From Sensory Plasticity to Behaviour Flashcards
1
Q
LYTHGOE (1979)
A
- larger eyes (compared to body ratio) = higher spatial resolution
- ie. lowest -> highest = human -> peregrine falcon -> honeybee -> drosophilia
- visual exceptions = myotis (bat) -> jumping spider (aka. much better vision than bat)
2
Q
DEVELOPMENT OF VISUAL SYSTEM IN MAMMALS POST BIRTH
A
DIFS IN VISUAL ABILITIES OF ADULTS/INFANTS
- 1st year = acuity develops v fast BUT continues also during later development (up to 20+ y) as eye (+lense) continues growing in size
- 1st month = eye-hand coordination already starts developing
- week 8 = babies focus view more easily
- 3 months = reaching for objects
- 8 months = crawling; develops eye-foot-hand coordination
- 10 months = increased visual generalisation for small features in non-relevant objects/improved human face discrimination (relevant objects)
3
Q
GIBSON & WALK (1960)
A
- “visual cliff” experiment
- same sized pattern viewed from dif distances generates disparities that visual system (at V1 lvl) interprets as same texture/object at dif distance
- young babies won’t crawl over glass as depth perception = already developed by 5 months; other infant mammals also don’t walk over; BUT dark-reared kittens fail
4
Q
ISSA ET AL. (1999)
A
- critical-period plasticity in visual cortex
- visual deprivation causes structural changes in brain
- experiments in kittens/monkeys revealed development/utilisation of V1 structures (orientation/ocular dominance columns) depend heavily on sensory experience
- brain functions compete for space; reorganisation takes place
- 1st evidence at neural lvl for critical sensory periods in early age post which development CANNOT be recovered (or only partially)
5
Q
COUREAUD ET AL. (2002)
A
- transnatal olfactory continuity in rabbit; beh evidence/STM consequence of disruption
- pre-natal brain development/learning/transnatal sensory memories
- mammalian newborns fully depended on milk; rabbit mothers lactate pups until day 28 post birth then pups find food independently; detecting/competing w/siblings for access to milk
6
Q
OLFACTORY SYSTEM OF HONNEYBEE
A
antenna (60k receptors) -> lateral proto-cerebrum -> mushroom body
7
Q
KROFCZIK ET AL. (2008)
A
- synaptic density/neuropile volumes change in insect brains during adult beh development BUT also depend on sensory experience
- honeybee queens experiencing higher temp during pupal development show larger neuropile volumes w/age post adult emergence (increase in microglomeruli number); workers reared in field colonies/greenhouse show difs in calycal bouton volumes/densities at dif ages/in dif rearing environments
8
Q
IMMUNOHISTOCHEMISTRY
A
- synapsins = phosphoproteins located in boutons of presynaptic neurons in mushroom body calyx
- synapsin genes = expressed in many animal brain neurons
- labelling synapsins w/antibody/Kenyon cells w/fluorescent dye (phalloidine) = gives 2-coloured images identifying MGs
9
Q
MINI SUMMARY
A
VISION & HEARING
- parallel pathways
- sensory maps
- similarities between senses
SENSORY LEARNING & MEMORY FORMATION
- synaptic plasticity in identified neurons/circuits
SPATIAL LEARNING
- egocentric/allocentric frameworks to locate sensory cues & guide actions in space
10
Q
KNUDSEN (2002)
A
- auditory cue values/locations in space
- sound waveform in right ear = delayed/attenuated relative to left ear
- correspondence of interaural timing dif (ITD) & interaural lvl dif (ILD) values w/locations in space for 6kHz sound; spatial pattern changes for other frequencies
11
Q
LOCATION OF SOUND SOURCES
A
- mapped into 2 dimensions onto MLD
- spatial reconstruction of auditory spaces in front of owl
- L/R = azimuth of agrees; +/- = elevation degrees; from ITD/ILD coding pathways converging in MLD
- in addition in inner part of auditory region neurons = organised in tonotopical layers (mapping interneurons according to frequency tuning); outer part = interneurons tuned to 6/8kHz (highest sensitivity range)
12
Q
DE BELLO, FELDMAN & KNUDSEN (2001)
A
- vision supplements hearing in owls for prey detection
- auditory map in external nucleus of midbrain = aligned w/retinoptic visual input & controls head movements (via hindbrain)
- during development experimental manipulations targeted auditory input (ear plug)/visual input (prism)
- sound-guided gaze movements displaced when removed (BUT not visual gaze)
- effect strong in owls <3 weeks (critical period); during critical period owls can learn better/correct larger misalignments than later
- ITD tuning of neurons = indicated by numbers in ICC/OT
13
Q
CATANIA & KAAS (1996)
A
- sensory maps exist in both vertebrate/invertebrate brains
- 3 somatosensory maps in cortex of star-nosed mole w/subdivided areas of dif tips of star-shaped nose (touch organ)
