Functional Magnetic Resonance Imaging

"Functional Magnetic Resonance Imaging - Advanced Neuroimaging Applications" is a concise book on applied methods of fMRI used in assessment of cognitive functions in brain and neuropsychological evaluation using motor-sensory activities, language, orthographic disabilities in children. The book will serve the purpose of applied neuropsychological evaluation methods in neuropsychological research projects, as well as relatively experienced psychologists and neuroscientists. Chapters are arranged in the order of basic concepts of fMRI and physiological basis of fMRI after event-related stimulus in first two chapters followed by new concepts of fMRI applied in constraint-induced movement therapy; reliability analysis; refractory SMA epilepsy; consciousness states; rule-guided behavioral analysis; orthographic frequency neighbor analysis for phonological activation; and quantitative multimodal spectroscopic fMRI to evaluate different neuropsychological states

The Syntactic Bits of Nouns: How Prior Syntactic Distributions Affect Comprehension, Production, and Acquisition

Usage-based linguistic theory argues that experience is the fundamental organizing principle of language. Linguistic representations are extracted from – and continuously tuned by – probabilistic features of language use. Much psycholinguistic evidence supports this argument, particularly in the domain of lexical processing. For example, how a word is distributed across its various lexical and morphological contexts influences how quickly it is recognized and produced in isolation. Fewer studies have explored how syntactic distributions affect lexical processing, and of these, even fewer have adopted comprehensive, abstract measurements of syntax. In this dissertation, I present several new information-theoretic tools for measuring the syntactic distributions of words based on the Dependency Grammar formalism. This formalism allows me to contrast two independent dimensions of syntactic structure: hierarchical status and word order. Further, I provide a new method for teasing apart information bound to syntactic and lexical contexts. I compute these measures for nouns based on two large corpora of English.These measures are correlated with behavior in several contexts. First, I re-analyze the noun-based trials of two previously published databases of visual lexical decision response time data, one simple and the other primed. I then turn to production, reporting two picture-naming studies. In the first, participants produce nouns in isolation. This task consitutes a stong attack on the hypothesis that syntactic distributions affect noun production; at least on its face, it does not require participants to access syntactic information in order to successfully complete the task. In a follow up, participants were asked to name the images using a syntactic frame (the + NAME). This task should promote syntactic access, increasing the likelihood that prior syntactic distributions should play a role. Finally, I test whether children are senstive to these syntactic distributions (based on adult speech) as they begin to produce nouns in syntactic contexts for the first time using a large, densely sampled longitudinal corpus of child speech.Results show that isolated noun processing is affected by prior syntactic distributions in both comprehension and production. However, the specific nature of these effects differs across modalities, and in production, as a function of whether the nouns were produced in isolation or within a syntactic frame. The measures also predict the age at which nouns first emerge in the speech of children

Cognitive therapy, working memory training, and the treatment of Methamphetamine Use Disorder - a functional MRI study

Background: In recent years, methamphetamine use disorder (MUD), which is associated with adverse outcomes and represents a significant public health burden, has become highly prevalent in Cape Town, South Africa. Protracted methamphetamine (MA) use has been linked with neural dysfunction and working memory deficits. Although current treatments have shown limited efficacy in addressing MUD, recent evidence indicates the potential of utilizing tailored brief cognitive therapy programs and working memory training to improve outcomes. The current study aims to investigate the potential impact of brief cognitive therapy and using working memory training as an adjunct in the treatment of MUD. Methods: Participants were recruited from an in-patient drug rehabilitation centre in Cape Town. The sample (n = 26) consists of male patients (between the ages of 18–50) diagnosed with MUD. MUD patients were randomly split into 2 groups that received 4 weeks of treatment, i.e. treatment as usual (cognitive therapy only (NT) (n= 12)) and cognitive therapy with working memory training (CT) (n = 14). Neuroimaging and psychological data were collected from participants pre- and post- intervention to assess the relative impact of said interventions. Results: Behavioural outcome measures and the n-back working memory task adapted for fMRI were measured and compared pre- and post- intervention. No significant differences were present between groups prior treatment on behavioural measures, demographic measures, and fMRI activity. The brief cognitive therapy appeared to reduce depression and impulsivity scores over the course of the intervention, with scores slightly lower in the CT group. An FDR corrected whole-brain repeated measures ANOVA on the main effect of group indicated significant activation in the left posterior cingulate, left anterior cingulate, and left lingual gyrus. Post hoc t-tests were then conducted to follow up the group main effect and significant differences under FDR correction were observed in the NT group (in contrast to the CT group) indicating significantly more activity in the left superior temporal gyrus, left insula, right posterior declive, and right lingual gyrus. Significant differences were also observed under FDR correction on a posthoc test on the CT group (in contrast to the NT group) indicating significantly less activity in the left lingual gyrus, left posterior declive, and right cuneus. 5 Conclusions: The findings tentatively suggest that the working memory training adjunct may have slightly enhanced working memory maintenance brain function relative to the treatment as usual group post-intervention. The evidence also suggests that there may have been inefficient neural functioning in the treatment as usual group during the working memory task compared to the group receiving the working memory training adjunct. The results demonstrated that brief cognitive therapy treatment did somewhat reduce depressive symptoms and impulsivity in this study, with indications of subtle treatment gains in the cognitive training group. Overall, the current study (despite numerous limitations) provides preliminary and tentative evidence of the possible benefits of brief term cognitive therapy and the potential promise of using working memory training as a treatment adjunct

The role of phonology in visual word recognition: evidence from Chinese

Posters - Letter/Word Processing V: abstract no. 5024The hypothesis of bidirectional coupling of orthography and phonology predicts that phonology plays a role in visual word recognition, as observed in the effects of feedforward and feedback spelling to sound consistency on lexical decision. However, because orthography and phonology are closely related in alphabetic languages (homophones in alphabetic languages are usually orthographically similar), it is difficult to exclude an influence of orthography on phonological effects in visual word recognition. Chinese languages contain many written homophones that are orthographically dissimilar, allowing a test of the claim that phonological effects can be independent of orthographic similarity. We report a study of visual word recognition in Chinese based on a mega-analysis of lexical decision performance with 500 characters. The results from multiple regression analyses, after controlling for orthographic frequency, stroke number, and radical frequency, showed main effects of feedforward and feedback consistency, as well as interactions between these variables and phonological frequency and number of homophones. Implications of these results for resonance models of visual word recognition are discussed.postprin

Interactive effects of orthography and semantics in Chinese picture naming

Posters - Language Production/Writing: abstract no. 4035Picture-naming performance in English and Dutch is enhanced by presentation of a word that is similar in form to the picture name. However, it is unclear whether facilitation has an orthographic or a phonological locus. We investigated the loci of the facilitation effect in Cantonese Chinese speakers by manipulating—at three SOAs (2100, 0, and 1100 msec)—semantic, orthographic, and phonological similarity. We identified an effect of orthographic facilitation that was independent of and larger than phonological facilitation across all SOAs. Semantic interference was also found at SOAs of 2100 and 0 msec. Critically, an interaction of semantics and orthography was observed at an SOA of 1100 msec. This interaction suggests that independent effects of orthographic facilitation on picture naming are located either at the level of semantic processing or at the lemma level and are not due to the activation of picture name segments at the level of phonological retrieval.postprin

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task