A behavioural and neurobiological investigation of basic reading processes

There are competing theories in the literature regarding the extent to which the translation of print to speech involves single or multiple routes. Regardless of the number of routes in a model, all models of reading must account for both sight vocabulary (SV) processing, which specializes in mapping whole-word representations, and phonetic decoding (PD) processing, which specializes in mapping sub-word representations. The purpose of the present work was to examine two hypotheses regarding the relationship between SV and PD: independence versus redundancy. Both behavioural and functional Magnetic Resonance Imaging (fMRI) experiments were conducted and the results supported the hypothesis that SV and PD are behaviourally and neurobiologically independent processes. Furthermore, in the interest of advancing all models of basic word recognition, the neurobiological representations of some of the sub-systems within SV and PD routes were explored and the contribution that particular brain regions make to the completion of naming particular stimuli was evaluated. Finally, basic and applied areas of research were integrated to demonstrate how diagnostic stimuli developed from basic reading research can inform us about impaired reading performance following traumatic brain injury

A Study of Null Effects for the Use of Transcranial Direct Current Stimulation (tDCS) in Adults With and Without Reading Impairment

There is evidence to support the hypothesis that the delivery of anodal transcranial direct current stimulation (tDCS) to the left temporoparietal junction can enhance performance on reading speed and reading accuracy (Costanzo et al., 2016b; Heth & Lavidor, 2015). Here, we explored whether we could demonstrate similar effects in adults with and without reading impairments. Method: Adults with (N = 33) and without (N = 29) reading impairment were randomly assigned to anodal or sham stimulation conditions. All individuals underwent a battery of reading assessments pre and post stimulation. The stimulation session involved 15 min of anodal/sham stimulation over the left temporoparietal junction while concurrently completing a computerized nonword segmentation task known to activate the temporoparietal junction. Results: There were no conclusive findings that anodal stimulation impacted reading performance for skilled or impaired readers. Conclusions: While tDCS may provide useful gains on reading performance in the paediatric population, much more work is needed to establish the parameters under which such findings would transfer to adult populations. The documentation, reporting, and interpreting of null effects of tDCS are immensely important to a field that is growing exponentially with much uncertainty

To Go or Not to Go: Exploring brain activation during response inhibition reading tasks

Objective: Response inhibition is an understudied component of reading that aids in the selection of appropriate responses amidst complicated tasks. Our objective was to explore the contribution of brain regions associated with response inhibition processing in reading tasks that vary in difficulty of response inhibition. Method: Participants (N = 15) completed two go/no-go reading tasks while in a functional magnetic resonance imaging (fMRI) scanner, with the instructions to “name aloud the letter strings that spell a real word.” For the minimal response inhibition condition, the foils, which are stimuli that should not be repsonded to, were nonwords with unfamiliar spelling and sound (e.g., “bink”). For the maximal response inhibition condition, the foils were pseudohomophones with unfamiliar spelling but familiar sound (e.g., “pynt”). The following brain regions associated with decision-making processes were analyzed: the anterior cingulate cortex (ACC), the dorsomedial prefrontal cortex (DMPFC), the inferior frontal gyrus (IFG), the middle temporal gyrus (MTG), the middle occipital gyrus (MOG), and the posterior insula (PI). Results: Significant differences in activation within the nonword task were found for the DMPFC and the PI (the ACC approached significance). Significant differences in activation within the pseudohomophone task were found for the ACC, the MTG, and the PI. The IFG was found to be greatly activated for all words that had familiar phonemes (sounds). The MOG was found to be activated across all tasks. Conclusion: We provide evidence for differential response inhibition processing in the decision-making network during reading tasks. This work is a necessary step in better understanding response inhibition ability for individuals with and without reading impairments

Computer-based cognitive intervention for aphasia: Behavioural and neurobiological outcomes

Aphasia, an acquired impairment of language that commonly occurs after stroke, can have significant consequences on all aspects of functioning of affected individuals. Some have proposed that the language deficits observed in aphasia are due to underlying limitations in cognitive processes that support language1-3. This ‘cognitive’ theory of aphasia is gaining increased attention in the research literature4, and is the impetus for the study of treatments for aphasia that target these underlying cognitive processes5-8. Indeed, studies of cognitive interventions in healthy populations have reported positive outcomes in behavioural (i.e. language and overall cognitive functioning9, 10) as well as neurobiological (i.e., brain function and/or structure11-13) domains, offering promise for the application of these types of interventions to aphasia. Recently, computer-based ‘brain training’ programs have become increasingly prevalent. BrainFitness (BF) is one such commercially available program; it has been used to show improvement in auditory processing speed, attention and working memory in typically aging adults14, 15. This program has the potential to be a useful intervention for individuals with aphasia, but questions regarding the clinical utility of the program and neural correlates of training-related behavioural changes remain. The purpose of this study was to investigate the effect of BF training in people with aphasia using behavioural and neurobiological outcome measures