- nose w/22 fleshy rays/large numbers of Eimer’s organs; ray nr11 on each nose side = short/more sensitive/has largest projection area in somatosensory map
14
Q
MERZENICH ET AL. (1984)
A
- somatosensory cortical map change following digit amputation in adult monkeys; sensory mapping can change w/perceptual experience/learning
- cortical representations can change w/use; owl monkey trained for several months at task using fingers 2-4
- reorganisation of somatosensory cortex maps following:
1. digit amputations in racoon/monkey
2. peripheral nerve stimulation in cats
3. passive touching of fingertips in humans (fMRI/primary & second somatosensory cortex)
15
Q
ELBERT ET AL. (1995)
A
- magnetic source imaging revealed that cortical representation of digits of left hand of string players = larger > controls
- effect = smallest for left thumb; no such difs observed for representations of right hand; cortical reorganisation in represntation of fingering digits = correlated w/age at which person had begun to play
- results suggest representations of dif parts of body in primary somatosensory cortex of humans depends on use/changes to conform current needs/experiences of individual
16
Q
MERABET & PASCUAL-LEONE (2010)
A
- recruiting new brain areas when 1 of sensory systems does not develop
- crossmodal recruitment of occipital visual cortex in blind/auditory cortex in deaf reported:
1. occipital recruitment for tactile processing ie. Braille reading/sound localisation/verbal memory
2. recruitment of auditory/language-related areas for viewing sign language/peripheral visual processing/vibro-tactile stimulation
17
Q
NEVILLE ET AL. (1998)
A
- human speech
- some animals can learn to produce human vocalisations (parrot/dogs/starlings) even to correctly name features/objects in simple discrimination tasks
- gorillas/chimpanzees trained in ASL; learned to represent several hundreds of objects/actions w/dif symbols; use in tasks
- language = related to large variations w/underlying patterns/increases w/learning which isn’t observed in apes BUT in young kids (using speech/ASL)
- in deaf people signing involved same areas as language production/additional areas
18
Q
THALER, ARNOTT & GOODALE (2011)
A
- neural correlated of natural human echolocation in early/late blind echolocation experts
- humans can learn to echolocate w/clicks
- sound of (own) clicks/echoes activate calcarine/temporal cortex in both early/late blind echolocation experts
- findings suggest areas devoted to vision = recruited for echo analysis
- C1/C2 trained w/experts’ sounds; showed high performance in some tasks
- all subjects showed activation in auditory areas
19
Q
MILNE ET AL. (2014)
A
- accuracy of echolocation in blind humans
- blind/sighted individuals can learn to echolocate
- human echolocators (n = 8; blind) adjusted click loudness/number clicks for detection of reflectors at various azimuth angles
- task = click; report absence/presence of objects (chance lvl = 50%)
- increasing click intensity/number improves signal-to-noise ratio (important for weak echoes); performance impairs if head isn’t moved
20
Q
URBANSKI ET AL. (2014)
A
- visual pathways
- main connections originating in retina synapse in lateral geniculate nucleus (LGN); project to primary visual cortex (V1)
- V1 sent extrastriate areas (V2/V3/V4)
- most of corticocortical/subcortico-cortical connections = reciprocal BUT nor represended for schema clarity
- pathways that bypass V1 = accounted to mediate blightsight/residual capabilities for visual discrimination in blind people/monkeys
21
Q
AJINA ET AL. (2015)
A
- human blindsight = mediated by intact geniculo-extrastriate pathway
- blindsight-type phenomena reveal residual functions when sensory system = damaged; V1 damage causes cortical blindness aka. loss of conscious vision
- patients able to perform visually-guided behs (ie. grasping/pointing to object location/avoiding obstacles) correctly at lvl above chance (aka. blindsight)
22
Q
BLINDSIGHT: OCULAR/OPTIC NERVE DAMAGE
A
PATHWAYS SPARED
- retino-hypothalamic pathway
REMAINING RESPONSE
- endocrine
FUNCTION
- sleep-wake cycle
23
Q
BLINDSIGHT: PRE-GENICULATE DAMAGE
A
PATHWAYS SPARED
- extra-geniculate pathways
REMAINING RESPONSE
- reflexive
FUNCTION
- pupil
24
Q
BLINDSIGHT: POST-GENICULATE DAMAGE
A
PATHWAYS SPARED
- extra-geniculate striate pathways
- extrastriate cortical areas
REMAINING RESPONSE
- implicit
- forced-choice guessing
FUNCTION
- reaction to seen stimulus
- detection of unseen stimulus
25
TAMIETTO & DE GELDER (2011)
- subconscious vision/emotions
- SC mediated pathways = interconnected w/amygdala
- rapid rapid processing of emotional info (in particular for salient stimuli) ie. faces/snakes
- short-cut to drive motor actions (ie. fast orienting eye movements)
