What is the role of the tissue surrounding neurons in decision making and taking control of impulses?
Short answer
This question is pretty broad as it basically translates to "what purpose serves neuroglia in neuronal communication"? In short: next to everything. 

Background
In the adult brain there are three types of glia: oligodendrocytes, astrocytes, and microglial cells (Purves, 2001). A few notable examples of their functions: 


Oligodendrocytes (peripherally called Schwann cells) generate myelin sheaths around neurons, which increases conduction speeds (saltatory nerve conduction) and increases the metabolic efficiency of neural communication. 
Astrocytes are a highly heterogeneic group of supportive cells. To put the impact of glia in perspective: this class of cells is considered to contain as many cell types as there are types of neurons in the brain. They are thought to mediate transfer of nutrients from blood capillaries to neurons, and they also assist in removal of neurotransmitters from the synaptic cleft and thereby speed up the recovery from synaptic activity and hence they increase the speed of information transfer (Tsacopoulos &amp; Magistretti, 1996). 
Microglia are the brain's immune cells, and are similar to peripheral macrophages. They act as the major inflammatory cell type in the brain, and respond to pathogens and injury. 


References
- Purves  et al (eds). Neuroscience, 2nd edition. Sunderland (MA): Sinauer Associates (2001)
- Tsacopoulos &amp; Magistretti, J Neurosci (1996); 76(3): 877-85