TY  - JOUR
A1  - Koessl, M.
A1  - Hechavarria, J. C.
A1  - Voss, C.
A1  - Macias, S.
A1  - Mora, E. C.
A1  - Vater, Marianne
T1  - Neural maps for target range in the auditory cortex of echolocating bats
JF  - Current opinion in neurobiology : reviews of all advances ; evaluation of key references ; comprehensive listing of papers
N2  - Computational brain maps as opposed to maps of receptor surfaces strongly reflect functional neuronal design principles. In echolocating bats, computational maps are established that topographically represent the distance of objects. These target range maps are derived from the temporal delay between emitted call and returning echo and constitute a regular representation of time (chronotopy). Basic features of these maps are innate, and in different bat species the map size and precision varies. An inherent advantage of target range maps is the implementation of mechanisms for lateral inhibition and excitatory feedback. Both can help to focus target ranging depending on the actual echolocation situation. However, these maps are not absolutely necessary for bat echolocation since there are bat species without cortical target-distance maps, which use alternative ensemble computation mechanisms.
Y1  - 2014
U6  - https://doi.org/10.1016/j.conb.2013.08.016
SN  - 0959-4388
SN  - 1873-6882
VL  - 24
SP  - 68
EP  - 75
PB  - Elsevier
CY  - London
ER  - 
TY  - JOUR
A1  - Hechavarria, Julio C.
A1  - Macias, Silvio
A1  - Vater, Marianne
A1  - Voss, Cornelia
A1  - Mora, Emanuel C.
A1  - Kossl, Manfred
T1  - Blurry topography for precise target-distance computations in the auditory cortex of echolocating bats
JF  - Nature Communications
N2  - Echolocating bats use the time from biosonar pulse emission to the arrival of echo (defined as echo delay) to calculate the space depth of targets. In the dorsal auditory cortex of several species, neurons that encode increasing echo delays are organized rostrocaudally in a topographic arrangement defined as chronotopy. Precise chronotopy could be important for precise target-distance computations. Here we show that in the cortex of three echolocating bat species (Pteronotus quadridens, Pteronotus parnellii and Carollia perspicillata), chronotopy is not precise but blurry. In all three species, neurons throughout the chronotopic map are driven by short echo delays that indicate the presence of close targets and the robustness of map organization depends on the parameter of the receptive field used to characterize neuronal tuning. The timing of cortical responses (latency and duration) provides a binding code that could be important for assembling acoustic scenes using echo delay information from objects with different space depths.
Y1  - 2013
U6  - https://doi.org/10.1038/ncomms3587
SN  - 2041-1723
VL  - 4
IS  - 10
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Kössl, Manfred
A1  - Voss, Cornelia
A1  - Mora, Emanuel C.
A1  - Macias, Silvio
A1  - Föller, Elisabeth
A1  - Vater, Marianne
T1  - Auditory cortex of newborn bats is prewired for echolocation
JF  - Nature Communications
N2  - Neuronal computation of object distance from echo delay is an essential task that echolocating bats must master for spatial orientation and the capture of prey. In the dorsal auditory cortex of bats, neurons specifically respond to combinations of short frequency-modulated components of emitted call and delayed echo. These delay-tuned neurons are thought to serve in target range calculation. It is unknown whether neuronal correlates of active space perception are established by experience-dependent plasticity or by innate mechanisms. Here we demonstrate that in the first postnatal week, before onset of echolocation and flight, dorsal auditory cortex already contains functional circuits that calculate distance from the temporal separation of a simulated pulse and echo. This innate cortical implementation of a purely computational processing mechanism for sonar ranging should enhance survival of juvenile bats when they first engage in active echolocation behaviour and flight.
Y1  - 2012
U6  - https://doi.org/10.1038/ncomms1782
SN  - 2041-1723
VL  - 3
IS  - 2
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Walter, Juliane K.
A1  - Castro, Victor Manuel
A1  - Voss, M.
A1  - Gast, Klaus
A1  - Rueckert, C.
A1  - Piontek, J.
A1  - Blasig, Ingolf E.
T1  - Redox sensitivity of the dimerization of occludin
N2  - Occludin is a self-associating transmembrane tight junction protein affected in oxidative stress. However, its function is unknown. The cytosolic C-terminal tail contains a coiled coil-domain forming dimers contributing to the self- association. Studying the hypothesis that the self-association is redox-sensitive, we found that the dimerization of the domain depended on the sulfhydryl concentration of the environment in low-millimolar range. Under physiological conditions, monomers and dimers were detected. Masking the sulfhydryl residues in the domain prevented the dimerization but affected neither its helical structure nor cylindric shape. Incubation of cell extracts containing full-length occludin with sulfhydryl reagents prevented the dimerization; a cysteine/alanine exchange mutant also did not show dimer formation. This demonstrates, for the first time, that disulfide bridge formation of the domain is involved in the occludin dimerization. It is concluded that the redox-dependent dimerization of occludin may play a regulatory role in the tight junction assembly under physiological and pathological conditions.
Y1  - 2009
UR  - http://www.springerlink.com/content/a0w10t7jgn01lk6h/
SN  - 1420-682X
ER  -