A neuropsychological approach to cognitive control
To successfully adapt our behavior to environmental demands, we need cognitive control. For example, suppose you are at a crossroads where an arrow indicates you to turn left while you actually have to turn right. To do this, you need to inhibit the information provided by the arrow and make your choice on the basis of your prior knowledge that you have to turn right. Frontal brain structures are believed to be important in these processes. Our research will focus on the interplay between these frontal brain structures and more posterior brain areas in implementing cognitive control processes. To this end, patients with frontal and/or posterior brain damage will be investigated upon their cognitive control abilities (collaboration with Jean-Christophe Bier, Erasmus hospital).
Behavioral and neurophysiological studies of speech perception in typical and atypical conditions
- Categorical perception of speech: development, effects of auditory training and influence of linguistic environment
- Speech processing in adverse conditions: effect of intrinsic and extrinsic limitations like hearing loss, noisy listening conditions, and attention load
- Development of a neurophysiological tool aiming at objectively assess auditory discrimination abilities
Cognitive deficits, genetics and brain imaging in children with attention-deficit hyperactivity disorder (ADHD)
ADHD affects 3 to 5% of the population and is the more frequent neurodevelopmental disorder. Children, adolescents and adults with ADHD have attentional disorders, executive deficits (e.g. difficulty to inhibit responses and impulsivity) and working (short term) memory impairments. With genetics and brain imaging (fMRI) studies, we try to identify the different aspects of the disorder and their relationships.
Consequences of literacy and schooling on linguistic and cognitive abilities: studies of illiterate adults
Contrary to speech, literacy is not universal, does not develop spontaneously and is ontogenetically open-ended, as are associated metalinguistic abilities. Literacy can thus be considered as an instance of cultural, human-specific, learning, which either represents an additional system of information processing, changing the mind in no significant way, or modifies what are often considered to be the universal properties of the human mind. We examine the latter hypothesis as regards various domains like speech processing and representations, semantic representations, memory, visual processing, etc. We do this by comparing illiterate adults with not only schooled literates but also “ex-illiterates” who never frequented school in childhood but benefited from special alphabetization classes as adults.
Feedback effects of literacy on memory: developmental studies
A strong association between on the one hand short-term and working memory (STM, WM) capacities and on the other hand reading achievement is well established in children, and the former are often considered as predictive of the latter. Although few studies have investigated the inverse relationship, adults who remained illiterate for socio-economic raisons display poorer STM and WM compared to literate and ex-illiterate adults (e.g., Kosmidis et al., 2011). These data point to an interactive process with feedback effects from literacy on memory processes and/or representations. Therefore, our main objective is to investigate to what extent and how literacy acquisition affects memory.
Impact of the goal activation on Executive Functions in normal subjects and brain-damaged patients
We explore the concept of executive functions, their cognitive dimensions and interactions. Specifically, we are interested in two functions: inhibition (to prevent the selection of an overlearned but inappropriate response or stimulus, e.g. not to drive in England, as we do in Belgium, on the right side of the road) and task switching (the ability to make some task and then switch to another one, e.g. to make an addition and then a subtraction). Using various paradigms that modify the representation of the goal activation, we study their specificity and interactions in normal and clinical populations: brain-damaged patients, multiple sclerosis, neurodegenerative disorders like Parkinson's disease and Huntington's disease.
Influence on attention of the emotions conveyed by speech and music
Is our attention attracted by emotional sounds like threatening words or melodies? How does this attraction works? We study these questions by using auditory adaptations of well-known experimental paradigms including the dot probe task, the emotional Stroop task and the attentional cuing paradigm.
Mild Cognitive Impairment, Dementia of the Alzheimer Type and Normal Ageing : comparative studies
Depuis plusieurs années, on décrit une altération cognitive légère chez des personnes dont le fonctionnement cognitif se distingue de celui de personnes âgées dites « saines » mais aussi de celui de personnes ayant développé la maladie d'Alzheimer. Ces personnes ont davantage de risque de développer la maladie d'Alzheimer. C'est pourquoi, on considère cette période comme une période intermédiaire entre le vieillissement normal et la maladie d'Alzheimer. Dans ce contexte, il est important de pouvoir identifier précocement les altérations cognitives spécifiques de l'altération cognitive légère. Le but de nos études est d'essayer de les identifier dans les domaines des activités complexes de la vie de tous les jours, de l'identification des odeurs, de la mémoire sémantique et de la mémoire autobiographique.
Neural mechanisms of rhythm perception
Relation between spoken and written language in healthy population and dyslexics: a neurophysiological and brain-imaging (TMS) approach
Learning to read and write changes the way brain processes spoken words: word sounds become segmented into small unities, sound and spelling become almost indissociable, the structure and function of some brain regions are deeply modified. We attempt to understand the nature and the underlying mechanisms of those changes at both the behavioral and functional levels. To understand how brain reads and why sometimes it does not, we compare the performance of normal readers to those who show reading deficit. We do this both as regards speech representations and the ability to construct abstract visual representations.
Representation of numbers
People are highly skilled in processing number information. We flexibly can use numbers to arrange meetings (e.g. the 16th July at 9.00 am), for complex calculations (e.g. 7 x 4 = 28) and so on. Our basic question is how these numbers are represented. It has repeatedly been demonstrated that numbers are processed using spatial representations. According to this idea, numbers are metaphorically represented on a “mental number line” on which small numbers are represented on the left hand side and larger numbers on the right hand side. In this view, numbers are spatially represented without any reference to language. Our research indicates that verbal concepts such as “small”, “large”, “left” and “right” are used to represent numbers. In the future, it will be important to understand how spatial representations and verbal concepts work together enabling our understanding of numbers (collaboration with Tom Verguts and Wim Fias, Ghent University).
The impact of linguistic forms in deriving affective contents
Understanding the meaning of an utterance depends not only on shared linguistic knowledge (the interpretation of what is said), but requires also access to what is implicated by that utterance, e.g., affective contents intended as positive/negative evaluations of the state of the world described by the utterance. Some linguistic forms can carry out affective contents. We focus on two of these forms, lexical reduplication (the immediate and intentional repetition of a word) and rhyme (the intentional and structured repetition of phonemes), and examine how these patterns are organized in memory as well as the interaction between short-term memory involved in on-line processing and long-term encyclopaedic memory (collaboration with M. Dominicy, SCoLa, ULB).
The limits of conscious processing
I you present information for a very brief moment, it cannot be consciously perceived but might nevertheless influence your behavior. For instance, you will be faster to process the word “nurse” if it was preceded by the presented but consciously unseen word “doctor” compared to an unrelated word “table”. We now ask the question whether it is possible to apply abstract rules to subliminally presented information (collaboration with Tom Verguts and Filip van Opstal, Ghent University, Magda Osma, University College London, and Axel Cleeremans, CO3, ULB).
Working memory and bisection tasks
The goal of the current research project is to understand how ordinal position information is encoded in working memory (WM) and how this information interacts with spatial attention as measured in bisection tasks. A key assumption of our project is that the ordinal position of information in WM is spatially coded and therefore can have an influence on bisection performance. We will compare the performance of normal participants with the performance of brain damaged patients on a variety of bisection tasks. Using this neuropsychological approach we will investigate which brain regions are important for the respective bisection tasks and to unravel the role of working memory load on this bisection performance.