{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:57200"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:57200","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Aspects of sound localization and spatial attention in barn owls and rats","abstract":"Attention improves processing of sensory stimuli. It may be directed to object features or to spatial positions. Orienting of attention towards spatial positions has been termed 'spatial attention'. In the visual system, an influence of attention on sensory processing was repeatedly demonstrated on the behavioral and neural level. Auditory attention, on the other hand, has been relatively neglected so far. In the current thesis, two animal models were chosen to investigate auditory spatial attention: first, the barn owl as a highly-developed auditory specialist and, secondly, the rat as an auditory generalist. An influence of spatial attention on sound localization has solely been demonstrated in humans so far. Since barn owls are important animal models in sound localization, I asked whether auditory attention can influence sound localization abilities in these birds. Using a cross-modal cueing paradigm, I could show that barn owls can initiate a head turn towards a sound source significantly earlier (37.4ms / 16% difference in mean response latency) when they are informed about the likely position of the next upcoming auditory stimulus. This benefit in reaction time was explained by the owl's ability to shift attention towards expected positions which resulted in a speeded detection of the stimulus and an earlier response. In a cueing paradigm the subjects are informed that the behaviorally relevant stimulus will be presented soon. In the mammalian species tested so far, this warning elicits a reduction in response latency that is related to the timing of the trial and not to the expected position of the next relevant stimulus. In the barn owl, I found clear effects of spatial attention, but, interestingly, no time-related attentional influences. Why the evaluation of the relative timing of events was not an evolutionary constraint for the barn owl remains open. The construction of internal space is considerably different between the auditory and the visual system which makes research on the mechanisms of auditory spatial attention very important. Surprisingly, less was known about internal representations of auditory space in the rat. Therefore, I investigated auditory neurons in a candidate structure in the rat's midbrain, the colliculus superior (SC) and asked whether auditory space is represented there. I found that most auditory neurons (73%) were broadly, but significantly tuned to the spatial location of a sound source. Preferred locations shifted from frontal to lateral in parallel to the neuron's position along the rostrocaudal axis of the SC. Both characteristics, spatially tuned neurons and their systematical arrangement, demonstrate the existence of an representation of auditory space in the rat SC. The neural basis of spatial attention in the auditory system is unknown so far. This is partially due to the lack of appropriate methods to record from awake animals. In the current thesis I adapted a method that was used in awake rats to record from the midbrain optic tectum (OT) of awake barn owls. During recording sessions owls performed a cue-directed selection paradigm, i.e. a modified cueing paradigm. By combining behavioral and neural measurements, I could test whether attention-related effects in behavior are reflected in the representation of auditory space in the barn owl's midbrain. I found two cognitive influences on auditory midbrain neurons that were seemingly independent: first, the intention to perform a specific movement, which induced a difference between the baseline activities of both OT hemispheres, and second, spatial attention, which enhanced or reduced neural responses to auditory stimulation depending on the behavioral relevance of the stimuli. Both effects are suited to explain the speeded detection and the shorter latency found in the behavioral study. Many auditory neurons (45%) in the barn owl's OT change their activity also during head movements: head turns towards contralateral directions are paralleled by an increase in spike rate and head turns towards ipsilateral directions by a decrease in spike rate below spontaneous levels. The role of midbrain neurons in premotor activation was so far indirectly shown by focal lesions or electrical stimulation. These data suggest that the midbrain of barn owls and rats is an important structure for sound localization. It combines sensory and motor functions, thus acting as sensorimotor interface. The existence of cognitive influences on the midbrain level indicates that midbrain neurons support not only reflexive but also non-reflexive functions, as e.g. goal-directed orienting towards auditory stimuli.","abstract_html":"Attention improves processing of sensory stimuli. It may be directed to object features or to spatial positions. Orienting of attention towards spatial positions has been termed 'spatial attention'. In the visual system, an influence of attention on sensory processing was repeatedly