Final Exam Short Answer

Question 1

What are the 5 basic senses, including subcategories of bodily sensations?

Answer 1

Vision
Audition
Olfaction
Gustation
Somatosensation (Thermoception, Nocioception, Equilibrioception, Mechanoreception, Proprioception)

Question 2

Which cranial nerves intervals the eye for movement and which zones are responsible for taste?

Answer 2

Eye Movement: CN III (Oculomotor) CN IV (Trochlear), CN VI (Abducens)

Taste: CN VII (Facial), CN IX (Glossopharyngeal), CN X (Vagus)

Question 3

What is the difference between Weber’s Law, Fechner’ Law, Steven’s Power Law?

Answer 3

Weber’s Law:
- The JND between stimuli is proportional to the stimulus magnitude

Fechner’s Law:
- Percieved intensity is logarithmically related to stimulus intensity

Steven’s Law:
- Perceived magnitude is related to stimulus intensity raised to a certain power

Question 4

Why are humans not ideal detectors according to signal detection theory?

Answer 4

Humans generate too much “noise”.

Question 5

What are the differences between presbyopia, myopia, and hyperopia?

Answer 5

Presbyopia:
- Age related
- loss of near vision due to reduced lens flexibility

Myopia:
- Caused by a elongated eyeball
- Nearsightedness, where distant objects appear blurry due to the focal point falling in front of the retina

Hyperopia:
- Caused by shortening of the eyeball
- Farsightedness, where nearby objects appear blurry due to the focal point falling behind the retina

Question 6

Compare and contrast scotopic and photopic vision.

Answer 6

Scotopic Vision:
- Low-light vision mediated by rod photoreceptors, providing sensitivity to dim light but limited color vision.

Photopic Vision:
- Bright-light vision mediated by cone photoreceptors, providing high acuity and color vision but less sensitivity in dim light.

Question 7

Describe the process of transducing visible light into neural signals in the photoreceptor.

Answer 7

In the photoreceptor, light activates photopigments, leading to a change in membrane potential and neurotransmitter release, initiating neural signals.

Question 8

What is the path of light as it enters the eye, is transduced into a nerve impulse, and leaves the eye?

Answer 8

Cornea -> Pupil -> Lens -> Retina (Photoreceptors, Horizontal, Bipolar, Amacrine, Ganglion) -> Optic Nerve -> Optic Chiasm -> Optic Tract -> Thalamus -> Visual Cortex

Question 9

Explain the Mach Band Illusion and its mechanism involving the anatomy and circuitry of the retina.

Answer 9

The Mach Band Illusion exaggerates the contrast at edges, enhancing differences between light and dark regions. This illusion arises from lateral inhibition in the retina, where horizontal cells amplify the contrast between adjacent photoreceptor signals.

Question 10

How are spatial acuity and light sensitivity determined by the anatomy and circuitry of the retina?

Answer 10

Spatial acuity is determined by the density of photoreceptors and the convergence of neural signals in the retina, with greater acuity in regions with higher receptor density and less convergence. Light sensitivity is determined by the presence of rod and cone photoreceptors, with rods being more sensitive in low light conditions.

Question 11

Illustrate/list the visual pathway from the photoreceptors to the visual cortex.

Answer 11

Photoreceptors -> Bipolar Cells -> Ganglion Cells -> Optic Nerve -> Optic Chiasm -> Optic Tract -> Lateral Geniculate Nucleus (LGN) -> Optic Radiation -> Visual Cortex (Occipital Lobe)

Question 12

Trace the geniculotriate pathway from the photoreceptors to the primary visual cortex.

Answer 12

Photoreceptors -> Bipolar Cells -> Ganglion Cells -> Optic Nerve -> Optic Chiasm -> Optic Tract -> Lateral Geniculate Nucleus (LGN) -> Optic Radiation -> Visual Cortex (Primary Visual Cortex)

Question 13

Describe the organization of the primary visual cortex and what visual perception functions are represented there.

Answer 13

The primary visual cortex (V1) is organized into columns and layers, with each column representing a specific location in the visual field. V1 processes basic visual features such as orientation, spatial frequency, and color, contributing to visual perception functions such as form and motion detection.

Question 14

Differentiate between Dorsal and Ventral Streams for extrastriatal visual processing.

