Synaptic Transmission and Neural Communication

Vocabulary terms covering the mechanisms of communication between neurons, synaptic structures, neural potential thresholds, and learning-related biological processes.

Synaptic cleft

The gap or space between the presynaptic and postsynaptic neurons, where synaptic transmission occurs between two neurons

Presynaptic neuron

The neuron that releases neurotransmitters from its axon terminal into the synaptic gap.

Postsynaptic neuron

The neuron that picks up or binds to neurotransmitters at its receptor sites.

Synaptic vesicles

Storage sacs located within the axon terminal (terminal button) that house neurotransmitters.

Synaptic transmission

When post-synaptic neurons are stimulated if pre-synaptic neurons release via neurotransmitters

Stopping synaptic transmission

Enzymes are released that destroy neurotransmitters; leftover neurotransmitters are reabsorbed by the presynaptic neurons

Resting potential

The stable negative charge of a neuron when it is not active, identified in the lecture as $-70\,mV$.

Threshold

The specific level of depolarization, identified as $-55\,mV$, required to automatically trigger an action potential.

All-or-none response

The principle that if a neuron reaches the required threshold, an action potential will occur completely; if not, it will not fire at all.

Enzymes

Substances released by the presynaptic neuron that destroy neurotransmitters in the synaptic gap to stop transmission.

Re-uptake pump

A mechanism that stops transmission by re-absorbing leftover neurotransmitters back into the presynaptic neuron.

Graded potentials

Signals that are not all-or-none responses, where a neuron receives thousands of inhibitory or excitatory signals from other neurons.

Hyperpolarization

A process where the cell becomes more negative, creating inhibitory signals that prevent an action potential from occurring.

Depolarization

A process where the cell becomes more positive, leading to excitatory postsynaptic potentials.

Spatial summation

The determination of whether a neuron fires based on the physical location or spacing of the presynaptic neurons feeding into it.

Temporal summation

The determination of whether a neuron fires based on the timing of the presynaptic neurons firing.

Pruning

A natural biological process of eliminating less active or old synaptic connections as we age.

Learning and neural connections

Learning and development are based on creating new synaptic connections and getting rid of older connections via pruning

Learning and neural connections (con’t)

Learning is easier with more synaptic connections

Long-term potentiation

A long-lasting increase in neural excitability in synapses along a specific neural pathway due to repeated synaptic activity.

Potentiated state

A strengthened connection between neurons characterized by increased neurotransmitter release and a higher number of receptor sites.

Neuroplasticity

The brain's ability to learn and change, which is higher in younger individuals and decreases as one ages.

Acetlycholine (ACh)

A neurotransmitter released by motor neurons controlling skeletal muscles and contributes to attention, arousal, and memory; is associated with alzheimers

Dopamine (DA)

A neurotransmitter contributing to the control of voluntary movement

Norenpinephrine (NE)

A neurotransmitter contributing to the modulation of mood and arousal

Serotonin

A neurotransmitter involved in the regulation of sleep, wakefulness, eating, and aggression

GABA

A neurotransmitter which serves as a widely distributed inhibitory transmitter contributing to regulation of anxiety, sleep, and arousal

Endorphins

A neurotransmitter which resembles opiate drugs in structure and effects, and also plays a role in pain relief, stress responses, and regulation of eating priority