demonstrated on the behavioral and neural level. Auditory attention, on the other hand, has been relatively neglected so far. In the current thesis, two animal models were chosen to investigate auditory spatial attention: first, the barn owl as a highly-developed auditory specialist and, secondly, the rat as an auditory generalist. An influence of spatial attention on sound localization has solely been demonstrated in humans so far. Since barn owls are important animal models in sound localization, I asked whether auditory attention can influence sound localization abilities in these birds. Using a cross-modal cueing paradigm, I could show that barn owls can initiate a head turn towards a sound source significantly earlier (37.4ms / 16% difference in mean response latency) when they are informed about the likely position of the next upcoming auditory stimulus. This benefit in reaction time was explained by the owl's ability to shift attention towards expected positions which resulted in a speeded detection of the stimulus and an earlier response. In a cueing paradigm the subjects are informed that the behaviorally relevant stimulus will be presented soon. In the mammalian species tested so far, this warning elicits a reduction in response latency that is related to the timing of the trial and not to the expected position of the next relevant stimulus. In the barn owl, I found clear effects of spatial attention, but, interestingly, no time-related attentional influences. Why the evaluation of the relative timing of events was not an evolutionary constraint for the barn owl remains open. The construction of internal space is considerably different between the auditory and the visual system which makes research on the mechanisms of auditory spatial attention very important. Surprisingly, less was known about internal representations of auditory space in the rat. Therefore, I investigated auditory neurons in a candidate structure in the rat's midbrain, the colliculus superior (SC) and asked whether auditory space is represented there. I found that most auditory neurons (73%) were broadly, but significantly tuned to the spatial location of a sound source. Preferred locations shifted from frontal to lateral in parallel to the neuron's position along the rostrocaudal axis of the SC. Both characteristics, spatially tuned neurons and their systematical arrangement, demonstrate the existence of an representation of auditory space in the rat SC. The neural basis of spatial attention in the auditory system is unknown so far. This is partially due to the lack of appropriate methods to record from awake animals. In the current thesis I adapted a method that was used in awake rats to record from the midbrain optic tectum (OT) of awake barn owls. During recording sessions owls performed a cue-directed selection paradigm, i.e. a modified cueing paradigm. By combining behavioral and neural measurements, I could test whether attention-related effects in behavior are reflected in the representation of auditory space in the barn owl's midbrain. I found two cognitive influences on auditory midbrain neurons that were seemingly independent: first, the intention to perform a specific movement, which induced a difference between the baseline activities of both OT hemispheres, and second, spatial attention, which enhanced or reduced neural responses to auditory stimulation depending on the behavioral relevance of the stimuli. Both effects are suited to explain the speeded detection and the shorter latency found in the behavioral study. Many auditory neurons (45%) in the barn owl's OT change their activity also during head movements: head turns towards contralateral directions are paralleled by an increase in spike rate and head turns towards ipsilateral directions by a decrease in spike rate below spontaneous levels. The role of midbrain neurons in premotor activation was so far indirectly shown by focal lesions or electrical stimulation. These data suggest that the midbrain of barn owls and rats is an important structure for sound localization. It combines sensory and motor functions, thus acting as sensorimotor interface. The existence of cognitive influences on the midbrain level indicates that midbrain neurons support not only reflexive but also non-reflexive functions, as e.g. goal-directed orienting towards auditory stimuli.","abstract_has_math":false,"creators":["Johnen, Anja"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Wagner, Hermann"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2003,"date_issued":"2003","date_published":"2003","updated_at":"2026-07-30T19:42:09Z","subjects":["info:eu-repo/classification/ddc/570","Biowissenschaften, Biologie","auditory","midbrain","awake","cueing"],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119261%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119261%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119261%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/57200","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wagner, Hermann"]},{"key":"dc:creator","label":"Author","values":["Johnen, Anja"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2003"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-4853"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/570","Biowissenschaften, Biologie","auditory","midbrain","awake","cueing"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/57200","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119261%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Attention