4.20 place theory of hearing, 4.21 frequency theory, 4.22 the auditory pathway, 4.23 sound localization, 4.24 multimodal integration, 4.25 skin and touch, 4.26 touch and sensitivity ND PERCEPTION

inner ear : basilar membrane

inner ear : basilar membrane

gets stimulated also corresponds with frequency

• base of the membrane 3-4x narrower than apex and therefore about 100x stiffer

narrow thick base

turned for high frequency

wide thin apex

tuned for low frequency

volley principle

summed activity of groups of cells can provide more accurate representation of frequency

cochlear nucleus

crossover of auditory signals to contralateral hemisphere

medial geniculate nucleus

structure within thalamus responsible for routing of auditory information

primary auditory cortex

organized similar to the cochlea (tonotopic map)

sound localization:

process of identifying where sounds come from achieved by: interaural time differences sound shadow

folds of the pinna

affect the intensities of frequencies differently depending on their elevation

multimodal integration

combining sensations from different modalities into single integrated perception

• dependent on spatial and temporal association mcgurk effect

mcgurk effect

auditory - visual illusion that illustrates how perceivers merge info for speech sounds across the sense

Somatosensory system

neural structures in the brain and body that produce the perception of touch also temp, body position and pain

mechanoreceptors

detects pressure and touch

nociceptors

detects heat and pain

seismic waves

caused by sudden movements of materials within the earth

touch sensitivity: acuity

ability to discern points of pressure

• two-point threshold test

• sensitivity corresponds with areas of greater neural representation in somatosensory cortex

haptics

exploratory sense of touch

active touch

the control of the position and movement of tactile sensing systems to facilitate information gain

passive touch

a form of touch characterized by sensory experiences that occur when the observer does that move

tactile agnosia

inability to recognize objects through active touch of the hands without sensory input

sensory integration

visual information influences perception of touch (rubber hand illusion)