PSYCH261 Chapter Notes -Temporal Lobe, Visual Agnosia, Visual Cortex

14 views6 pages
PSYCH&261&–&Physiological&Psychology&
!
Module&6.3:&Parallel&Processing&in&the&Visual&Cortex!
!
Parts!of!the!brain’s!visual!system!receive!information!on!a!need6to6know!basis!
One!part!of!the!brain!detects!colour,!another!senses!location,!another!perceives!movement!
At!least!80!brain!areas!contribute!to!vision!in!different!ways!
o As!a!result,!it!is!possible!to!retain!certain!aspects!of!vision!after!localized!brain!
damage!
!
The!“What”!and!“Where”!Paths!
Primary!visual!cortex!(V1)!sends!information!to!secondary&visual&cortex!(V2)!for!
processing!and!transmission!
o Reciprocal&connections:!V1!sends!information!to!V2,!and!V2!returns!information!
to!V1!
Ventral&stream:!“what”!pathway,!through!temporal!cortex!
o Specialized!for!identifying!and!recognizing!objects!
o If!damaged,!can!recognize!objects!through!other!features!(ex.!touch,!odour,!etc.)!but!
can!still!see!where!the!objects!are!
Dorsal&stream:!“where”!pathway,!through!parietal!cortex!
o Helps!motor!system!locate!objects!
o If!damaged,!know!what!things!are,!just!don’t!know!where!they!are!
Inferior&temporal&cortex:!cells!respond!to!unidentifiable!objects!
o Cells!that!respond!to!particular!stimuli!respond!equally!to!negative!or!mirror!
images,!but!not!to!a!physically!similar!stimulus!
o Cells!respond!according!to!what!the!viewer!perceives,!not!what!the!stimulus!
physically!is!
o Respond!the!same!way!regardless!of!changes!in!size,!position,!angle!
Visual&agnosia:!inability!to!recognize!objects!
o Usually!results!from!damage!in!temporal!cortex!
Brain!does!not!have!specialized!areas!that!respond!to!specific!types!of!objects!
o Parahippocampal!cortex!responds!strongly!to!pictures!of!places!
o Fusiform!gyrus!in!right!hemisphere!responds!strongly!to!faces!
Ability!to!recognize!faces!is!more!precise!for!faces!similar!to!familiar!faces!
o Brain!learns!“average”!of!faces!it!sees!and!detects!small!deviations!from!that!
o Infant’s!concept!of!“face”!requires!eyes!to!be!on!top,!but!face!does!not!have!to!be!
realistic!
o Depends!on!variety!of!brain!areas,!including!occipital!cortex,!anterior!temporal!
cortex,!prefrontal!cortex,!fusiform!gyrus!
o Prosopagnosia:!inability!to!recognize!faces!
!
Colour!Perception!
Area!V4!is!important!in!responding!to!changes!in!colour!
o Correspond!to!apparent!or!perceived!colour,!which!depends!on!tonal!context!
o Damage!leads!to!loss!of!colour!constancy!
!
Motion!Perception!
Middle&temporal&cortex!(MT!/!V5)!and!medial&superior&temporal&cortex!(MST)!are!
activated!by!motion!
o Receive!input!from!magnocellular!path,!which!detects!overall!patterns!
o Colour!insensitive!
Cells!in!MT!detect!acceleration,!deceleration,!overall!speed,!and!respond!to!motion!in!three!
dimensions!
o Also!responds!to!photographs!that!imply!movement!
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in
Cells!in!dorsal!portion!of!MST!respond!to!expansion,!contraction,!rotation!of!visual!scene!
o Record!movement!of!single!objects!and!record!movement!of!background!
o Messages!sent!to!ventral!part!of!MST!where!cells!respond!to!objects!that!move!
relative!to!background!
Enables!distinction!between!result!of!eye!movements!and!result!of!object!movements!
