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  • Akshara-syllable mappings in Bengali: A language-specific skill for reading

    3 July 2018

    © Cambridge University Press 2014.Writing systems Writing systems differ in the phonological units they represent. In alphabetic scripts, the basic unit represented by a grapheme is essentially a phoneme although the nature of this correspondence can vary. In languages such as Finnish, every grapheme is realized by only one phoneme and every phoneme represents one grapheme, making these transparent orthographies. Conversely, in opaque orthographies, a phoneme can be realized by different graphemes (e.g. compare /u:/in ‘to’, ‘too’, ‘two’), and a grapheme by many different phonemes (e.g. the letter [a] in ‘late’, ‘above’, ‘cat’ and ‘car’). In syllabic scripts such as Cherokee written units represent syllables. In contrast, the symbols in alphasyllabic scripts are orthographic syllables but can also be segmented into phonemes (Nag, 2011). In this chapter we examine how sound–symbol mappings influence the ability to read and process phonological units. As we will see, the unique properties of the Bengali writing system make it particularly useful for examining this question. Phonological and orthographic structure of Bengali Bengali has 7 oral vowels (/i/, /u/, /e/, /o/, /æ/, /ɔ/, /a/), 4 semi-vowels (/j/, /w/, //, //) and 30 consonants (Ray, Hai & Ray, 1966). Many diphthongs are possible and necessarily consist of one semi-vowel, though only two diphthongal symbols /oi/and /ou/are represented in the symbol register. All vowels can be nasalized. Vowel deletion (like schwa deletion) is common in the language, particularly in word medial and final positions. This phenomenon is governed by rules of syllabification, and in marginal cases by word etymology, phonotactic constraints and morphological compositions.

  • Global Collaboration, Learning from Other Fields.

    3 July 2018

    Neuroscience research is becoming increasingly more collaborative and interdisciplinary with partnerships between industry and academia and insights from fields beyond neuroscience. In the age of institutional initiatives and multi-investigator collaborations, scientists from around the world shared their perspectives on the effectiveness of large-scale collaborations versus single-lab, hypothesis-driven science.

  • Sex and APOE: A memory advantage in male APOE ε4 carriers in midlife.

    3 July 2018

    Short-term memory in middle-aged individuals with different APOE alleles was examined using a recently developed task which is sensitive to medial temporal lobe (MTL) damage. Individuals (age-range: 40-51 years) with ε3/ε3, ε3/ε4 and ε4/ε4 APOE genotypes (N = 60) performed a delayed estimation task with a sensitive continuous measure of report. The paradigm allowed us to measure memory for items and their locations, as well as maintenance of identity-location feature binding in memory. There was a significant gene-dosage dependent effect of the ε4 allele on performance: memory decay or forgetting was slower in ε4 carriers, as measured by localization error and after controlling for misbinding errors. Furthermore ε4 carriers made less misbinding errors. These findings were specific to male carriers only. Thus, male ε4 carriers are at a behavioral advantage in midlife on a sensitive task of short-term memory. The results would be consistent with an antagonistic pleiotropy hypothesis and hightight the interaction of gender on the influence of APOE in cognition.

  • Preparatory α-band oscillations reflect spatial gating independently of predictions regarding target identity.

    3 July 2018

    Preparatory modulations of cortical α-band oscillations are a reliable index of the voluntary allocation of covert spatial attention. It is currently unclear whether attentional cues containing information about a target's identity (such as its visual orientation), in addition to its location, might additionally shape preparatory α modulations. Here, we explore this question by directly comparing spatial and feature-based attention in the same visual detection task while recording brain activity using magnetoencephalography (MEG). At the behavioral level, preparatory feature-based and spatial attention cues both improved performance and did so independently of each other. Using MEG, we replicated robust α lateralization following spatial cues: in preparation for a visual target, α power decreased contralaterally and increased ipsilaterally to the attended location. Critically, however, preparatory α lateralization was not significantly modulated by predictions regarding target identity, as carried via the behaviorally effective feature-based attention cues. Furthermore, nonlateralized α power during the cue-target interval did not differentiate between uninformative cues and cues carrying feature-based predictions either. Based on these results we propose that preparatory α modulations play a role in the gating of information between spatially segregated cortical regions and are therefore particularly well suited for spatial gating of information.NEW & NOTEWORTHY The present work clarifies if and how human brain oscillations in the α-band support multiple types of anticipatory attention. Using magnetoencephalography, we show that posterior α-band oscillations are modulated by predictions regarding the spatial location of an upcoming visual target, but not by feature-based predictions regarding its identity, despite robust behavioral benefits. This provides novel insights into the functional role of preparatory α mechanisms and suggests a limited specificity with which they may operate.

  • Temporal expectations guide dynamic prioritization in visual working memory through attenuated alpha oscillations.

