https://padlet.com/11amerc/8ttfbn1kx95b en-us 2017-03-09 20:32:06 UTC 2023-05-02 21:42:23 UTC hello@padlet.com 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159128334 The aim of the experiment was to investigate the effect of kitten's visual development with a restricted visual environment from a young age, this consisted of either vertical stripes or horizontal stripes and in which the kitten could move freely. ]]> 2017-03-09 20:39:35 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159128334 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159430627 Before Blakemoore and Cooper's study, Hubel and Wiesel carried out a number of studies relating to the visual system. In 1962, they carried out an study titled Receptive Fields, Binocular Interaction and Functional Architecture in the Cat's Visual Cortex. This showed higher levels of processing from the previously established transition from the retina to the visual cortex as they found out in their 1952 study. It was showed that in the striate complex, they are neurons called simple and complex cells. Both of these types of cells responses responded to slits of light but in different ways. Complex cells a greater latitude in position of the of the slit of light while giving little response to spots of light. This concludes that at least one type of neuron is orientation-specific and many of these neurons are stimulated by exposure to either eye so are binocular. In 1970, Hubel and Wiesel discovered in a further study that complete visual deprivation in kittens, being reared in complete darkness, would cause the number of neurons to decrease; monocular deprivation would cause a sharp decline in the number of neurons associated with the closed eye. As well as this, cats are more susceptible to the effects of eye closure at an early age.This begins suddenly at the start of the fourth week, remains high and then starts to decline at some point during the sixth or eighth week before going away at the end of the third month. Monocular closure of an adult cat for over a year produces no detectable effects. 

]]> 2017-03-11 12:29:25 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159430627 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159439915 Kittens raised in the laboratory who were all housed in complete darkness until they were 2 weeks old. ]]> 2017-03-11 15:30:32 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159439915 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440212 2017-03-11 15:35:44 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440212 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440278 The study was an laboratory experiment with an independent measures design. ]]> 2017-03-11 15:36:54 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440278 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440315 The kittens were kept in complete darkness unless they were either in the visual display apparatus or being tested. Each kitten spent an average of 5 hours a day in a visual display apparatus from 2 weeks old until 5 months when they were tested. The visual display apparatus was a vertical cylinder, 46 cm in diameter, with a vertical floor halfway up in which the kitten could move freely. The kitten could see no corners as there wasn't an edge to the floor or it's own body because of a collar which restricted vision of the paws but still allowed normal binocular vision. The laboratory floor and ceiling was a long way away due to the cylinder only being 2 metres long. The entire inner wall of the visual display apparatus contained high-contrast  black and white stripes which as the independent variable, were either vertical or horizontal. While Blakemoore and Cooper didn't raise normal kittens (exposed to a normal visual environment), findings from this study were compared to the previously established standard of brain development in a normal cat. The dependant variable of this experiment was measured in multiple ways. First of all, the kittens were placed in a small well-lit room with chairs and tables in which visual reactions were observed.  Observations were made on the following abilities:

- To move around and respond  to objects
- To jump from a chair to a table
- To follow a moving object
- To judge distance of objects in order to touch them
- Startle response
- Visual placing 
- Response to a rod place vertically or horizontally 

In addition to this, biological studies were taken from 7.5 months of the individual neurons in the primary visual cortex to investigate how they responded to lines of different orientations and whether they were monocular or binocular. This was carried out by anaesthetising the cat and and presenting bright slits of light while taking recordings from the individual neurons. Overall, recordings were taken from 125 neurons from two kittens (horizontally and vertically reared). ]]> 2017-03-11 15:37:46 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159440315 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159491229 2017-03-12 13:12:40 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159491229 11amerc https://padlet.com/11amerc/8ttfbn1kx95b/wish/159495337 Observations:

Whereas the kittens behaviour responded normally in bright light, their behaviour was different to that of a normal regardless of the independent variable. Kittens moved primarily by touch rather than sight, they also failed to place their paws outs when held above a table top showing a lack of visual placing. The kittens also showed no startle response when an object was moved fast towards them and showed signs of fear when they reached the edge of a surface they were standing on. Whilst most of these deficiencies were temporary and was overcome in about 10 hours of normal visual experience, some of the visual defects were permanent. Kittens bumped into stationary objects, followed moving objects with jerking head movements whilst also being poor at judging the distance of objects away in order to touch them - often misjudging the distance when reaching out to teach it. There was a difference in the cat's behaviour depending on the visual environment it was raised in. When a startle response was tested for with a Perspex sheet with stripes or on it, the kitten only responded if the stripes were in the same orientation as the condition it was raised in. In the same way, a kitten raised in the horizontal stripes condition only responded to a rod held and moved horizontally whereas it would show no interest to a rod held vertically. 

Physiological Investigation:

Out of all the neurons studied, there was only one that was found to not be orientation-specific. 75% of neurons were found to be binocular in both kids, their orientation sensitivities were completely different to that of a normal cat. As opposed to being inactive, the orientation of the stripes in the rearing of the environment caused the the neurons to respond around that particular axis.  

]]> 2017-03-12 14:12:34 UTC https://padlet.com/11amerc/8ttfbn1kx95b/wish/159495337