projects
The probabilistic account of human reasoning
The general aim is to contribute to the development of the new probabilistic/Bayesian paradigm in the psychology of reasoning, and so to integrate the subjects of reasoning and decision making. The main projects are investigating how well subjective probability theory accounts for human inference, and the relation between the judged probability of conditionals in natural language and subjective conditional probability. More specific topics include the study of inferring conditionals from disjunctive beliefs and the similarity between indicative conditionals and conditional bets. For further information contact Professor Over.
Neurorehabilitation of neurovisual deficits
We use a number of experimental approaches to develop treatments for hemianopia. For example, light-bending prisms have been used to treat VFDs by bringing visual information that normally falls in the blind side into the sighted side. However, this approach has not been scientifically evaluated so it is not known whether A) the prisms really reduce visual disability or B) the prisms benefit patients in their daily life beyond the lab. In one current project, Rachel Clannachan is investigating the clinical efficacy of prisms in a large sample of hemianopic patients (this project is funded by OneNorthEast and supported by the Stroke Association). We are also investigating ways in which unconscious visual process (e.g. ‘blindsight’) can be used to facilitate compensatory exploration therapy. For further information contact Dr. Smith.
Attention and Awareness
Research in this area makes use of paradigms in which participants fail to become aware of what should be obvious changes to a visual display (e.g. change blindness and inattentional blindness) and patients who have deficits of visual awareness or attention following brain damage (e.g. Hemianopia and hemineglect). Our findings so far suggest that it is usually necessary for a person to attend to a sensory event in order for it to reach conscious awareness, although some sensory events are sufficiently salient to ‘force’ their way into awareness. Intriguingly, we have also been able to use Inhibition of Return to reduce awareness of visual events. Recently, we have begun to investigate the effects of working memory on awareness in patients with deficits of attention with the aim of investigating the extent to which working memory can boost sensory inputs enough for them to enter awareness.For further information contact Dr. Smith.
Attention and eye-movements
The main focus of work in this area is to more precisely characterise the role of the eye-movement system in guiding attention. Much of this work has involved investigating the effect of lesions of the oculomotor system on attention. This research shows that problems making eye-movements lead to subtle deficits of reflexive attention, such that salient peripheral events fail to capture attention. Interestingly, although oculomotor problems can disrupt reflexive attention they do not appear to disrupt inhibition of return, suggesting that 1) IOR does not depend on an initial attention shift and 2) IOR can be mediated by neural areas that are not directly responsible for generating eye-movements. Importantly, voluntary attention appears to be much more robust to damage to the oculomotor system, perhaps because voluntary attention can be driven by many cognitive systems (e.g. working memory). More recently, Dan Hedley has begun to investigate the effects of operant conditioning of eye-movements on spatial attention. For further information contact Dr. Smith.
Home-based training for patients suffering from hemiblindness.
In this project we assess a computer-based training which patients conduct themselves in their own home. The aim of the training is to help patients with hemiblindness to improve their ability to explore their visual environment and to read. This project is funded by the National Institute for Health Research. For further information contact Dr. Schenk.
Can prism adaptation cure unilateral neglect?
Unilateral neglect is a common consequence of stroke and leaves patients unable to turn their attention to (typically) the left half of their environment. Unilateral neglect has famously been described as the best predictor of a poor rehabilitation outcome. Patients with this disorder are severely disabled and current treatment approaches often fail to lead to substantial improvements. A new approach involves the prismatic goggles. Several studies suggested that training patients with neglect while they wear prismatic goggles leads to significant and surprisingly long-lasting improvements. In this project we try to understand the mechanism underlying these improvements and explore whether this technique can be used as effective treatment for unilateral neglect. For further information contact Dr. Schenk.
Visual form blindness and visuomotor control
Patient DF has a rare visual disorder. She is unable to perceive the size and shape of visual objects. However, her ability to interact with objects is still remarkably well-preserved. This interesting discrepancy suggests that visual information for perceptual analysis and visuomotor control are based on different neural representations. In this project we examine in detail the perceptual and visuomotor skills of patient DF and other patients with similar deficits to find out more about how visual information is used to form our perceptual representations and guide our actions. For further information contact Dr. Schenk.
Spatial frames of reference in visuospatial priming
When searching for a visual item we become significantly faster when the spatial location of this item is repeated in subsequent trials. This is called visuospatial priming and is a well-established phenomenon. It remains unclear which spatial reference frame is used to code the repeat-location of the search target. Examining this question will allow us to better understand the representational format that is used for visuospatial memory. For further information contact Dr. Schenk.