    3 July 2018

    While working memory is generally considered a highly dynamic mnemonic store, popular laboratory tasks employed to understand its psychological and neural mechanisms (such as change detection and continuous reproduction) often remain relatively "static", involving the retention of a set number of items throughout a shared delay interval. In the current study, we investigated visual working memory in a more dynamic setting, and assessed: 1) whether internally guided temporal expectations can dynamically and reversibly prioritize individual mnemonic items at specific times at which they are deemed most relevant and 2) the neural substrates that support such dynamic prioritization. Participants encoded two differently colored oriented bars into visual working memory in order to retrieve the orientation of one bar with a precision judgement when subsequently probed. To test for the flexible temporal control to access and retrieve remembered items, we manipulated the probability for each of the two bars to be probed over time, and recorded EEG in healthy human volunteers. Temporal expectations had a profound influence on working memory performance, leading to faster access times as well as more accurate orientation reproductions for items that were probed at expected times. Furthermore, this dynamic prioritization was associated with the temporally specific attenuation of contralateral alpha (8-14 Hz) oscillations that, moreover, predicted working memory access times on a trial-by-trial basis. We conclude that attentional prioritization in working memory can be dynamically steered by internally guided temporal expectations, and is supported by the attenuation of alpha oscillations in task-relevant sensory brain areas. SIGNIFICANCE STATEMENT: In dynamic, everyday-like, environments, flexible goal-directed behavior requires that mental representations that are kept in an active (working memory) store are dynamic too. We investigated working memory in a more dynamical setting than is conventional, and demonstrate that expectations about when mnemonic items are most relevant can dynamically and reversibly prioritize these items in time. Moreover, we uncover a neural substrate of such dynamic prioritization in contralateral visual brain areas and show that this substrate predicts working memory retrieval times on a trial-by-trial basis. This places the experimental study of working memory, and its neuronal underpinnings, in a more dynamic and ecologically valid context, and provides new insights into the neural implementation of attentional prioritization within working memory.

  • Measuring the role of conditioning and stimulus generalisation in common fears and worries

    29 June 2018

    Common and persistent fears may emerge through learning mechanisms such as fear conditioning and generalisation. Although there have been extensive studies of these learning processes in healthy but also psychiatric samples, many of the tasks used to produce conditioning and assess generalisation either use painful and aversive stimuli as the unconditioned stimuli (UCS), or suffer from poor belongingness between the conditioned stimuli and the UCS. Here, we present novel data from a paradigm designed to examine fear conditioning and generalisation in healthy individuals. Two female faces served as conditioned threat cue (CS+) and conditioned safety cue (CS-) respectively. The CS+ was paired repeatedly with a fearful, screaming face (unconditioned stimulus). Generalisation included intermediate faces which varied in their similarity to the CS+ and CS-. We measured eyeblink startle reflex and self-reported ratings. Acquired fear of the CS+ generalised to intermediate stimuli in proportion to their perceptual similarity to the CS+. Our findings demonstrate how fears of new individuals may develop based on resemblance to others with whom an individual has had negative experiences. The paradigm offers new opportunities for probing the role of generalisation in the emergence of common and persistent fears. © 2013 Copyright Taylor and Francis Group, LLC.

  • Natural scenes viewing alters the dynamics of functional connectivity in the human brain.

    29 June 2018

    Spontaneous fMRI fluctuations are organized in large-scale spatiotemporal structures, or resting-state networks (RSN). However, it is unknown how task performance affects RSN dynamics. We use MEG to measure slow (∼0.1 Hz) coherent fluctuations of band-limited power (BLP), a robust correlate of RSN, during rest and movie observation and compare them to fMRI-RSN. BLP correlation, especially in α band, dropped in multiple RSN during movie although overall topography was maintained. Variability of power correlation increased in visual occipital cortex, and transient decrements corresponded to scenes perceived as "event boundaries." Additionally, stronger task-dependent interactions developed between vision and language networks in θ and β bands, and default and language networks in γ band. The topography of fMRI connectivity and relative changes induced by the movie were well matched to MEG. We conclude that resting-state and task network interactions are clearly different in the frequency domain despite maintenance of underlying network topography.

  • Carousel

    23 August 2017

  • Perception and Autism

    13 June 2017

    Cathy's research

  • Participate

    4 June 2013

    Most research in Experimental Psychology involves the measurement of human behaviour, and so we need volunteers to participate in experiments. Experiments in the department involve a range of activities, from playing computer games to filling out questionnaires. Some may involve physiological measurements, such as the tracking of eye movements, the measurement of brain activity using electroencephalography (EEG) or functional MRI. We recruit participants across a wide age range, from children to older individuals. All of our experiments take place under the guidelines of the local ethics committee, and all participants are always free to withdraw from a study at any time. Many researchers offer remuneration to compensate volunteers for their time.

  • Get Involved

    6 October 2017

  • Get Involved

    1 June 2018

  • CRL Projects

    18 January 2018

    Wellcome Language and Reading Project

  • Research Projects

    17 October 2017

    The aim of this research is to improve the safety and experience of care for elderly patients as they move from hospital to home, sometimes via intermediate care (support from health and social care services). This period is known as the 'transition'. Patients now spend less time in hospital than they did 10 years ago (5 days compared to 8 days). This can benefit both patients, who prefer to be at home, and hospitals, who can treat more patients if patient stays are shorter.

  • Collaborators

    26 September 2014