Prosodically controlled derivations in the mental lexicon

Swedish morphemes are classified as prosodically specified or prosodically unspecified, depending on lexical or phonological stress, respectively. Here, we investigate the allomorphy of the suffix -(i)sk, which indicates the distinction between lexical and phonological stress; if attached to a lexically stressed morpheme, it takes a non-syllabic form (-sk), whereas if attached to a phonologically stressed morpheme, an epenthetic vowel is inserted (-isk). Using mismatch negativity (MMN), we explored the neural processing of this allomorphy across lexically stressed and phonologically stressed morphemes. In an oddball paradigm, participants were occasionally presented with congruent and incongruent derivations, created by the suffix -(i)sk, within the repetitive presentation of their monomorphemic stems. The results indicated that the congruent derivation of the lexically stressed stem elicited a larger MMN than the incongruent sequences of the same stem and the derivational suffix, whereas after the phonologically stressed stem a non-significant tendency towards an opposite pattern was observed. We argue that the significant MMN response to the congruent derivation in the lexical stress condition is in line with lexical MMN, indicating a holistic processing of the sequence of lexically stressed stem and derivational suffix. The enhanced MMN response to the incongruent derivation in the phonological stress condition, on the other hand, is suggested to reflect combinatorial processing of the sequence of phonologically stressed stem and derivational suffix. These findings bring a new aspect to the dual-system approach to neural processing of morphologically complex words, namely the specification of word stress.Peer reviewe

Phonological Variations Are Compensated at the Lexical Level : Evidence From Auditory Neural Activity

Dealing with phonological variations is important for speech processing. This article addresses whether phonological variations introduced by assimilatory processes are compensated for at the pre-lexical or lexical level, and whether the nature of variation and the phonological context influence this process. To this end, Swedish nasal regressive place assimilation was investigated using the mismatch negativity (MMN) component. In nasal regressive assimilation, the coronal nasal assimilates to the place of articulation of a following segment, most clearly with a velar or labial place of articulation, as in utan mej "without me" > [MODIFIER LETTER TRIANGULAR COLONtam mejMODIFIER LETTER TRIANGULAR COLON]. In a passive auditory oddball paradigm, 15 Swedish speakers were presented with Swedish phrases with attested and unattested phonological variations and contexts for nasal assimilation. Attested variations - a coronal-to-labial change as in utan "without" > [MODIFIER LETTER TRIANGULAR COLONtam] - were contrasted with unattested variations - a labial-to-coronal change as in utom "except" > *[MODIFIER LETTER TRIANGULAR COLONtLATIN SMALL LETTER OPEN On] - in appropriate and inappropriate contexts created by mej "me" [mejMODIFIER LETTER TRIANGULAR COLON] and dej "you" [dejMODIFIER LETTER TRIANGULAR COLON]. Given that the MMN amplitude depends on the degree of variation between two stimuli, the MMN responses were expected to indicate to what extent the distance between variants was tolerated by the perceptual system. Since the MMN response reflects not only low-level acoustic processing but also higher-level linguistic processes, the results were predicted to indicate whether listeners process assimilation at the pre-lexical and lexical levels. The results indicated no significant interactions across variations, suggesting that variations in phonological forms do not incur any cost in lexical retrieval; hence such variation is compensated for at the lexical level. However, since the MMN response reached significance only for a labial-to-coronal change in a labial context and for a coronal-to-labial change in a coronal context, the compensation might have been influenced by the nature of variation and the phonological context. It is therefore concluded that while assimilation is compensated for at the lexical level, there is also some influence from pre-lexical processing. The present results reveal not only signal-based perception of phonological units, but also higher-level lexical processing, and are thus able to reconcile the bottom-up and top-down models of speech processing.Peer reviewe

Mapping prosody onto the lexicon : Memory traces for lexically specified prosodic information in the brain

