Jette Hannibal - Inthinking The nervous system NS: gathers and processes information, produces responses to stimuli, coordinates the workings of different cells CNS (brain + spinal cord): receives, processes, interprets, and stores incoming sensory information (e.g. Taste, state of internal organs) PNS: deals with input and output of CNS through sensory and motor neurons.
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Jette Hannibal - Inthinking The nervous system NS: gathers and processes information, produces responses to stimuli, coordinates the workings of different.
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Jette Hannibal - Inthinking
The nervous system
NS: gathers and processes information, produces responses to stimuli, coordinates the workings of different cells
CNS (brain + spinal cord): receives, processes, interprets, and stores incoming sensory information (e.g. Taste, state of internal organs)
PNS: deals with input and output of CNS through sensory and motor neurons.
Jette Hannibal - Inthinking
The nervous system
Millions of neurons in different sizes and shapes organized in a network for transmission of information.
Communication between neurons: electric conduction and chemical transmission
A large concentration of neurons in the brain and the spinal cord. 80% are found in the brain’s Cerebral cortex
Neurons: basic structural unit of NS
Jette Hannibal - Inthinking
Structure of neurons
Cell body or nucleus (contains DNA) Dendrites: information transmission Axons: the cell body. Terminal buttons: storage of
neurotransmitters. Synaptic gap: between dendrites and
terminal buttons. Where neurotransmitters “pass” information from neuron to neuron.
Jette Hannibal - Inthinking
Neuron
Jette Hannibal - Inthinking
Neuronal communication
Within neurons: Action potential Between neurons: Synaptic transmission
of neurotransmitters
Jette Hannibal - Inthinking
Action potential
Electro-chemical messages AP occurs when a neuron sends
information down an axon AP caused by an exchange of Sodium and
Potassium ions across the neural membrane
Jette Hannibal - Inthinking
Neurotransmitters
Chemical messengers from neuron to neuron.
Messages may also travel from neurons to to muscles and organs in the body, such as lungs or the intestines.
Jette Hannibal - Inthinking
Synaptic gap
Synaptic vesicles with neurotransmitters at one side of the gap (terminal buttons): pre-synaptic gap. Like “keys”
Receptor sites for neurotransmitters (like locks) at the other side of the gap: post-synaptic gap
1/10000 of a second to travel across the synaptic gap
Jette Hannibal - Inthinking
Brain, neurons, neurotransmitters – how it works
http://www.youtube.com/watch?v=haNoq8UbSyc
Jette Hannibal - Inthinking
Neurotransmitters
Produced in the terminal buttons and diffused across the synaptic gap to bind to receptor sites.
The neuron on the postsynaptic side of the gap more or less likely to fire as a result of synaptic transmission.
Psychoactive drugs can change properties of neurotransmitter release, neurotransmitter reuptake and the availability of receptor binding sites.
Jette Hannibal - Inthinking
Neurotransmitter processes
Excitatory: increases the frequency of action potential
Inhibitory: decreases the frequency of action potential
De-activation: effect of neurotransmitter stopped (destroyed by special enzyme)
Re-uptake: reabsorbed by the terminal buttons. Drugs can inhibit re-uptake so that the
neurotransmitter remains longer in the synaptic gap
Jette Hannibal - Inthinking
Brief intro to principles of neurotransmission
Click here to see how neurotransmission works.
Jette Hannibal - Inthinking
Examples of neurotransmitters
Dopamine: (inhibitory) Controls arousal levels in the brain; vital for physical motivation (e.g. associated with craving in addiction)
Serotonin: (inhibitory) Controls mood and anxiety levels High levels of serotonin are associated with optimism.
Acetylcholine (ACh): (excitatory) Controls activity in the brain connected with attention, learning and memory
Noradrenaline: (excitatory) involved in mental arousal and elevated mood
Jette Hannibal - Inthinking
Dopamine and serotonin
Jette Hannibal - Inthinking
The reward pathway - dopamine
Stimulation of the reward center is linked to release of dopamine
Rats will continuously press a lever that gives a small electrical stimulation to the pleasure center