Lecture 12: Sensory Coding and Vision

Question 1

Spontaneous Firing

Answer 1

• A sensory neuron occasionally fires spikes with no (obvious) reason to any sensory stimulus
• A sensory stimulus an cause the neuron to change its firing rate

Question 2

Selectivity

Answer 2

A neuron will respond to some stimuli and not others

Question 2

Rastor Plot

Answer 2

A plot of trials of neurons plotted over time, and you can see where there is an increased firing rate across many neurons, allowing us to tell that the neuron is responsive to a particular stimulus

Question 2

Neural Rate Code

Answer 2

Information is coded by spike rate

Question 3

Receptive Field of a Neuron

Answer 3

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

Question 4

Neural Temporal Code

Answer 4

Information is coded by spike timing

Question 5

Cortical Maps

Answer 5

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

Question 5

Cortical Plasticity

Answer 5

• Experience can reshape sensory representations
• Ex. trained monkeys, amputees/phantom limb, etc.

Question 5

Do you see with your eyes? The case of Mike May

Answer 5

• Mike May was blinding by a chemical explosion at age 3
• Scarring of cornea blocked light
• At 46, he underwent new surgery that cleared the corneas
• He was still unable to properly see since the brain pathways that interpret visual information from the eyes were not functioning

Question 5

Homunculus

Answer 5

• Refers to an orderly representation of the body in the brain
• The proportions of cortical somatosensory representations in different species reflect species-specific sensitivity