About us

To achieve cognitive representation of sensory processes, sensory information derived from our senses (e.g. audition, vestibulation, olfaction/taste, somatosensation, nociception and vision) must, following its initial perception at the level of the sensor, be integrated at the level of the cortex. The transduction of this sensory information during first-order cortical integration, is followed by increasingly complex higher order processing, which enables the fine-tuning of the sensory percept such that behaviour and memory result.

In this collaborative research centre our goal is to implement a systems neuroscience approach to clarify key aspects of sensory processing at the cortical level. To do this we study humans and animals and integrate our empirical observations into computational models. We are particularly interested in understanding how sensory information processing leads to learning and memory formation, or to higher order representations such as categorisation, spatial representation, and explicit memory.

In the first funding period of the SFB we observed that elevations in cortical excitability comprise a key element of perceptual learning. At the level of categorisation, we observed that the avian analog of the mammalian prefrontal cortex plays a critical role in this process. In humans, we observed that different forms of categorisation (e.g. that are abstraction- or exemplar-based) require processing in different brain structure constellations including distinct components of the medial temporal lobe. At the level of spatial memory processing in the hippocampus, we observed both empirically and computationally, that it is likely that it is the saliency and not the modality of the sense that drives synaptic encoding resulting in memory. These data also form the basis for a further computational model that proposes distinct roles for the hippocampus and neocortex in episodic and semantic memory consolidation.

Based on our current findings, we focused in the second phase of the SFB on the clarification of how different cortical and subcortical structures interact in the enablement of information integration, on the scrutiny of the processes underlying the subsequent cortical reorganisation and plasticity, and on the mechanisms and brain structures that enable higher order representations of memory and sensory experience.

In vertebrates, sensory perception and its implementation for subsequent behaviour, derives from six general systems comprising the auditory, vestibular, olfactory/taste, somatosensory, nociceptive and visual systems. Many decades of research have been invested in acquiring an understanding of the molecular basis of sensation, pioneered, for example, by the clarification of the basic molecular fundamentals of sight (1960s) and somatosensation (1970s), and later of hearing (1980s) and olfaction (1990s).

Thus, a fundamental concept of how sensation is enabled has been achieved, but the precise means by which perceived sensory signals are integrated and represented at the cortical level is, as yet, unclear. An understanding of how sensory information is transduced from the levels of first order cortical integration, to information that undergoes higher order processing, such that a fine-tuning of the sensory percept occurs that in turn drives behaviour and memory formation, can only be achieved by a systems approach to studying sensory processes. This has rarely been attempted. Thus, although a wealth of data is available about the individual steps of these processes, several missing links are still present in our understanding of the chain of events required to translate sensory perception and integration into higher order representation.

Our goal is to implement a systems neuroscience strategy to clarify key aspects of sensory processing. Thus, to acquire a holistic understanding of how sensory signals result in complex behaviour and memory formation, we studied three exemplary sensory systems (olfaction, somatosensation and vision) in both animal models and humans, and followed the processing of these signals from the level of cortical integration through to the final acquisition of a sensation-based memory engram.

The proposed research programme therefore aims to examine the integration and representation of sensory processes at three levels:

1. at the level of first order perception and neuronal integration

2. at the level of second order integration and primary representation in the archicortex

3. at the higher level of high-order representation and modification of the sensory percept in the neocortex