improves processing of sensory stimuli. It may be directed to object features or to spatial positions. Orienting of attention towards spatial positions has been termed 'spatial attention'. In the visual system, an influence of attention on sensory processing was repeatedly demonstrated on the behavioral and neural level. Auditory attention, on the other hand, has been relatively neglected so far. In the current thesis, two animal models were chosen to investigate auditory spatial attention: first, the barn owl as a highly-developed auditory specialist and, secondly, the rat as an auditory generalist. An influence of spatial attention on sound localization has solely been demonstrated in humans so far. Since barn owls are important animal models in sound localization, I asked whether auditory attention can influence sound localization abilities in these birds. Using a cross-modal cueing paradigm, I could show that barn owls can initiate a head turn towards a sound source significantly earlier (37.4ms / 16% difference in mean response latency) when they are informed about the likely position of the next upcoming auditory stimulus. This benefit in reaction time was explained by the owl's ability to shift attention towards expected positions which resulted in a speeded detection of the stimulus and an earlier response. In a cueing paradigm the subjects are informed that the behaviorally relevant stimulus will be presented soon. In the mammalian species tested so far, this warning elicits a reduction in response latency that is related to the timing of the trial and not to the expected position of the next relevant stimulus. In the barn owl, I found clear effects of spatial attention, but, interestingly, no time-related attentional influences. Why the evaluation of the relative timing of events was not an evolutionary constraint for the barn owl remains open. The construction of internal space is considerably different between the auditory and the visual system which makes research on the mechanisms of auditory spatial attention very important. Surprisingly, less was known about internal representations of auditory space in the rat. Therefore, I investigated auditory neurons in a candidate structure in the rat's midbrain, the colliculus superior (SC) and asked whether auditory space is represented there. I found that most auditory neurons (73%) were broadly, but significantly tuned to the spatial location of a sound source. Preferred locations shifted from frontal to lateral in parallel to the neuron's position along the rostrocaudal axis of the SC. Both characteristics, spatially tuned neurons and their systematical arrangement, demonstrate the existence of an representation of auditory space in the rat SC. The neural basis of spatial attention in the auditory system is unknown so far. This is partially due to the lack of appropriate methods to record from awake animals. In the current thesis I adapted a method that was used in awake rats to record from the midbrain optic tectum (OT) of awake barn owls. During recording sessions owls performed a cue-directed selection paradigm, i.e. a modified cueing paradigm. By combining behavioral and neural measurements, I could test whether attention-related effects in behavior are reflected in the representation of auditory space in the barn owl's midbrain. I found two cognitive influences on auditory midbrain neurons that were seemingly independent: first, the intention to perform a specific movement, which induced a difference between the baseline activities of both OT hemispheres, and second, spatial attention, which enhanced or reduced neural responses to auditory stimulation depending on the behavioral relevance of the stimuli. Both effects are suited to explain the speeded detection and the shorter latency found in the behavioral study. Many auditory neurons (45%) in the barn owl's OT change their activity also during head movements: head turns towards contralateral directions are paralleled by an increase in spike rate and head turns towards ipsilateral directions by a decrease in spike rate below spontaneous levels. The role of midbrain neurons in premotor activation was so far indirectly shown by focal lesions or electrical stimulation. These data suggest that the midbrain of barn owls and rats is an important structure for sound localization. It combines sensory and motor functions, thus acting as sensorimotor interface. The existence of cognitive influences on the midbrain level indicates that midbrain neurons support not only reflexive but also non-reflexive functions, as e.g. goal-directed orienting towards auditory stimuli."