how many taste buds in a taste cell
buds contian 50-100 taste cells
papillae
3 different kinds of folds in the tongue that hold taste buds
- fungiform
- foliate
- circumvallate
lifespan of taste cells
around 1 week
salt molecular mechanism
utilizes driving force of Na
- voltage dependant Na channel
sour molecular mechanism
fluxes H ions
- mutation of polycistic kidney disease associated with channel
sweet bitter and umami taste transduction
protein cascade- heterodimers made up of 2/3 types of t1 receptors: T1R1/2/3
taste map
not true- similar detection in all 5 aspects of the tongue
taste cell afferants
geniculate ganglion- greater petrosal and chorda tympani
inferior ganglion cells- petrosal and nodose ganglion cells
- terminate in nucleus of solitary tract
projection of taste
- nucleus of solitary tract (rostral)
- ventral postereomedial thalamus (VPM)
- gustatory cortex (insula, front operculum)
DMN X: reflex pathway involved in salivation, swallowing, coughign
3 types of neuron like taste cells
have a taste receptor
- lack synaptic vesicles
- more similar to glial cells
type 1/2/3
microendoscopy
two photon imaging - lens to image deep areas of brain
- imaged geniculate ganglion and visualized different populations of neurons
- expressed Ca sensory (cAMP and GFP)
responses of ganglion cells to basic taste qualities
found that each cell responds selectively to 1 tastant and no other
- argues against signal being mixed at synapse
gustotopic maps
shows activity segregated in different parts of gustatory cortex
- becomes spatially segregated (not combinatorial like smell)
photostimulation of bitter and sweet corticies
drives aversive and appetitive behavior
- expressed channel rhodopsin in cortex and saw perception of sweet and bitter even though they cannot detect