Answer 14

Dorsal Stream: Processes spatial information and guides actions, involved in the “where” pathway.

Ventral Stream: Processes object identification and recognition, involved in the “what” pathway.
- Lingual Gyrus (Object)
- Fusiform Gyrus (Face)
- Parahippocampal Gyrus (Place)

Question 15

List 5 of the 7 Principles of Perceptual Organization discussed in lecture and describe each.

Answer 15

Proximity: Elements close to each other tend to be perceived as a group.

Similarity: Elements that are similar in appearance are perceived as a group.

Closure: Incomplete figures are perceived as complete.

Continuity: Lines are perceived as following the smoothest path.

Figure-ground: Objects are perceived as either figures (distinct shapes) or ground (background).

Question 16

How does the Reichardt detector work?

Answer 16

The Reichardt detector is a neural model that detects motion by comparing signals from adjacent photoreceptors with a time delay, allowing it to respond selectively to directional motion.

Question 17

Trace the stops along the tectopulvinal pathway and discuss this pathway’s contribution to visual perception.

Answer 17

Superior Colliculus -> Pulvinar Nucleus -> Extrastriate Cortex (Dorsal Stream)

The tectopulvinal pathway contributes to visual attention, eye movements, and spatial orientation.

Question 18

Describe how the trichromatic theory of color reception works to interpret a combination of 440nm and 530nm light.

Answer 18

According to the trichromatic theory, the combination of 440nm (blue) and 530nm (green) light stimulates both S (short-wavelength) and M (medium-wavelength) cones, resulting in the perception of cyan.

Question 19

Distinguish between the additive and subtractive nature of color mixtures with examples for each.

Answer 19

Additive Color Mixing: Combining different wavelengths of light to create new colors, as seen in RGB displays.

Subtractive Color Mixing: Combining pigments or filters that absorb certain wavelengths of light, as seen in CMYK printing.

Question 20

How does the anatomy of the ear help with hearing? Discuss the mechanical feature that amplifies sound.

Answer 20

The anatomy of the ear, specifically the shape of the outer ear (pinna) and ear canal, helps to collect and funnel sound waves towards the eardrum (tympanic membrane). The middle ear contains three small bones (ossicles) – the malleus, incus, and stapes – which transmit vibrations from the eardrum to the oval window of the cochlea, amplifying the sound signal in the process.

Question 21

Follow the path of sound pressure waves from the outer ear to its transduction into neural impulses, and then through the auditory pathway into the cortex.

Answer 21

Outer Ear (Pinna and Ear Canal) -> Tympanic Membrane (Eardrum) -> Ossicles (Malleus, Incus, Stapes) -> Oval Window -> Cochlea -> Hair Cells in Cochlear Duct -> Auditory Nerve -> Brainstem (Cochlear Nuclei) -> Inferior Colliculus -> Medial Geniculate Nucleus (Thalamus) -> Primary Auditory Cortex

Question 22

Describe frequency theory and place theory. List the shortcomings of both theories.

Answer 22

Frequency theory proposes that the pitch of a sound is determined by the frequency of neural impulses sent to the brain, while place theory suggests that different pitches are detected based on the location along the basilar membrane of the cochlea where maximum vibration occurs.

Shortcomings of frequency theory include difficulty in explaining perception of high frequencies, while place theory faces challenges in accounting for perception of low frequencies.

Question 23

Discuss the mechanical feature that amplifies sound.

Answer 23

The mechanical feature that amplifies sound is the leverage provided by the ossicles (malleus, incus, stapes) in the middle ear.

Question 24

When Rinne’s test reports Left ear BC>AC and Weber’s test lateralizes Right, what is the diagnosis?

Answer 24

The diagnosis is Conductive Hearing Loss in the left ear.

Question 25

Describe the Jeffress Neural Coincidence Model and what perceptual quality of hearing it enables.

Answer 25

The Jeffress Neural Coincidence Model proposes that the brain detects the location of a sound source by comparing arrival times of sound waves at the two ears, with neurons in the brainstem firing maximally when inputs from both ears coincide. This enables the perception of sound localization.

Question 26

Compare and contrast between horizontal and vertical sound localization.

