© Camilla Butti 2009 ii Table of contents Table of contents ......................................................................................................................... iii Abstract ........................................................................................................................................ vi Riassunto ................................................................................................................................... viii List of publications ........................................................................................................................ x List of figures ............................................................................................................................... xi List of tables ............................................................................................................................... xiv Abbreviations .............................................................................................................................. xv Chapter 1 .................................................................................................................................... 16 General introduction .................................................................................................................... 16 Review of cetacean evolutionary history, taxonomy, and classification ........................................ 16 General organization of the cetacean brain ................................................................................... 17 Surface configuration, cortical organization and main general features......................................... 17 Gyral pattern and localization of cortical areas ............................................................................. 18 Cetacean brain evolution .............................................................................................................. 19 Cetacean cognition....................................................................................................................... 20 The cortical regions of interest ..................................................................................................... 21 General notes ............................................................................................................................... 21 The prefrontal cortex (PFC) ......................................................................................................... 22 The anterior insular (AI) and frontoinsular (FI) cortices ............................................................... 23 The cortical regions of interest in the cetacean brain .................................................................... 24 Goals of the present thesis ........................................................................................................... 25 Chapter 2 .................................................................................................................................... 29 Cytoarchitecture and chemoarchitecture of the prefrontal and insular cortex in cetaceans............. 29 Introduction ................................................................................................................................. 29 Materials and methods ................................................................................................................. 31 Specimens and histological preparation ........................................................................................ 31 Immunohistochemistry ................................................................................................................ 31 Results ......................................................................................................................................... 32 Cytoarchitecture........................................................................................................................... 32 Anterior cingulate cortex (ACC) .................................................................................................. 32 Anterior insular cortex (AI).......................................................................................................... 33 Frontopolar cortex (FPC) ............................................................................................................. 33 iii Notes on the cytoarchitecture of ACC, AI, and FPC in other relevant species .............................. 34 Anterior cingulate cortex (ACC) .................................................................................................. 34 Trichechus manatus latirostris ..................................................................................................... 34 Loxodonta africana ...................................................................................................................... 34 Odobenus rosmarus rosmarus...................................................................................................... 34 Anterior insular cortex (AI).......................................................................................................... 34 Trichechus manatus latirostris ..................................................................................................... 34 Hexaprotodon liberiensis ............................................................................................................. 35 Odobenus rosmarus rosmarus...................................................................................................... 35 Frontopolar cortex (FPC) ............................................................................................................. 35 Trichechus manatus latirostris ..................................................................................................... 35 Diceros bicornis .......................................................................................................................... 35 Chemoarchitecture ....................................................................................................................... 35 Calretinin ..................................................................................................................................... 36 Discussion ................................................................................................................................... 37 Chapter 3 .................................................................................................................................... 48 Glia/neuron index in the cetacean brain ........................................................................................ 48 Introduction ................................................................................................................................. 48 Materials and methods ................................................................................................................. 49 Specimens and histological preparation ........................................................................................ 49 Identification of cortical areas, neurons, and glia .......................................................................... 50 Stereologic design ........................................................................................................................ 50 Statistical analysis ........................................................................................................................ 51 Results ......................................................................................................................................... 52 Discussion ................................................................................................................................... 53 Chapter 4 .................................................................................................................................... 66 Von Economo neurons in the cetacean brain ................................................................................ 66 Introduction ................................................................................................................................. 66 Materials and methods ................................................................................................................. 67 Brain specimens and tissue processing ......................................................................................... 67 Stereologic design ........................................................................................................................ 67 Statistical analysis ........................................................................................................................ 70 Results ......................................................................................................................................... 70 Quantitative analysis .................................................................................................................... 70 VENs in other species .................................................................................................................. 71 iv Discussion ................................................................................................................................... 72 Chapter 5 .................................................................................................................................... 91 General