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Alumni and Former lab members

PostDoc

Silke Künzel

Silke Künzel

PostDoc

Publications

Hofmann V, Sanguinetti-Scheck JI, Künzel S, Geurten B, Gómez-Sena L, Engelmann J (2013) Sensory flow shaped by active sensing: sensorimotor strategies in electric fish. J Exp Biol 213: 2487-2500, doi:10.1242/jeb.082420 | LINK

Künzel S, Bleckmann H, Mogdans J. (2011) Responses of brainstem lateral line units to different stimulus source locations and vibration directions.Journal of Comparative Physiology A, 197(7), 773-787.| LINK

Künzel S (2009) Electrophysiological Characterisation of Brainstem Lateral Line Neurons in Goldfish, Carassius auratus: Frequency Selectivity, Spatial Excitation Patterns and Flow Sensitivity. Dissertation, Rheinische Friedrich-Wilhelms-University Bonn, urn:nbn:de:hbz:5N-20211

Fest S (2003) Electrophysiological and Histological Characterization of Brainstem Lateral Line Neurons in Goldfish, Carassius auratus. Diploma Thesis, Rheinische Friedrich-Wilhelms-University Bonn

Conference Proceedings - Talks

Künzel S, Hofmann V, Sanguinetti JI, Engelmann J (2012) Linking behavior and sensory processing: Analysis of distance estimation capability in neurons of the Mormyrid ELL. 105th Annual Meeting of the German Zoological Society, University of Konstanz, Germany

Conference Proceedings - Posters

Hofmann V, Künzel S, Sanguinetti JI, Engelmann J (2013) Object detection and distance discrimination by mormyrid ELL neurons. German Zoological Society 106th Annual Meeting (Satellite Symposium "Neuroethology" & main meeting), Munich, Germany.

Künzel S, Mayer U, Engelmann J (2013) Immediate early gene activation in weakly electric fish (Gnathonemus petersii) during learning and recall of a spatial memory task. German Zoological Society 106th Annual Meeting (Satellite Symposium "Neuroethology" & main meeting), Munich, Germany

Künzel S, Hofmann V, Sanguinetti JI, Engelmann J (2012) Linking behavior and sensory processing: Analysis of distance estimation capability in neurons of the Mormyrid ELL. 10th International Congress of Neuroethology, College Park, MD, USA

Künzel S, Bleckmann H, Mogdans J. (2009) Responses of brainstem lateral line neurons in goldfish, Carassius auratus, to bulk water flow. Natural and Biomimetic Mechanosensing Conference, Dresden

Künzel S, Bleckmann H, Mogdans J. (2009) Responses of brainstem lateral line neurons in goldfish, Carassius auratus, to water flow in different directions. 32nd Göttingen Neurobiology Conference

Fest S, Scholze B, Bleckmann H, Mogdans J. (2008) Spatial excitation patterns in the fish lateral line: from hydrodynamics to central representations. CILIA Summer School, Sant Feliu de Guixols, France

Fest S, Bleckmann H, Mogdans J. (2007) Receptive fields of brainstem lateral line neurons in goldfish, Carassius auratus. 100th Annual Meeting of the German Zoological Society, Cologne

Fest S, Bleckmann H, Mogdans J. (2007) Responses of lateral line brainstem neurons to dipole stimuli of different frequencies in Goldfish, Carassius auratus. 31st Göttingen Neurobiology Conference

Fest S, Bleckmann H, Mogdans J. (2007) Frequency characteristics of brainstem lateral line neurons in goldfish, Carassius auratus, Neuro-Meeting Bo-Ac-Co, Köln

Fest S, Engelmann J, Bleckmann H, Mogdans J. (2005) In vivo whole-cell recordings from brainstem lateral line neurons in goldfish, Carassius auratus. 30th Göttingen Neurobiology Conference

Fest S, Engelmann J, Bleckmann H, Mogdans J. (2004) Morphology of flow-sensitive and flow-insensitive brainstem lateral line neurons. 7th Int. Congress of Neuroethology, Nyborg Strand, Denmark

PhD students

Volker Hoffmann

Volker Hoffmann

PhD student

Research

Side view of Gnathonemus petersii´s head. Electroreceptors in the skin can be seen as bright dots.

