Neurobio Eam 2

Tastant

A chemical that stimulates the sense of taste

Taste receptor cell

Respond to tastants and initiate signaling pathways that lead to perception of taste. 50-150 within a taste bud.

Receptor potential

A stimulus-induced change in the membrace potential of a sensory receptor cell

Sensory Transduction

Process by which an environmental stimulus causes an electrical response (receptor potential) in a sensory receptor cell

Odorant

chemical that stimulates the sense of smell

Oflactory receptor neurons (ORN)

Activated by odorants, lead to perception of smell

Population coding

A combination of responses from a large number of broadly tuned neurons to specify the identity of a particular stimulus

glomerulus

Recieves inputs from one tyep of ORN expressing the same receptor

Sensory map

Orderly arrangement of neurons correlated with certain features of the environment

Temporal coding

Representation of info encoded by the timing of action potentials rather than average rate

Pitch

Frequency (low pitch = low frequency)

Amplitude

Loudness

Characteristic frequency

A given frequency for which a neuron is most responsive

Tonotopy

The systematic organization with an auditory structure based on the sound frequency (high freqncy at the base, low frequency at the apex)(sounds >200 Hz)

Phase locking

The consistent firing of a neuron at the same phase of a sound wave (low frequency)

Interaural time delay

difference in the time for the same sound to reach each ear; sound reaches closest ear first, works for sounds with freq ranging 20-2000 Hz

Interaural intensity delay

difference in intensity of the same sound at each ear (larger at closest ear, 2000-20000Hz)

Mechanoreceptors

Convert mechanical force into neural signals

Receptive field

the region of a sensory surface that when stimulated, change the membrane potential of a neuron

Mechanosensitive ion channels

Convert mechanical force into receptor potential or mechanoreceptors

Dermatomes

The area of skin innverated by the right and left dorsal roots of a signal spinal segment

somatotopy

The topographic organization of somatic sensory pathway in which neighboring receptors in the skin feed information to the neighboring cells in a target brain structure (sensory map for somatic system)

Rod

Photoreceptor; sensitive to light for nighttime vision

Cone

photorecpetor; less sensitive to light, color vision

Retina

Where we perceive light; central retina (fovea) mostly cones, peripheral mosty rods

Retinal

Vitamin A derivative that is light sensitive and co-factor for Rhodopsin (GPCR) in rods

receptive field (vision)

area of retina where light changes neuron’s firing rate

Center/surround receptive fields

two kinds of retinal ganglion cells; On center/off surround— activity highest when light on in center, off center/on surround— activity lowest when light on in center

lateral inhibition

inhibitory neurons laterally inhibit each neuron’s neighbors

Optic Chiasm

Ganglion cell axons from nasal retina cross here

LGN (Lateral geniculate nucleus)

structure in the thalamus that recieves information from retinal ganglion cells

Nasal side

area of sight closest to nose

temporal sides

outer part of field of view

Ipsilateral side

same side

contralateral side

opposite side

retinotopy

The topographic organization of visual pathways in wich neighboring cells in the retinal send information to neighboring cells in a target brain structure

Motor unit

one motor neuron and all the muscle fibers it innervates

Motor neuron pool

All alpha motor neurons that innervate a single muscle

Excitation-contraction coupling

Motor neurons excited —> AP triggers Ca 2+ release from sarcoplasmic reticulum —> Ca2+ binds to tropnin, inducing contraction —> EPSE ends —> sarcolemma returns to resting potential, Ca2+ reuptake

gamma loop

gamma motor neuron connected to intrafusal fiber, connected to Ia afferent axon to activate alpha motor neuron, contracts muscle

Reciptorical inhibition

Centeral pattern generator