Hoofdstuk 8 Flashcards
One difference between auditory and visual senses
their sensitivity to temporal and spatial information
(auditory - temporal)
(visual - spatial)
Pure tones
sounds with a sinusoid waveform (when pressure change is plotted against time)
pitch
the perceived property of sounds that enables them to be ordered from low to high
Hertz = vibrations per second
subjective experience of loudness is measured in decibels
Eventhough amplitude and frequency are independent physical properties of soundswaves
the subjective properties most closely associated with them (pitch and loudness) are not processed by the brain in a completely different way
Fundamental Frequency (Fo)
the lowest frequency component of a complex sound that determines the perceived pitch
- missing fundamental phenomenon: if the fundamental frequency is removed, pitch is not perceived to change, because the brain reinstates it
Timbre
- like pitch, is a psychological characteristic of a sound
- perceptual quality that enables us to distinguish between different musical instruments
EAR
Outer (pinna - earlobe + auditory canal)
Middle
Inner
Middle Ear
Converts airborne vibrations to liquid-borne vibrations with minimal loss of energy
3 bones: malleus (hammer), incus (anvil) Stapes (stirrup) - transfer mechanical pressure on eardrum, to smaller membrane (Oval Window) in the fluid filled Cochlea
Inner Ear
contains chambers that are important for senses of hearing (cochlea) and balance (including the semi circular canals)
Cochlea: liquid-borne sounds to neural impulses
- membrane within cochlea (basilar membrane) contains tiny hairs linked to receptors
4/5 synapses in the auditory pathway
from the ear to the brian, starting with projections from the auditory nerve to the cochlear nuclei in the brainstem, and ending with projections from the Medial Geniculate Nucleus to the primary auditory cortex (temporal lobe) = main area to receive auditory-based thalamic input
Secondary auditory cortical areas
Belt = projections from primary auditory cortex
Parabelt = projections from belt region
Tonotopic Organization
the principle that sounds close to eachother in frequency are represented by neurons that are spatially close to eachother in the brain
Neurons of the auditory cortex do not just resoond to frequency-related info
they also respond to particular loudness levels and particular spatial locations (contralaterally, dus rechteroor/linker auditory cortex)
2 options for identifying where a sound is located
1) interaural difference - the difference in timing between a sound arriving in each ear (localizing sound)
2) Distortions of the Soundwave by the head and pinnae = Head-Related Transfer Function HRTF
Head Related Transfer Function HRTF
the brain develops an internal model of how sounds get distroted by the unique shape of one’s own ears and head and is able to use this to infer likely location
- Planum Temporale = posterior to the primary auditory cortex, isinvolved in integrating the senory input iwht the learned HRTF for different parts of space
Inter-Aural
left/right
Distortions of Auditory input by pinnae
left/right
top/bottom
Auditory stream Segregation
division of a complex auditory signal into different sources or auditory objects (cocktail party)
- parietal lobes help with cocktailparty problem
Mismatch Negativity MMN
an ERP component that occurs when an auditory stimulus deviates from previously presented auditory stimuli
- lowelevel phenomenon
- occurs in absence of attention
Notes (music) played together can sound
right (consonance) or clash (dissonance)
Amusia
auditory agnosia in which music perception is affected more than the perception of other sounds
Tone-Deafness (congenital Amusia)
a developmental dificulty in perceiving pitch relationships
Prosody
changes in the stress pattern of speech (e.g. to add emphasis), the rhythym of speech or the intonation (e.g. rising/falling pitch to indicate questioning or sarcasm)
Melody
patterns of pitch over time
