Presentation on theme: "Chap 15 Chemical senses. Here comes your footer Page 2 日常觀察 為何狗的嗅覺這麼好？ 為何冰的東西比較沒味道？ 吃和聞的味道如何 combine? Flavor = smell + taste Chemical senses."— Presentation transcript:
Chap 15 Chemical senses
Here comes your footer Page 2 日常觀察 為何狗的嗅覺這麼好？ 為何冰的東西比較沒味道？ 吃和聞的味道如何 combine? Flavor = smell + taste Chemical senses are 守門員 - 動用情緒，回憶 - 阻止不好的食物進入體內，或者遠離不好的環境 一些問題
Here comes your footer Page 3 嗅覺（ Olfactory system ） 生存 溝通 Menstrual synchrony Pheromones 味道 Anosmia Detection threshold Yes/no procedure -trials with odors along with “blank” trials -This can result in bias Forced-choice -one with odorant and one without -Participant indicates which smells strongest 功能 偵測
Here comes your footer Page 5 嗅覺（ Olfactory system ） Difference threshold 氣流影響濃度 Ofactometer Recognition threshold knowing names helps recognition 氣味難以用語言形容 偵測
Neural codes for olfactory quality Olfactory mucosa is located at the top of the nasal cavity. -Odorants come in contact with the olfactory receptor neurons (ORN). Page 6
Neural codes for olfactory quality 嗅神經 (olfactory receptor neurons, ORN) -Contains olfactory receptors -350 receptors (note: only 4 visual pigments) -But, only one olfactory receptor for one ORN Page 7
Neural codes for olfactory quality Olfactory bulb -ORNs of a particular type send their signals to one or two glomeruli -How do the glomeruli respond to different odorants? -Optical imaging Page 10
Neural codes for olfactory quality Olfactory bulb - 嗅球反應是取決於分子與結構的特性 - hardwired response? e.g. cat odor Page 12
Higher Level Olfactory Processing Signals from the olfactory bulb are sent to -primary olfactory (piriform) cortex in the temporal lobe and amygdala. -Amygdala plays a role in emotional reactions to odors. -(then to) secondary olfactory (orbitofrontal) cortex in the frontal lobe.
Here comes your footer Page 14 Higher order olfactory processing
Here comes your footer Page 15 Higher order olfactory processing 我們通常都同時聞到並可以分 辨兩種以上的氣味 過去經驗影響嗅覺 e.g. 白酒 (Morrot et al., 2001)
Here comes your footer Page 18 Higher order olfactory processing de Araujo et al. People were exposed to a mixture of a sweat-like smell and a cheddar cheese flavoring. On some trials, they saw the label “cheddar cheese,” and on others, the label “body odor.” Pleasantness ratings were higher for the cheddar cheese trials. fMRI scans showed activity in the orbitofrontal cortex to be associated with the pleasantness ratings.