How does the central nervous system extract information from the environment? What are active behavioral strategies to optimize this information extraction? How does the central nervous system represent, process and analyze such sensory signals?

Along this line of research I am currently working on the active electrolocation system of the elephant nose fish, Gnathonemus petersii. This weakly electric fish emits short electric pulses (electric organ discharge = EOD) that built up an electric field around the body of the animal. Objects nearby the fish distort this field and thus modulate the voltage distribution (electric image) on the skin of the animal that holds an array of electroreceptors (see picture). These alterations are used by the animal for active electrolocation.

By moving relative to an object during sampling, spatial and temporal changes in the sensory input (= electric flow) are generated that comprise potential perceptual cues. My current research investigates if and how fish exploit these sensory possibilities during unrestrained and task related behavioral experiments.

Furthermore I am interested in information encoding of medullary electrosensory units (ELL). How ELL units respond to stationary and dynamic stimulation with physical objects is investigated with electrophyiological methods (see picture below).

Publications

Hollmann V, Hofmann V, Engelmann J (2016) A somatotopic map of the active electrosensory sense in the midbrain of the mormyrid Gnathonemus petersii | Journal of Comparative Neurology (accepted)

Hofmann V, Geurten BRH, Sanguinetti-Scheck JI,  Gómez-Sena L, Engelmann J (2014) Motor patterns during active electrosensory acquisition.; Front Behav Neuorsci, 8(186): 1-14, doi:10.3389/fnbeh.2014.00186 | LINK

Hofmann V, Sanguinetti-Scheck JI, Künzel S, Geurten B, Gómez-Sena L, Engelmann J (2013) Sensory flow shaped by active sensing: sensorimotor strategies in electric fish.; J Exp Biol 213: 2487-2500, doi:10.1242/jeb.082420, | LINK

Hofmann V, Sanguinetti-Scheck JI, Gómez-Sena L, Engelmann J (2013) From static electric images to electric flow: Towards dynamic perceptual cues in active electroreception; J Phys-Paris 107: 95-106, | LINK

Conference Proceedings - Talks

Hofmann V, Sanguinetti JI, Geurten B, Gómez-Sena L, Engelmann J (2013) Sensorimotor patterns during electrolocation behavior of mormyrid fish. Satellite Symposium "Neuroethology" of the 106th annual meeting of the German Zoological Society, Munich, Germany.

Hofmann V, Sanguinetti JI, Geurten B, Gómez-Sena L, Engelmann J (2012) Towards an alphabet of motor patterns in active electrolocation behavior of Gnathonemus petersii. Satellite Symposium "Weakly electric fishes: Neural systems, behavior and evolution" of the ICN 2012, College Park, MD, USA.

Hofmann V, Sanguinetti J, Gómez-Sena L, Engelmann J (2011) Analysing sensory related behavior in active electrolocation: Linking motor patterns to electric flow information. 104th Annual Meeting of the German Zoological Society, Saarbrücken.

Conference Proceedings - Posters

Hofmann V, Pedraja FE, Engelmann J (2014) Estimation of object distance based on electrosensory input dynamics. 107th annual meeting of the DZG 2014, Goettingen, Germany.

Hofmann V, Künzel S, Sanguinetti JI, Engelmann J (2013) Object detection and distance discrimination by mormyrid ELL neurons. Satellite Symposium "Neuroethology" & main meeting of the DZG 106th annual meeting 2013, Munich, Germany.

Hofmann V, Sanguinetti JI, Geurten B, Gómez-Sena L, Engelmann J (2013) Sensorimotor patterns during electrolocation behavior of mormyrid fish. DZG 106th annual meeting 2013, Munich, Germany.

Kassing V, Hofmann V, Engelmann J (2013) Functional connectivity between ELL and the torus semicircularis of the weakly electric fish Gnathonemus petersii. Sattelite Symposium "Neuroethology" of the 106th annual meeting of the German Zoological Society, Konstanz, Germany.

