Upload
virgil-fitzgerald
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
1
Chapter 3: The Biological Bases of
Behavior
2
Communication in the Nervous System
• Hardware:1) Glia: structural support and insulation (Glue) 2) Neurons: communication (receives, integrate & transmits)
Dendrites – receive message
Soma – cell body
Axon – transmit message
Myelin sheath- speeds up transmission
Terminal Button- end of axon, release message
Synapse- gap between Button & Dendrite
3
Structure of the Neuron
4
The Neural Impulse
1) Resting Potential- Neuron is Ready› -70 millivolts
2) Action Potential- Neuron Fires (down axon)› Sodium + ions flow in, Potassium - ions flow out
3) Refractory Period- Neuron is Recharging› The minimum time after firing, cannot fire until charged
All or None Principle- Neuron fires at the same speed whether it was strong or weak. Either fires or doesn't.
5
The Neural Impulse
6
The Synapse: Chemicals as Signal Couriers
• Neurotransmitters: is the chemical message that transmit info from one neuron to another.– Presynaptic neuron (Terminal Button)
• Synaptic vesicles: Contain Neurotransmitters
– Postsynaptic neuron (Dendrites)• Receptor sites: Located on dendrites, each receptor
site receive specific neurotransmitters
7
8
When a Neurotransmitter Binds:The Postsynaptic Potential
Postsynaptic Potential (PSP)Changes the probability of the postsynaptic neuron firing
– Excitatory PSP: Positive voltage shift, increase firing
– Inhibitory PSP: Negative voltage shift, decrease firing
• Reuptake: All the excess neurotransmitters that don’t bind to a receptor site get sucked up into the terminal button
• Synaptic connections– Elimination and creation– Synaptic pruning
9
Overview of Synaptic Transmission
10
Synaptic Pruning
Types of Neurons
• Sensory Neurons– Nerves that carry information to the central
nervous system Connect the sense organs to the brain and spinal cord
• Motor Neurons– Nerves that carry information from the central nervous
system Carries messages from the brain and spinal cord to other parts of your body
• Inter Neurons– Nerve cells in the brain and spinal cord responsible for
processing information related to sensory input and motor output 11
The Neural Chain
12
13
Neurotransmitters
Specific neurotransmitters work at specific synapses– Lock and key mechanism– (15 – 20) neurotransmitters known at present• Agonist – mimics neurotransmitter action• Antagonist – opposes action of a
neurotransmitter
14
Common Neurotransmitters and Some of their Functions
15
Neurotransmitter Helpful Hints
• ACh- AAMM• DA- Sell Dope at the Park (Parkinson)
Movement & Pleasure
• NE- Norma PMS (Mood & Arousal)
• Serotonin- Sleep/Wakefulness, Eating/Aggression (Ninja Turtles, SEWA)
• GABA- Inhibitor
• Endorphins- Natural pain reliever
16
Organization of the Nervous System
• Central nervous system (CNS)Brain & Spine (It is the center)
– Hindbrain. Back bottom– Midbrain. Core– Forebrain. Outer
• Peripheral nervous system (PNS)Bones. Organs. Muscles. (Is everything else)
– Somatic nervous system (SNS) voluntary• Afferent = (In) toward the CNS• Efferent = (Out) away from the CNS
– Autonomic nervous system (ANS) automatic• Sympathetic (Fight or Flight)• Parasympathetic (Calming)
17
Organization of the NS
18
The CNS & PNS
19
The Autonomic Nervous System (ANS)
20
Studying the Brain: Research Methods
• Electroencephalography (EEG). Brain Waves • Damage studies/lesioning • Electrical stimulation (ESB). Mapping out the Brain
• Brain Imaging – – CT Scan (computerized tomography). X-Ray of brain structure – PET Scan (positron emission tomography). Brain function,
shows activity in the brain with radioactive glucose. – MRI Scan (magnetic resonance imaging). 3D pictures
– fMRI Scan (functional magnetic resonance imaging). Additional oxygen & blood flow. Structure & function
21
Accidents
Phineas Gage Story• Personality changed
after the accident.
What this this tell us?• That different part of
the brain control different aspects of who we are.
