Week Nine - Sensation & Perception

Question 1

What is Sensation?

Answer 1

The manner in which our sense organs receive information from the environment

Question 2

What is Perception?

Answer 2

The manner by which people select, organise, and interpret sensations
- understanding a stimulus

Question 3

What is Transduction?

Answer 3

The manner by which physical energy is converted into sensory neural impulses

Question 4

What is the former sensory system organisation?

Answer 4

receptors > thalamus > primary sensory cortex > secondary sensory cortex > association cortex

COMPLETELY BOTTOM-UP APPROACH

Question 5

What is the neocortex?

Answer 5

A thin sheet of cells covering the rest of the brain

Question 6

How are cells organised in the neocortex?

Answer 6

Into 6 stereotypical layers.

The types of cells, their spatial arrangement and connections are pretty much the same in every part of the neocortex

Question 7

What is the sensory organ and receptors for vision?

Answer 7

The eye
Rods and Cones
They transduce neural signals up the optic nerve

Question 8

Explain the process in the primary visual pathway

Answer 8

retina - optic nerve - optic chiasm - thalamus - occipital lobe

Question 9

Explain the process in the primary auditory pathway

Answer 9

auditory nerve - cochlear nuclei - superior olivary nuclei - inferior colliculus - medial geniculate - auditory cortex

Question 10

What is the thalamus?

Answer 10

The gateway to the cortex (relay station)

Question 11

What doesn’t pass through the thalamus?

Answer 11

Olfaction

Question 12

What is a Multisensory Integration area?

Answer 12

The area in which information is assimilated from various individual sensory systems and coordinated

Question 13

How does hearing occur?

Answer 13

It occurs via sound waves, which result from rapid changes in air pressure caused by vibrating objects

Question 14

What is pitch? (amplitude)

Answer 14

Frequency of vibration measures in hertz

Question 15

What is Loudness? (frequency)

Answer 15

Function of sound wave intensity

Question 16

What does timbre do? (complexity)

Answer 16

Provides information about the nature or complexity of the sound

Question 17

Where are primary auditory receptors located? What are they?

Answer 17

In the cochlea (inner ear)

They are tiny hair cells that convert sound energy to neural impulses and send them along to the primary auditory cortex

Question 18

What is the route of transduction of auditory information?

Answer 18

cochlea > superior olives > colliculi > thalamus > primary auditory cortex

Question 19

What is the external ear called?

Answer 19

The pinna

Question 20

What is the name of the eardrum?

Answer 20

Tympanic membrane

Question 21

What is the middle ear?

Answer 21

A hollow region between the eardrum and the cochlea, containing the ossicles

Question 22

What are ossicles?

Answer 22

The middle ear bones (these vibrate from sound waves and transmit it to the inner ear)

• malleus
• incus
• stapes

Question 23

What is the Cochlea?

Answer 23

A snail-shaped structure of the inner ear containing the organ of corti

Question 24

What is the Organ of Corti?

Answer 24

A sensory organ for the auditory system (the eye basically)

• basilar membrane
• hair cells
• tectorial membrane

Question 25

What does the stimulation of hair cells trigger?

Answer 25

Action potentials in the auditory nerve

Question 26

What does the basilar membrane consist of?

Answer 26

A base and an apex

Question 27

What do natural, low-frequency and high-frequency sounds do in the basilar membrane?

