes specific to this language.

Evoked potential correlates of stimulus deviance during wakefulness and sleep in cat — animal model of mismatch negativity

Auditory evoked potentials (EPs) elicited by standard (STs) and deviant tones (DTs) of different probabilities were studied in freely moving cats during wakefulness and sleep. A large double peaked negativity, so-called mismatch negativity (MMN), was evoked by the unattended low probability DTs. The EPs recorded from the AI and AII areas of the auditory cortex showed more dynamic changes than the vertex and association cortical responses. The amplitude of the MMN was inversely proportional to the probability of DTs. The latency of the MMN showed dependence both on the location of the recording site and on the probability of DTs. During slow wave sleep (SWS) the MMN of increased latency could be evoked only at the lowest probabilities. The cortical distribution of the MMN changed in the SWS.

Pre-attentive detection of vowel contrasts utilizes both phonetic and auditory memory representations

Event-related brain potentials (ERP) were recorded to infrequent changes of a synthesized vowel (standard) to another vowel (deviant) in speakers of Hungarian and Finnish language, which are remotely related to each other with rather similar vowel systems. Both language groups were presented with identical stimuli. One standard-deviant pair represented an across-vowel category contrast in Hungarian, but a within-category contrast in Finnish, with the other pair having the reversed role in the two languages. Both within- and across-category contrasts elicited the mismatch negativity (MMN) ERP component in the native speakers of either language. The MMN amplitude was larger in across- than within-category contrasts in both language groups. These results suggest that the pre-attentive change-detection process generating the MMN utilized both auditory (sensory) and phonetic (categorical) representations of the test vowels.

Predictors of developmental dyslexia in European orthographies with varying complexity

BACKGROUND  The relationship between phoneme awareness, rapid automatized naming (RAN), verbal short-term/working memory (ST/WM) and diagnostic category is investigated in control and dyslexic children, and the extent to which this depends on orthographic complexity. METHODS General cognitive, phonological and literacy skills were tested in 1,138 control and 1,114 dyslexic children speaking six different languages spanning a large range of orthographic complexity (Finnish, Hungarian, German, Dutch, French, English). RESULTS Phoneme deletion and RAN were strong concurrent predictors of developmental dyslexia, while verbal ST/WM and general verbal abilities played a comparatively minor role. In logistic regression models, more participants were classified correctly when orthography was more complex. The impact of phoneme deletion and RAN-digits was stronger in complex than in less complex orthographies. CONCLUSIONS Findings are largely consistent with the literature on predictors of dyslexia and literacy skills, while uniquely demonstrating how orthographic complexity exacerbates some symptoms of dyslexia.

Auditory Evoked Potentials Reflect Serotonergic Neuronal Activity—A Study in Behaving Cats Administered Drugs Acting on 5-HT1A Autoreceptors in the Dorsal Raphe Nucleus

A valid indicator of central serotonergic neurotransmission would be useful for various diagnostic and psychopharmacological purposes in psychiatry. However, known peripheral serotonergic measures only partially reflect serotonergic function in the brain. Previous findings suggest that the intensity dependence of auditory evoked potentials (AEPs) is closely related to central serotonergic activity. The present study examines the effects of microinjection of a 5-HT1A agonist (8-OH-DPAT) and a 5-HT1A antagonist (spiperone) into the dorsal raphe nucleus (DRN) on AEP recorded epidurally from the primary and secondary auditory cortex in behaving cats. We found a stronger intensity dependence only of AEP from the primary auditory cortex after 8-OH-DPAT, which inhibits the firing rate of serotonergic DRN neurons, and a weaker intensity dependence after spiperone, which increases serotonergic cell firing, as compared to baseline measurements. These results demonstrate that the intensity dependence of AEP is inversely related to serotonergic neuronal activity and that it may be a promising tool for assessing central serotonergic function in humans (e.g., identifying patients with low serotonergic neurotransmission).

Interactions between transient and long-term auditory memory as reflected by the mismatch negativity

The mismatch negativity (MMN) event-related potential (ERP) component is elicited by any discriminable change in series of repetitive auditory stimuli. MMN is generated by a process registering the deviation of the incoming stimulus from the trace of the previous repetitive stimulus. Using MMN as a probe into auditory sensory memory, the present study addressed the question of whether the sensory memory representation is formed strictly on the basis of an automatic feature analysis of incoming sensory stimuli or information from long-term memory is also incorporated. Trains of 6 tone bursts (standards with up to 1 deviant per train) separated by 9.5-sec intertrain intervals were presented to subjects performing a visual tracking task and disregarding the auditory stimuli. Trains were grouped into stimulus blocks of 20 trains with a 2-min rest period between blocks. In the Constant-Standard Condition, both standard and deviant stimuli remained fixed across the session, encouraging the formation of a long-term memory representation. To eliminate the carryover of sensory storage from one train to the next, the first 3.6 sec of the intertrain interval was filled with 6 tones of random frequencies. In the Roving-Standard Condition, the standard changed from train to train and the intervening tones were omitted. It was found that MMN was elicited by deviants presented in Position 2 of the trains in the Constant-Standard Condition revealing that a single reminder of the constant standard reactivated the standard-stimulus representation. The MMN amplitude increased across trials within each stimulus block in the Constant- but not in the Roving-Standard Condition, demonstrating long-term learning in that condition (i.e., the standard-stimulus trace indexed by the MMN amplitude benefitted from the presentations of the constant standard in the previous trains). The present results suggest that the transient auditory sensory memory representation underlying the MMN is facilitated by a longer-term representation of the corresponding stimulus.