Hofmann V, Sanguinetti JI, Gómez-Sena L, Engelmann J (2012) Spatiotemporal analysis of static electric images: A tool to investigate electric flow? 105th Annual Meeting of the German Zoological Society, Konstanz & 10th International Congress of Neuroethology, College Park, MD, USA.

Hofmann V, Sanguinetti JI, Geurten B, Gómez-Sena L, Engelmann J (2012) Towards an alphabeth of motor patterns in active electrolocation behavior of Gnathonemus petersii. 10th International Congress of Neuroethology, College Park, MD, USA.

Künzel S, Hofmann V, Sanguinetti JI, Engelmann J (2012) Linking behavior and sensory processing: Analysis of distance estimation capability in neurons of the Mormyrid ELL. 10th International Congress of Neuroethology, College Park, MD, USA.

Sanguinetti JI, Hofmann V, Engelmann J, Gómez-Sena L (2012) Towards dynamic perceptual cues in active electroreception: Modelling of electric image flow based on sensory related behaviour. 10th International Congress of Neuroethology, College Park, MD, USA.

Hofmann V, Zelick RD, Bleckmann H (2011) Responses of midbrain lateral line units in goldfish, Carassius auratus, may be used to determine flow velocity. International Congress Flow Sensing in Air and Water, Bonn.

Hofmann V, Zelick RD, Bleckmann H (2009) Responses of midbrain lateral line units in the goldfish, Carassius auratus, to bulk water flow. NBM - Natural and Biomimetic Mechanosensing, International Conference, Dresden.

Hofmann V, Zelick RD, Bleckmann H (2009) Neuronal encoding of bulk water flow in the midbrain of the goldfish (Carassius auratus). 32nd Göttingen Neurobiology Conference, Eighth Meeting of the German Neuroscience Society, Göttingen.

PhD Thesis

Sensorimotor interactions in an active sensory system. Universität Bielefeld

Diploma Thesis

Responses of midbrain lateral line units in the torus semicircularis of the goldfish, Carassus auratus, to bulk water flow. Rheinische Friedrich-Wilhelms-Universität Bonn

Vanessa Hollmann

Vanessa Hollmann

PhD student

Research

I. Optical Imaging in the optic tectum of the zebrafish (Danio rerio)

The tectum is well known for its role in coordinating voluntary movements with multimodal sensory input. To achieve this, several sensory modalities are processed and mapped within the tectum. Our first experiments address the question of short-term plasticity of orientation, direction and velocity tuning in the optic tectum of the mature brain. In the developing brain training-induced emergence of direction selectivity and plasticity of orientation tuning appear to be widespread phenomena found in the visual pathway across different classes of vertebrates. Moreover, short-term plasticity of orientation tuning in the adult brain has been demonstrated in several species of mammals. However, it is unclear whether neuronal orientation and direction selectivity in non-mammalian species remains modifiable through short-term plasticity in the fully developed brain. So far, our data indicate that, even within the fully developed optic tectum, short-term plasticity might have an important role in adjusting neuronal tuning functions to current stimulus conditions. Further experiments could deal with multisensory processing in this brain area, especially if and how mechanosensory and visual information are put in register in the tectum. It is also a future aim of our lab to extend the approach of optical imaging to electrolocation as well, but since this is a novel approach not tested in electric fish so far, we’ll initially investigate this in zebrafish.

 

