| Chapter 2: The brain Why is it important to study how the brain works in psychology? Most of our experiences are mediated through the brain: thought, emotions, perceptions... The brain also controls our bodily functions, which in turn impact our psychological states: hunger, drowsiness The brain has no direct connection with the environment. Transduction is the transformation of physical stimulations into electrical and chemical signals the brain can interpret. Neurons are the basic elements of the brain. When they receive enough stimulation through their dendrites they emit an action potential, which travels along the axon of the neuron. An action potential is an all-or-none phenomenon. At the end of the axon, the action potential releases neurotransmitters that were stored in vesicles. These neurotransmitters then cross the synapse and affect the receptors on the dendrites of the next neuron. This is where drugs have their effects. When a neuron has emitted (fired) an action potential, it takes time for the neuron to be ready to fire again. This is the refractory period. |
 |