Midterm 2 Flashcards
What is sound?
The air vibrates, and that information has to be transformed into a neural code to represent sound and speech
What is a pure tone?
A pure tone consists of only a single frequency. Its wave form is a pure sine wave
What is a complex tone?
A complex tone is a sound wave that repeats with a given pattern, BUT the pattern is not a sine wave
What is timbre?
Quality of auditory sensations produced by the tone of a sound wave. Two non-identical sounds can have the same loudness and pitch
What does timbre depend on?
Timbre depends on the frequency spectrum, the sound pressure and the temporal characteristics of the sound
What is a Shepard Tone?
An audio illusion that creates the feeling of consistent, never-ending rising/falling. The illusion is achieved by playing overlapping notes that are one octave apart
What is the human cochlea?
The cochlea is a hollow, spiral-shaped bone found in the inner ear that plays a key role in the sense of hearing and participates in the process of auditory transduction. Sound waves are transduced into electrical impulses that the brain can interpret as individual frequencies of sound
What is Tonotopy?
Tonotopic organization refers to the systematic topographical arrangement of neurons as a function of their response to tones of different frequencies
Where in Tonotopy found?
Along the basilar membrane in the ear and in the primary auditory cortex
Describe the neurons in the Secondary Auditory Cortex?
Neurons in the secondary auditory cortex represents a greater range of frequencies, loudness, location, and combinations of features
What is there a specialization for in the auditory region?
Speech, Music, and Voice Recognition
Describe the ventral stream?
WHAT you’re hearing. There’s some evidence that suggests there are selective processing regions (neurons) for some categories of sound
Describe the dorsal stream?
For where/how: Localization. There’s inter-aural time difference (loudness and timing): when your head is tilted, sound arrives at one ear before the other. Distortion: Sound will be more distorted if it occurs on the other side of your head
What is Overt Attention Eye Movements?
Head and eye movements can be employed to gaze directly at an item. This is often referred to as an overt shift of attention. It’s the most direct way to shift attention, but poor resolution in the periphery means that you are aware primarily of things near the center of gaze (fovea)
What is Covert Attention?
Attention directed to a location that is different from that on which the eyes are fixated
What is Endogenous attention?
Goal-driven attention is referred to as top-down or endogenous attention
What is Exogenous attention?
Stimulus-driven attention is referred to as bottom-up or exogenous attention, being driven by external events in the environment
Describe Exogenous (bottom-up) attention:
Feature/stimulus driven, “reflexive” or automatic, fast, and temporary
Describe Endogenous (Top-down)
Goal or experience driven, voluntary, slower, and can be persistent
Describe feature-based attention selection (hint: two):
“Preattentive” so single-feature, parallel, and versus. “Attentive” feautre integration and serial
Attention spreads….
Within objects more than between objects
What is the Cocktail Party problem?
The brain’s ability to focus one’s auditory attention on a particular stimulus while filtering out a range of other stimuli, such as when a party goer can focus on a single conversation in a noisy room
What is the correlation between all sensory systems and attention?
All sensory systems can be influenced by attention, and attention influences perception. For example, distraction and pain
Why is a hypothesis a liability?
A hypothesis drives attention towards specific patterns of data, and leads to missing other patterns
What are two deficits of attention?
Neglect and Balint’s Syndrome
What is spatial neglect?
They are generally defined as an inability to perceive, report and orient to sensory events towards one side of space, contralateral to the side of the lesion, with or without a primary sensory deficit
What is object-based neglect?
The impairment is called object-based visual neglect because the neglect is with respect to each object, and not to the visual field. Loss of attention or awareness to left side of OBJECT
What is brain region is relevant to space-centered neglect?
More dorsal regions: Inferior Parietal Lobe (IPL) and Temporal Parietal Lobe (TPL)
What brain region is relevant to object-centered neglect?
More ventral regions: Superior Temporal Gyrus
What is Balint’s Syndrome?
An inability to visualize more than one object in the visual field at a time (psychic paralysis of gaze or visual inattention). An inability to identify different items in a visual scene simultaneously (a spatial disorder of attention or simultagnosia). A failure to reach an object with his right hand but able to do so with the left hand (Misreaching or optic ataxia)
What are the two deficits of attention discussed in class?
Traumatic Brain Injury: Deficit of sustained attention and Multimedia use
What is frequency?
How many times a wave cycles every second (period). Shorter period = Higher Pitch, Longer period = Lower Pitch
What is amplitude?
How high the waves become. Smaller amplitude = Quieter, Larger amplitude = Louder
Give an overview of Auditory Pathway
1) There is energy in the world, in the form of air compression. 2) Sound waves enters the ear, get focused by the shape of the ear. 3) Receptors in cochlea transform into neural activity. 4) Signals transmitted down auditory pathway in brain
What are the four parts of the ear (ear structure)
Pinna, Ear Canal, Tympanic Membrane, 3 bones (stapes, maleus, incus)
What is the Pinna?
Focus sound into the ear canal
What is the Ear Canal?
Carry the sound further into the ear to tympanic membrane
What does the Tympanic Membrane do?
Vibrate in response to sound waves
What do the 3 bones (stapes, maleus, incus) do?
Carry information to cochlea
Describe the cochlea’s organization
Organized in a tonotopy meaning the cells at one end respond to the highest frequencies and cells at the other end respond to the lowest frequencies of sound waves, with a gradient in between
How does the cochlea transform sound waves into neural activity?
Cochlea is covered in hair cells. The movement of the fluid in the cochlea moves the hair cells. Movement of hair cells physically pulls open ion channels to start transduction of signal
What are cochlear implants and what does it do?
Partially restoring hearing in those with deafness caused by cochlea damage. Directly stimulate the auditory nerves to get information to the brain. The brain will partially rewire to interpret signals.
What is McGurk effect?
The McGurk effect is an illusion whereby speech sounds are often mis-categorized when the auditory cues in the stimulus conflict with the visual cues from the speaker’s face.
What does the McGurk effect show?
Integration of information across sensory modalities
Is the auditory system more sensitive to temporal or spatial information?
Temporal (changes relative to time). The auditory system is tuned to detect temporal information, such as rapid changes in frequency that characterize certain speech sounds, and in grouping information together over time, such as in extracting melody from music
What is the belt region?
Part of the secondary auditory cortex, with many projections from the primary auditory cortex
What is the Parabelt region?
Part of the secondary auditory cortex, receiving projections from the adjacent belt region
What is the anterior belt region sensitive to?
Specialization for “what” - pathway to ventral stream
What is the posterior belt region sensitive to?
Spatial selectivity “where” - pathway to dorsal stream
What is inattentional blindness?
A failure to be aware of a visual stimulus because attention is directed away from it
Change Blindness
A failure to notice the appearance/disappearance of objects between two alternating images
What is attention?
Attention is a mechanism that allows us to voluntarily suppress unnecessary information and focus on necessary information
What are the 3 modes of selection?
Location-based, Feature-based, and Object-based
Describe location-based selection
Attending to the location of an object