Intro to Behavioral Neuroscience Week #2

Sensory Neuron

unipolar neuron, one end is highly sensitive to senses

motor neuron

multipolar molecule, soma is in the spinal cord and receives excitation from other neurons and conducts impulses along axon to the muscle.

Dendrites

tree-like branch structures extending from a neuron that receive chemical and electrical signals from other nerve cells

Dendritic spines

provide sites for postsynaptic contact, highly plastic which allows for rapid changes in connectivity following environmental experiences

Cell body (soma)

contains: nucleus, mitochondria, ribosomes, etc

Axon

transmits nerve impulses toward other neurons, organs, and muscles

T or F: Neurons can only have one axon

True

Bifurcate

axon branches into two

What are at the end of axons?

Presynaptic terminal or boutons

Presynaptic terminals or boutons

release chemicals to communicate with other neurons occurs here

myelin sheath

Insulating lipids that cover axons increase electrical effciency

Nodes of Ranvier

interruptions in the myelin sheath increase speed and efficiency

Afferent axon

refers to bringing information TOWARD a structure

Efferent axon

refers to carrying information AWAY from a structure

Interneurons

specialized nerve cells that are contained witin a single structure

What are the 4 zones the information must go through on a neuron?

Input, Integration, Conduction, Output

1- Input Zone (Receive)

Where a neuron receives information from other neurons, mostly dendrites (some cell body)

2- Integration Zone (Decide)

Neuron cell body/axon hillock combines all the incoming information and decides if it has enough information to send its own signal

3- Conduction Zone (Carry)

If the neuron decides to send the signal, it travels down the axon toward the next neuron

4- Output Zone (Send)

Axon terminals release neurotransmitters to communicate with the next neuron.

Synapse

The site of communication between neurons

Active Zone

The region of the presynaptic bouton that regulates neurotransmitter release

Synaptic Vesicles

Tiny hollow sphere inside presynaptic terminals that contain neurotransmitters

Neurotransmitters

Chemical substances used to communicate with postsynaptic neuron.

What are the 4 functional zones of a neuron?

Input zone, integration zone, conduction zone, output zone

What is the input zone?

Mostly dendrites; receives information from other neurons

What is the integration zone?

The cell body/axon hillock combines the incoming information to determine whether to send a signal

What is the conduction zone?

The axon; carries the neuron’s electrical signal away from the cell body.

What is the output zone?

Axon terminals/boutons; where the neuron’s activity is transmitted across synapses

What do dendrites do?

Receive information from other neurons

What are dendritic spines?

Tiny highly plastic things on dendrites that provide sites for postsynaptic contact

What does the soma/cell body contain?

The nucleus, ribosomes, and other cellular structures

What does the axon do?

Transmits nerve impules toward other neurons, organs, or muscles

What are presynaptic terminals/boutons?

End point of an axon where chemicals are released to communicate with other neurons

What is a synapse?

A site of communication between neurons

What is the active zone?

The region of the presynaptic bouton that regulates the release of neurotransmitters.

What are synaptic vesicles?

Tiny spheres that contain neurotransmitter molecules

What are neurotransmitters?

Specialized chemical substances used to communicate with the postsynaptic neuron

What do neurotransmitters do at a synapse?

They are released from vesicles, cross the synaptic cleft, and bind to postsynaptic receptors

What are postsynaptic receptors?

Specialized proteins on the postsynaptic cell that bind neurotransmitters and cause localized changes in electrical activity

What is the postsynaptic density (PSD)?

A protein-dense network attached to the postsynaptic membrane that contains many receptors and helps make synapses modifiable

What is the difference between presynaptic and post synaptic?

Presynaptic= sending side; Postsynaptic= receiving side

What does afferent mean?

Bringing information toward the structure

What does efferent mean?

Carrying information away from the structure

What is an interneuron?

A neuron whose dendrites and axons are completely contained within a single structure

What are gila?

Major components of the nervous system that exchange chemicals with adjacent neurons

Type of gila: What do astrocytes do?

Support neurons, regulate local blood flow, participate in synaptic communication, and help form/prune synapses

Type of gila: What do microglia do?

Survey for damage, respond to injury, remove debris, and participate in synapse formation/elimination

What is the main difference between oligodendrocytes and Schwann cells?