Lexical access, the matching of auditory information onto lexical representations in the brain, is a crucial component of online language processing. To understand the nature of lexical access, it is important to identify the kind of acoustic information that is stored in the long-term memory and to study how the brain uses such information. This dissertation investigates the contribution of prosodic information to lexical access and examines language-specific processing mechanisms by studying three typologically distinct languages: English, Turkish, and Swedish. The main research objective is to demonstrate the activation of long-term memory traces for words on the sole basis of prosodic information and to test the accuracy of typological phonological descriptions suggested in the literature by studying electrophysiological measurements of brain activation. A secondary research objective is to evaluate three distinct electrophysiological recording systems. The dissertation is based on three papers, each examining neural responses to prosodic changes in one of the three languages with a different recording system. The first two papers deal directly with the interplay between prosody and the lexicon, and investigate whether prosodic changes activate memory traces associated with segmentally identical but prosodically different words; the third paper introduces morphology to this process and investigates whether prosodic changes activate memory traces associated with potential lexical derivations. Neural responses demonstrate that prosodic information indeed activates memory traces associated with words and their potential derivations without any given context. Strongly connected neural networks are argued to guarantee neural activation and implementation of long-term memory traces. Regardless of differences in prosodic typology, all languages exploit prosodic information for lexical processing, although to different extents. The amount of neural activation elicited by a particular piece of prosodic information is positively correlated with the strength of its lexical representation in the brain, which is called lexical specification. This dissertation could serve as a first step towards building an electrophysiological-perceptual taxonomy of prosodic processing based on lexical specification

Effects of Suprasegmental Features on the Processing of Spoken Words in the Human Brain: Evidence from Mismatch Negativity (MMN)

The study reported in the present paper aimed to determine the effect of prosodic cues on automatic word processing in the brain by comparing the mismatch negativity (MMN) component of the event-related potentials (ERP) elicited by isolated words and pseudowords. More specifically, it attempted to explore the influence of changes in certain suprasegmental cues such as fundamental frequency and intensity on the perception of linguistic stress patterns by native speakers of American English. The material chosen was a pair of English words in which a change of function from noun to verb is commonly associated with a shift of stress from the first to the second syllable. Neurophysiological brain activity was recorded to series of frequent (standard) stimuli and three types of rare (deviant) stimuli differing from the standard in one of three different ways: frequency, intensity, or in both features, and the mismatch negativity (MMN) component of event-related potentials (ERP), a brain correlate of automatic preattentive auditory processing, was computed. The results of the experiment showed that in both word and pseudoword conditions, deviants elicited MMNs in a biphasic nature; one with a time course of 110-160 ms and another with a time course of 200-300 ms. These negative deflections could be interpreted to reflect the deviation of a sound from the transient auditory memory trace of the standard. However, it was unclear whether the MMNs were elicited by a change of word stress as a linguistic pattern and, ergo, lexical activation or just changes in acoustic features. Additionally, the results of the experiment showed intensity, fundamental frequency, and combination of them contributed differentially to the prosodic information and hence, differed in their MMN amplitudes. Statistical analysis showed that the combination of the two acoustic dimensions is the most effective cue for stress perception

Santral erken puberteli̇ hastalarda GNRH agoni̇sti̇ tedavi̇si̇ni̇n antropometri̇k ölçümlere etki̇si̇

Amaç: Çalışmamızda idiyopatik santral erken puberte (SEP) tanılı kız hastalarda Gonadotropin Releasing Hormone agonist (GnRHa) tedavisinin, antropometrik bulgular üzerindeki etkileri ve tedavinin öngörülen erişkin boya (ÖEB) etkisini değerlendirilmeyi amaçladık. Materyal ve metod: Çalışmaya Haziran 2013 – Aralık 2018 tarihleri arasında Pamukkale Üniversitesi Çocuk Endokrinoloji polikliniğine başvuran idiyopatik SEP tanısı ile takipli en az 2 yıldır GnRHa uygulanan hastalar alındı. Hastaların verileri, klinik, laboratuvar ve görüntüleme parametreleri hastane kayıtlarından incelenerek kaydedildi. Kemik yaşı (KY) BoneXpert® yazılımı ile dijital olarak değerlendirildi. Bulgular: Hastaların tanı esnasındaki yaş ortalaması 8.02 ± 1.07 yıldı. Ortalama takip süresi 2,23±0,47 yıl idi. Hastaların vücut ağırlık, vücut ağırlık SDS (standart sapma skoru), vücut kitle indeksi (VKİ) ve VKİ SDS’lerinde izlemlerde giderek arttığı görüldü. Tedavinin 6, 12, 18, 24. ay ve tedavi sonunda VKİ ve VKİ SDS değerlerindeki artış, tedavi başlangıç değerlerine göre istatistiksel olarak anlamlı idi. Tedavinin başlangıcında 23 (% 18.6) hasta aşırı kilolu ve 17 (% 13.8) hasta obez iken tedavinin sonunda 37 (% 30.0) hasta aşırı kilolu ve 26 (% 21.3) hasta obezdi. Normal kilolu hastalarda GnRHa tedavisi sonunda ortalama VKİ SDS değerinde tedavi başlangıcına göre anlamlı artış saptandı (p<0.05). Aşırı kilolu ve obez hastalarda tedavi sonundaki ortalama VKİ SDS değerinde tedavi başlangıcına göre azalma saptandı. Bu azalma istatistiksel olarak anlamlı değildi (p=0.706). Tedavi başlangıcı (160,91 ± 6,85) ile kıyaslandığında son izlemde (162,10 ± 6,17) hastaların ÖEB’sinde istatistiksel olarak anlamlı bir artış olduğu bulundu (p<0.05). Tedavi sonunda ortalama ÖEB’nin (162,10±6,17 cm), ortalama HB’yi (160,98±6,17 cm) geçtiği saptandı. Son izlemde boy SDS, KY SDS, KY/TY oranında, KY-TY farkında, tedavi başlangıç değerine göre istatistiksel olarak anlamlı azalma saptandı (p<0.05). YBH ve YHB SDS’sinin izlemlerde giderek azaldığı saptandı. Sonuç: GnRHa tedavisinin ÖEB’yi ve kilo alımını arttırdığı bulundu. GnRHa tedavisinin tedavi başlangıcında normal kilolu olan hastalarda kilo alımını arttırırken, aşırı kilolu ve obez hastalarda kilo azalmasına neden olduğu bulundu. Puberte başlangıcından erişkin döneme kadar izlemlerin yapıldığı ve hedef boya ulaşma durumunun gözlemlenebildiği daha kapsamlı ve uzun takip süreli çalışmalara ihtiyaç vardır.Objective: the aim of study is to evaluate effects of Gonadotropin Releasing Hormone agonist(GnRHa) treatment on the antropometric findings of girls diagnosed with Idiopathic central precocious puberty . Materials and method: Patients who visited Pamukkale University Pediatric Endocrinology polyclinic diagnosed with idiopathic central precocious puberty and are followed with at least 2 years of recieving GnRH agonists were taken in to the study between the periods of June 2013 and December 2018. The data of the patients were analysed from the hospital’s records of the clinic,laboratory and imaging parameters. The bone age was digitally evaluated using BoneXpert® software. Results : During the diagnosis of the patients,the median age was 8.02 ± 1.07 years. The average follow up period was 2,23±0,47 years. The body weight, the Standard Deviation of the body weight, Body Mass Index(BMI) and the Standard Deviation of the Body Mass Index of the patients were found to increase progressively. The increment in the values of the Body Mass Index and the Standard Deviations of the Body Mass Index after 6,12,18 and 24 months of the treatment was found to be statistically significant compared to the values at the inception of the treatment. While at the onset of the treatment, 23 (18.6%) of the patients were overweight and 17 (13.8%) of the patients were obese, at the end of the study ,37 (30%) of the patients became overweight and 26 (21.3%) of the patients became obese. It was found that in patients with normal weight, the increase in the average Standard Deviations of the Body Mass index after treatment with GnRH agonists compared to that of the onset of the treatment was statistically significant (p<0.05). In morbidly obese and obese patients the average Standard Deviation of the Body Mass Index at the end of the treatment was found to decrease compared to that of the onset of the treatment. This decrement was not found to be statistically significant(p=0.706). When compared to the onset of treatment (160,91 ± 6,85), it was found that at the end of the follow up (162,10 ± 6,17) there was a statistically significant increment in the predicted adult height of the patients (p<0.05). At the end of the treatment,it was found out that the average predicted adult height(162,10±6,17 cm) has surpassed the average mid parental height (160,98±6,17 cm) of the patients. At the last follow up the standard deviation of the height,bone age, the ratio of the bone age to the chronological age,the differences between bone age and the chronological age ,when compared to the values at the onset of treatment, there was a statistically significant decrease (p<0.05). Upon follow up,it was found out that there was a progressive decrease in the growth velocity and the standard deviation of the growth velocity. Conclusion: It was found out that there was an increase in the predicted bone age and the body weight with the treatment of GnRH agonists. While at the onset of treatment, patients with normal weight eventually gained weight,patients that were morbidly obese and those that were obese were found have a decrease in weight with the treatment of GnRH agonists. There is a need for the conduction of more extensive and long duration studies from the onset of puberty to the period of adulthood where follows ups can be conducted and the state of the mid parental height being monitored

