Sensory Coding and Perception

Question 1

The 5 steps of sensory coding

Which 2 are sensory processing

Answer 1

Stimulus  --------Sensory Processing
Sensation---------Sensory Processing
Perception
Emotion
Memory

Question 2

Sensory Coding

What does the graph look like

Answer 2

How the brain detects and processes sensory stimuli
How the quantitative aspects of physical stimuli correlate with the neural activity they evoke
X-axis- Stimulus intensity
Y-axis- Neural activity

Question 3

Sensation

Answer 3

The activation of sensory brain pathways by a physical stimulus

Question 4

Perception

Answer 4

The extraction of a mental representation from a sensation

A sensory cue can give rise to different or misleading perceptions

Question 5

Psychophysics

What does the graph look like

Answer 5

How the quantitative aspects of physical stimuli correlate with the sensations they evoke
X-axis- Stimulus intensity
Y-axis- Stimulus detection %
Psychometric curve

Question 6

Receptor Neurons

Answer 6

Specialized cells that respond to physical sensory stimuli
“Respond”=electrochemically
Convert sensory stimuli into neural signals

Question 7

What can a response in a receptor neuron evoke

Answer 7

A response in the neurons synaptically connected to it

That neuron can evoke a response in the next neuron

Question 8

What is the response in neurons commonly called

Answer 8

Spikes

Question 9

What are 2 ways to measure neuron spikes

Answer 9

1. Electrophysiologically

2. Optically

Question 10

Electrophysiological Recording

Answer 10

Intracellular- measures the membrane potential (including spikes)
Extracellular- Measures spikes and the local field potential (LFP)

Question 11

Local Field Potential

Answer 11

Aggregate neural activity in the area

Question 12

Calcium-Sensitive Dyes

Answer 12

Optical recording of action potentials
Molecules that become fluorescent in the presence of calcium
More calcium=more florescence

Question 13

Spontaneous Firing

Answer 13

A sensory neuron occasionally fires spikes with no obvious relation to any sensory stimulus
A sensory stimulus can cause the neuron to change its firing rate

Question 14

Neural code

Answer 14

Rate (frequency) code vs. Temporal code
Rate: information coded by a spike rate
Time: information coded by spike timing

Question 15

Receptive field of a Neuron

Answer 15

A sensory neuron will respond to some stimuli and not others

The region of sensory space in which a stimulus will modify the firing of that neuron

Question 16

What do spiking response give rise to

Answer 16

Our perception

Question 17

What do our brain regions contain

Answer 17

Millions of neurons

These network responses are highly complex

Question 18

Cortical Maps

Answer 18

“Topography”

Touch information from adjacent parts of the body are represented in adjacent parts in the cortex

Question 19

Homunculus

Answer 19

“Tiny Man”

Refers to an orderly representation of the body in the brain

Question 20

Why are the proportions of different cortical somatosensory representations different

Answer 20

Because of species-specific sensitivity

Question 21

Cortical Plasticity

Answer 21

An experience can reshape sensory representations
A monkey was trained to perform a task that required using the tips of fingers 2, 3, and 4.
After training there is a substantial enlargement of the cortical representation of the stimulated fingers

Question 22

Phantom Limb

Answer 22

In amputees, stimulation of face or arm can elicit phantom limb sensations