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University 99 S. : graph. Darst. (2003). = Aachen, Techn. Hochsch., Diss., 2002"]},{"key":"dc:title","label":"Title","values":["Aspects of sound localization and spatial attention in barn owls and rats"]}]}],"canonical_facts":{"dc:contributor":["Wagner, Hermann"],"dc:coverage":["DE"],"dc:creator":["Johnen, Anja"],"dc:date":["2003"],"dc:description":["Attention improves processing of sensory stimuli. It may be directed to object features or to spatial positions. Orienting of attention towards spatial positions has been termed 'spatial attention'. In the visual system, an influence of attention on sensory processing was repeatedly demonstrated on the behavioral and neural level. Auditory attention, on the other hand, has been relatively neglected so far. In the current thesis, two animal models were chosen to investigate auditory spatial attention: first, the barn owl as a highly-developed auditory specialist and, secondly, the rat as an auditory generalist. An influence of spatial attention on sound localization has solely been demonstrated in humans so far. Since barn owls are important animal models in sound localization, I asked whether auditory attention can influence sound localization abilities in these birds. Using a cross-modal cueing paradigm, I could show that barn owls can initiate a head turn towards a sound source significantly earlier (37.4ms / 16% difference in mean response latency) when they are informed about the likely position of the next upcoming auditory stimulus. This benefit in reaction time was explained by the owl's ability to shift attention towards expected positions which resulted in a speeded detection of the stimulus and an earlier response. In a cueing paradigm the subjects are informed that the behaviorally relevant stimulus will be presented soon. In the mammalian species tested so far, this warning elicits a reduction in response latency that is related to the timing of the trial and not to the expected position of the next relevant stimulus. In the barn owl, I found clear effects of spatial attention, but, interestingly, no time-related attentional influences. Why the evaluation of the relative timing of events was not an evolutionary constraint for the barn owl remains open. The construction of internal space is considerably different between the auditory and the visual system which makes research on the mechanisms of auditory spatial attention very important. Surprisingly, less was known about internal representations of auditory space in the rat. Therefore, I investigated auditory neurons in a candidate structure in the rat's midbrain, the colliculus superior (SC) and asked whether auditory space is represented there. I found that most auditory neurons (73%) were broadly, but significantly tuned to the spatial location of a sound source. Preferred locations shifted from frontal to lateral in parallel to the neuron's position along the rostrocaudal axis of the SC. Both characteristics, spatially tuned neurons and their systematical arrangement, demonstrate the existence of an representation of auditory space in the rat SC. The neural basis of spatial attention in the auditory system is unknown so far. This is partially due to the lack of appropriate methods to record from awake animals. In the current thesis I adapted a method that was used in awake rats to record from the midbrain optic tectum (OT) of awake barn owls. During recording sessions owls performed a cue-directed selection paradigm, i.e. a modified cueing paradigm. By combining behavioral and neural measurements, I could test whether attention-related effects in behavior are reflected in the representation of auditory space in the barn owl's midbrain. I found two cognitive influences on auditory midbrain neurons that were seemingly independent: first, the intention to perform a specific movement, which induced a difference between the baseline activities of both OT hemispheres, and second, spatial attention, which enhanced or reduced neural responses to auditory stimulation depending on the behavioral relevance of the stimuli. Both effects are suited to explain the speeded detection and the shorter latency found in the behavioral study. Many auditory neurons (45%) in the barn owl's OT change their activity also during head movements: head turns towards contralateral directions are paralleled by an increase in spike rate and head turns towards ipsilateral directions by a decrease in spike rate below spontaneous levels. The role of midbrain neurons in premotor activation was so far indirectly shown by focal lesions or electrical stimulation. These data suggest that the midbrain of barn owls and rats is an important structure for sound localization. It combines sensory and motor functions, thus acting as sensorimotor interface. The existence of cognitive influences on the midbrain level indicates that midbrain neurons support not only reflexive but also non-reflexive functions, as e.g. goal-directed orienting towards auditory stimuli."],"dc:identifier":["https://publications.rwth-aachen.de/record/57200","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119261%22"],"dc:language":["eng"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-4853"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University 99 S. : graph. Darst. (2003). = Aachen, Techn. 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