Oligodendrocytes= CNS; Schwann cells= PNS myelin

What do radial gila do?

Guide neuron migration and the growth of axons and dendrites

What is the blood brain barrier (BBB)?

A separation between circulating blood and the extracelular fluid surrounding the brain

What are the two layers of the BBB?

Specialized endothelial cells and astrocytes.

What is passive transport?

Movement across the BBB that can happen freely by diffusion.

What is active transport?

Movement across the BBB that requires energy and is more tightly regulated.

Give examples of substances using passive transport across the BBB.

Oxygen, Carbon dioxide, steroid hormones, alcohol, and some fat-soluble compounds

Give examples of substances using active transport across the BBB

Glucose and amino acids

What are the two major divisions of the nervous system?

Central nervous system and peripheral nervous system

What makes up the CNS?

Brain and spinal cord

What makes up the PNS?

Somatic and autonomic nervous systems

What does the somatic nervous system do?

Carries messages from sensory organs to the CNS and from the CNS to muscles

What does the autonomic nervous system regulate?

Automatic behaviors (HR etc)

What is the main role of the autonomic nervous system?

maintaining homeostasis

What is homeostasis?

Regulation of the internal environment to maintain a stable and constant condition

What does the sympathetic nervous system do?

Prepares the body for fight or flight; increases heart rate, blood pressure, and respiration

What neurotransmitter is used by sympathetic postganglionic neurons?

Norepinephrine

What does the parasympathetic nervous system do?

Promotes resting functions such as digestion and lowers hr and blood pressure

What neurotransmitter is released by parasympathetic postganglionic neurons?

Acetylcholine

What is gray matter?

The central part of the spinal cord, densely packed with cell bodies and dendrites

What is white matter?

Mostly myelinated axons that carry information

What does the dorsal root ganglion do?

Brings sensory information into the CNS

What is a ganglion?

A group of neuronal cell bodies outside the CNS

What is a nucleus?

A group of neuronal cell bodies within the CNS

What are tracts?

Clumps of axons

What information travels through the dorsal side of the spinal cord?

Incoming sensory information

What information travels through the dorsal side of the spinal cord?

Incoming sensory information

What information travels through the ventral side?

Outgoing motor information

What are the 3 major divisions of the brain?

Forebrain, midbrain, hindbrain

What structures make up the hindbrain?

Myelencephalon (medulla) and metencephalon (cerebellum and pons)

What does the medulla control?

Vital reflexes such as breathing and hr, etc

What does the cerebellum do?

regulates motor movement, balance, and coordination

What does the pons do?

Contains structures important for sleep-wake regulation

What does the superior colliculus do?

helps orient to visual stimuli

What does the inferior colliculus do?

Helps orient auditory stimuli

What are the superior and inferior colliculi collectively called?

The tectum

What are the two major parts of the forebrain?

Diencephalon and telencephalon

What does the hypothalamus do?

Controls endocrine function through the pituitary and is involved in motivated behaviors such as eating, drinking, reproduction, and defensive behaviors

What does the pituitary glad do?

Produces hormones and is controlled by the hypothalamus

What does the thalamus do?

Processes/relays sensorimotor information between corical and subcortical systems

What are the 3 parts of the basal ganglia?

Caudate nucleus, putamen, and globus pallidus

What is the basal ganglia associated with?

Voluntary movement, procedural learning, and habit behaviors

What functions is the limbic system broadly involved in?

Emotion, behavior, motivation, long-term memory, and olfaction

what structures are part of the limbic system?

Olfactory bulb, hippocampus, amygdala, hypothalamus, and cingulate gyrus

What does the hippocampus do?

IS critical for converting/storing short-term memories into long-term memories and for spatial learning

What does the amygdala do?

Is involved in emotional expression, especially fear-evoking/threatening situations

What is the neocortex?

Cortex containing six distinct layers (lamine)

What is the allocortex?

A type of cortex with fewer than six layers.

What is the corpus callosum?

A large bundle of axons connecting the two cerebral hemispheres

Where are the 4 lobes of the cerebral cortex?

Frontal, parietal, temporal, occipital

What does the occipital lobe usually process

Vision

What does the parietal lobe usually process?

Somatosensory info