Answer 27

``` natural = excite cells across the membrane low = excite cells near the apex high = excite cells near the base ```

Question 28

What is the general process of how sound waves get in?

Answer 28

They vibrate the eardrum, which causes reactions in the bones then affecting the oval window, fluid moves around causing hair cells to bend in different ways depending on the soundwave

Question 29

What is the secondary auditory cortex?

Answer 29

The superior temporal gyrus

Question 30

Auditory signals are conducted to what two areas of the association cortex?

Answer 30

Prefrontal cortex | Posterior parietal cortex

Question 31

What and Where pathway

Answer 31

Anterior Auditory Pathway more involved in identifying sounds (what) (front) Posterior Auditory Pathway more involved in locating sounds (where) (back)

Question 32

What are Odorants?

Answer 32

Molecules that give off a smell (they bind to receptors in olfactory cilia)

Question 33

What are Glomerculi?

Answer 33

Clusters of convergent olfactory sensory neurons

Question 34

What is taste referred to as?

Answer 34

Gustation

Question 35

Where are taste receptors located?

Answer 35

Tongue and oral cavities in clusters of about 50

Question 36

What are the 4 primary tastes

Answer 36

sweet, sour, salty, bitter

Question 37

What is the 5th taste?

Answer 37

Umami (meat or savoury)

Question 38

Explain the receptor information about salty and sour taste?

Answer 38

salty and sour do not have receptors, they merely just act on ion channels

Question 39

What is the process of gustation?

Answer 39

receptors (papillae) > solitary tract > thalamus > cortex

Question 40

What is the Somatosensory system composed of?

Answer 40

Three separate and interacting systems Exteroceptive - external stimuli (touch, pressure, pain) Proprioceptive - body position Interoceptive - internal body conditions (eg temperature, blood pressure)

Question 41

What do Merkel's Disks do?

Answer 41

Detect regular touch

Question 42

Meissner's corpuscles?

Answer 42

Detect light touch

Question 43

Pacinian corpuscles?

Answer 43

Detect Deep pressure (gradual skin indentation)

Question 44

Ruffini corpuscles?

Answer 44

Detect temperature on the skin

Question 45

Nociceptors?

Answer 45

Detect pain

Question 46

What are the 2 major pathways in the Somatosensory system?

Answer 46

Dorsal-column medial-lemniscus system: Mainly touch and proprioception Anterolateral System: Mainly pain and temperature

Question 47

What does the iris do?

Answer 47

Controls how much light enters the eye

Question 48

What is the pupil?

Answer 48

A hole where the light enters the eye

Question 49

What does the retina do?

Answer 49

Receives light that the lens has focussed and converts it into neural signals for the brain

Question 50

What does the optic nerve do?

Answer 50

Travels from the retina to the brain

Question 51

What is the fovea?

Answer 51

It is the central part of our eye responsible for acuity (sharpness of vision) and this is why we move our eyes

Question 52

What is the 'blindspot'

Answer 52

A region of the retina that contains no rods or cones - therefore nothing to detect vision

Question 53

Where are our sensory receptors in the eye?

Answer 53

At the back - moves along the cells to the front of the eye via the optic nerve

Question 54

What are cones?

Answer 54

Photopic (daytime) vision. High acuity colour information in good lighting. Only found at the fovea

Question 55

What are rods?

Answer 55

Scotopic (night time) vision. | High sensitivity, allowing for low-acuity vision in dim light but lacks detail and colour

Question 56

Difference between ganglion cells for each cone and rod?

Answer 56

``` Cone = 1:1 Rods = many rods for each ganglion cell ```

Question 57

How does vision reach the primary visual cortex?

Answer 57

Travels on optic nerve > reaches optic chiasm > crosses over to lateral geniculate (thalamus) > goes to primary visual cortex

Question 58

Explain the flow of visual information

Answer 58

Thalamic relay neurons > visual cortex (striate) > visual cortex (prestriate) > visual association cortex

Question 59

What happens to receptive fields as visual flows through the hierarchy?

Answer 59

They become larger and respond to more complex and specific stimuli

Question 60

What kind of cells do receptive fields have?

Answer 60

Simple cortical cells | Complex cortical cells

Question 61

Which part of the brain gets sensory input from all systems?

Answer 61

The superior colliculus

Question 62

What is found with those with Synesthesia?

Answer 62

Stronger white matter connectivity - more axons between sensory areas

Question 63

What is total deafness in humans caused by?

Answer 63

1. Conductive deafness (damage to ossicles) | 2. Nerve deafness (damage to cochlea)

Question 64

What does parietal cochlea damage result in?

Answer 64

Loss of hearing at particular frequencies

Question 65

What is Anosmia?

Answer 65

Inability to smell | Commonly caused by a blow to the head that damages olfactory nerves

Question 66

What is Ageusia?

Answer 66

Inability to taste (not common at all)

Question 67

What is Astereognosia?

Answer 67

Inability to recognise objects by touch

Question 68

What is Asomatognosia?

Answer 68

The failure to recognize parts of one’s own body

Question 69

What is a loss of colour vision called?

Answer 69

Achromatopsia - caused by bilateral damage to the occipital lobe in V4

Question 70

What is Akinetopsia?

Answer 70

Selective loss of motion perception (eg cant see moving cars)

Question 71

What is Scotomas?

Answer 71

Discrete regions of blindness

Question 72

What is neglect syndrome?

Answer 72

Involuntary failure to attend to sensory stimuli presented in the side of space opposite to the site of brain injury (eg only shaving one side of your face)