The Brain 1: Neurons and Synapses

Neurons

provide communication within the brain by receiving and sending electric signals

Cell body (Soma)

Contains the nucleus, the core of the neuron, and organelles necessary for neuron function

Dendrites

Fibers that bring or receive information from other neurons

Axon

Large fibers that send information from nucleus to other neurons

The electrical activity, or charge of a Neuron

differs from the inside and the outside of the neuron. Charged particles constantly flow in and out of the neuron membrane

Resting Potential

the neuron is stable and not being activated. The charge within the neuron is more negative than the charge outside of the neuron.

Action Potential is

An electrical signal sent from one end of a neuron to the other, and occurs when the charge of a neuron passes a certain threshold

The all-or-nothing rule

A neuron is either firing or not

Communication between neurons

happens across synapses

Synapse

Fluid filled gap between axon terminal and dendrite through which information is chemically transmitted between neurons

Signaling pathway

When a signal reaches the axon terminal, synaptic vesicles containing neurotransmitters are released. The neurotransmitters cross the synapse and enter the dendrite of the receiving neuron.

synaptic vesicles

Tiny spheres containing neurotransmitters found in the axon terminals that are manufactured in the cell body

Glial Cells (Glia)

made of myelin, whose main job is to increase and control the flow of nutrients to activate neurons and help neurons migrate to correct positions during prenatal development of the brain

Myelin

Coats the axon of longer neurons, and improves the efficiency of transmission by preventing electricity dissipation

As individuals develop, synapses are

pruned/destroyed. A properly pruned brain is more efficient.

Experiences determine

which synapses are pruned. If used, synapses will be maintained.

Rosenweig et al. 3 group of rat experiment results

Compared to the other two groups of rats that were raised alone or raised as a group, the enriched rats displayed faster learning in mazes and laboratory experiences, more synaptic connections, and healthier and larger neuronal cell bodies and glial cells