Objectives Gain a general understanding of the nervous system Gain knowledge of the structure and function of the neuron Navigate your way around the major brain areas and understand their function ID: 633185
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Slide1
Neuroscience and BehaviorSlide2
Objectives
Gain a general understanding of the nervous system
Gain knowledge of the structure and function of the neuron
Navigate your way around the major brain areas and understand their functionSlide3
Nervous System HierarchySlide4
Central nervous system
Brain
~2% of body weight, uses ~20% of resources
Composed of bunches of
neurons
, which form nerves
Spinal cord
Complex tangle of nerves that stretch from brain to tailbone
Collects & transmits info between brain and peripheral nervous system
Also initiates
reflexes
: automatic responses to an eventSlide5
Peripheral Nervous System
PNS links the CNS to the organs, muscles, and glands of the body
PNS has two parts
Somatic
(SNS): nerves controlling voluntary muscle movements
Autonomic
(ANS): controls glands, organs, blood vessels
ANS has two parts
Sympathetic
: arouses body to prepare for action (fight or flight)
Parasympathetic
: slows down body to reserve energySlide6
Sympathetic and ParasympatheticSlide7
The Neuron
All brain activity originates with the neuron
The messengers of the brain-world
These cells receive signals from neurons or sense organs, process the signals, and send them to other neurons, muscles, or organs
Three types
Sensory: respond to sensory organ input
Motor: send signals to muscles to control movement
Interneurons: the go-between of sensory and motor neurons
We have about 100 billion neurons
Most, but not all, can be re-grown (severe spinal cord injury vs. cutting your finger)Slide8
The NeuronSlide9
The Neuron: Structure
Cell body
: houses nucleus
Cell Membrane
: skin of the cell
Axon
: cable extending from the cell body
Impulse from cell body travels along axon to its end, where terminal buttons release
neurotransmitters
(chemical messengers), received by other neurons
Axon is covered by
myelin sheath
, which is composed of a fatty substance that helps impulses travel the length of the axon
Dendrite
Branches extending from cell membrane that receive neurotransmitters from other neuronsSlide10
The Dendrite
Increases receptive surface of the neuron
Contacts occur along surface of dendriteSlide11
The Axon
Axon hillock
Myelin sheath
Nodes of Ranvier
The points just between the myelin sheathsSlide12
The Neuron in Action
When a neuron receives impulses from other neurons, the cell membrane allows open exchange of positively and negatively charged ions
Action potential
(change in electrical charge) runs down axon to terminal buttons
This all starts with the
axon hillock
– the gatekeeper of the neuron
Terminal buttons release neurotransmitters
Neurotransmitters cross the synaptic cleft to the dendrite of the receiving neuronSlide13
The Neuron in actionSlide14
Communication in the Neuron
All-or-nothing
The action potential either happens or it doesn’t
Non-decremental
Action potentials don’t change in amount (voltage) as they travel
Refractory period
Neurons need 2ms to recover before they can transmit again
Threshold
The minimum level of stimulation required to trigger a neural impulse
Once you reach the threshold, the action potential doesn’t get biggerSlide15
Several Neurotransmitters
Acetylcholine (Ach)
Slows down the body, memory, and attention (involved in Alzheimer’s disease)
Dopamine (DA)
Voluntary movement, attention, and learning; high levels are associated w/ schizophrenia
Endorphin
Reduce sensitivity to pain; linked with pleasure (opiate-like)
Serotonin
Arousal, sleep; Prozac increases levels of serotonin
Norepinephrine
Helps control alertness and arousal; low levels can depress moodSlide16
History of Studying the Brain
Franz Joseph Gall (1758 – 1828)
Phrenology
The study of the structure of the skull to determine a person’s character and mental capacity
26 ‘organs’ on the surface
of the brainSlide17
History of Studying the Brain
Phrenological Map of the SkullSlide18
History of Studying the Brain
Flourens (1794 – 1867)
Emphasized the importance of experimental research of the brain
Carefully controlled experiments on animals to determine localities of brain and their functions
Moved the field of brain research into a more scientific arenaSlide19
The Brain
Three main parts
Brain Stem
Limbic System
Cerebral CortexSlide20
Areas of the BrainSlide21
Brain Stem
Region of the brain where the spinal cord enters the skull and swells
Medulla
Regulates heart-rate, breathing, blood pressure, and motor movements
Cerebellum
Controls skilled motor movementsSlide22
Brain Stem
Pons
Connects the two hemispheres of the cerebellum
Reticular formation
Sleep (Moruzzi & Magoun, 1961)
Attention
Thalamus
Relay center
Filters & organizes information from sensesSlide23
Limbic System
Hypothalamus
Feeding
Reproductive behavior
Temperature (Barbour, 1912)
Hippocampus
Memory
H.M.
Amygdala
Feeding
Memory
EmotionSlide24
Cerebral Cortex
Two halves, four lobes
Frontal lobe
Motor cortex
Parietal lobe
Sensory cortex
Prosopagnosia
Unilateral neglect
Temporal lobe
Auditory areas
Occipital lobe
Visual areasSlide25
Two Cerebral Hemispheres
Contralateral arrangement
Corpus callosum
Thick band of nerve fibers connecting the hemispheres
It’s how the 2 hemispheres communicate
Right-brained vs. left-brained?
ORSlide26
Left & Right Functions