Brain & Behaviour Psychology

Brain and its Computational Tasks

 

An important goal is to discover the distributed neural networks supporting task performance, and to validate the resulting spatial brain patterns using known network structures and/or links with behavioral responses. It’s a huge topic and I will address here only some aspects of performance perceived through visual sensation.

Physical space in the brain where neurons are located is an essential feature of the organization in the brain one that allows areas of visual seeing where pattern of lights are similar and area they are different. To place it in context, let’s start with an observation of visual perception. One of the key objectives of brain is to locate where objects are placed in space and that involves defining boundaries and assigning with other objects figuring out where one object begins and other ends. The overall process is called as Figure-Ground Segregation and brain does it so beautifully that we are hardly aware of it. For example look at this picture:

Our brain automatically decides what constitutes this object, when it does; it is grouping different parts of visual seeing by distant parts of objects that corresponds to different entities such as in jigsaw puzzle which is an ambiguous scene perceived as conveyed by the pictures portrayed on the puzzle or we can perceive puzzle pieces as objects. Look another ambiguous picture below; which can perceive either as a Vase on a dark background or two faces on a light background because you cannot perceive both the images simultaneously.

The brain group things together by defining where are the things changing and local circuity in retina defines where are the things changes by recognizing the boundaries, the process is called as Centre-surround organization making the neurons more sensitive to different backgrounds as compared to same backgrounds (camouflage).

As we know, photoreceptors are sensitive to only those rays that are falling on them and this area is called as receptive field from where the neurons are connected to the other neurons through excitatory and inhibitory neurotransmitters and transmit or inhibit the message respectively. This is what happening in Centre-surround organization where the photoreceptors located in the receptive field is net excited where is the neurons located annulus to the receptive field is net inhibited making an optimal stimuli.

Brain mapping is an important aspect of organization not only for visual perception but also for other functions also. The neurons from the retina carry the message and transmit it to the cortex through optic nerve. The neurons make synapses at the lateral geniculate nucleus and then to visual cortex. Interestingly, the neurons keep relationship with other neurons through synapses and do not lose the stimuli in their world. The map on the cortex is called as retinotopic maps. In summary, the visual cortex preserves the messages that originate in the eye. But how the brain defines the borders? This is been perceived by the neurons sensitive to different orientations at the given place and time called as Orientation selectivity. This can be applied at the illusory contours as seen in Kanizsa Triangle shown below. Lastly, one of the most important features of this is that the dancers move synchronously so as to perceive us as a single unified object.

 

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About the author

Syed Muhammad Mustahsan Zaidi

I am a final year medical student at Sindh medical college, Dow university of Health Sciences. I am also an editorial member at two international journals and I have 8 national and international publications.