Complex Neural Pathways

• • Neurones connected in many different ways in CNS

  • Allows many complicated interactions between neurones

  • Allows nervous system to carry out many complex functions
• Diverging Neural Pathways - Allows a nerve impulse from a single neurone to be transmitted to several destinations simultaneously.
• • Diverging neural pathways influence several neurons at the same time.

  – coordinated temperature control by hypothalamus

  – fine motor control

  – balance
• Converging Neural Pathways - Small impulses from several receptors are passed to one sensory neurone
• Converging neural pathways increase the sensitivity to excitatory or

  inhibitory signals.

  • The additive effect stimulates this neurone enough to cause it to transmit a nerve impulse e.g rods and cones in the eyes
• In the eye there are 2 kinds of light receptors using different pigments:

  – rods

  – cones

  • Cones detect colour but only react to strong light

  • Rods react to dim light and do not detect colour
• Efficiency of rods is increased by connecting several to the same

  neurone – A nerve impulse from one rod would not be enough to

  stimulate neurone.
• Reverberating pathway neurones later in the pathway link with earlier ones sending the impulse back through the pathway.
• The reverberation circuit allows us to maintain an action until we stop thinking about it, such as holding our breath.