A neuroanatomical examination of embodied cognition: semantic generation to action-related stimuli

The theory of embodied cognition postulates that the brain represents semantic knowledge as a function of the interaction between the body and the environment. The goal of our research was to provide a neuroanatomical examination of embodied cognition using action-related pictures and words. We used functional magnetic resonance imaging (fMRI) to examine whether there were shared and/or unique regions of activation between an ecologically valid semantic generation task and a motor task in the parietal-frontocentral network (PFN), as a function of stimulus format (pictures versus words) for two stimulus types (hand and foot). Unlike other methods for neuroimaging analyses involving subtractive logic or conjoint analyses, this method first isolates shared and unique regions of activation within-participants before generating an averaged map. The results demonstrated shared activation between the semantic generation and motor tasks, which was organized somatotopically in the PFN, as well as unique activation for the semantic generation tasks in proximity to the hand or foot motor cortex. We also found unique and shared regions of activation in the PFN as a function of stimulus format (pictures versus words). These results further elucidate embodied cognition in that they show that brain regions activated during actual motor movements were also activated when an individual verbally generates action-related semantic information. Disembodied cognition theories and limitations are also discussed

Exploring different types of inhibition during bilingual language production

Multilinguals have to control their languages constantly to produce accurate verbal output. They have to inhibit possible lexical competitors not only from the target language, but also from non-target languages. Bilinguals' training in inhibiting incongruent or irrelevant information has been used to endorse the so-called bilingual advantage in executive functions, assuming a transfer effect from language inhibition to domain-general inhibitory skills. Recent studies have suggested that language control may rely on language-specific inhibitory control mechanisms. In the present study, unbalanced highly proficient bilinguals completed a rapid naming multi-inhibitory task in two languages. The task assessed three types of inhibitory processes: inhibition of the non-target language, inhibition of lexical competitors, and inhibition of erroneous auditory feedback. The results showed an interaction between lexical competition and erroneous auditory feedback, but no interactions with the inhibition of the non-target language. The results suggested that different subcomponents of language inhibition are involved during bilingual language production

A citizenâs stake in sovereign wealth funds

Over the past five years, Sovereign Wealth Funds (SWFs) have become a prominent phenomenon in contemporary capitalism. Described as government investment vehicles that invest state wealth in financial markets, the majority of the world's 60-plus funds have been established since the year 2000. Despite extensive treatments of SWFs' geopolitical and international significance, ethical and domestic level analyses are sparse. In response, this thesis interrogates three key normative questions raised by the funds for the domestic citizen-state relationship: (1) How (and by whom) should sovereign funds be managed? (2) How should sovereign wealth be invested? (3) How should the earnings of sovereign fund investment be distributed? In answering these questions, this thesis aims to dispel ambiguity over the ownership status of sovereign funds, evident in popular and academic discourse and within communities that establish these entities. For this task, it draws on recently revived fiduciary theory of the citizen-state relationship to argue that the rightful owner of these funds is the citizenry - not states or governments who enjoy physical and legal possession of SWFs. It goes on to examine the implications of this fiduciary state conception of SWF ownership, asking how citizen-owners should enjoy control over and benefit from the distinct constituent parts of their SWF property: the institution of the fund, the underlying sovereign wealth and the financial returns earned on the investment of its assets. The model of citizen ownership defended demands substantially increased popular control over SWF management and the investment of sovereign wealth, as well as direct benefit rights for citizen-owners to fund income through individualised distribution of investment returns. Examination of existing practice among SWFs demonstrates that this normative ideal is far, although not impossibly distant from current institutional practice.</p

A tale of two sovereign funds: China's exceptionalism in sovereign wealth management through CIC and SAFE

China is the only country in the world with two sovereign investment vehicles dedicated to managing excess foreign reserves for return, not just safety and liquidity. As the investment profile and behaviour of both funds align with the aims of the government's economic agenda, it is tempting to view China's two sovereign funds as part of a coordinated effort to further state investment policy. However, analysis of the origin of China's multi-sovereign investor regime shows that this approach is primarily a product of intense bureaucratic rivalry within the Chinese public service, rather than a considered strategy of the sponsoring government. This rivalry had a detrimental impact on aspects of the CIC's institutional design and early investment decision making. Comparison of the CIC, China's flagship sovereign investor, to its peer Asian funds in Korea and Singapore reveals that relative to regional reserve investment corporations, the CIC lacks robust mechanisms to achieve effective arms-length governance from its state sponsor. Reforms to the Chinese sovereign fund to ensure greater clarity of mission and alignment of purpose with internal decision making would ensure Chinese exceptionalism in sovereign investment transitions from cautionary to exemplary