Motion&blindness:!ability!to!see!objects!but!not!whether!they!are!moving!or!how!fast/which!
direction!
o Better!at!reaching!for!moving!object!than!describing!its!motion!
o Visual!areas!of!brain!decrease!activity!during!voluntary!eye!movements!(saccades)!
o Opposite!may!also!occur:!someone!can!detect!direction!something!is!moving!but!be!
blind!aside!from!that!as!they!receive!direct!input!from!lateral!geniculus!nucleus!of!
thalamus!
!
Module&7.1:&Audition&
!
Physics!and!Psychology!of!Sound!
Amplitude:!intensity!of!sound!wave!
Loudness:!related!to!amplitude!but!not!identical!to!it!
o Rapidly!talking!person!sounds!louder!than!slow!music!of!same!amplitude!
Frequency:!number!of!compressions!per!second!(Hz)!
o Higher!frequency!sounds!are!higher!in!pitch!
o Ability!to!perceive!high!frequencies!decreases!with!age!and!exposure!to!loud!noises!
!
Structures!of!the!Ear!
Pinna:!structure!of!flesh!and!cartilage!attached!to!head!
o Localizes!source!of!sound!by!altering!reflection!of!sound!waves!
o Each!person’s!pinna!is!shaped!differently!
Tympanic&membrane!/!eardrum:!vibrates!at!same!frequency!as!sound!waves!that!hit!it!
o Converts!sound!waves!into!pressure!on!oval!window!
o Incus,&malleus,&stapes!(hammer,!anvil,!stirrup):!tiny!bones!that!transmit!
vibrations!to!oval!window!
o Oval&window:!membrane!of!inner!ear!
Cochlea:!located!within!inner!ear!
o Contains!three!long!fluid6filled!tunnels:!scala!vestibule,!scala!media,!scala!tympani!
o Vibrations!in!cochlea!displace!hair&cells,!allowing!them!to!excite!cells!of!auditory!
nerve!(8th!cranial!nerve)!
!
Pitch!Perception!
Place&theory:!each!frequency!activates!hair!cells!at!only!one!place!along!basilar!membrane!
o Nervous!system!distinguishes!frequencies!based!on!which!neurons!respond!
o Basilar!membrane!is!too!tightly!bound!to!resonate!like!piano!string!
Frequency&theory:!basilar!membrane!vibrates!in!synchrony!with!a!sound,!causing!auditory!
nerve!axons!to!produce!action!potentials!at!same!frequency!
o Due!to!refractory!period,!maximum!firing!rate!of!neuron!is!1000!Hz!which!is!lower!
than!the!highest!frequencies!we!hear!
Current!theory!combines!and!modifies!both!theories!
o Low!frequency!sounds:!basilar!membrane!vibrates!in!synchrony!with!sound!waves,!
and!auditory!nerve!axons!generate!one!action!potential!per!wave!
! Stronger!sounds!activate!more!neurons!
! Frequency!of!impulses!identifies!pitch!
! Number!of!firing!cells!identifies!loudness!
o Higher!frequencies:!action!potentials!are!phase6locked!to!peaks!of!sound!waves!
Volley&principle:!auditory!nerve!produces!volleys!of!impulses!for!sounds!up!to!~4000!per!
second,!even!though!no!individual!axon!approaches!that!frequency!
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Psych 261 physiological psychology. Module 6. 3: parallel processing in the visual cortex. If damaged, know what things are, just don"t know where they are. Stronger sounds activate more neurons. Frequency of impulses identifies pitch. Auditory cortex: auditory information reaches primary auditory cortex (a1) in superior temporal cortex. Directly in front of you: reaches both ears at same time. Every sound wave has phases with consecutive peaks 360 degrees apart. If sound is coming from side of head, reaches two ears out of phase. How much out of phase a sound wave is depends on frequency of sound, size of head, direction of sound. Module 7. 2: the mechanical senses: respond to pressure, bending, distortions of a receptor. Include touch, pain, body sensations, vestibular sensations (position/movement of head), audition. Input from touch receptors in head enters cns from cranial nerves: below head, enters from spinal cord and spinal nerves. Inescapable pain stimulates endorphins and inhibits further pain.

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers