News

Unveiling the history of early modern humans through ancient genomes

Unveiling the history of early modern humans through ancient genomes Speaker: Prof. Fu Qiaomei (Professor and Head of Ancient DNA Lab Institude of Vertebrate and Paleontology and Paleoanthropology, Chinese Academy of Sciences) Overview: With a growing pool of genomic data from past humans from many different times and locations, it is increasingly possible to study the large-scale patterns of the genetic history of humans over time and space. The speech covers the major features of human genetic prehistory, focusing on studies of ancient modern humans from primarily pre-agricultural cultures in different regions of the world. Analysis of the genomic data from ~45-35,0000-year-old modern humans shows: multipe distinct populations were present in Eurasia; some contributed to present-day populations - individuals from Russia and Belgium show the closest relationship to present-day Europeans and an individual from North China shows the closest relationship to present-day East Asians; however, other individuals highlight lost populations - at least two individuals from Western Siberia and Romania represent populations that did not contribute to any present-day Eurasians. In the period bracketing the Last Glacial Maximum, population subdivision, movement and partial or complete replacements are common themes in regional human prehistory. In West Eurasia, this is directly shown using specimens from ~35-15,000 years ago. An ~35,000-year-old individual from Belgium, different from other branches of early modern humans in Europe, carries some population representing ancestry that reaappered in ~19-14,000-year-old individuals. This is likely related to population fragmentation and migration that occured in human populations during the late-glacial period.

Perfect pitch - why do some people have this ability?

Perfect pitch - why do some people have this ability? Speaker: Prof. Mary Waye (Research Professor The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong) Overview: Perfect Pitch (also called Absolute Pitch) is the ability to recognize the pitch of a musical tone accurately and instantaneously, without having an external reference. This is considered to be a rare trait and previously Sacks (1995) reported that approximately 1 in 10,000 people has this ability. It is thought that perfect pitch is a dominant trait that is heritable (probably determined by a single gene, or very few genes), but that trait needs to be developed through early music training. Apparently perfect pitch cannot be learnt even though relative pitch (i.e. ability to distinguish pitch with an external reference) can be learnt readily. Some people manage to learn a pseudo-perfect pitch ability that is not nearly as exact as perfect pitch (in terms of accuracy, the speed of recognition and range of the pitch). The part of the brain that might be responsible for pitch has been studied: As the Heschl's gyrus was shown to be larger in professional musicians, it was thought to be important for pitch recognition. Later studies comparing brain scans of perfect pitch possessors with non-possessors found that there is in greater activities in the left superior temporal sulcus (Bermudez and Zatorre, 2009), and another more recent study shown that there is greater intracortical myelination for AP musicians in the anterior region of the supratemporal plane, particularly the medial region of the right planum polare (PP; Kim & Knösche, 2016) . With the help of a website developed by Dr. Jane Gitschier and her colleagues (now not available anymore), our group has recruited more than 50 subjects with perfect pitch with the aim to find the gene for perfect pitch. This talk will give an account of our research in the identification of the gene locus for perfect pitch in Hong Kong Chinese by a candidate gene approach. Some speculations about the potential biological mechanism of perfect pitch attainment will also be discussed.

Understanding Chinese reading process based on multi-level neurocognitive modulations

Understanding Chinese reading process based on multi-level neurocognitive modulations Speaker: Dr Tao Ran (Department of Linguistics, The University of Hong Kong) Overview: Reading Chinese is a complex task. Understanding the modulations from other modalities of language processing and basic cognitive abilities is essential to portraying a full picture of Chinese reading process. Here I present two studies showing how writing ability and the attentional state influence reading processing. In study one, we measured a group of participants’ (N = 32) reading and writing abilities in scales of accuracy and fluency. The participants also performed a reading task and a writing task while their brain activities were recorded by functional Magnetic Resonance Imaging (fMRI). We found significant positive correlations between participants' reading and writing abilities and extensive overlap in brain activation networks between the two tasks. Participants' writing ability is positively correlated with the connectivity strength in the reading task in the brain areas specifically involved in reading or writing process. These results suggested a positive influence of writing ability on the reading process. In study two, the attentional modulation on the reading process was examined on another group of participants (N = 31). They performed two variants of sustained attention to response task (SART) during which their attentional states were intermittently reported (e.g., mind wandering or not). Participants’ response times did not significantly change during mind wandering when the task was to respond to the concurrent word stimulus. In contrast, the participants’ response slowed down during mind wandering when they needed to maintain short-term memory of word semantics information from the preceding trial. Study two suggested that attention modulates semantic maintenance and synthesis but not retrieval. These two studies shed light on our understanding of Chinese reading process in terms of how it is affected by other language modalities such as writing and basic cognitive abilities such as attention. Unsolved questions and future directions will be discussed.

