Les sens chimiques
Prof. Alan Carleton
Département de Neurosciences Fondamentales
• Le système olfactif principal
• Organe voméronasal et détection des phéromones
• La perception des goûts
Les sens chimiques
GUSTATION
Organisation anatomique de la perception du goût
Les bourgeons du goût et papilles gustatives
Organisation des bourgeons du goût
20 µm
Bourgeons du goût:
Homme (10000) Rat (1000)
500 CV
Amer
Caffeine
Quinine-HCl
Atropine
Denatonium
Sucré
Fructose
Sucrose
Artificial Sweeteners
Umami
MSG
Salé
NaCl
KCl
Acide
Nicotinic Acid
Tartaric Acid HCl
Citric Acid
Les saveurs du goût
Bitter Sweet Umami
40 T2Rs T1R2/T1R3 T1R1/T1R3 Salt Sour
Ion channels GPCRs
ENAC
Epithelial Na Chan. Pkd2l1
Les receptors du goût
Transduction
ATP 5-HT
T1R2-T1R3 T1R1-T1R3 ENAC
Epithelial Na Chan.
PKD2L1
TRP channel
Transduction
Representation sensorielle sur la langue
Gustatoray pathways in the human brain
Gustatoray pathways in the rodent brain
Gilbertson et al. J Neurosci (2001)
Codage de l’information sensorielle
Codage de l’information sensorielle
Mouse behaviour
Mueller et al. Nature (2005)
Codage de l’information sensorielle
Cortical neurons
Stapleton et al. J Neurosci (2006)
Représentation sensorielle dans le cortex
Vision Audition
Location of the gustatory cortex in the rodent brain
mca
rhv S1BF
GC
S1
Pir lot
GC rs IC
• Changes in Reflectance upon activation
• Functional Population Activity
• Successfully used to establish spatial organization of other sensory areas
• Good Spatial Resolution
Methods – Intrinsic imaging
Functional localization of the gustatory cortex
Accolla, Bathellier, Petersen and Carleton. Journal of Neuroscience (2007) 27:1396-1404
Signals are taste specific
Represention des goûts dans le cortex
Control C T A Extinction
C
B
Pleasant Unpleasant
A
Sweet Salty Bitter Sour
mca
rhv
Somatosenrory
Gustotopic map in the taste cortex
Gustotopic map in the taste cortex
OLFACTION
Organization of the human olfactory system
Organization of the olfactory systems
Photo: courtesy of Prof. Rodriguez (UNIGE)
(Omp-TauLacZ) Tg mouse Grueneberg
Ganglion (GG)
Vomeronasal
Organ (VNO) Main olfactory
Epithelium (MOE)
Olfactory
Bulb (OB)
Grueneberg ganglion
Grueneberg ganglion
Chemical senses receptors
Vomeronasal receptors
Organization of the olfactory systems
V2R V1R
OR
Transduction in the VNO
Sexual behavior controlled by the vomeronasal organ
Sexual behavior controlled by the vomeronasal organ
A functional circuit underlying male sexual behaviour in the female mouse brain Tali Kimchi, Jennings Xu & Catherine Dulac
Nature 448, 1009-1014 (2007)
Organization of the olfactory system
Organization of the main olfactory system
Organization of the main olfactory system
The main olfactory epithelium
Sensory neurons in the main olfactory epithelium
Sensory neurons in the main olfactory epithelium
Organization of the main olfactory epithelium
Transduction in the MOE
Transduction in the MOE
Transduction in the MOE
Organization of the olfactory system
The Nobel Prize in Physiology or Medicine 2004
L. Buck R. Axel
(M50-TauLacZ) Tg mouse
~1000 olfactory
receptors in mice
Zonal organization
Simplex and complex odors
Odor detection in mammals
cyclohexanol CH 3
O
O
O O
CH 2 OH OH
O CH 3 O
O
anisole acétophenone
1,8 cinéole
dl- camphre
cyclodecanone
heptanol
cyclohexanone 2-heptanone
Sicard, G. and Holley, A. (1984). Receptor cell responses to odorants: similarities and differences among odorants. Brain Research, 292, (2), 283-96.
• One receptor is not specific of a single molecule
• Different odors are detected by different sets of receptors
Olfactory epithelium Sensory neuron
Chemodetection
Odor coding = Combinatorial coding
Imaging odor maps
Blood vessels pattern
Functional Map
IOS imaging of odorant evoked activity in the
olfcatory bulb
Functional organization of cortical regions
IOS imaging of odorant evoked activity in single trials
Ethyl Butyrate Amyl
acetate
Odor maps
Methyl Benzoate Water
Amylacetate Benzaldehyde
Hexanal
Carvone + (1) Carvone + (2)
Odor evoked glomeruli maps
A m yl ac et at eM e t h yl B e n z o at eB e n z al d eh yd eMouse C57Bl6- Odor maps from 03525510255010020051025501002005102550100200
Amylacetate
Methyl Benzoate
5 10 25 50 100 200
5 10 25 50 100 200
Olfactory mediated behavior
Organization of the olfactory system
Anosmia: loss of the sense of smell
Anosmia: loss of the sense of smell
Mouse
Human
Anosmia: loss of the sense of smell
Sensory neurons Mitral cells
Olfactory bulb circuitry
V es s el s
Odor Flow (sccm)
AA
EB
10
0.6 AA 0.4 EB
0.4 AA 0.6 EB
10
0.4
-0.5 0.5
-0.7
Frontal
Olfactory bulb
Medial
Spatial patterns of odor mixtures measured by intrinsic Imaging are highly similar in trained mice
Abraham et al. (2004). Neuron. 44:865-76
G lom er ul i
∆R/R
Behavioural assessment of olfactory performances
Abraham et al. (2004). Neuron. 44:865-76
Mice can discriminate odors in a single sniff
1% AA vs. EB
Correct (%
40 100
80
60
40
13 1
Trials (block of 100) Cineol vs. eugenol
0.6AA+04EB vs.
0.4AA+0.6EB
Correct response (%)
Abraham et al. (2004). Neuron. 44:865-76
500 400 300 200 100
0
1%AA
1%EB Mix
D iscri mi n a ti o n t ime (ms) *
Olfactory bulb circuitry
Genetic manipulation of granule cell inhibition
Granule cell inhibition modulate odor discrimination
More inhibition Less inhibition
Odor representation in the olfactory cortex
Stettler and Richard Axel. Neuron (2009)
Odor representation in the olfactory cortex
Stettler and Richard Axel. Neuron (2009)
