信鴿利用地標指引自己安全返航,。然而當(dāng)這種鳥以65千米每小時的速度掠過天空時,，它們?nèi)绾巫粉櫳硐聨装倜滋幍哪切┦煜さ牡攸c呢,？科學(xué)家們正在嘗試用一種新的裝置來解答這一問題，而這種裝置能夠讓他們在信鴿飛行時記錄鳥類的大腦活動,。
信鴿在嚴格意義上究竟是如何找到回家之路的一直是個未解之謎,。一些研究推測，鳥類能夠利用嗅覺,、太陽的方向,，或地球磁場來導(dǎo)航，科學(xué)家同時還知道,，信鴿能夠利用視覺地標,。為了搞清信鴿的大腦如何處理這些視覺信號，瑞士蘇黎世大學(xué)的Alexei Vyssotski和同事研制出了一種名為Neurologger2的裝置,，后者能夠在跟蹤鳥類路徑的同時記錄其飛越熟悉地點時的大腦活動,。
Neurologger2的重量僅為兩克，它使用一種腦電圖來記錄大腦活動,。研究人員首先訓(xùn)練26只信鴿將一座閣樓當(dāng)做自己的家,。隨后，他們在這些鳥類的大腦中植入微電極,，并將其與Neurologger2相連,。研究人員為這些信鴿配備了全球定位系統(tǒng)監(jiān)視器，最后在距離閣樓10公里到30公里沿線的不同地點放飛了這些信鴿,。研究人員在最近的《當(dāng)代生物學(xué)》雜志網(wǎng)絡(luò)版上報告了這一研究成果,。
在這些信鴿飛回家后,，研究人員取下相關(guān)裝置，隨后將鳥類大腦活動的記錄與它們當(dāng)時的位置進行了比較,。Vyssotski發(fā)現(xiàn)，當(dāng)信鴿沿著地標飛行時,，例如一條熟悉的高速公路、它們大腦中的高頻腦電波突然變得更加密集,。研究人員同時注意到,，與飛越一片沒什么特色的水面相比，這些信鴿在飛過熟悉的地形時,，高頻腦電波會產(chǎn)生更多的峰值。Vyssotski推測，高頻腦電波可能與鳥類識別已知的地點有關(guān),。
從事動物認知研究的美國達勒姆市新罕布什爾大學(xué)的Brett Gibson指出,，這項研究提供了鳥類在飛行期間大腦內(nèi)部的一個有趣景象,。Gibson說：“盡管如此，我還是想知道這些大腦活動是否僅僅與導(dǎo)航有關(guān),，還是更廣泛地涉及到事物的認知，以及到底是什么觸發(fā)了這些活動,。”而這正是Vyssotski的研究小組在接下來試圖解釋的問題,。
從事鸚鵡研究的美國哈佛大學(xué)的心理學(xué)家Irene Pepperberg也十分熱衷于這項新的技術(shù)。她說：“這是第一篇論文,，表明我們能夠利用一種實時系統(tǒng)來分析鳥類大腦的神經(jīng)生物學(xué)特征,。”Pepperberg表示：“鳥類大腦究竟是如何處理大量不同類型的感官信息的，這項技術(shù)真的能夠告訴我們很多。”
而Neurologger2也并非僅僅適用于鳥類,。Vyssotski如今正在同世界各地研究樹懶,、小鼠和海洋哺乳動物——例如海豚和海豹——的科學(xué)家進行合作,。（生物谷Bioon.com）
生物谷推薦原始出處：
Current Biology, 25 June 2009 doi:10.1016/j.cub.2009.05.070
EEG Responses to Visual Landmarks in Flying Pigeons
Alexei L. Vyssotski1,7,,,Giacomo Dell'Omo1,Gaia Dell'Ariccia1,Andrei N. Abramchuk2,Andrei N. Serkov1,3,Alexander V. Latanov3,Alberto Loizzo4,David P. Wolfer1,5,6andHans-Peter Lipp1
1 Institute of Anatomy, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
2 Moscow Institute of Electronic Technology, Passage 4806, Bldg. 5, 124498 Zelenograd, Russia
3 Chair of Higher Nervous System Activity, Faculty of Biology, Moscow State University, Vorobievi Gori 1-12, 119992 Moscow, Russia
4 Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanita, 299 Viale Regina Elena, 00161 Rome, Italy
5 Institute of Human Movement Sciences and Sport, ETH Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
6 Zurich Center for Integrative Human Physiology, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
7 Present address: Institute of Neuroinformatics, University of Zurich/ETH Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
GPS analysis of flight trajectories of pigeons can reveal that topographic features influence their flight paths. Recording electrical brain activity that reflects attentional processing could indicate objects of interest that do not cause changes in the flight path. Therefore, we investigated whether crossing particular visual landmarks when homing from a familiar release site is associated with changes in EEG.Birds carried both data-loggers for recording GPS position and EEG during flight. First, we classified characteristic EEG frequencies of caged birds and found five main bands: A: 03, B: 312, C: 1260, D: 60130, and E: 130200 Hz. We analyzed changes in these activity bands when pigeons were released over sea (a featureless environment) and over land. Passing over the coastline and other prominent landmarks produced a pattern of EEG alterations consisting of two phases: activation of EEG in the high-frequency bands (D and/or E), followed by activation of C.Overlaying the EEG activity with GPS tracks allowed us to identify topographical features of interest for the pigeons that were not recognizable by distinct changes of their flight path.We provide evidence that EEG analysis can identify landmarks and objects of interest during homing. Middle-frequency activity (C) reflects visual perception of prominent landmarks, whereas activation of higher frequencies (D and E) is linked with information processing at a higher level. Activation of E bands is likely to reflect an initial process of orientation and is not necessarily linked with processing of visual information.
