Biological - (CLASSIC) - brain plasticity - BLAKEMORE & COOPER Flashcards
the thalamus of a cat is part of the brain made up of a number of structures such as the…
hypothalamus, epithalamus
define neuroplasticity in cats
the brain changes with experience and studies have shown that changes in the visual stimuli that cats receive is correlated with changes with changes in RNA structures
what is flexibility of cerebral encoding from visual information
the brain will process the different information it sees in different ways leading to experience specific brain adaptations. From this we can conclude that if two cats see very different things their brains will develop in different ways
explain what happens when a normal kitten sees something upright, laid down or on a slant
the brain creates a neural pathway to represent that angle of orientation so that it will recognize and respond appropriately to that stimulus if it sees it again
explain what would happen if a cat has only seen vertical lines
it will lack a system of neurons for horizontal lines in their brain and will be unable to see them
explain the difference between monocular vision and binocular vision
monocular vision is vison in which each eye is used separately whereas binocular vision is vision in which both eyes are used together
which cortex do the neurons from the eyes connect to
visual
what happens to the neurons if one of the kittens eyes is covered
cortical cells loose input from that eye between 3 weeks to 6 months
what has research shown about the cells/neurons in the visual cortex
each cell prefers a certain orientation - some cells prefer to detect horizontal/vertical
what behaviors does the kitten display if it has been reared only seeing horizontal lines
no visual placing reaction
np startle reaction
does not follow moving objects unless makes a noise
what can be concluded from the research
visual aspects are acquired rather than innate
why could a kitten reared in a horizontal orientation not see a table top
early visual experiences - only been exposed to horizontal lines - developed neurons that prefer horizontal orientations so can only detect horizontal orientations
aim of the study
investigate kittens’ visual development of a restricted visual environment consisting of either vertical stripes only or horizontal stripes only
research method
lab experiment which used independent measures design
DVS
-their visuomotor behavior once they were placed in an illuminated environment - whether the horizontal raised kittens could detect vertically aligned objects
-neuronal activity in the brain to investigate plasticity
sample
kittens randomly allocated to one of two conditions (horizontal or vertical)
two of the kittens (one reared in a horizontal and one reared ina vertical environment) were used to study petrophysical effects - anesthetized and used their brain
describe the procedure
the kittens were housed from birth in a completely dark room
from age of 2 weeks put into apparatus for average of 5 hours per day
it could not see its body as it wore a wide black collar that restricted its visual field to a width of about 130 degrees
routine was stopped when the kittens were 5 months old which was considered well beyond the critical period in which total visual deprivation causes psychological defects
kittens were taken for several hours each week from their dark cages to a small well lit room furnished with tables and chairs
their visual reactions were observed and recorded
at 7.5 months two of the kittens were anaesthetized so their neurophysiology could be examined
describe the apparatus the kittens were put in
kittens stood on a clear glass platform inside a tall cylinder which the entire inner surface was covered with high contrast black and white stripes either vertical or horizontal
there were no corners to its environment and no edges
behavioral observations
-pupil responses were normal but showed no visual placing when brought up to a table top
-no startle responses when an object was thrust towards them
-guided themselves mainly by touch and not vision
-showed behavioural blindness - kittens raised in horizontal environment could not detect vertically aligned objects
permanent defects shown by cats
-always followed moving objects with very clumsy jerky head movements
-often tried to touch things moving on the other side of the room well beyond their reach
neurophysiological examination results
horizontal plane recognition cells did not fire off in the kitten from the vertical environment and vertical plane cells did not fire off in the kitten from the horizontal environment so there was distinct orientation selectively showing the kittens suffered from physical blindness
about 75% of cells in both cats were clearly binocular and in almost every way the responses were like that of a normal kitten showing little neurophysical response to the rearing environments
a kitten raised in a vertical environment had no neurons within 20 degrees of a horizontal orientation
conclusions
kittens showed behavioral blindness in that the kittens raised in the horizontal environment could not detect vertically aligned objects and vice versa concluding that visual experiences in the early life of kittens can modify their brains and have profound perceptual consequences
the kitten raised in a vertical environment had no neurons within 20 degrees of a horizontal orientation concluding that a kittens nervous system adapts to match what it visually experiences
strength of research method
high levels of control over extraneous variables e.g kittens exposure to visual apparatus was precisely timed and they were kept in a dark room otherwise so we can be confident the IV whether kittens raised in vertical or horizontal orientation was effecting the DV behavior and neuronal activity
strength of quantitative data collected
easily compared - can easily compare horizontally and vertically reared cats on the number of neurons with optimal orientation degrees of the opposite orientation to lines in their rearing environment - can see that the rearing environment has affected the neurons in the kittens visual cortex providing evidence for brain plasticity
weakness quantitative data
lack of detail and insight - no information about the behavioral consequences of being reared in the vertical or horizontal environment - limited understanding/conclusions about the consequences of the reported changes to neurons in the visual cortex
strength qualitative data
insight and detail - kittens had no startle response, always followed moving objects with very clumsy jerky head movements - good because we get an understanding of the consequences of the reported changes to neurons in the visual cortex
weaknessqualitative data
cannot be easily compared - can’t easily compare behavioral consequences of being raised in a vertical and a horizontal rearing environment - difficult to determine if different rearing environment has caused differences in the kittens development
weakness of sample
small sample - only 2 kittens reported on the neurological findings - the findings about the effects of the environment on the activity of the neurons may not generalize to all cats
strength of concurrent validity
both behavioral and neurological measures were taken to measure the effect of the restricted visual rearing environment. Both showed evidence that the kittens raised in the horizontal visual environment did not see in the vertical orientation and the opposite was true of the kittens raised in the vertical environment. The fact that both showed such evidence suggests that both measures i.e the behavioral and neurological measures were valid measures of the effect of the restricted visual environments
comment on how the study is reliable
standardized controlled procedure so could be replicated - special apparatus i.e clear glass platform inside a tall cylinder the entire surface of which was covered with high contrast black and white stripes, vertical or horizontal, cat in their for an average of 5 hours a day and in the dark otherwise
mment on how the study is not reliable
only 2 kittens provided the results of the physiological part of the study so too few to be confident that the findings about the effect of rearing environment on the development of the visual cortex are externally reliable
comment on how the study is ethical
only 2 kittens used and no fewer could possibly have been used as two needed to raise in a vertical and another in a horizontal environment
comment how this study is not ethical
kittens would have suffered some pain and distress from the invasive procedure and distress from being separated from their mothers while in the visual apparatus and being tested although it was noted that the kittens did not appear upset by the monotony of their surroundings so this may have not been the case
comment on the practical applications
helps us understand the effects of visual deprivation in growing children e.g if visual impairments are not detected and corrected early enough these findings potentially suggest that potentially long term damage may be done to the cortical areas associated with the particular types of stimuli that cannot be seen by the child
