Cognitive Neuroscience - The Nervous System

The nervous system has two major divisions, the [blank_start]central nervous system[blank_end] and the [blank_start]peripheral nervous system[blank_end].

The central nervous system consists of [blank_start]the brain[blank_end] and [blank_start]the spinal cord[blank_end].

The four principle parts of neurons are: [blank_start]dendrites[blank_end], [blank_start]soma[blank_end], [blank_start]axon[blank_end] and [blank_start]axon terminals[blank_end].

The role of dendrites is to [blank_start]receive information[blank_end] from [blank_start]other neurons[blank_end] or from a [blank_start]stimulus in the environment[blank_end].

The [blank_start]soma[blank_end] of a neuron integrates the information received by dendrites, and decides whether or not to send information of its own.

[blank_start]Axon terminals[blank_end] of a neuron send the neuron's signals to other neurons.

The [blank_start]axon[blank_end] of a neuron carries the neuron's output information.

Information from one neuron is transmitted to another neuron at [blank_start]synapses[blank_end].

The membrane potential at a given time is determined by the [blank_start]distribution of ions[blank_end] across the [blank_start]cell membrane[blank_end].

An action potential is a brief change in [blank_start]membrane potential[blank_end].

During an action potential, the opening of [blank_start]potassium ion channels[blank_end] permits an [blank_start]outflow of potassium ions[blank_end], which eventually returns the membrane potential to its resting value.

During an action potential, the opening of [blank_start]sodium ion channels[blank_end] permits an [blank_start]inflow of sodium ions[blank_end], which depolarizes the neuron.

At terminal buttons, [blank_start]synaptic vesicles[blank_end] contain [blank_start]neurotransmitters[blank_end], which serve as chemical signals for communication between neurons.

The neurotransmitter molecules released into a synaptic cleft can open up ion channels on the postsynaptic membrane, which permits [blank_start]ion flow[blank_end] across the postsynaptic membrane.

After ion channels are opened up y neurotransmitter molecules, the flow of ions across the postsynaptic membrane could either have an [blank_start]excitatory[blank_end] effect, which makes the postsynaptic neuron more likely to fire, or have an [blank_start]inhibitory[blank_end] effect, which makes the postsynaptic neuron less likely to fire.

[blank_start]Anterior[blank_end] or [blank_start]rostral[blank_end] refers to the direction toward the front of the brain.

[blank_start]Superior[blank_end] or [blank_start]dorsal[blank_end] refers to the top of the brain.

[blank_start]Inferior[blank_end] or [blank_start]ventral[blank_end] refers to the bottom of the brain.

[blank_start]Posterior[blank_end] or [blank_start]caudal[blank_end] refers to the back of the brain.

[blank_start]Medial[blank_end] means toward the centre of the brain, away from the side.

[blank_start]Lateral[blank_end] means toward the side of the brain, away from the centre.

The brain has three major divisions: the [blank_start]forebrain[blank_end], the [blank_start]midbrain[blank_end], and the [blank_start]hindbrain[blank_end].

The cerebral hemispheres are covered by the [blank_start]cerebral cortex[blank_end], which is greatly convoluted.

The grey matter mainly consists of [blank_start]cell bodies[blank_end], whereas the white matter mainly consists of [blank_start]axons[blank_end].

The lateral surface of the cerebral cortex is divided into four lobes, [blank_start]frontal[blank_end], [blank_start]parietal[blank_end], [blank_start]temporal[blank_end], and [blank_start]occipital[blank_end] lobes.

The [blank_start]temporal[blank_end] lobe is ventral to the frontal lobe and the parietal lobe.

The [blank_start]occipital[blank_end] lobe is caudal to the parietal and the temporal lobe.

The limbic system includes the [blank_start]limbic cortex[blank_end] (or [blank_start]cingulate gyrus[blank_end]), the [blank_start]hippocampus[blank_end], and the [blank_start]amygdala[blank_end].

The [blank_start]basal ganglia[blank_end] of the forebrain and the [blank_start]cerebellum[blank_end] of the hindbrain both play important roles in the control of movement.

The [blank_start]thalamus[blank_end] relays all sensory information (except smell) from sensory organs to the cerebral cortex.

The [blank_start]hypothalamus[blank_end] is the main interface between the brain and the hormonal systems of the body.

The [blank_start]pons[blank_end] of the hindbrain relays information from the cerebral cortex to the cerebellum.

The [blank_start]medulla[blank_end] is the most caudal portion of the brain stem, which regulates vital functions such as breathing and heart rate.