Psych 110 Final (UC, Riverside)

Microglia

Mediate immune responses in the central nervous system by acting as macrophages, clearing cellular debris and dead neurons from nervous tissue through the process of phagocytosis (cell eating)

The myelin sheath is formed by:

The cell membranes of glial cells (Schwann cells in the peripheral and oligodendroglia in the central nervous system).

Oligodendrocite

Provide support and insulation to axons in the central nervous system of some vertebrates, equivalent to the function performed by Schwann cells in the peripheral nervous system

Exoscytosis

Excretion of neurotransmitters into the synaptic cleft

If a small stimulus (depolarization) is enough to produce an action potential in a neuron, then a larger depolorizing stimulus will:

Activate a similar action potential. Action potentials don't change in amplitude

What causes an action potential?

Voltage-gated Sodium (Na+) channels opening up (depolarization)

What causes the action potential to end (repolarize)?

-voltage gated Na+ channels close and inactivate
-voltage-gated K+ channels open

Refractory period

the amount of time after an AP when it is more
difficult (relative refractory period) or impossible (absolute refractory
period) to fire another AP

Multiple sclerosis is caused by the destruction of:

Myelin

Major difference between neurons and glia

1. glial cells do not have action potential
2. neurons so not regenerate except in the olfactory cortex and the hippocampus
3. neurons are much longer (axons)

Resting potential

The outward flow of K+ (concentration) balances the inward flow of K+
(electrical)
3 Na+ for every 2 K+

Hyper-polarization

Membrane potential is more negative

One important principal of neural division is:

The fate of cells is progressively restricted

Tripartite synapses

1) NTs from the synapse can "spill over" and affect perisynaptic astrocytes.

2) NT receptors on glia can trigger Ca2+
signals in glia.

3) Ca2+ in glia can evoke local release of NT back onto neuron (extrasynaptic).

Dominant excitatory neurotransmitter in the brain:

Glutamate

Ventral horn

Description: part of gray matter, contains somatic motor nuclei
function: transmission of neural signals

6 layers of the neocortex each serve different functions. The function of layer 6 is:

Send information from the neocortex to other structures

Divisions of the autonomic nervous system:

Sympathetic and parasympathetic

Autonomic nervous system

The part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes

Broken up into the parasympathetic and the sympathetic systems

Sympathetic nervous system

The part of the autonomic nervous system that contains chiefly adrenergic fibers and tends to depress secretion, decrease the tone and contractility of smooth muscle, and increase heart rate (fight or flight)

Radial glia function:

Migrate neurons

Temporal summation

Several weak pinches in rapid succession

Spatial summation

Several weak pinches i adjacent locations

Agonists

Bind to receptors and activate them

Antagonists

Block receptors:
a. competitive-directly compete with binding of natural agonist

b. non-competitive-decrease activity of receptor, not by competition

Ligands

Binds to a given molecule

Acetylcholine

1. ionotropic-nicotinic (nicotine=agonist)
a. generally excitatory

b. in PNS-released by motorneurons, cause muscle contraction

c. in CNS-modulation?

2. metabotropic-muscarinic (muscarine=agonist)

Glutamate (amino acid)

most common excitatory neurotransmitter in CNS
a. ionotropic
i. AMPA -rapid excitation, "normal" transmission
ii. NMDA -unusual ion channel
a. gated by glutamate and depolarization =coincidence detection?

b. passes calcium into neuron

c. important for learning, development, toxicity

b. metabotropic

GABA (gamma-amino butyric acid) (amino acid)

dominant inhibitory NT in brain
a. ionotropic and metabotropic receptors

b. prevents "runaway" excitation

c. block of GABA can cause epilepsy

d. sedation

Glycine (amino acid)

Dominant inhibitory neurotransmitter in spinal chord

Dopamine (catecholamines) (monoamines)

i. involved in reinforcement/addiction, voluntary movement

ii. deficit in dopamine in basil ganglion leads to Parkinson's

Monoamines

Single amine group.

Two types: catecholamines and indoleamines

Norepineohrine (catecholamines)

i. neurotransmitter in central nervous system - arousal/modulation/learning

Epinephrine (catecholamines)

i. released from the adrenal gland activates sympathetic nervous system: "fight or flight" response

Serotonin (indoleamines)

Synthesized from tryptophan (amino acid)

Peptides

short chain of amino acids (proteins are long chains of amino acids)

1. require protein synthesis machinery

a. in nucleus (maybe in nerve terminals)

2. generally modulatory (metabotropic)

3. endorphins

a. opiates (morphine, heroin) are agonists at these receptors

b. first peptide receptor isolated

4. many others

Dale's principal

A neuron releases one neurotransmitter type at all of its terminals

Intrinsic (nature)

Can occur in isolation, based on genetic programs

Extrinsic (nature)

Triggered by environmental factors

Critical period

A period during development during which a process is susceptible to modification

If, for some reason, the organism does not receive the appropriate stimulus during this "critical period" to learn a given skill or trait, it may be difficult, ultimately less successful, or even impossible, to develop some functions later in life

Endoderm

Generates most internal organs

Ectoderm

Nervous system, skin, sensory organs

Mesoderm

Muscles, bones, connective tissue, vascularure

Flow of visual information

Photoreceptors, bipolar cells, retinal ganglion cells, optic nerve, brain

Rods (photoreceptor)

Abundant in the periphery of the retina. Outnumbers cones by about 20 to 1. Responds to faint light but are not useful in daylight. Gives the best resolution

Cones (photoreceptors)