22
Lesions
• Purposeful removal or destruction of some part of the brain.
• Frontal Lobotomy
23
Brain Regions & Functions• Hindbrain:
– Medulla. vital functions – Pons. facial expression, sleep & dreaming– Cerebellum. movement & balance
• Midbrain: (Plug into hard drive)
– Reticular Formation. sensory functions • Forebrain:
– Basal ganglia. Regulates muscle contraction/movements– Thalamus. All senses except smell– Hypothalamus. 4 “F’s”– Limbic system
• Hippocampus. Learning & Memory (Hip to the campus)• Amygdala. Emotion (Amy is emotional)
– Cerebrum. Outer layer of brain (largest) is covered by…– Cerebral cortex. Wrinkles in the outer layer 1.5 sqf (gray
matter)
24
The Cerebrum:Two Hemispheres, Four Lobes
• Cerebral Hemispheres – two specialized halves connected by the corpus callosum
• Contralateral Control- each hemisphere controls opposite sides of the body– Corpus Collosum- connects the hemispheres
• Lateralization- left & right hemispheres have different functions– Left hemisphere – verbal processing: language, speech,
reading, writing– Right hemisphere – nonverbal processing: spatial,
musical, visual recognition
25
The Cerebrum:Two Hemispheres, Four Lobes
• Four Lobes:– Occipital – vision– Parietal – somatosensory/motor cortex– Temporal - auditory– Frontal – movement, executive control
systems
26
Structures & areas in the human brain
27
Brain Reorganization
• Corpus Callosum neural fiber connecting the 2 brain hemispheres & carrying messages between the hemispheres.
• Split Brain was used to cure epilepsy by cutting the corpus callosum.
• Brain Plasticity is the brain’s capacity to overcompensate for a loss of a brain function. Higher in children.
28
The Cerebral Hemispheres & The Corpus Callosum
29
Spilt Brain
30
The Cerebral Cortex in Humans
31
The Primary Motor Cortex
32
Language processing in the brain
33
The Endocrine System: Hormones
Hormones – Chemical messengers produced by the endocrine glands and circulated in the blood
Similar to neurotransmitters in that they are also messengers
Slower communication system, but with longer lasting effects
The Endocrine System: Glands• Endocrine glands
– Pituitary – “master gland,” growth hormone– Thyroid – helps regulate the energy level in
the body metabolic rate– Adrenal – help to arouse the body in times of
stress, Located above the kidneys, Release epinephrine (adrenaline) and norepinephrine
– Pancreas – regulates the level of sugar in the blood
– Gonads – sex hormones, Ovaries (females) and testes (males) influence emotion and physical development. 34
35
Genes & Behavior:The Field of Behavioral Genetics• Behavioral genetics = the study of the
influence of genetic factors on behavioral traits• Chromosomes – strands of DNA carrying
genetic information– Human cells contain 46 chromosomes in pairs
(sex-cells – 23 single)– Each chromosome – thousands of genes, in pairs
• Dominant, recessive/Homozygous, heterozygous
• Genotype- Genetic makeup• Phenotype- manifested in characteristics • Polygenic Inheritance- characteristics
influenced by more than one gene
36
Genetic Material
37
Research Methods in Behavioral Genetics
• Family studies – does it run in the family?
• Twin studies – compare resemblance of identical and fraternal twins on a trait
• Adoption studies – examine resemblance between adopted children and their biological and adoptive parents
38
Genetic Relatedness
39
Family studies of risk for Schizophrenic Disorders
40
Twin studies of Intelligence &Personality
41
Modern Approaches to theNature vs. Nurture Debate
• Molecular Genetics = the study of the biochemical bases of genetic inheritance– Genetic mapping – locating specific genes -
The Human Genome Project
• Behavioral Genetics– The interactionist model– Richard Rose (1995) – “We inherit
dispositions, not destinies.”
42
Evolutionary Psychology:Behavior in Terms of Adaptive Significance
• Based on Darwin’s ideas of natural selection– Reproductive success key
• Adaptations – behavioral as well as physical– Fight-or-flight response– Taste preferences– Parental investment and mating