The speed of magnitude processing and executive functions in controlled and automatic number comparison in children: an electro-encephalography study

BackgroundIn the numerical Stroop paradigm (NSP) participants decide whether a digit is numerically or physically larger than another simultaneously presented digit. This paradigm is frequently used to assess the automatic number processing abilities of children. Currently it is unclear whether an equally refined evaluation of numerical magnitude occurs in both controlled (the numerical comparison task of the NSP) and automatic (the physical comparison task of the NSP) numerical comparison in both children and adults. One of our objectives was to respond this question by measuring the speed of controlled and automatic magnitude processing in children and adults in the NSP. Another objective was to determine how the immature executive functions of children affect their cognitive functions relative to adults in numerical comparison.Methods and resultsThe speed of numerical comparison was determined by monitoring the electro-encephalographic (EEG) numerical distance effect: The amplitude of EEG measures is modulated as a function of numerical distance between the to-be-compared digits. EEG numerical distance effects occurred between 140–320 ms after stimulus presentation in both controlled and automatic numerical comparison in all age groups. Executive functions were assessed by analyzing facilitation and interference effects on the latency of the P3b event-related potential component and the lateralized readiness potential (LRP). Interference effects were more related to response than to stimulus processing in children as compared with adults. The LRP revealed that the difficulty to inhibit irrelevant response tendencies was a major factor behind interference in the numerical task in children.ConclusionThe timing of the EEG distance effect suggests that a refined evaluation of numerical magnitude happened at a similar speed in each age group during both controlled and automatic magnitude processing. The larger response interference in children than in adults suggests that despite the similar behavioural profile of children and adults, partially different cognitive processes underlie their performance in the NSP. Further, behavioural effects in the NSP depend on interactions between comparison, facilitation/interference and response-related processes. Our data suggest that caution is needed when using the NSP to compare behavioural markers of the numerical processing skills of children and adults.

A combined event-related potential and neuropsychological investigation of developmental dyscalculia

Adolescents with developmental dyscalculia (DD) but no other impairments were examined with neuropsychological tests and with event-related brain potentials (ERPs). A matched control group and an adult control group were tested as well. Behavioural and ERP markers of the magnitude representation were examined in a task where subjects decided whether visually presented Hindu-Arabic digits were smaller or larger than 5. There was a normal behavioural numerical distance effect (better performance for digits closer to the reference number than for digits further away from it) in DD. This suggests that semantic magnitude relations depend on a phenomenologically (nearly) normal magnitude representation in DD, at least in the range of single-digit numbers. However, minor discrepancies between DD subjects and controls suggest that the perception of the magnitude of single digits may be slightly impaired in DD. Early ERP distance effects were similar in DD and in control subjects. In contrast, between 400 and 440 ms there was a focused right-parietal ERP distance effect in controls, but not in DD. This suggests that early, more automatic processing of digits was similar in both groups, and between-group processing differences arose later, during more complex controlled processing. This view is supported by signs of decelerated executive functioning in developmental dyscalculia. Further, DD subjects did not differ from controls in general mental rotation and in body parts knowledge, but were markedly impaired in mental finger rotation, finger knowledge, and tactile performance.

The recognition of phonologically assimilated words does not depend on specific language experience

In a series of 5 experiments, we investigated whether the processing of phonologically assimilated utterances is influenced by language learning. Previous experiments had shown that phonological assimilations, such as /lean#bacon/ → [leam bacon], are compensated for in perception. In this article, we investigated whether compensation for assimilation can occur without experience with an assimilation rule using automatic event-related potentials. Our first experiment indicated that Dutch listeners compensate for a Hungarian assimilation rule. Two subsequent experiments, however, failed to show compensation for assimilation by both Dutch and Hungarian listeners. Two additional experiments showed that this was due to the acoustic properties of the assimilated utterance, confirming earlier reports that phonetic detail is important in compensation for assimilation. Our data indicate that compensation for assimilation can occur without experience with an assimilation rule, in line with phonetic-phonological theories that assume that speech production is influenced by speech-perception abilities.