Multilingualism and the brain

Multilingualism and the brain Speaker: Prof. Brenden Weekes (Chair Professor Division of Speech and Hearing Sciences, Director, Laboratory for Communication Science, The University of Hong Kong) Overview: A majority of the global population is multilingual. Although many studies have investigated the cognitive processes used to produce words in multilingual speakers, one criticism of this research is the emphasis on Indo-European languages typically always including English as the dominant language. The question posed in this presentation is whether cognitive processes that have been assumed in models of language processing (naming, reading and spelling) extend to multilingual speakers. This is not a trivial question. Multilingual speakers can use very different writing systems. Indeed, even within a language e.g. Japanese and Korean - two or more scripts must be learned to become literate (monolingual bi-scriptals). If the same cognitive mechanisms used to read and to spell in one type of script impact on reading and spelling skills in different scripts then several clinical implications arise e.g. in the diagnosis and treatment of aphasia, dyslexia and dysgraphia in multilingual speakers. One feature of the presentation will be reports of multilingual speakers who display reading and spelling disorders in typologically distant scripts. These cases highlight the striking similarities across languages.

The effect of right hemisphere stimulation on language recovery in left-brain damage patients with chronic aphasia

The effect of right hemisphere stimulation on language recovery in left-brain damage patients with chronic aphasia Speaker: Dr Mehdi Bakhtiar (Research Assistant Professor Department of Chinese and Bilingual Studies, The Hong Kong Polytechnic University) Overview: Over the past decades, the application of transcranial direct current stimulation (tDCS), has received an increasing attention as a potential complement to traditional behavioral therapy for stroke patients with Aphasia. However, different tDCS parameters were employed including the stimulation of right versus left hemisphere and application of anodal (excitatory) versus cathodal (inhibitory) stimulations. There are two opposing hypotheses, namely the interference hypothesis and the compensatory hypothesis regarding the role of right hemisphere (RH) activation in language recovery following the brain damage in the left hemisphere. The present preliminary study aims to investigate the effect anodal tDCS of RH inferior frontal gyrus in left-hemispheric damaged patients with chronic aphasia to a) examine the compensatory versus interference role of RH in language recovery, and b) to confirm that the application of tDCS for language intervention does not induce any adverse effects on other cognitive functions. Four right-handed native Cantonese-speaking patients with aphasia following the left-hemisphere lesions participated in a randomized, double-blind, sham-controlled crossover experiment. The participants received five consecutive days of 20-minutes anodal tDCS (one mA) and five consecutive days of 20-minutes sham tDCS (with randomized order), together with 40 minutes of online naming therapy delivered by a speech therapist. The patients’ speech, language and, cognitive functioning was tested before and after the anodal and sham conditions using a picture naming task and other standardized language and cognitive assessment batteries. In general, the patients showed more improvement in terms of their naming abilities following sham condition versus the anodal tDCS of RH, though the difference was statistically significant in one patient. No adverse effects of tDCS application were found on the cognitive functions as well. The results of the current study suggest that the excitatory stimulation of the right inferior frontal gyrus may exert an inhibitory effect on word learning in chronic patients with aphasia, which could be interpreted more in the favor of the interference hypothesis. However, the results need to be supported by the further group studies using different paradigms to verify the role of RH activation on language recovery in patients with aphasia across the different post-stroke stages.

