Food addiction and the mere exposure effect
Over the last decade, health care professionals have been exposed to the emergence of a new form of addiction. High-energy food products (i.e., rich in fat and/or sugar), which are everyday more available on the market, are engaging a strong reward response and have been shown to lead to addictive behaviors similar to those caused by drugs. However, addictive processes not only rely on a hyperactive reward system but also on a hypoactive inhibitory system. We have the greater interest in contributing to the better understanding of the inhibition system among obese persons. For this purpose, and in the first instance, we investigate the neural correlates of impulsivity processes among this population. A better definition of the brain areas which functioning is impaired and which promote compulsive eating may be promising for the development of reliable non-pharmacological therapeutic approaches, such as non-invasive transcranial stimulation.
As obesity treatment not only rely on the quantitative but also the qualitative aspect of food ingestion, we are also interested in investigating the behavioral acceptance of light products among obese persons and the neuroplastic processes responsible for this adaptation.
Predictive coding for tactile detection and learning
How does our brain adapt to a new environment based on experience? How does our brain update its beliefs and predict sensory inputs when the environment changes? In Bayesian inference, an observer builds beliefs about world states based on observations and assumptions about the statistical structure of the world. We combine functional neuroimaging techniques (fMRI) and computational modelling (i.e., Bayesian modelling) to explore prediction-based decision-making processes involved in tactile detection, learning and memory. We are investigating how the participates update their decision-makings about subsequent predictions especially after they made wrong predictions during a probabilistic tactile learning. We are also interested in how Acetylcholine and Dopamine differentially regulate the integration of tactile perception and expectations during tactile inference and learning by modulating the recurrent information flow within a hierarchy network.
Furthermore, we shall investigate prediction-based decision-making processes involved in tactile detection and learning with a specific focus on state-dependent effects of reward and punishment. The pharmacological effects on the Bayesian inference and decision-making during tactile detection and learning will also be studied in our project.
Supported by the German Research Foundation (SFB 874, Project A10)
cross-modal transfer during categorization learning
We are interested in how cross-modal transferring happens during categorization learning, using two different sensory modalities: vision and touch. To understand this mechanism, we created digital items called "embryos" which we use in a virtual reality set-up for visual training, and as 3D-printed haptic models for tactile training.
In addition to the behavioral experiment, we are interested in understanding the induced neuronal-plasticity in the resting-state fMRI after the associated categorization learning.
Supported by the German Research Foundation (SFB 874, Project A1)
Effects of Attentional Modulation on Learning and Brain Activation Patterns in the Renewal Effect of Extinction, Measured by fMRI
The renewal effect describes the recovery of a previously extinguished response in situations where the test context differs from the extinction context. Renewal occurs in various learning situations, in fear conditioning just as well as in appetitive and instrumental learning. In our studies without a fear component, only up to three thirds of participants show a renewal effect and the corresponding activation pattern with involvement of hippocampus and ventromedial prefrontal cortex. Also, participants showing renewal exhibit hippocampal activation already during initial acquisition of associations, and not only during extinction. Moreover, the tendency to show or not to show renewal appears to be stable over repeated learning sessions. In our project, we focus upon internal and external factors that promote the renewal effect. While participants learn a predictive task in the MRI scanner, we manipulate context parameters and learning performance, and analyze the resulting strength of the renewal effect.
Supported by the German Research Foundation (SFB 1280)
HOW DOES VISUAL PERCEPTUAL LEARNING INTERACT WITH PLASTIC CHANGES AND EXCITABILITY IN HUMAN VISUAL CORTEX?
Our project aims to identify the mechanisms that drive visual perceptual learning and to clarify whether it is possible to modulate training-induced task improvement by manipulating cortical excitability. Based on preliminary work in the somatosensory system, we explore individual baseline excitability as a potential predictor of learning success and reorganization in visual cortex and analyze the temporal dynamics of cortical excitability and reorganization during the ongoing learning process. We investigate the effect of plasticity-relevant neurotransmitter receptors on cortical excitability and visual perceptual learning.
Supported by the German Research Foundation (SFB 874)
Cortical correlates of motoric decoupling in professional drummers
Our hands are one of our primary tools to interact with other people. Patients, who are restricted in this interaction, e.g. not able to use both hands / arm, due to amputation, neurological diseases and such, suffer from a massive worsening of life quality.
A fascinating property of motor-control is the fundamental asymmetric organization. While simple rough-motor tasks can be executed with both hands in equal measure, there are only a few individuals who can perform fine-motoric tasks, like writing or drawing with both hands likewise. Most people have a dominant side and have a preference to perform such fine-motor tasks with either right or left hand. In contrast to untrained individuals, professional drummers have the ability to play different rhythms and beats with both hands and feet. While untrained tend to mirror movements from the dominant side to the non-dominant side, drummers can decouple their motor-performance to allow playing divergent rhythms.
The underlying cortical basis for this ability is unknown and will be evaluated in this study using functional, structural and spectroscopic imaging techniques.
The resulting finding of this study can contribute to further understand the role of neuronal plasticity of motor control due to training and learning. Therefore, they can further help to understand and improve rehabilitation processes in neurological disturbance of hand functions.
Supported by the RUB (FoRUM)
Modulation of GABAergic mechanisms in the sensorimotor cortex induced by repetitive sensory stimulation (NeiS)
Most of neuroplasticity research investigates the effects induced by training or excitatory stimulation in the sensory and motor system. To the contrary, deprivation as plasticity-inducing event in the human nervous system received little attention. With the current project, we want to shed light on the less known effects of cortical reorganization following stimulation of the extremities. The protocols used resemble long-term deprivation as well as potentiation models, therefore lead to reversible impairment or likewise improvement in tactile discrimination. Our main interest lies in the dynamics of neurotransmitters and resting-state networks accompanying these interventions.
Supported by the RUB (FoRUM)