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Publication
Measuring neurophysiological markers of acoustic signal processing in bottlenose dolphins with a new non-invasive device
Advisor(s)
Abstract(s)
Medidas neurofisiológicas, como os ERPs (Event-
Related Potentials), podem ser extremamente valiosas para
aumentar a compreensão de como os animais comunicam
através de sinais acústicos. Os ERPs são flutuações na
voltagem da actividade cerebral representadas no tempo após
eventos específicos, podendo ser interpretadas através da sua
polaridade, latência, amplitude, e distribuição de picos de
voltagem. A recolha de dados foi efectuada através de
eléctrodos de superfície em três machos Tursiops truncatus, com
13, 12 e 5 anos, no Zoomarine Algarve, Portugal. Foi
desenvolvido um novo método não invasivo, o Ring-Cap &
Tail, para fixar os eléctrodos activos em posições determinadas
permitindo a sua captação simultânea. Foi utilizado o
Paradigma do estímulo Oddball, apresentado aos sujeitos em
pares aleatórios onde 85% dos estímulos eram frequentes e
15% eram raros. Os dados sugerem a presença de
componentes de ERP endógenos como o N200 e P550,
encontrados por Woods e seus colegas em 1986, o que suscita
particular interesse visto estarem implicados no
reconhecimento de sinais. Estes componentes de ERP podem
fornecer aos investigadores dados adicionais para a avaliação
da informação contida em sinais acústicos. São também
assinaladas diferenças no tempo de processamento entre os
sujeitos, possivelmente relacionados com a idade. O novo
método não invasivo mostrou ser muito eficaz podendo ser
considerado uma ferramenta promissora para próximos
estudos de electrofisiologia.
ABSTRACT: Neurophysiological measures such as ERPs (Event- Related Potentials) may be extremely valuable to research, advancing our understanding of how animals use acoustic signals to communicate. ERP waveforms are voltage fluctuations associated in time with specific events and they can be interpreted by the polarity, latency, amplitude, and distribution of voltage peaks. The ERP data was collected with surface electrodes from three male bottlenose dolphins (Tursiops truncatus), with 13, 12 and 5 years old, at Zoomarine (Algarve, Portugal). An efficient, new, non-invasive method was developed, the Ring-Cap & Tail, to enable the simultaneously recording data from multiple active electrodes in standardized locations. The Oddball Paradigm was used with stimuli presented in random pairs, the frequent stimuli 85% of the time and the rare one 15% of the time. Data analysis suggests the presence of endogenous ERP components, like the N200 and P550, found by Woods and colleagues in 1986, which are of particular interest, because they may imply stimulus recognition by the subject. These ERP components could provide researchers with an additional way to evaluate the communicative information contained in acoustic signals. The data also suggest differences in processing time between subjects, possibly related to age The Ring-Cap & Tail was very effective and proved to be a promising tool for electrophysiological studies.
ABSTRACT: Neurophysiological measures such as ERPs (Event- Related Potentials) may be extremely valuable to research, advancing our understanding of how animals use acoustic signals to communicate. ERP waveforms are voltage fluctuations associated in time with specific events and they can be interpreted by the polarity, latency, amplitude, and distribution of voltage peaks. The ERP data was collected with surface electrodes from three male bottlenose dolphins (Tursiops truncatus), with 13, 12 and 5 years old, at Zoomarine (Algarve, Portugal). An efficient, new, non-invasive method was developed, the Ring-Cap & Tail, to enable the simultaneously recording data from multiple active electrodes in standardized locations. The Oddball Paradigm was used with stimuli presented in random pairs, the frequent stimuli 85% of the time and the rare one 15% of the time. Data analysis suggests the presence of endogenous ERP components, like the N200 and P550, found by Woods and colleagues in 1986, which are of particular interest, because they may imply stimulus recognition by the subject. These ERP components could provide researchers with an additional way to evaluate the communicative information contained in acoustic signals. The data also suggest differences in processing time between subjects, possibly related to age The Ring-Cap & Tail was very effective and proved to be a promising tool for electrophysiological studies.
Description
Dissertação de Mestrado apresentada ao ISPA - Instituto Universitário
Keywords
Electrofisiologia Potenciais evocados Tursiops truncatus Electrophysiology ERP Tursiops truncatus