Clinical application of repetitive transcranial magnetic stimulation (rTMS) for swallowing disorders following stroke

Clinical application of repetitive transcranial magnetic stimulation (rTMS) for swallowing disorders following stroke Speaker: Dr Ivy Cheng (Speech Therapist Chance Developmental Support Centre) Overview: Swallowing disorders (dysphagia) is common among stroke patients. Recovery of swallowing functions after stroke relies on the reorganization of neurological systems (neural plasticity). Studies have found that repetitive transcranial magnetic stimulation (rTMS) can be used to promote neural plasticity and improve swallowing functions in acute stroke survivors. rTMS is a non-invasive neuromodulation technique that can increase or decrease cortical excitability through electromagnetic induction. Cortical excitability refers to how readily motor responses can be elicited by external stimulation of the cortex. It can be affected by aging and neurological diseases.  Swallowing involves complex coordination of muscles and the tongue muscles are especially important for swallowing. However, little is known about the changes in cortical excitability of the tongue with aging and after stroke. For the clinical application of rTMS, much research has been done with the acute post-stroke dysphagic population, yet its therapeutic potential for the chronic population remains uncertain. A series of studies have been conducted to investigate (1) the changes in cortical excitability of the tongue with aging and stroke, and (2) the effectiveness of rTMS as a treatment for chronic post-stroke dysphagia. The findings of the studies showed that the cortical excitability of the tongue was significantly reduced in adults aged above 65 and in stroke survivors when compared to age-matched healthy adults. There was a substantial inter-individual variability in the responses to rTMS. Group-level analysis revealed insignificant treatment effects. However, individual analysis suggested that individuals with higher cortical excitability may respond better to rTMS than those with lower cortical excitability.

Comprehension of Chinese relative clauses in a trilingual acquisition context

Comprehension of Chinese relative clauses in a trilingual acquisition context Speaker: Dr Angel Chan (Associate Professor Department of Chinese and Bilingual Studies, The Hong Kong Polytechnic University) Overview: Chinese relative clauses (RCs) have word order properties that are distinctly rare across languages of the world; such properties provide a good testing ground to tease apart predictions regarding the relative complexity of subject and object RCs in acquisition and processing. This study considers these special word order properties in a multilingual acquisition context, examining how Cantonese(L1)-English(L2)- Mandarin(L3) trilingual children process RCs in two Chinese languages differing in exposure conditions. Studying in an English immersion international school, these trilinguals are also under intensive exposure to English. Comparisons of the trilinguals with their monolingual counterparts are made with a focus on the directionality of cross-linguistic influence. The study considers how various factors such as language exposure, structural overlaps in the target languages, typological distance, and language dominance can account for the linguistic abilities and vulnerabilities exhibited by a group of children in a trilingual acquisition context. Twenty-one trilingual five-to- six-year- olds completed tests of subject- and object- RC comprehension in all three languages. Twenty-four age-matched Cantonese monolinguals and 24 age-matched Mandarin monolinguals served as comparison groups. Despite limited exposure to Mandarin, the trilinguals performed comparable to the monolinguals. Their Cantonese performance uniquely predicts their Mandarin performance, suggesting positive transfer from L1 Cantonese to L3 Mandarin. In Cantonese, however, despite extensive exposure from birth, the trilinguals comprehended object RCs significantly worse than the monolinguals. Error analyses suggested an English-based head-initial analysis, implying negative transfer from L2 English to L1 Cantonese. Overall, we identified a specific case of bi-directional influence between the first and second/third languages. The trilinguals experience facilitation in processing Mandarin RCs, because parallels and overlaps in both form and function provide a transparent basis for positive transfer from L1 Cantonese to L3 Mandarin. On the other hand, they experience more difficulty in processing object RCs in Cantonese compared to their monolingual peers, because structural overlaps with competing structures from English plus intensive exposure to English lead to negative transfer from L2 English to L1 Cantonese. The findings provide further evidence that head noun assignment in object RCs is especially vulnerable in multilingual Cantonese children when they are under intensive exposure to English. Chan, A., Chen, S., Matthews, S. & Yip, V. (2017). Comprehension of subject and object relative clauses in a trilingual acquisition context. Frontiers in Psychology: Language Sciences. https://doi.org/10.3389/fpsyg.2017.01641

