Psychology - Nervous System

Based on Jacaranda Psychology Unit 3/4 Textbook (2023)

three main roles of the nervous system

receive, process and coordinate a response to information

central nervous system (CNS)

consists of the brain and spinal cord; receives, processes and co-ordinates a response to sensory information

peripheral nervous system (PNS)

the network of nerves that connects the brain and spinal cord to the rest of the body, carrying information to and from the CNS

somatic nervous system (SNS)

the part of the peripheral nervous system that controls voluntary movement of skeletal muscles, and carries sensory/motor information to and from the CNS

autonomic nervous system (ANS)

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart), providing feedback to the brain about their activities

parasympathetic nervous system

helps maintain the internal body environment in a steady, balanced state of normal functioning (homeostasis)

sympathetic nervous system

activates internal muscles, organs and glands to prepare the body for vigorous activity/to respond to stress

enteric nervous system (ENS)

embedded in the walls of the GI tract, dedicated to its functioning

connected by the vagus nerve

detects the physiological condition of the GI tract

integrates information about its state

provides outputs to control gut movement

ganglia

small clusters of neurons and nerve fibres

SAME

sensory (afferent) and motor (efferent)

conscious response

a voluntary and intentional reaction to a sensory stimulus that involves awareness

unconscious response

an involuntary, unintentional reaction to a sensory stimulus that does not involve awareness

perception

the interpretation of sensory information so meaning can be assigned

neural pathway

one or more circuits of interconnected neurons that forms a communication network

major functions of the spinal cord

• receive sensory information from the body and send the messages to the brain for processing

• receive motor information from the brain and send it to relevant parts of the body to control muscles, glands and organs

neurotransmitter

a chemical substance produced by a neuron that carries a message to other neurons or cells in muscles, organs or other tissue

neurotransmission

the process of transferring information between neurons

involves neurochemicals binding to complementary receptor sites of postsynaptic neurons

neural synapse

the site where communication typically occurs between two adjacent neurons

includes the terminal buttons of a pre-synaptic neuron, the space between the pre- and post-synaptic neurons (synaptic gap), and the receptor sites/dendrites of the other

reuptake

neurotransmitters that do not bind to receptor sites are absorbed back into the terminal buttons of the presynaptic neuron

excitatory effect

stimulate/activate postsynaptic neurons to perform their functions/make them likely to fire

inhibitory effect

block/prevent postsynaptic neurons from firing

glutamate

primary excitatory neurotransmitter in the CNS, involved in learning, memory, perception, thinking and movement

excessive glutamate can lead to neural damage/death

GABA

primary inhibitory neurotransmitter in the CNS, involved in fine-tuning neurotransmission to maintain its optimal level

lack of GABA can lead to seizures, phobia or anxiety

neuromodulators

a subdivision of neurotransmitters that influence/enhance the effects of other neurotransmitters

dopamine

primarily an excitatory (could be inhibitory) neurotransmitter that is also a neuromodulator

roles in voluntary movements, pleasure, motivation, appetite, reward-based learning and memory

serotonin

an inhibitory neurotransmitter that is also a neuromodulator

roles in mood, emotional processing, sleep onset, appetite and pain perception

synaptic plasticity

the ability of the synapse to change in response to experience

sprouting

the creation of new extensions (bushier axon fibres) on a neuron to allow it to make new connections with other neurons

rerouting

new connections are made between active neurons to create alternate neural pathways (usually due to damage)

pruning

elimination of weak, ineffective or unused synapses to fine-tune information

long-term potentiation (LTP)

activity-dependent, long-lasting enhancement of synaptic transmission due to repeated strong stimulation

long-term depression (LTD)

long-lasting decrease in the strength of synaptic transmission and neuronal response as a result of lack of stimulation

similarities between LTP and LTD

• activity-dependent

• involve glutamate

• changes in excitability

• long-lasting effects

• forms of long-lasting neural plasticity