Neuroscience & Psychology

ObjectivesGain a general understanding of the nervous systemGain knowledge of the structure and function of the

neuronNavigate your way around the major brain areas and

understand their function

Nervous System Hierarchy

Central nervous systemBrain

~2% of body weight, uses ~20% of resourcesComposed of bunches of neurons, which form nerves

Spinal cordComplex tangle of nerves that stretch from brain to

tailboneCollects & transmits info between brain and peripheral

nervous systemAlso initiates reflexes: automatic responses to an

event

Peripheral Nervous System

PNS links the CNS to the organs, muscles, and glands of the body

PNS has two partsSomatic (SNS): nerves controlling voluntary muscle

movementsAutonomic (ANS): controls glands, organs, blood

vesselsANS has two parts

Sympathetic: arouses body to prepare for action (fight or flight)

Parasympathetic: slows down body to reserve energy

Sympathetic and Parasympathetic

The NeuronAll brain activity originates with the neuronThe 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 typesSensory: respond to sensory organ inputMotor: send signals to muscles to control movement Interneurons: the go-between of sensory and motor neurons

We have about 100 billion neuronsMost, but not all, can be re-grown (severe spinal cord injury

vs. cutting your finger)

The Neuron

The Neuron: StructureCell body: houses nucleusCell Membrane: skin of the cellAxon: 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

DendriteBranches extending from cell membrane that receive

neurotransmitters from other neurons

The DendriteIncreases receptive surface of the neuronContacts occur along surface of dendrite

The AxonAxon hillockMyelin sheathNodes of Ranvier

The points just between the myelin sheaths

The Neuron in ActionWhen a neuron receives impulses from other

neurons, the cell membrane allows open exchange of positively and negatively charged ionsAction potential (change in electrical charge) runs down

axon to terminal buttonsThis all starts with the axon hillock – the gatekeeper of

the neuronTerminal buttons release neurotransmittersNeurotransmitters cross the synaptic cleft to the

dendrite of the receiving neuron

The Neuron in action

Communication in the Neuron

All-or-nothingThe action potential either happens or it doesn’t

Non-decrementalAction potentials don’t change in amount (voltage) as they

travelRefractory period

Neurons need 2ms to recover before they can transmit again

ThresholdThe minimum level of stimulation required to trigger a

neural impulseOnce you reach the threshold, the action potential doesn’t

get bigger

Important 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 mood

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 surfaceof the brain

History of Studying the Brain

Phrenological Map of the Skull

History of Studying the Brain

Flourens (1794 – 1867)Emphasized the importance of experimental research

of the brainCarefully controlled experiments on animals to

determine localities of brain and their functionsMoved the field of brain research into a more scientific

arena

Areas of the Brain

Five Major Brain Areas CEREBRAL CORTEX is involved in your higher mental functions

of perceptual awareness, recognition and interpretation of sensory stimuli (mostly based on memories).

PREFRONTAL CORTEX is involved in your conscious thinking processes, especially making choices by using your brainpower

LIMBIC SYSTEM is involved in the expression of your instincts and feeling processes, including your moods, since it includes your hypothalamus and amygdala parts;

CEREBELLUM is involved in your posture and many coordinated movements;

BRAINSTEM controls your body's most basic unconscious life-sustaining functions, including your breathing and heartbeat.

Cerebral CortexTwo halves, four lobes

Frontal lobe (seat of intelligence)Motor cortex (walking, chewing)

Parietal lobeSensory cortex

Prosopagnosia (face blindness) Unilateral neglect (only realize half)

Temporal lobeAuditory areas (opposite ear)

Occipital lobeVisual areas (opposite eye)

Prefrontal CortexThe prefrontal cortex (PFC) is the very front of the

brain, located right beneath the forehead. It is in the anterior (front) region of the frontal lobes.

It is responsible for the executive functions, which include mediating conflicting thoughts, making choices between right and wrong or good and bad, predicting future events, and governing social control — such as suppressing emotional or sexual urges.

The prefrontal cortex is the brain center most strongly implicated in qualities like sentience, human general intelligence, and personality.

Limbic SystemHormonal system*Hypothalamus

FeedingReproductive behaviorTemperature

HippocampusMemory

AmygdalaFeedingMemoryEmotion

CerebellumThe cerebellum (Latin for little brain) is a region

of the brain that plays an important role in motor control. It is also involved in some cognitive functions such as attention and language, and probably in some emotional functions such as regulating fear and pleasure responses.

Brain MappingHow your brain is laid out. Actually, how any

animals brain is laid out.Two parts, linked together, but functioning as

one unit/different units.Distinct differences between hemispheres. Left

handed-ness or right handed-ness.

Left & Right Functions

Two Cerebral HemispheresContralateral arrangementCorpus callosum

Thick band of nerve fibers connecting the hemispheres

It’s how the 2 hemispheres communicateRight-brained vs. left-brained? Bicamerialism??

OR

Brain StemRegion of the brain where the spinal cord enters the

skull and swellsMedulla

Regulates heart-rate, breathing, blood pressure, and motor movements

CerebellumControls skilled motor movements

Brain StemPons

Connects the two hemispheres of the cerebellumReticular formation

SleepAttention

ThalamusRelay center

Filters & organizes information from senses

Preserve Your Brain

This is a “normal”brain firing

This is a brainthat has just doneecstasy