GUSTATION AND OLFACTION

what is sensory

recieves information input from the environment and converts EXTERNAL stimuli to neural impulses

raw input

what is perception

how the brain integrates sensory information

interpreting the info - hear a song - “this is my favorite song”

what are exteroceptors

receptors that detect stimuli from EXTERNAL environment

skin (touch)

eyes (vision)

ears (hearing)

nose (smell)

tongue (taste)

what are interoceptors

receptors that detect stimuli from internal organs

blood pressure

hunger

thirst

heart rate

gut feelings (literally)

conditioned taste aversion (aversion leaving averting)

learned avoidance of a particular test

rats like sweet tastes and naturally prefer sugar over water

after RADIATION treatment that made rats sick after ingesting the sugar solution, they avoided sweet tastes (averted from it)

results: association occurs in the amygdala

taste perception in obestiy

objective: uncover possible differences between obese and lean individuals in the brain response to the sensory experience of food while in a state of hunger and anticipation

methods: PET scans after oral administration of 2 ml of a liquid formula meal and measured changes in regional cerebral flow

results: subjects with obesity had an increased blood flow in the gustatory cortex. Obese individuals show greater activation of their gustatory cortex in response of anticipation and intake of food, compared to lean subjects

Olfactory stimulation and new neuron integration and behavior

goal: to understand how odor exposure relates to recruiting new neurons to the olfactory bulb and how this relates to the function of the olfactory system.

subjects: adult male mice assigned to one of two groups

1. long-term exposure to odor - lavender, rosemary, cloves

2. no odor exposure

methods: combination of biochemical and behavior experiments by measuring the new number of new neurons in the olfactory bulb and olfactory memory 

results: found that mice in an olfactory-enriched environment have more new neurons integrated into their olfactory bulbs

Integrating Senses:

Objective: to determine that relative importance of different types of memory and sensory capabilities in wine expertise 

Subjects: 20 subjects, 10 with famous sommeliers from France and Switzerland and 10 matched controls and were exposed to wine tasting vs tasteless water directly delivered into the mouth 

Methods: fmri during the taste and after taste phase

Results: Experts had more immediate and targeted sensory reaction to wine and stimulation 

Experts had a LARGER insula and entorhinal cortex 

Sommeliers brains show specialization in the association areas and memory networks 

what area of the nose are pheromones detected by

vomeronasal organ

uses of pheromones

Lee-Boot effect

• Female mice housed together (no

males) have long, irregular

reproductive cycles

• Urinary pheromone from adrenal

gland

• Whitten effect

• When a male is introduced, the

female reproductive cycles

become shorter and more regular

• Urinary pheromone from males

synesthesia

 Stimulating one sense causes the perception of another

• Experience more than one sense simultaneously

• Documented since the 1800s, very rare (concentrated in artists)

• Over 60 documented variants

• hearing colors, seeing sounds

• Most common: seeing letters as colors

• Vincent Van Gogh and pharell williams

what are the eight sensory sensations

touch

sight

smell

taste

hearing

interoception - internal organs

proprioception - where we are in time and space

vestibular - balance

what is papillae

on the surface of the tongue that actually hold the taste buds

where are fungiform papillae

on the front of the tongue

where are circumvallate papillae

on the back of tongue

where are foliate papillae

on the sides of tongue

gustatory cortex

in the insula, it is how we taste things and sends to our thalamus from thalamus to any part of the brain like hippocampus

true or false taste cells are neurons

false

odorants

airborne molecules that stimulate olfactory system and lead to smell perception

olfactory epithelium

lining of the nos that holds olfactory neurons

olfactory nerve

cranial nerve, axons bring odor information into the brain

olfactory bulb

primary olfactory cortex and projects to many other brain regions (hippocampus, hypothalamus, amygdala)

neuroplasticity in olfaction experiment

mice are curious and novelty-seeking seeking and they want to explore new things

mice were presented with the same odor twice in a row

if mice remember the scent, they won’t explore as much

trigeminal system

multiple sensations

mint feels cold in your mouth

lee boot and whitten effect

lee boot: female mice houses together have long irregular reproductive cycles

whitten: when a male is introduced the female will have shorter reproductive cycles

what are the five tastes

umami

sweet

salty

sour

bitter