Abundant in and near the fovea. Essential for color vision

Bipolar cells

Found in the retina and sends their information to ganglion cells

Magnocellular (retinal ganglion cell)

Large cell bodies and receptive fields, specialized for detection of movement (peripheral retina)

Parvocellular (retinal ganglion cell)

Small cell bodies and small receptive fields, specialized for object/detail perception (central retina)

Koniocellular (retinal ganglion cell)

Small cell bodies, similar to the parvocellular neurons, but they occur throughout the retina

3 major streams

Motion, shape, and color

Dorsal stream

Visual path in the parietal cortex that helps motor system locate objects. The "WHERE" path (mostly magnucellular)

Ventral stream

Visual path in the temporal cortex that are specialized for identifying and recognizing objects. The "WHAT" path (mostly parvocellular)

Lateral geniculate nucleus (LGN)

Information from magno and parvocellular ganglion cells stays separated (SEGREGATED) in the visual thalamus

3 types of mechanosensation

1. somatosensation
2. proprioception
3. vestibular sensation

Somatosensation (mechanosensation)

Sensation of the body and movement (touch, pressure, vibration, pain, thermal sensation)

Proprioception (mechanosensation)

"body sense"/ where your are (muscles)

Vestibular sensation (mechanosensation)

Balance

Substance P

Primary afferent that responds to painful stimulation, gives a burning sensation

Pariaqueductal gray area

Primary control center for decreasing pain modulation surrounding the cerebral aqueduct in the midbrain

Sensitization

Painful stimuli can increase the responsiveness of nearby painful stimuli

Allodynia

"other pain": painful/inflammation can convert non-painful stimuli to painful (sunburns)

mechanical: just

wearing a shirt
thermal: warm or cool =pain

Vestibular system

Sensory information about motion, equilibrium, and spatial orientation is provided by the vestibular apparatus which includes the utricle, saccule, and 3 semicircular canals in each ear

Utricle & saccule

Respond to changes in the position of the head with respects to gravity (linear acceleration)

Semicircular cannals

Linned with cilia (microscopic hair) filled with a liquid substance, know as endolymph. The body's balance organs responsible for detecting acceleration in the three perpendicular planes

Otolith

Found inside the saccule or utricle of the inner ear. Involved with sensing gravity and movement (it's a little ball that can come in contact with cilia)

Gate theory

Non-painful stimuli (mood, stress, etc.) can modulate pain (rubbing an area in pain reduces the sensation)

Dorsal column pathway

Touch, vibration, etc.

Spinothalamic tract

Pain and temperature

Amplitude

The intensity of a sound wave (height of each wave)

Loudness

A sensation related to amplitude but not identical to it

Frequency

The number of compression of a sound per second, measured in hertz (umber of waves per second)

Pitch

Related aspect of perception. Higher frequency sounds are higher in pitch

External acoustic meatus (outer ear)

Funnels in sound and protects tympanic membrane

Pinna (outer ear)

Helps locate the source of a sound by altering the reflections of sound waves

Tympanic membrane (middle ear)

Vibrates at the same frequency as the sound waves that strike it and transmits the vibrations to the ossicles

Ossicles (middle ear)

Amplifies pressure/sound waves

1. Hammer (Malleus)
2. Anvil (Incus)
3. Stirrup (Stapes)

Place theory

Basilar membrane resembles the strings of a piano in that each area along the membrane is tuned to a specific frequency

Volley principle

Groups of neurons of the auditory system respond to a sound by firing action potentials slightly our of phase with one another so that when combined, a greater frequency of sound can be encoded and sent to the brain to be analyzed

Frequency theory

Basilar membrane vibrates in synchrony with a sound, causing auditory nerve axons to produce action potentials at the same frequency

Tonotopic map

Located in the primary auditory cortex (PAC) in which cells in each area respond mainly to tones of a particular frequency

Sound localization

1. time of arrival
2. loudness
3. phase difference

Amygdala

Responsible for emotion (enjoyment of food-hedonics [pleasant/unpleasant])

Hypothalamus

Regulation thirst, hunger, sleep, etc.

Ingestive behaviors

Local reflex arcs in the MEDULLA can directly control ingestive behaviors like swallowing, vomiting, lip smacking, chewing, salvation

Olfactions

Smell (chemicals) which are transduced into action potentials. Enter the nose and bind with the olfactory cilia (dendrites)

Glomerulus

The primary cell in sensation of smell which will then send projections for further processing. Works better with complex smells

Population coding

Different patterns of glomeruli are activated by different olfactants which produce different/unique smells

Parkinson's disease is caused by the loss of:

Dopamine containing cells

Cells in the primary motor cortex have direct projections to:

Spinal motorneurons

Mamallian olfactoy is different because of:

The hundreds/ thousands of receptor subtypes

Information from the tongue and mouth is directly sent to the:

Nucleus of the solitarius (NTS)

Motor unit

All muscles that a given motor neuron innervates

Motor Pool

All motor neurons that innervate a given muscle

Primary motor cortex (PMC)

Involved in executing an action (fine motor control)

Cerebellum

Responsible for knowing where you are in space (coordination), making adjustments, and sends signals to the PMC. Involved in classical conditioning

Basil ganglion

Prevents unwanted/involuntary movement (resting hand tremor in Parkinson's disease)

Primary excitatory neurotransmitter in the central nervous system is:

Glutamine

Primary inhibitory neurotransmitter in the brain is:

GABA

Neuromuscular juntion

Neurotransmitter is acetylcholine acting at nicotinic receptors. Only one very elaborate synapse per adult muscle fiber.