Lexical specification of prosodic information in Swedish: Evidence from mismatch negativity

Like many of the other Germanic languages, the Swedish stress system has mostly been given a phonological analysis. Recently, however, the central role of morphology has started to be recognized. Similar to the lexical specification of tonal accent, the Swedish stress system is claimed to be morphologically determined and morphemes are thus categorized as prosodically specified and prosodically unspecified. Prosodically specified morphemes bear stress information as part of their lexical representations and are classified as tonic (i.e., lexically stressed), pretonic and posttonic, whereas prosodically unspecified morphemes receive stress through a phonological rule, which is right-edge oriented, but sensitive to prosodic specification at that edge. The presence of prosodic specification is inferred from vowel quality and vowel quantity; if stress moves away, vowel quality and quantity change radically in phonologically stressed morphemes whereas traces of stress remain in lexically stressed morphemes. The present study is the first to investigate if stress is a lexical property of Swedish morphemes by comparing the mismatch negativity (MMN) responses to vowel quality and quantity changes in phonologically stressed and lexically stressed words. In a passive oddball paradigm, 15 native speakers of Swedish were presented with standards and deviants, which differed from the standards in formant frequency and duration. Given that vowel quality and quantity changes are associated with morphological derivations only in phonologically stressed words, the MMN responses are expected to be larger in phonologically stressed words than in lexically stressed words that lack such an association. The results indicated that the processing differences between phonologically and lexically stressed words were reflected in the amplitude and topography of the MMN responses. Confirming the expectation, the MMN amplitude was larger for the phonologically stressed word than for the lexically stressed word and showed a more widespread topographic distribution. The brain did not only detect vowel quality and quantity changes but also used them to activate memory traces associated with derivations. The present study therefore implies that morphology is directly involved in the Swedish stress system and that changes in phonological shape due to stress shift cue the upcoming stress and the potential addition of a morpheme

Phosphodiesterase 10A levels are related to striatal function in schizophrenia : a combined positron emission tomography and functional magnetic resonance imaging study

Pharmacological inhibition of phosphodiesterase 10A (PDE10A) is being investigated as a treatment option in schizophrenia. PDE10A acts postsynaptically on striatal dopamine signaling by regulating neuronal excitability through its inhibition of cyclic adenosine monophosphate (cAMP), and we recently found it to be reduced in schizophrenia compared to controls. Here, this finding of reduced PDE10A in schizophrenia was followed up in the same sample to investigate the effect of reduced striatal PDE10A on the neural and behavioral function of striatal and downstream basal ganglia regions. A positron emission tomography (PET) scan with the PDE10A ligand [11C]Lu AE92686 was performed, followed by a 6 min resting-state magnetic resonance imaging (MRI) scan in ten patients with schizophrenia. To assess the relationship between striatal function and neurophysiological and behavioral functioning, salience processing was assessed using a mismatch negativity paradigm, an auditory event-related electroencephalographic measure, episodic memory was assessed using the Rey auditory verbal learning test (RAVLT) and executive functioning using trail-making test B. Reduced striatal PDE10A was associated with increased amplitude of low-frequency fluctuations (ALFF) within the putamen and substantia nigra, respectively. Higher ALFF in the substantia nigra, in turn, was associated with lower episodic memory performance. The findings are in line with a role for PDE10A in striatal functioning, and suggest that reduced striatal PDE10A may contribute to cognitive symptoms in schizophrenia