There are many studies which suggest that cortical connection mostly occurs through feedback connections. However, feedback connections are not clearly understood. In these research papers, the experimenters focus on the role of feedback in the visual cortex. Although research has been done on this topic, it is difficult to study cortical feedback signals. I will use research by researchers Nassi, Lomber & Born (2013) for the first article. For the second article I will use the work of Bastos, Vezoli, Kennedy & Fries (2015). Lastly, I will use the paper by Hupe, James, Payne, Lomber, Girard & Bullier (1998) to demonstrate the work that has been done on this topic and to demonstrate what we have learned about this topic so far. I will begin
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The surround suppression is an important term since the researcher mentions that “[f]eedback connections, have typically been assigned a supportive role in surround suppression” (Nassi, Lomber & Born, 2013, p. 8504). Different studies have also used different species such as cats and squirrels, different ways of inactivation like cooling which is used in the study of Nassi et al (2013), the different areas that are studied by researchers such as V2 or MT for one type of animal while studying PTV for another animal. Another difference from most studies is that the researcher usually conducts their experiments on anesthetized animals while Nassi et al (2013) conducted their experiment on animals that were alert. According to Nassi et al (2013), “[a]nesthesia has been reported to strongly affect feedback signals from V1 to the LGN” (p. 8515). Nassi et al (2013) discuss how their results demonstrate that feedback from areas V2 and V3 do not play a major role to generate orientation in V1. They also found that by inactivating the feedback, there was also a reduction in the strength of surround suppression and it was significantly reduced while using the cooling …show more content…
Area V1 is made up of 6 layers (Chadhuri, 2011). It is also known as the striate cortex while the areas beyond the striate cortex are known as the extrastriate areas (parallel processing through extrastriate cortex. Both Hupe et al (1998) and Nassi et al (2013) used the method of cooling inactivate the area so the response could be studied. Hupe et al (1998) used the method of cooling on the superior temporal sulcus (STS), located in area V5. The researchers of this paper explain how “the strength of the effect of V5 inactivation depended on the visibility of the stimuli used for testing neurons in area V3” (Hupe, James, Payne, Lomber, Girard & Bullier, 1998, p. 784). Thus, inactivation of area V5 has an effect on the neurons of area V3. For this experiment, the researchers used a bar. The moving bars are usually used for motion stimuli. The authors explain how feedback connections are involved in the integration of information concerning different parts of the visual field. The authors were able to find that for “low-salience stimuli, the bar is barely visible when both the bar and the background are moving at the same time” (Hupe et al, 1998, p. 785). Yet, the bar is visible when it is on a stationary background. The results of the experiments also demonstrate that by cooling the STS, there is less activation and fewer responses in the area V1, V2 and V3. However, the areas
The surround suppression is an important term since the researcher mentions that “[f]eedback connections, have typically been assigned a supportive role in surround suppression” (Nassi, Lomber & Born, 2013, p. 8504). Different studies have also used different species such as cats and squirrels, different ways of inactivation like cooling which is used in the study of Nassi et al (2013), the different areas that are studied by researchers such as V2 or MT for one type of animal while studying PTV for another animal. Another difference from most studies is that the researcher usually conducts their experiments on anesthetized animals while Nassi et al (2013) conducted their experiment on animals that were alert. According to Nassi et al (2013), “[a]nesthesia has been reported to strongly affect feedback signals from V1 to the LGN” (p. 8515). Nassi et al (2013) discuss how their results demonstrate that feedback from areas V2 and V3 do not play a major role to generate orientation in V1. They also found that by inactivating the feedback, there was also a reduction in the strength of surround suppression and it was significantly reduced while using the cooling …show more content…
Area V1 is made up of 6 layers (Chadhuri, 2011). It is also known as the striate cortex while the areas beyond the striate cortex are known as the extrastriate areas (parallel processing through extrastriate cortex. Both Hupe et al (1998) and Nassi et al (2013) used the method of cooling inactivate the area so the response could be studied. Hupe et al (1998) used the method of cooling on the superior temporal sulcus (STS), located in area V5. The researchers of this paper explain how “the strength of the effect of V5 inactivation depended on the visibility of the stimuli used for testing neurons in area V3” (Hupe, James, Payne, Lomber, Girard & Bullier, 1998, p. 784). Thus, inactivation of area V5 has an effect on the neurons of area V3. For this experiment, the researchers used a bar. The moving bars are usually used for motion stimuli. The authors explain how feedback connections are involved in the integration of information concerning different parts of the visual field. The authors were able to find that for “low-salience stimuli, the bar is barely visible when both the bar and the background are moving at the same time” (Hupe et al, 1998, p. 785). Yet, the bar is visible when it is on a stationary background. The results of the experiments also demonstrate that by cooling the STS, there is less activation and fewer responses in the area V1, V2 and V3. However, the areas