Attention Network May Play Role in Vision Restoration Resulting from Brain Damage

By Annamaria Cavaleri ‘22

visual_field.jpg

Figure 1. The visual field of a person with homonymous hemianopia.

Hemianopia is defined as a decreased vision or blindness in half of the visual field because of trauma or stroke. Although research on in this field is limited, neuroimaging evidence suggests that a person’s attention may play a role in restoring vision. Recent studies have shown that vision training has the ability to partially restore vision by improving the deficiency of visual sectors in the brain (1).

In this study, the researchers collected evidence from functional magnetic resonance imaging (fMRI) that connected visual training with the attention network of the brain. Seven chronic hemianopic patients who had lesions in the visual cortex underwent vision rehabilitation training for 1.5 hours a day, six days per week for five weeks. Each training session lasted about 60 minutes and consisted of 120 trial training sessions. During the sessions, participants had to respond to visual stimuli shown on a computer monitor, as well as participate in a pre-test and post-test that included contrast sensitivity training and perimetry testing. The training was done with one eye open and the other covered with an eye patch.

Upon assessment of the data collected from the training sessions, it was shown that patients had improved visual function at the location that had been trained. The fMRI scan displayed that the training had facilitated the strengthening of the cortical connection between the right temporoparietal junction (the part of the brain that deals with reorienting of attention), the insula (the region that processes of information to produce emotions), and the anterior cingulate cortex (the area of decision making and physiological processes).

The results of this study demonstrate the importance of attention and the right temporoparietal junction as an aspect of vision restoration training. It would be beneficial to conduct future studies to clarify whether the rehabilitation of attention networks is directly linked to training or the rebalancing of bottom-up sensory streams. Discovering that the brain’s attention network is a key mechanism in partially reversing blindness is an exciting advance and opens the possibilities for new types of therapy.

 

References

  1. Q. Lu, et. al., Visual rehabilitation training alters attentional networks in hemianopia: An fMRI study. Clinical Neurophysiology 129 (2018) doi: 10.1016/j.clinph.2018.05.027.
  2. Image retrieved from: http://www.ssc.education.ed.ac.uk/courses/vi&multi/vnov072i.html
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