Lecture 13 - Medical discoveries related to psychology

Question 1

Measurement, an advantage of science

Answer 1

• Newton: Gravity is not visible but measurable
• Descartes: Animal spirit real but not measurable
• Helmholtz: Nerve impulses are measurable
• Fechner: Mental experiences are measurable too,
  indirectly: Logarithmic scale of physical stimuli
  represents the scale of mental experiences.
• Galton: Intelligence and personality traits can be
  measured (tested)
• Gall, Broca, Wernicke, Penfield, Olds – Mental processes “mapped”
  in the brain centers or nuclei?

Question 2

Medical discoveries
in 18th – 20th c.
related to
mental health: BRAIN STUDIES

Answer 2

The invention of anesthetics and tranquilizers

1823 Pierre Flourence: Damage of brain structure in animals
1860 Eduard Hitzig: Stimulation of brain surface in wounded soldier
1863 Pierre-Paul Broca: Lesion/cancer of the left frontal lobe (motor
aphasia)
1874 Carl Wernicke: Lesion/cancer of the left temporal lobe (sensory
aphasia

Franz Joseph Gall (1757 - 1825) The 1st concept of the brain localization of
mental traits. His follower, Dr. Spurzheim developed a method called
phrenology:
the skull inundations “associated” with mental traits.
1870 Gustav Fritsch: Electric stimulation of the brain in animals
to observe movements, vocalization etc.
1860 L.N. Simonoff: Electric stimulation of animals’ brainstem
implanted electrodes
1918 Montreal Neurological Institute studies
1928: Dr. Wilder Penfield: Brain surgeries on epileptic patients
under local anesthesia. Gentle electric stimulation
of the brain evoked visual and auditory hallucinations
1954 James Olds & Peter Milner: “Pleasure centres” in animals.
Nowadays: the role of dopamine and nucleus accumbens

The cartesian concept continued: efferent and afferent nerves.
C. Bell (motor nerves), F. Magendie (sensory nerves)

Question 3

Johannes Müller (1801 - 1858)

Answer 3

Berlin
Doctrine of specific nerve energies.
5 kinds of sensory nerves, each containing a specific type of energy: visual,
acoustic, tactile etc. Johannes Muller was a fellow of Herman von Helmholtz
(1821-1894)
No matter what kind of stimulus is acting on the eyeball or the optic nerve:
light, heat or touch: It always evokes an optic sensation. It is so because a
specific energy
within the optic nerve has been stimulated producing a visual sensation

Question 4

Hermann von Helmholtz (1821 - 1894)

Answer 4

The greatest physiologist of the XIX century.
Fellowship under Johannes Müller (Berlin) supervision
Professor of physiology and medicine Königsberg, Bonn, Heidelberg, and
Berlin
W. Wundt was his assistant professor at Heidelberg
Measuring of speed of nerve conductance: 165 - 350 ft/sec.
Chronometry: reaction time.
Unconscious inferences in depth perception.
Perceptual adaptation.
Color vision.
* Color receptors: the cones
* Ophthalmoscope
* Depth perception cues: unconscious inferences
* Hair cells on the basilar membrane
Chronometer to measure the reaction time and the speed of the nerve
conductance in the
the dissected nerve of a frog attached to the calf muscle
H. Helmholtz: What is specific: the nerve energy, the receptor or the brain
center?
Cones: details and colour vision.
Rods: sensitive to light black/white only
photoreceptors on the retina:m rods (black/white vision) and cones (colour
vision)
trichromatic theory: three types of cones sensitive to blue, green or red

The unconscious inferences in size constancy and depth perception
The size constancy: We use the linear perspective to assess the distance
of the object at A and B position and, along with the retinal image size, we
judge
the object as the same in either position.
Depth perception cues: Linear perspective, The relative size of known
objects,
Distance from the horizon, Structure of the image, and Eyeball convergence

Question 5

Further studies on the brain
in XIX and XX centuries

Answer 5

Dr. W. Penfield (1891 - 1976) pioneering studies on brain localization of
sensory
and motor functions. His followers continued studying brain anatomy
(centres, nuclei) and
physiology (nerve impulse)

CORTICAL LOBES AND AREAS
OLD BRAIN STRUCTURES
Sub-cortex & brainstem
The limbic system, paleo-brain, visceral brain
Autonomic Nervous System, Limbic System, RAS
1949 G. Moruzzi & H. Magoun – RAS
1921 J. Langley - ANS
1902 – 1921 Discoveries of hormones
Psychosomatic medicine
Franz Alexander - personality proneness
Michel DeMuzan, P. Sifneous - alexithymia
1950 Meyer Friedman & Ray Rosenman “Type A personality”
Studies of the neuronal cell
1921Loewi neurotransmitter acetylcholine nervus vagus
1932 Edgar Adrian nerve impulse with Sherrington synapses Nobel
The resting potential: the negatively charged ions inside
and positively charged mostly outside of axon -70mV (millivolt
Sir Sherrington: discovery of synapses