Question

The three principles with regards to the sensory cortex (mechanisms of perception), with one of them being hierarchical organization. Using the somatosensory system as an example (specifically the exteroceptive part of that system),

--> State each level of the hierarchy with regards to this system, beginning with the one at the lowest level of the hierarchy to the final uppermost level. You must give the name at each level as it corresponds with this system. (Explain Thoroughly Please)

Answer 1

The hierarchical system regarding the somatosensory system is as follows:

The somatosensory system receives sensory information from the thalamus:

The somatosensory system is organized as follows ( areas are arranged from the lowest to the highest based on the complexity of the function they do)

1. Areas 3b and 3a
   1. Most of the sensory information from the ventral posterior nuclear complex is received by the 3b area of the somatosensory cortex
   2. the information it receives is touch
   3. The 3b area of the somatosensory cortex receives information about the joint, vibration and position sense.
2. Areas 1 and Area 2
   1. Area 1 recieves information from the area 3b
   2. Here, the information is further analysed
   3. this area is responsible for understanding texture
   4. Area 2 recieves information from Area 3b and 3a
   5. This areas helps to understand the size and shape of the stimulus

Information from the primary somatosensory cortex projects into the secondary somatosensory cortex. They come in two streams one that enters the lateral parietal cortex ( Area S2 ) and other to the posterior parietal cortex ( 5, 7)

S2 further refines the processing of sensory information and projects into the limbic system

Posterior parietal cortex receives information from

1. the primary sensory cortex ( this information is coming from the contralateral side of the body)
2. sensory information from the eyes (visual)
3. Sensory information from the ears ( auditory)
4. Sensory information from the same side of the body

This area is vital for using sensory information for planning and executing an action. This area sends information to the frontal lobe.