Neural mechanisms of colour vision
How are the signals from the three classes of cone photoreceptors processed to give rise to our perceptions of hue, saturation and brightness? What are the neural computations that permit the efficient transmission of colour information from retina to cortex? We study these questions using psychophysical measurements of visual performance, inspired by physiological descriptions of the underlying neural circuitry. For further information contact Dr. Smithson.
Light adaptation
How is the human visual system able to operate over a range of environmental light levels that spans 9 log10 units? We relate specific signatures of visual performance to changes in the visual pathway at the molecular, cellular and neural-population levels. For further information contact Dr. Smithson.
Colour constancy in a changing world
Our aim is to better understand the determinants of colour appearance of lights and surfaces in a changeable world. Colour constancy – the extent to which an observer can stably recognize the spectral reflectance of an object’s surface (or in perceptual terms, its colour), despite changes in conditions of observing that change the spectral properties of the light reaching the eye – is typically studied with snapshot representations of visual scenes. Our novel approach is to work within a stimulus environment that is dynamic. For further information contact Dr. Smithson.
Sensory storage of spatio-temporal objects
Many of the objects of visual perception are intrinsically spatiotemporal. The aim of this project is to better understand how such spatiotemporal objects are represented and stored in the brain. Understanding the brain's capacity to buffer incoming information is important in understanding human interaction with a constantly changing visual environment. For further information contact Dr. Smithson.
Perceptual learning in vision and hearing
Repeated practice with a target stimulus can improve detection and discrimination thresholds. In this project we measure detection thresholds in noise and manipulate the predictability of the noise, whilst keeping the target constant. We ask whether perceptual learning changes the specificity of early perceptual filters, or the way in which this information is utilized by later mechanisms. Analogous experiments in vision and hearing suggest modality specific differences. For further information contact Dr. Smithson.
From astronomy to vision science
In collaboration with the Centre for Advanced Instrumentation (Department of Physics), we are using optical and image-processing techniques to tackle problems in vision science. Our main research efforts utilize adaptive optics, spectral suppression spectroscopy and high-speed tracking. We're particularly interested in visual impairments related to age-related macular degeneration and disability glare, and in the measurement and control of eye-movements. For further information contact Dr. Smithson.
How do different areas of the brain interact?
We are investigating this question using visual search tasks which involves various brain regions (e.g. posterior parietal cortex, frontal eye fields, V5) for different aspects of processing. Using the neuodisruption technique of transcranial magnetic stimulation, we can not only delineate the critical and temporal relative involvements of these regions, but also investigate (using dual-site stimulation) how these regions interact. For further information contact Dr. Ellison.
What does the posterior parietal cortex contribute to visuomotor transformation?
Using kinetic performance recording, we are investigating how disruption of posterior parietal cortex affects pointing function in a task for which parietal cortex is not involved for a simple present/absent response. Finding from this question will help us understand loss of function following parietal stroke and therefore there are ramifications for neuropsychological rehabilitation. For further information contact Dr. Ellison.
Can we replicate blindsight in olfaction?
The subcortical pathway underlying the phenomenon of blindsight has been well tested over the years. However, we are investigating anosmic people who cannot consciously smell or identify an odour but if given a two alternative forced choice, their performance is near perfect. Performance differs according to the aetiology of anosmia and so a thorough investigation is underway to delineate the prevalence of this effect on each anosmic group. Only then can we make predictions as to the cause of this phenomenon. For further information contact Dr. Ellison.
How are auditory emotion cues normally decoded in the brain?
Relative to what we know about processing of facial emotions by the brain, we know precious little about how auditory emotion cues are processed. In this group of studies, I am using fMRI to characterise the normal neuroanatomical bases of prosodic emotion decoding. Current avenues of exploration include discriminating between prosodic emotions, comparing linguistic and emotional prosody interpretation, and dealing with increasing conflict between lexico-semantic and prosodic emotion cues. More recently, I am also using fMRI to explore the neural mechanisms supporting the expression of emotional prosody. For further information contact Dr. Mitchell.
