Chapter 8 - Physiology and Psychophysics

Question 1

What philosophical question was able to be addressed with the new scientific advances of the 18th and 19th century?

Answer 1

By what mechanisms do empirical events come to be represented in consciousness?

Question 2

What is the Bell-Magendie law?

Answer 2

This law demonstrated that sensory nerves enter the dorsal roots of the spinal cord and motor nerves emerge from the ventral roots

Question 3

Why was the Bell-Magendie law significant?

Answer 3

• it separated nerve physiology into sensory and motor functions
• it was now no longer possible to think of nerves as conveyors of animal spirits
• sensory nerves carried sensory information from receptors to the brain
• motor nerves carried impulses from brain to muscles and glands
• this suggested separate sensory and motor regions in the brain

Question 4

What did Johannes Muller demonstrate?

Answer 4

• that each of the 5 types of sensory nerves results in a characteristic sensation

Question 5

What was Muller’s theory of adequate stimuli?

Answer 5

Stimulation to which sensory organ is maximally sensitive

Question 6

What was Helmholtz’s principle of conservation of energy?

Answer 6

• speed of nerve conduction (this helps us preserve energy)…

Question 7

What was Helmholtz’s theory of sensation and perception?

Answer 7

Sensation: mental experience caused by the stimulations of sensory receptors
Perception: mental experience arising through the interpretation of a sensation based on unconscious interference

Question 8

What was Hering’s alternate theory of colour vision?

Answer 8

His theory suggested that receptors in the eye which respond in an opponent process manner, red-green, blue-yellow, black-white.

Question 9

What was Helmholtz’s theory of colour vision?

Answer 9

Trichromatic theory - we have three rods that allow us to see colour - blue corresponds to a short rod, green to a medium length rod and red to a long rod

Question 10

What is phrenology?

Answer 10

The pseudoscience that mental faculties could be determined by the bumps and depressions in one’s skull

Question 11

What did Pierre Flourens do?

Answer 11

Extirpation - he systematically destroyed parts of the brain to observe the resulting consequences

Question 12

What were the contributions of Paul Broca and Carl Wernicke?

Answer 12

using the clinical method (observations in the clinical setting), they were able to localize language and communication functions in the brain

Question 13

What were the contributions of Fritsch and Hitzig?

Answer 13

Electrophysiology: using electrical stimulation of brain neurons, they found:

• the cortex is not insensitive
• when a certain area of the cortex is stimulated, muscular movements on the opposite side of the body are elicited, thus discovering the motor cortex
• the sensory cortex was also discovered