Multi-scale adaptation in brain sensory pathways

• Applicant: Dr. Amalia Papanikolaou
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Human Cognitive and Systems Neuroscience
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 318826974

The brain is constantly altered by experience, a process known as experience-dependent plasticity. Knowledge of the brain mechanisms that provide this plasticity is important for understanding perception, learning and memory, but also for understanding how the brain recovers function after injury or disease. A striking form of rapid experience-dependent plasticity is that caused by adaptation. Adaptation refers to a process during which the brain adjusts its responses to the current sensory environment. The effects of adaptation are found throughout all stages of sensory processing and have been shown to occur over a wide range of timescales. However, the mechanisms under which these effects operate and their functional role remain unclear. This project aims to investigate the dependence of brain responses on the statistical history of stimulation at multiple timescales. I propose to use a combination of high-field fMRI and multi-electrode electrophysiology to measure adaptation effects, using the mouse visual system as a model system. The first set of experiments will determine how different timescales of adaptation are sustained across different stages of hierarchy and parallel streams of the visual system. Simultaneous measurements from multiple brain areas will be obtained, to determine how adaptation at different timescales affects the sensitivity and coordination of neurons across two major pathways of the visual system: the retino-geniculo-cortical pathway and the retino-colliculo-cortical pathway. This will be the first research program to study the effects of sensory adaptation at the macroscopic and microscopic level. The second set of experiments will aim to establish, for the first time, a relationship between adaptation and learning. I will use multi-unit electrophysiology and pharmacological methods in mice to understand how short-term changes in the brain, induced by adaptation, are transformed to more permanent effects. This will be the first study to establish a causal link between adaptation and learning and will give valuable insight into the functional role of visual adaptation. The proposed study will provide an unprecedented attempt to bridge the gap between two forms of plasticity (adaptation and learning) and will therefore advance our understanding of the relationship between sensory coding and behavior. The knowledge gained will be important for understanding the plasticity of neurons distributed across stages of the visual system, whose disruption is associated with a number of psychiatric disorders, including schizophrenia, autism spectrum disorders and epilepsy.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Samuel Solomon, Ph.D.