 II. Topographic organisation of the octavolateral line nucleus in zebrafish (Danio rerio)

Topographic and somatotopically organized neuronal maps are frequently found throughout the animal kingdom. A puzzling exception to this ubiquitous representation of the external world in an egocentric manner is the medial nucleus of the mechanosensory lateral line system (MON). The MON is the first-order medullary lateral line sensory nucleus, processing mechanosensory information before it is passed to the ventro-lateral nucleus of the midbrain torus semicircularis (vlTS). Several studies have shown that the peripheral organization of the neuromasts is preserved in the termination of the lateral line nerve in the MON, such that the rostro-caudal fish axis is reflected in the anterio-posterior and ventro-dorsal axis of the terminals in the MON. Further there is physiological evidence that this mapping can also be found in the vlTS of the goldfish. Here neuromast information from anterior body regions is processed more rostrally than that of posterior regions. Thus a topographic representation is well documented at the afferent level and a functional mapping has as well been found in the torus semicircularis. For the MON efferent cells itself however, no topography has been described so far, with the exception of the vocal midshipman (Porychthys notatus). Using the zebrafish Danio rerio we here aim to overcome this gap by focussing on the connectivity between MON and vlTS. To do so, we inject different fluorescent dyes simultaneously into the vlTS along different positions in the rostro-caudal axis. Based on retrogradely labeled neurons in the hindbrain, we reconstruct the connectivity and built a 3D representation to better quantify the mapping between MON and midbrain levels.

 

 III. Anatomical and functional organization of parallel maps in electrolocation

In the last part of the thesis, we will investigate topographic representations of electrosensory information in the weakly electric fish (Gnathonemus petersii). The first stage of processing electrosensory information is the electrosensory lateral line lobe (ELL). Incoming information is here mapped within three different somatotopic maps, the medial zone (MZ), the dorso-lateral zone (DLZ) and the ventro-lateral zone (VLZ). In many verebrates parallel processing in topographically ordered maps is essential for efficient sensory processing. We’ll anatomically explore the degree of convergence of sensory input in the DLZ and MZ, as to better understand the spatial tuning properties of both zones. This will be done by classical tract tracing and labeling studies combined with immunohistochemical analysis of subclasses of neurons enabling us to determine the degree of convergence and to establish if processing in both zones occurs in a columnar fashion. In contrast to the well investigated MZ of the ELL, we presently know little about the organization, connectivity and sensory processing in the DLZ. Contrary to the MZ, the afferents projecting to the DLZ are sensitive to both amplitude and phase information contained in the electric signal, while the MZ receives only amplitude information. Both parameters are essential for the animals to decipher their environment and are thought to at least partially converge in higher brain regions. The second question we address is how this different sensory information is processed in higher brain areas. Therefore, tracing studies where fluorescent dyes are injected into the ELL are performed and the resulting termination sites in the Nucleus lateralis (NL) are observed. With this study we will gain information about the convergence of the sensory information in higher brain areas as well as information about possible available topographic maps in higher brain areas. These data will also be used to investigate which neurons in the ELL convey inter-zonal connectivity and how this may be used to enhance parallel sensory processing.

Publications

Hollmann V, Hofmann V, Engelmann J (2016) A somatotopic map of the active electrosensory sense in the midbrain of the mormyrid Gnathonemus petersii | Journal of Comparative Neurology (accepted)

Hollmann V, Lucks V, Kurtz R, Engelmann J (2015) Adaptation-induced modification of motion selectivity tuning in visual tectal neurons of adult zebrafish | Journal of Neurophysiology 114: 2893–2902, DOI: 10.1152/jn.00568.2015 | LINK

Kassing V, Engelmann J, Kurtz R (2013) Monitoring of single-cell responses in the optic tectum of adult zebrafish with dextran-coupled calcium dyes deliverd via local electroporation PLoS ONE 8(5): e62846, doi:10.1371/journal.pone.0062846, | LINK

Pusch R, Kassing V, Riemer U, Wagner HJ, von der Emde G, Engelmann J (2013) A grouped retina provides high temporal resolution in the weakly electric fish Gnathonemus petersii J Phys-Paris 107: 84-94, | LINK

Conference Proceedings - Talks

Hollmann V, Hofmann V, Engelmann J (2015) Anatomical and functional connectivity of sensory maps in electrolocation. Satellite Symposium "Neuroethology" of the 108th annual meeting of the DZG, Graz, Austria.

Kassing V, Engelmann J, Kurtz R (2012) Monitoring of single-cell responses in the optic tectum of adult zebrafish via optical imaging. 105th annual meeting of the DZG, Konstanz, Germany.

Conference Proceedings - Posters

Hollmann V, Hofmann V, Engelmann J (2015) Anatomical and functional connectivity of sensory maps in electrolocation. 108th annual meeting of the German Zoological Society, Graz, Austria.