A Study on the Evolution of Voval Tract from Chimpanzees to Humans

A Study on the Evolution of Voval Tract from Chimpanzees to Humans Speaker: Prof. Kong Jiangping (Department of Chinese Language and Literature, Peking University) Overview: As is well known, vowels [a, i, u] are regarded as the basic vowels in human speech. Chimpanzee, on the other hand, can only produce sounds reminiscent of [a] and [u] because of their small back cavity and the specific structure of their tongue muscles, which make it impossible for them to form the vocal-track shapes as observed in human. The differentiation of chimpanzee and modern human dates back to 5 million years ago. Since tongue muscles and larynx cannot be fossilized, it is difficult to reconstruct vocal tracts simply based on the fossils of ancient homos. Kong’s team has established the physiological models of chimpanzee and modernhuman based on 3D MRI data, which include the parameters of front cavity length,back cavity length, and similarity of vocal tract shapes. Through the vocal tractsimulation from chimpanzee to modern human, about fifty thousand 3D vocal tracts are reconstructed, and sounds produced in the vocal tracts have been synthesized. By conducting speech sound perception tests, the team explores the time vowels couldhave emerged. Further research will deepen our understanding of the evolution of speech organs, as well as the origin of human language.

Tone Development in Mandarin-Speaking Children

Tone Development in Mandarin-Speaking Children Speaker: Dr Peng Gang (Associate Professor Department of Chinese and Bilingual Studies, The Hong Kong Polytechnic University) Overview: Children start to produce their first words by the age of one; by four, most children have developed the ability to use their native language; by six or seven, they become veteran users of their native language. Studies on tone production have suggested very early mastery of Mandarin tones and reported that children produce tones correctly around age two. However, early production of tones in children before three years of age does not mean that children have the same tonal production ability as adults. On Mandarin tone perception, although the literature suggests that three-year- old children have already achieved a relatively high perceptual accuracy of all four Mandarin tones, research on the developmental course of categorical perception (CP) of Mandarin tones is still limited. To track the detailed developmental course of children's fine-grained perception of Mandarin tones, we have explored how CP of Mandarin tones (Tone 1 vs. Tone 2) develops along age among four- to seven-year- old children. Our results indicate that six-year- olds have already acquired adult-like identification competence of Mandarin Tones 1 & 2. Moreover, the ability to discriminate more fine-grained across-category tonal differences has been enhanced gradually with age due to perceptual accumulation.

A lens to the language deficit in schizophrenia: Verbal memory and voxel based morphometry in first episode non-affective psychosis

A lens to the language deficit in schizophrenia: Verbal memory and voxel based morphometry in first episode non-affective psychosis Speaker: Prof. Rosa Ayesa-Arriola (Centro de Investigación Biomedica En Red del Área de Salud Mental, Psychiatry Department, University Hospital Marques de Valdecillapeech Therapist) Overview: Deficits in auditory-verbal memory have been reported by the vast majority of published research in schizophrenia and also detected in first episode psychosis (FEP), confirming they are already present at the early stages of the illness. However, the specific neurocognitive constructs underlying defective verbal memory and their neuroanatomical correlates remains poorly understood in patients of schizophrenia spectrum disorders. In this talk I will explore results from both the Rey Auditory Verbal Learning Test (RAVLT) and structural MRI using voxel based morphometry taken from a large cohort of FEP patients and healthy controls. I will discuss how the RAVLT provides insight into language processing, specifically through distinct memory processes, including: a) acquisition/learning b) sensitivity to interference c) retrieval; d) retention or rate of forgetting; e) and retrieval efficiency. In combination with the RAVLT we have used patient and control brain morphometry to identify significant correlations between lateralized proactive and retroactive interference in the frontal lobe, retention with the right occipital cortex, and the role of grey matter reduction in the frontal and occipital cortical areas with retention and interference. Our findings suggest specific relationships between different neuroanatomical structures and discrete memory processes with these structures playing an important role in verbal memory deficits found in FEP.