Audition

Question 1

Identify the aspects of timbre that must be distinguished by auditory processing:

Answer 1

The perceived pitch of an auditory stimulus is determined by the frequency of vibration, which is measured in hertz (Hz). Loudness is a function of intensity- the degree to which the compressions and expansions of air differ from each other. Timbre provides information about the nature of the particular sound.

Question 2

Compare the roles of arrival time, phase difference, intensity difference, and timbre in perception of spatial location:

Answer 2

To different arrival times of the sound waves at the left and right ears to determine the horizontal location of the intermittent sound. Phase differences include the simultaneous arrival, at each ear, of different portions (phases) of the sound wave to detect the horizontal location of. Continuous sound. Coincidence-detecting cells compare binaural input and help determine location. Some neurons in the auditory system respond differentially to binaural stimuli of different intensity in each ear, which means that they provide information that can be use to detect the source of tones of high frequency. Difference in timbre is used to determine the vertical location of a sound.

Question 3

Describe the roles of the two processing streams of the auditory cortex in the perception of complex sounds:

Answer 3

The anterior stream involved in perception of complex sounds (“what”) and the posterior stream is involved in perception of location (“where”). Damage to these streams can lead to impairment of various aspects of auditory perception, even though the individuals are not deaf. Inhibiting structures in these pathways result in specific deficits in perceiving “what” and “where” for auditory stimuli.

Question 4

Differentiate between sensation and perception:

Answer 4

• Sensation= the receiving of stimuli from the outside environment
• Perception= the organising and interpreting if sensory information.

Question 5

Describe visible light, hue, saturation, and brightness in the perception of light:

Answer 5

• Visible light: the spectrum of light we can actually detect and interpret with our photoreceptors.
• Hue: dominant wavelength (colour)
• Brightness: intensity (dark/light)
• Saturation: purity (how many other wavelengths are being taken in by the eye?)

Question 6

Identify the structures of the eye and describe their function in visual processing:

Answer 6

Fovea: A depression in the retina of the eye where the centre of the field of vision is focused; cones are concentrated here
Retina: A layer at the back of the eyeball that contains the sensory receptors required for sight
Iris: The coloured part of the eye; regulates light entrance
Cornea: The outermost layer of the eye (clear) that protects the eye and refracts light
Pupil: Hole in the eye that opens to allow light into the eye
Lens: A transparent, curved structure that helps refract and focus light
Optic Nerve: Transmits impulses to the brain from the retina

Question 7

Contrast the location and function of the rods and cones:

Answer 7

RODS: Located in the retina, monochromatic vision, sensitive to low intensity light, poor acuity, higher in amount in eye
CONES: Located in the fovea, colour vision, requires lot of light to respond, good acuity, less amount in the eye

Question 8

Describe the process of transduction of visual stimuli:

Answer 8

• Light particles (photons) are taken in through the lens of the eye, hits the back of the eye, captures by the photoreceptors located in the back of the eye, rods and cones then send out signals that activate the bipolar cells which send the message on to the ganglion cells, the message is then carried through the optic nerve to the brain where perception of the stimulus will occur.
• BIPOLAR CELLS: Located in the middle layer of the retina and conveys info from photoreceptors to the ganglion cells
• GANGLION CELLS: Located in the retina that receives info from the ganglion cells and its axons send message to the optic nerve
• PHOTOPIGMENTS: Molecules that have the ability to absorb light and initiate transduction; four of them differentiate in spectral sensitivity

Question 9

Compare the characteristics of central and peripheral vision, including receptive fields and eye movements:

Answer 9

• CENTRAL VISION: Vision within the fovea
• PERIPHERAL VISION: Vision outside of the fovea
• VERGENCE MOVEMENT: Simultaneous movement of both eyes in opposite directions to obtain/maintain single binocular vision
• SACCADIC MOVEMENT: Quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction
• PURSUIT MOVEMENT: Smooth, gliding movement of the eye across the phases of fixation

Question 10

identify the structures of the vestibular system:

Answer 10

The five major vestibular structures are located in the inner ear and include: the utricle, the saccule, and the lateral, superior, and posterior semicircular canals.