Hollmann V & Engelmann J (2015) Topographic organisation of the octavolateral line nucleus in zebrafish, Danio rerio. 108th annual meeting of the German Zoological Society, Graz, Austria.

Lucks V, Hollmann V, Kurtz R, Engelmann J (2015) Adaptation-induced modification of motion selectivity tuning in visual tectal neurons of adult zebrafish. 108th annual meeting of the German Zoological Society, Graz, Austria.

Kassing V, Engelmann J (2014) A quest for excitation: Immunohistochemical analysis of a circuit for sensory gating in the ELL of Gnathonemus petersii. 107th annual meeting of the German Zoological Society, Göttingen, Germany.

Lucks V, Kassing V, Kabbert J, Kurtz R, Engelmann J (2014) Short-term plasticity of orientation tuning in the optic tectum of adult zebrafish (Danio rerio). 107th annual meeting of the German Zoological Society, Göttingen, Germany.

Kabbert J, Lucks V, Kassing V, Engelmann J, Kurtz R (2014) The Need for Speed: Alteration of Velocity Tuning Functions via Adaptation in the Optic Tectum of Adult Zebrafish (Danio rerio). 107th annual meeting of the German Zoological Society, Göttingen, Germany.

Kassing V, Engelmann J (2013) Connectivity of the MON of the Zebrafish, Danio rerio. 106th annual meeting of the German Zoological Society, Munich, Germany.

Kassing V, Hofmann V, Engelmann J (2013) Functional connectivity between ELL and the torus semicircularis of the weakly electric fish Gnathonemus petersii. Sattelite Symposium "Neuroethology" of the 106th annual meeting of the German Zoological Society, Munich, Germany.

Kassing V, Engelmann J, Kurtz R (2012) Calcium Imaging in the optic tectum of adult zebrafish (Danio rerio), 10th International Congress of Neuroethology, College Park, MD, USA.

Kassing V, Engelmann J (2012) Anatomical and functional organization of parallel maps in electrolocation, Satellite Symposium of the ICN 2012, Weakly electric fishes: Neural systems, behavior and evolution, College Park, MD, USA.

Kassing V, Wilkens L, Hofmann M (2010) Physiology and Morphology of different units in the tectum opticum of the paddlefish (Polyodon spathula), 9th Congress of the International Society for Neuroethology. Salamanca, Spain

Kassing V, Wilkens LA, Hofmann MH (2010) Multimodal units in the tectum opticum of the paddlefish (Polyodon spathula), 103. Jahresversammlung der Deutschen Zoologischen Gesellschaft, Hamburg, Germany

Kassing V, Wilkens LA, Hofmann MH (2010) Multimodal units in the tectum opticum of the paddlefish (Polyodon spathula), International graduate course “Sensory Ecology”, University of Lund, Sweden.

Diploma Thesis

Funktionsmorphologie und Neurobiologie der basalen Pectenmuskeln bei Skorpionen der Gattung Pandinus (Functional morphology and neurobiology of the basal pectine muscles of scorpions of the genus Pandinus). Rheinische Friedrich-Wilhelms-Universität Bonn

Uwe Meyer

Uwe Meyer

Dr. Uwe Mayer moved to the Center for Mind/Brain sciences at the university of Trento, Italy.

Juan Sanguinetti

Juan Sanguinetti

Sabine Wolf-Homeyer

Sabine Wolf-Homeyer

Master students

Johanna Kabbert

Johanna Kabbert

Master student

Research

Transversal section of the zebrafish left optic tectum. Somata, axons and dendrites are stained with DAPI.

