NROSCI 81 Exam 1

Drug

An exogenous chemical that significantly changes certain cell functions at relatively low doses

Exogenous

Produced outside the body

Does drug status depend on legal status?

No. A substance can be a drug whether it is legal or illegal

Psychoactive drug

A drug that acts in the brain and changes thinking or mood or behavior

Does psychoactive mean addictive?

No. Psychoactive effects do not require addiction

Instrumental drug use

Using a drug to achieve a practical goal such as relieving anxiety or staying awake

Recreational drug use

Using a drug mainly for an enjoyable experience

Drug-use intent versus legal status

The person's goal and the drug's legal status are separate ways to classify use

Why use animal models?

They can have simpler nervous systems and allow comparisons across species with fewer ethical constraints

Four Fs

Feeding fighting fleeing and reproductive behavior

CNS housekeeping activities

Regulation of heartbeat body temperature balance and breathing

Reception

Detection of a stimulus by a sensory receptor

Transduction

Conversion of stimulus energy into a neural signal

Transmission

Movement of neural information to the appropriate place

Integration

Combination and interpretation of incoming neural information

Decision and action

Production of a response based on integrated information

Effector

A muscle or other target that carries out a nervous system response

Stretch reflex sequence

Muscle stretch activates a spindle then a sensory afferent reaches the spinal cord then a motor efferent contracts the muscle

Muscle spindle

A sensory receptor within muscle that detects stretch

Afferent neuron

A sensory neuron that carries information toward the CNS

Efferent neuron

A motor neuron that carries commands away from the CNS

Monosynaptic stretch reflex

The spindle afferent directly excites a motor neuron for the same muscle

Interneuron role in a stretch reflex

It can inhibit the opposing muscle so that muscle relaxes

Intrafusal fibers

Muscle fibers inside the spindle that help detect stretch

Extrafusal fibers

Muscle fibers that produce most of a muscle's force

Alpha motor neuron

A motor neuron that drives extrafusal muscle fibers

Gamma motor neuron

A motor neuron that adjusts intrafusal fibers to keep the spindle sensitive

Dorsal spinal root

Route by which sensory information enters the spinal cord

Ventral spinal root

Route by which motor commands leave the spinal cord

Spinal gray matter

Region containing local neuron cell bodies and integration circuits

Spinal white matter

Region containing longer axon pathways

Sensory neuron cell body in a spinal reflex

It lies outside the spinal cord

Can a spinal reflex occur before conscious awareness?

Yes. The local spinal circuit can produce a response before conscious awareness

Central nervous system

The brain and spinal cord

Peripheral nervous system

The nerves connecting the CNS with the rest of the body

Somatic nervous system

Pathways for bodily sensation and skeletal muscle control

Autonomic nervous system

Pathways that regulate organs and glands and cardiac or smooth muscle

Sympathetic division

Autonomic division that supports fight-or-flight responses

Parasympathetic division

Autonomic division that supports rest and digestion

How many cranial nerve pairs are there?

Twelve

Cranial nerve I olfactory

Smell

Cranial nerve II optic

Vision

Cranial nerve III oculomotor

Most eye movements

Cranial nerve IV trochlear

Eye movement

Cranial nerve V trigeminal

Face sensation and jaw movement

Cranial nerve VI abducens

Eye movement

Cranial nerve VII facial

Facial muscles and taste or gland functions

Cranial nerve VIII vestibulocochlear

Hearing and balance

Cranial nerve IX glossopharyngeal

Throat and taste functions

Cranial nerve X vagus

Throat and internal organ functions

Cranial nerve XI accessory

Neck and shoulder movement

Cranial nerve XII hypoglossal

Tongue movement

Gyrus

A ridge or raised fold of cerebral cortex

Sulcus

A groove between cortical gyri

Why is cortex folded?

Folds increase cortical surface area and support specialized connected regions

Occipital lobe

Early visual processing

Parietal lobe

Somatosensation including touch and pain plus later visual processing

Temporal lobe

Hearing memory and language comprehension

Frontal lobe

Movement planning working memory planning and inhibition of inappropriate behavior

Brainstem divisions

Midbrain pons and medulla

Medulla

Breathing and other vital functions

Pons

Sleep arousal and communication among brain regions

Midbrain

Movement arousal and reward

What runs through all brainstem levels?

Sensory and motor axons

Cerebellum

Helps plan coordinated movement and correct movement errors

How does the cerebellum support motor learning?

It compares intended movement with actual movement and changes synapses with experience

Diencephalon

Brain region containing the thalamus and hypothalamus

Thalamus

A relay for information traveling to and from the neocortex

Hypothalamus

Regulates autonomic functions motivated behaviors sleep-wake cycles and hormone release

Pituitary gland in the study guide

A hormone releasing gland controlled by the hypothalamus

Limbic system

Connected areas involved in emotional behavior motivation memory sexual behavior and reward or punishment

Hippocampus

Supports memory consolidation and provides context

Amygdala

Coordinates autonomic responses with emotional states

Cerebral cortex in limbic behavior

Interacts with deeper structures to guide behavior

Ventral tegmental area or VTA

A midbrain source of dopamine neurons that project to the nucleus accumbens

Nucleus accumbens or NAc

A region involved in motivation and drug related reinforcement

VTA to NAc pathway

A dopamine pathway that drugs can affect directly or indirectly during reward

Basal ganglia

A set of circuits that helps select and smooth voluntary movement

Basal ganglia structures on the slides

Striatum globus pallidus and substantia nigra

Striatum

The caudate and putamen together

Stimulants in basal ganglia

Their action can increase motor activity

Principle of dynamic polarity

Information in a model neuron usually flows from dendrites through soma and axon to terminals

Who described dynamic polarity?

Ramón y Cajal

Dendrites

Branched structures that receive many neuronal inputs

Dendritic spines

Specialized sites that increase the number of synaptic input locations

Soma

The neuron cell body containing the nucleus and other organelles

Axon hillock

A trigger zone where combined inputs can initiate an action potential

Axon

The part of a neuron that conducts action potentials toward the terminals

Axon terminals

Output regions that release neurotransmitter

Synapse

A junction where a presynaptic cell exchanges information with a postsynaptic cell

Presynaptic zone

The transmitter releasing side of a synapse

Postsynaptic zone

The transmitter receiving side of a synapse

Synaptic cleft

The narrow gap between presynaptic and postsynaptic zones

Sensory neuron functional role

Reception of information from a receptor

Interneuron functional role

Integration of information within a neural circuit

Motor neuron functional role

Delivery of commands to an effector

Four neural signaling components

Graded input then trigger-zone integration then action-potential conduction then output

Electrical to chemical to electrical signaling

An action potential triggers transmitter release and transmitter creates a postsynaptic voltage change

Receptor potential

A graded electrical change produced when a sensory receptor transduces a stimulus

Synaptic potential

A graded postsynaptic voltage change caused by neurotransmitter action