Phone: +49 69 / 798 42066
Echolocating bats can estimate the distance to an object with the help of the echo delay. The echo delay is defined as time range from emitting an echolocation call until the arrival of the corresponding echo. Combination selective neurons tuned to specific echo delays have been physiologically described in the auditory midbrain and auditory cortex of bats. In the fruit-eating bat, Carollia perspicillata, at neocortical levels, echo delays are topographically organized along the rostro-caudal axis of the high frequency field of the dorsal auditory cortex.
During my PhD project I investigate the generation and organization of the topographic map of echo delays in the auditory cortex of C.perspicillata.
The echo delay map has previously been described as “blurry” and variable. These observations are based on single- and multi-unit recordings with single glass electrodes or carbon electrodes. To find out the factors inducing the so-called “blurriness” and to take a closer look into the general organization of the map I record with multiple-electrode arrays that cover most of the map.
Additionally, I study the cortical map of echo-delays by presenting the animals with natural echolocation signals whose parameters are within a behavioural relevant range to see the entire organization of the map in a behavioural context
Finally, with pharmacological experiments and tracer studies I want to identify the neurons and the neurotransmitters that are involved in the organization of the map in the auditory cortex and I want to find out whether the map is completely relayed from subcortical nuclei or it is re-implemented to some extent in the auditory cortex.
Hechavarría JC, Beetz MJ, Macias S, Kössl M (2016). Vocal sequences suppress spiking in the bat auditory cortex while evoking concomitant steady-state local field potentials. Sci Rep. 2016 Dec 15, 6: 39226. doi: 10.1038/srep39226
Beetz MJ, Hechavarría JC, Kössl M (2016). Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams. Sci Rep. 2016 Oct 27; 6: 35991. doi: 10.1038/srep35991
Beetz MJ, Pfeiffer K, Homberg U. (2016). Neurons in the brain of the desert locust Schistocerca gregaria sensitive to polarized light at low stimulus elevations. J Comp Physiol A 202:759-781.
Beetz MJ, Hechavarría JC, Kössl M (2016). Temporal tuning in the bat auditory cortex is sharper when studied with natural echolocation sequences. Sci Rep. 2016 Jun 30;6:29102. doi: 10.1038/srep29102.
Hechavarría JC, Beetz MJ, Macias S, Kössl M. (2016) Distress vocalization sequences broadcasted by bats carry redundant information. J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 202:503-15.
Beetz MJ, Hechavarría JC, Kössl M (2016) Precise target-distance coding during cortical suppression in echolocating bats.
"Twelfth Congress of the International Society of Neuroethology" (Montevideo, Uruguay, 30th March- 3rd April 2016).
Beetz MJ, El Jundi B, Heinze S, Homberg U. (2015). Topographic organization and possible function of the posterior optic tubercles in the brain of the desert locust Schistocerca gregaria. J Comp Neurol. 523:1589-607.
Beetz MJ, Hechavarría JC, Kössl M (2015). About how cortical neurons of bats cope with fast echolocation sequences: Multi-electrode and single-electrode recordings with natural echolocation stimuli. “Eleventh Göttingen Meeting of the German Neuroscience Society” (Göttingen, Germany, 18.-21. March 2015).
MSc-Thesis Phillips University of Marburg/Goethe University Frankfurt am Main Electrophysiological and morphological characterization of visually sensitive interneurons of the posterior protocerebrum from the desert locust Schistocerca gregaria.
Jerome M. Beetz, Basil el Jundi, Stanley Heinze, Uwe Homberg. Topographic organization of the posterior optic tubercle in the locust brain: Possible role in the generation of an internal sky compass. 10th Göttingen Meeting of the German Neuroscience Society
BSc-Thesis Philipps Unversity of Marburg Topografische Orgnaisation des posterioren optischen Tuberkels in der Wüstenheusschrecke Schistocerca gregaria.