Currently, our focus of interest comprises the investigation of underlying mechanisms involved in neuronal short-term plasticity to motion adaptation in neurons in the optic tectum of adult zebrafish. Over the past years studies in various species of fish have shown that the optic tectum is critically linked with visual tasks, such as prey detection or optic flow evaluation. Neurons in the optic tectum in fish, as well as in the primary visual cortex in cats and area MT in macaques appear to be involved in the discrimination of texture orientation as well as speed of motion and direction (Hietanen et al., 2007; Krekelberg et al., 2006; Niell and Smith, 2005). Neurons in the optic tectum in fish respond to certain velocity ranges of pattern motion (Grama and Engert, 2012). However, activity dependent shifts of the velocity range, which have been described for mammalian visual cortex, have not yet been demonstrated in fish. Within the last years the usage of transgenic zebrafish lines and the application of calcium sensitive dyes have become a common approach to investigate neuronal processing. However, studies concerning visual motion processing are mostly performed on zebrafish larvae due to their simple maintenance and easy methodological handling. In particular with regard to neuronal plasticity, it is questionable whether obtained data in still developing brain areas are transferable to adult zebrafish. As opposed to the mentioned studies, we are investigating the underlying neuronal mechanisms of short-term plasticity regarding the velocity tuning functions of single neurons in the optic tectum of adult zebrafish.                    

So far, from preliminary results, we conclude that neurons in the optic tectum of adult zebrafish indeed indicate the ability to show short-term plasticity in response to velocity adaptation protocols. Moreover, we could show that velocity tuning functions of tectal neurons do not appear to follow fixed cell properties, but rather exhibit plastic characteristics that can be disclosed by velocity adaptation protocols. In general, the majority of cells display orientation selectivity for 0°/180° and motion responses peak in a range from 4 Hz to 12 Hz. Motion adaptations below or above peak velocity lead to repulsive shifts of the tuning functions, inferring increased relative sensitivity for the non-adapted velocities. In contrast, adaptation at peak velocity generates a bimodal velocity tuning. Additionally, adaptation tends to cause response attenuation over the entire velocity range. In turn, this is consistent with a proposed two-channel model of speed adaptation by Hietanen et al., 2007. Thus, implications for physiological relevance of velocity adaptation might include “novelty detection”, as cells become more sensitive to novel stimuli during sustained uniform stimulation. In addition, the observed overall attenuation of response magnitude might be a feature to optimize energy expenditure. Our future prospects also comprise the investigation of dendritic tuning functions for the investigation of computational mechanisms underlying short-term plasticity and to unravel potential interactions between different cell types and structures. Accordingly, with the use of histological techniques, such as zebrafish brain bleaching in urea solution and production of histological sections, processed with DAPI, we aim to distinctly identify individual cells as well as their potential affiliation to certain brain layers. Ultimately, it is also of great interest to conduct behavioural studies, deducing and inferring implications of adaptation-induced changes of neuronal tuning for associated locomotor control.

Conference Proceedings - Posters

Kabbert J, Lucks V, Kassing V, Engelmann J, Kurtz R (2014) The need for speed: Alteration of velocity tuning functions via adaptation in the optic tecttum of adult zebrafish (Danio rerio). 107th annual meeting of the DZG 2014, Goettingen, Germany.

Lucks V, Kassing V, Kabbert J, Kurtz R, Engelmann J (2014) Short-term plasticity of orientation tuning in the optic tectrum of adult zebrafish (Danio rerio). 107th annual meeting of the DZG 2014, Goettingen, Germany.

Bachelor Thesis

Impact of Citrobacter rodentium infection on Innate Lymphoid Cells (ILCs) and Cytokine expression in B57 BL/6N mice and germ free mice (GF)

Keshav Ramachandra

Keshav Ramachandra

Master student

Master thesis

Hydrodynamic stimuli induced escape

Bachelor thesis

SSVEP based dialer using Brain Machine Interfaces

Martin Ruoff

Martin Ruoff

Master student

Student Assistants

Research

3D-reconstruction of the Zebrafish (Danio reiro) brain with detailed substructures based on anatomical data for determination of topography in the lateral line system. A similar reconstruction is going to be carried out with the brain of the elephant-nose fish (Gnathonemus petersii).

Administrative & technical staff

Damaris Klocke

Damaris Klocke

Technical Assistant

Occupation

As a chemical-technical assistant by training, Damaris supports the group during scientific studies with her expertiese in histology and different anatomical techniques. More than that she backs during administrative duties and maintains the animal care facilities.



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