Brain and cognition - Chapter 2 (part 1)

Neurons

Signaling units that transmit information

Glial cells

Have several different functions (4 types):

Astrocytes, Oligodendrocytes, Microglial cells and Schwann cells

Astrocytes

Glial cell that surrounds neurons and are in contact with blood vessels. Can modulate neuron activity. In the central nervous system.

Oligondendrocyte

Form myelin around neurons in the central nervous system.

Microglial cells

Devour and remove damaged cells, in the central nervous system.

Schwann cells

Form myelin around neurons, in the peripheral nervous system.

Blood-brain barrier (BBB)

Barrier of Astrocytes which protects neurons in the brain from pathogens and drugs.

Myelin

Increases the speed of the information getting transported through a neuron.

Soma

Cell body (Not the nucleus)

Intracellulair fluid

The cytoplasm of the cell (salty, made up of ions)

Dendrites

Receive input from other neurons

Axon

Outputs a signal to other neurons via axon terminals.

Spines

Little knobs where neurons receive input from other neurons.

Synapses

Where the electrical signal is passed on from one cell to the next. Includes both the presynaptic and postsynaptic part.

Axon collaterals

Axons that branch together which allows them to transmit signals to more than one cell.

Presynaptic neuron

When output synapses are connected to other neurons.

Postsynaptic neuron

When the input synapses on dendrites connect to the other neuron.

Resting membrane potential

-70 mV across the neuronal membrane, when no signal is being sent.

Ion channels

Allows ions to pass through the membrane with the concentration (not against), passive transport

Ion pumps

Ion transport against gradients (low→ high), active transport (costs energy)

Permeability

Extent to which ions can pass through ion channels

Electrochemical equilibrium

Stable force/ position of electrochemical charge.

Electronic conduction

Ionic current that diminishes because of the distance from the site

K+

Potassium

Na+

Sodium

A-

Organic anions

Action potential

Rapid polarization and depolarization on the neuron’s output

Voltage-gated ion channel

Transmembrane ion channel that changes molecular conformation

Axon hillock

Specialized region of the neuronal soma where the axon emerges.

Spike-triggering zone

At the juncture of the soma and axon of the neuron, where voltage gated sodium channels are located. Which can be triggered to create an action potential.

Nodes of Ranvier

Gaps between myelin patches where action potential can be generated.

Equilibrium potential

Same amount of ions go in and out of the cell.

Refractory period

Period when the neuron is not able to generate an action potential.

Saltatory conduction

Conduction of the signal through myelinated neurons, which goed extra fast

Ligand-gated channels

Channel that can be opened through neurotransmitters that bind to it.

EPSP

Excitatory postsynaptic potential, channels that change the potential towards a more positive state

IPSP

Inhibitory postsynaptic potential, channels that change the potential towards a more negative state

Decremental conduction

Spread of the signal through the dendrites towards the soma

Temporal summation

When EPSP/IPSP follow in close succession at the same location and will trigger an action potential.

Spatial summation

EPSP occur at the same time at different locations, will trigger an action potential

ARP

Absolute refractory period, Na+ channels are closed, new action potential cannot be generated

RRP

Relative refractory period, action potential can only happen with larger than normal depolarizing currents.

Multiple sclerosis

Disease when myelin sheaths are destroyed

Synaptic transmission

Transfer a signal from one neuron to another

Synaptic cleft

Gap between the neurons at the synapse.

Vesicles

Contain the neurotransmitters (blaasje)

2 types of postsynaptic receptors

Ligand gated ion channels and GPCR (G-protein-coupled receptors)

Neuro

Glutamate

Excitatory neurotransmitter. Most prevalent.

GABA

Gamma-Aminobutyric acid, Inhibitory neurotransmitter, second most prevalent

Acetylcholine

(Ach), excitatory neurotransmitter, activates muscles (neuromuscular junctions)

Dopamine

Excitatory neurotransmitter, helps with cognitive functioning and motor control, Parkinson is associated with deficits here, comes from the substantia nigra and ventral tegmental area.

Serotonin

Excitatory neurotransmitter, is associated with mood and cognition, used to treat depression, comes from the rap he nucleus.

Norepinephrine

Excitatory neurotransmitter, helps in arousal as in fight or flight response, comes. From the locus coerleus

Neurosteroids

Involved in neurobiological responses

Microcircuit

Localized interconnected network of neurons

Neural networks

More complex networks made up of multiple microcircuits

CNS

Central nervous system, brain and spinal cord

PNS

Peripheral nervous system, everything except for the brain and the spinal cord

Autonomic motor system

Controls involuntary action of smooth muscles (heart etc.)

Somatic motor system

Controls voluntary muscles of the body

Sympathetic system

Uses norepinephrine as neurotransmitter, for fight or flight responses

Parasympathetic system

Uses acetylcholine as its neurotransmitter, for conserving energy