Neural correlates of prosodic emotion recognition (EPC) and its relation with theory of mind (ToM)
The aim of this study is to reveal the neural correlates of emotional prosody comprehension (EPC) and to disentangle the processing of simple emotions, social emotions, complex mental states and emotional theory of mind. Neuropsychological models of EPC organization in the brain have been proposed. However, the empirical evidence supporting these models is still fragmented. This study will combine DTI and functional connectivity analysis in order to demonstrate the functional interactions and structural underpinnings in the neural network supporting normal EPC processing. The white matter tracking will be important for interpreting the functional MRI data and establishing how activated regions are linked together in networks, opening new horizons toward better neuropsychological models of EPC. This investigation will also assess the overlap between EPC and emotional ToM at the neural level and how this overlap is associated with task performance. It is expected that the overlap between EPC and ToM will be greater in individuals who demonstrate high performance accuracy in these tasks. For further information contact Dr. Mitchell.
Contributions of emotional prosody comprehension deficits in the formation of hallucinations in schizophrenia: insights from neuroimaging.
Hallucinations and EPC deficits seem to be associated at the behavioral level. Both phenomena also appear to share the same neural substrate. This study aims to identify the neural correlates of EPC in schizophrenic patients with and without history of hallucinations, as well as in controls. The first analysis will focus on the interactions between functionally segregated regions in order to understand how the associated patterns of brain activity are coordinated during the execution of EPC, distinguishing between forward and backward connections. This study will compare functional connectivity in the network supporting EPC in patients with and without hallucinations. Finally, a DTI analysis will be performed to study anatomical connectivity within the EPC neural network in patients with and without AVH. Combining fMRI with DTI will help us to understand whether the difficulties that AVH schizophrenic patient have in EPC relate to physiological and or structural dysfunction. For further information contact Dr. Mitchell.
What role does inhibitory control play in resisting the lure of the causal conjunction fallacy?
Our behavioural study (Crisp and Feeney, 2009) showed that the causal conjunction fallacy first demonstrated by Kahneman and Tversky (1983) is a function of the strength of the causal connection between constituent events. We explained these findings in terms of conflict between graded output from an automatic heuristic reasoning process and a more effortful analytical process. We want to use this paradigm to address the point at which the analytical system intervenes in the reasoning process. Behavioural research on base-rate neglect suggests that people detect a conflict between a response based on the base rates and a response based on the individuating information, but nonetheless fail to inhibit the appealing heuristic response in favour of the correct probabilistic answer (De Neys and Glumicic, 2008). Recent brain imaging data (De Neys, Vartanian and Goel, 2008) shows that when heuristic and analytical processes cue contrasting answers, regardless of which response is given, there is activation in the anterior cingulate cortex (ACC), an area involved in conflict detection. However, when people refrain from giving the heuristic response, there is additional activation in the right lateral prefrontal cortex (RLPFC), a region involved in response inhibition (Aron, Robbins and Poldrack, 2004). We want to investigate whether there is a relationship between RLPFC activation and the strength of the causal link when people manage to resist the causal conjunction fallacy. This would underscore our suggestion that stronger causal links between conjuncts make it increasingly more effortful to inhibit the heuristic response. For further information contact Dr. Mitchell or Professor Over.
Scalar implicatureand conflict detection: An fMRI study.
Some words are ambiguous. For example, in the statement "some elephants have trunks", some could mean “some, and possibly all” or “some, but not all”. The latter interpretation depends on the detection of a scalar implicature where we assume that the speaker used the most informative term allowable, and so because they did not use “all” we infer that they meant “some but not all”. Under this reading, the sentence is false. Some theories claim that it requires effort to detect scalar implicatures. So, rejecting our example sentence as false should be associated with more effort than accepting it as true. In this study we will test the veracity of that claim. In particular we will be interested in the extent to which activation in areas of the frontal cortex associated with cognitive control is associated with successful and unsuccessful detection of scalar implicatures. For further information contact Professor Over or Dr. Mitchell.
Perception of prosodic and semantic aspects of language in asymmetrical Parkinson’s disease.
PD patients may show impairments in production of emotional prosody, which is demonstrated clinically in their frequent use of monotonous intonation. However, difficulty interpreting emotional prosody has not been demonstrated in all studies, suggesting it may only be apparent in some sub-groups of patients. One obvious difference between patients is an asymmetry in the degree of motor impairment, which is usually worse on one side of the body. This project aims to determine if we can correlate impairments of aspects of language processing with lateralised impairments of motor function. For further information contact Dr. Mitchell.
Emotion processing in Parkinson’s disease.