Answer 26

Horizontal sound localization relies on differences in arrival times and loudness at the two ears, while vertical sound localization relies on the filtering effects of the head and ears. Horizontal localization is more precise due to interaural time differences, while vertical localization is less precise due to the shape of the pinna.

Question 27

Sketch out the language circuit and provide a description of the labelled parts

Answer 27

A1, Wernicke’s Area, Arcuate Fasciculus, Broca’s Area, M1

Wernicke’s Area is involved in language comprehension, Broca’s Area in language production, and the Arcuate Fasciculus connects the two areas.

Question 28

What happens when there is dysfunction in the language circuit (Wernicke’s, Broca’s, Arcuate Fasciculus)

Answer 28

Dysfunction in these areas can result in specific types of aphasia:

Wernicke’s aphasia (fluent but nonsensical speech)

Broca’s aphasia (non-fluent, effortful speech with intact comprehension)

Conduction aphasia (difficulty repeating phrases and poor speech repetition).

Question 29

Compare and contrast between music and speech perception.

Answer 29

Music perception involves processing pitch, melody, harmony, and rhythm, while speech perception focuses on phonetic elements and linguistic content. Both involve auditory processing in the brain, but music perception may activate additional brain regions involved in emotional processing and memory.

Question 30

Among Sheppard’s Tone, Phonemic Restoration, and McGurk Effects, describe 2 of them (include principles of auditory perception that explains them).

Answer 30

Sheppard’s Tone is an auditory illusion where a tone seems to continually rise in pitch, although it actually repeats in a cycle. This illusion occurs due to the way the brain processes sound frequencies and integrates them over time. The McGurk Effect involves the perception of a different phoneme when conflicting auditory and visual cues are presented simultaneously. This effect highlights the brain’s reliance on multisensory integration in speech perception.

Question 31

Damage to the right side of the spinal cord at T1 (simplified to the level of the shoulder) would result in what pattern of sensory loss?

Answer 31

Damage to the right side of the spinal cord at T1 would result in contralateral (opposite side) loss of pain and temperature sensation and ipsilateral (same side) loss of touch and proprioception sensation below the level of injury.

Question 32

Describe the structure and function of free nerve endings found in the somatosensory system (Where they are found, how do they work, what sensations their stimulation can elicit, how fast do they propagate signals)

Answer 32

Free nerve endings are found throughout the skin and internal organs. They detect various stimuli such as pain, temperature, and pressure. Upon stimulation, they generate action potentials that propagate along sensory nerves to the central nervous system. Free nerve endings are involved in the transmission of both fast and slow pain signals.

Question 33

A brief description of the structure and function of the four main types of somatosensory receptors.

Answer 33

Meissner’s corpuscles:
- Location: Found in hairless skin, especially in fingertips and lips.
- Function: Detect light touch, low-frequency vibration, and texture.
- Adaptation: Rapidly adapting.

Merkel cells (discs):
- Location: Found in basal epidermal layer of skin, fingertips, lips, and genitalia.
- Function: Detect sustained pressure and texture.
- Adaptation: Slowly adapting.

Pacinian corpuscles:
- Location: Found in deeper dermis and hypodermis, as well as joints and organs.
- Function: Detect deep pressure, high-frequency vibration, and rapid pressure changes.
- Adaptation: Rapidly adapting.

Ruffini endings:
- Location: Found in dermis of hairless skin, ligaments, and joint capsules.
- Function: Detect skin stretch and sustained pressure.
- Adaptation: Slowly adapting.

Question 34

Give brief descriptions of 2 disorders/dysfunctions associated with damage to the parietal association cortex.

Answer 34

Damage to the parietal association cortex can result in spatial neglect syndrome, where individuals fail to attend to stimuli presented in one side of space despite intact sensory abilities. Another disorder is apraxia, which involves difficulty performing skilled or purposeful movements despite intact motor function, often due to an inability to plan and coordinate movements.

Question 35

Compare and contrast between Cross-fibre coding and Specificity coding with examples in sensation modalities.

Answer 35

Cross-fibre coding involves different neurons responding to different qualities of a stimulus within the same sensory modality. For example, in the visual system, different neurons may respond to different orientations of lines. Specificity coding involves specific neurons responding to specific features of a stimulus. An example is the olfactory system, where different odorant molecules activate specific olfactory receptors.