Brain and Behavior

Neuronal structure

• Cell body• Dendrites• Axon

– Terminal buttons

• Vesicles• Transporter

molecules

– Myelin

Synapse

• Synapse - gap between two neurons

Communication within a neuron

• Action potential– Brief electrical charge that

travels down an axon as charged ions move in and out of the axon’s membrane

Communication within a neuron

• Action potentials– Threshold of excitation– Cell body to terminal buttons– All-or-none firing– Rate of firing

Communication between neurons

• Neurotransmitters– Chemical messengers

released when action potential reaches the terminal button

– Carry message across the synapse

– Fit into receptors on the receiving neuron

• Excitatory• Inhibitory

Communication between neurons

• Synaptic communication is terminated when neurotransmitter is removed from the synapse– Reuptake– Enzymatic deactivation

Neurotransmitters

• Acetylcholine

• Dopamine

• Norepinephrine

• Serotonin

• Glutamate

• GABA

Drugs

• All psychotropic drugs work by binding to receptors in the brain– Agonists– Antagonists

Nervous system

Central nervous system

- Brain

- Spinal cord

Peripheral nervous system

- All nerves extending from CNS

Nervous system

Autonomic nervous system controls physiological arousal

____________division (arousing)

___________ division (calming)

Pupils dilate EYES Pupils contract

Decreases SALIVATION Increases

Perspires SKIN Dries

Increases RESPIRATION Decreases

Accelerates HEART Slows

Inhibits DIGESTION Activates

Secrete stresshormones

ADRENALGLANDS

Decrease secretionof stress hormones

Types of neurons

• Sensory neurons

• Motor neurons

• Interneurons

Reflexes

• Automatic responses to stimuli– Occur entirely within the spinal cord

Brain divisions & regions

• Brain stem– Myelencephalon

• Medulla

– Metencephalon• Cerebellum

– Mesencephalon• Reticular formation

Brain divisions & regions

• Diencephalon – Thalamus– Hypothalamus

Brain divisions & regions

• Telencephalon– Cerebral cortex

• Complex thought and behavior

– Limbic system• Emotions

– Basal ganglia• Coordination and balance

Cerebral cortex

• Frontal lobe

• Temporal lobe

• Parietal lobe

• Occipital lobe

Cerebral cortex

• Frontal lobe– Prefrontal cortex– Motor cortex

• Parietal lobe– Sensory cortex

Cerebral cortex

• Temporal lobe– Auditory cortex

• Occipital lobe– Visual cortex

Courtesy of V

.P. Clark, K

. Keill, J. M

a. M

aisog, S. Courtney, L

.G.

Ungerleider, and J.V

. Haxby,

National Institute of M

ental Health

Lateralization of cortical function

• Left hemisphere– Language areas

• Broca’s area• Wernicke’s area

– Analyzing sequences

• Right hemisphere– Emotion– Spatial relations

Corpus Callosum

• Connects the two cortical hemispheres

Corpus Callosum

Ma

rtin M

. Ro

the

r

Courtesy of T

erence William

s, University of Iow

a

Split Brain Patients

With the corpus callosum severed, objects (apple) presented in the right visual field can be named.

Objects (pencil) in the left visual field cannot.

Limbic system

• Hippocampus

• Amygdala

• Hypothalamus

• Nucleus accumbens

Basal ganglia

• Coordinates balance and motor output– Caudate– Putamen– Globus pallidus