This project is examining the pattern of verbal and visual emotional processing deficits in Parkinson’s disease patients, and exploring the suggestion the basal ganglia play a role in the processing of emotional information. For further information contact Dr. Mitchell.
Comprehension of prosodic and facial emotions by patients with bipolar disorder.
This project is using psychophysical and behavioural indices of prosodic emotion decoding to determine if distinct profiles of impairment can be established across the symptomatic phases of the illness; depressed, manic and euthymic. For comparison, we are also probing these impairments in patients with unipolar/major depression. Without examining both visual and auditory emotion deficits, theories of emotion processing in bipolar disorder may not be able to adequately explain the nature of this impairment. For further information contact Dr. Mitchell.
The consequences of age-related decline in interpretation of emotion cues.
Most studies of emotional prosody begin by referring to its importance for maintaining social contact and psychological well-being. However, in normal populations, very few studies have explicitly investigated this hypothesis. Recently it has been suggested that even healthy older adults have an emotional prosody comprehension deficit. Whilst we may use studies of neurological and psychiatric populations to try to predict the impact of these deficits on the well-being of older adults, there are reasons to suspect a dissimilar pattern of effects in the latter group. This proposal aims to determine which aspects of social well-being decline in tandem with age-related declines in the ability to decode the emotion conveyed by prosody. For further information contact Dr. Mitchell.
Cognitive sex differences
On a number of cognitive tasks, women and men show consistently performance differences with some tasks favouring women and some favouring men. The origins of these cognitive sex differences are yet unknown. Research from various scientific fields suggests that a complex interaction of biological, psychological and social factors is involved. The research focus of our group focuses on how sex hormones, gender stereotypes and specific cognitive strategies affect cognitive sex differences. For further information contact Dr. Hausmann.
Sex hormones and functional brain organisation
Sex hormones have potent neuromodulatory properties which affect the functional organisation of the brain during early ontogenesis and later in life. This research investigates the underlying mechanisms of sex hormonal effects on hemispheric asymmetries and interhemispheric interaction using functional imaging (e.g. fMRI, TMS, EEG), behavioural paradigms (e.g. visual-half field stimulation, dichotic listening) and direct observation. For further information contact Dr. Hausmann.
Evolutionary advantages of hemispheric asymmetry
Since hemispheric asymmetry is a fundamental principle of brain organization in humans and animals, it has been argued that an asymmetrical brain must be evolutionarily adaptive. However, it is yet unclear wherein the evolutionary advantage of an asymmetrical brain lies. This research will help to elucidate possible evolutionary advantages of hemispheric asymmetries by using behavioural tools and neuroscience techniques. For further information contact Dr. Hausmann.
Hemispheric asymmetries in emotional face processing
A long debate concerns whether the right hemisphere is relatively specialized to process emotions in general (right hemisphere hypothesis), or whether the right hemisphere is specialized to process negative emotions, whereas the left hemisphere processes positive emotions (valence hypothesis). By investigating split brain patients and neurological healthy participants, this project will allow new insights in the functional brain organisation of emotional (face) processing. For further information contact Dr. Hausmann.
Neural correlates of progression in bipolar disorder
The etiology of bipolar disorder is still not fully understood. Two different conceptions have been proposed: (a) bipolar disorder may be caused by impairment of the growth and development of the brain, and (b) bipolar disorder may result from neurodegenerative processes which progress over the course of the illness. By studying brain abnormalities at different phases of the illness using MRI and cortical pattern matching, a high-spatial resolution imaging technique, we will be able to evaluate the significance of each conception. For further information contact Dr. Hausmann.
Mental rotation in split-brained patients
This project investigates the relative contribution of the left and right cerebral hemisphere in mental rotation. This project investigates neurologically healthy participants and split-brain patients, whose commissures connecting the left and the right cerebral hemisphere have been resected. Commissurectomised patients provide the unique opportunity to investigate spatial skills of each hemisphere independently from each other. For further information contact Dr. Hausmann.
The neurocognitive basis of left-right discrimination
Mixing up left with right is a ubiquitous phenomenon that more or less everybody is susceptible to. Relatively little, however, is known about what causes left-right errors or correct left-right decisions. Using left-right discrimination tasks that were developed by our group, we seek to answer questions such as why are some people less susceptible to left-right confusion than others, what are the underlying neural and cognitive mechanisms of left-right confusion and how can left-right errors be prevented? For further information contact Dr. Hausmann.