1. Neuroscience & the Brain
Unit 2
Neuroscience & the Brain

2. Biological psychology
Study the link between biological activity and psychological events
Branch of psychology concerned with the links between biology and behavior
Examples – behavioral geneticists, behavioral neuroscientists, biopsychologists, etc.

3. Neural communication
Neuron – a nerve cell, basic building block of the nervous system
Each consists of a cell body and its branching fibers
Dendrite – neuron’s bushy, branching extensions that receive messages and conduct impulses toward the cell body
DENDRITES LISTEN – brings info in
Axon – neuron extension that passes messages through its branches to other neurons or to muscles/glands
AXONS SPEAK – sends message (to other neurons or muscles or glands)

5. NEURAL COMMUNICATION
Myelin sheath – fatty tissue layer that insulates some axons
Speeds their impulses
Fully laid down around 25 – neural efficiency, judgment and self-control grow
Degeneration = multiple sclerosis – communication to muscles slow – loss of muscle control

6. Action potential
neural impulse – brief electrical charge that travels down axon
Speed varies – 2mph – 180mph
Time to react and take action
Neurons are like batteries – generate electricity
Inside axon = +ions
Outside axon = -ions
Resting potential – even # of + and –
like a gate – no message sent
Depolarization – unfreezes the axon [gate] allowing the message to send
Refractory period – resting period – when extra atoms are pushed out

8. THREshold
The level of stimulation required to trigger a neural impulse – action potential
When excitatory ions minus the inhibitory ions exceed minimum intensity (threshold), the neuron fires an action potential.
ALL OR NONE RESPONSE – either fire or don’t (full strength)

9. Neural firing and a toilet…
Like a neuron, a toilet has an “ action potential ”. When you flush, an “impulse” is sent down a sewer pipe.
Like a neuron, a toilet has a refractory period . There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilled.
Like a neuron, a toilet has a resting potential . The toilet is “charged” when the tank is full and it is capable of being flushed again.

10. Neural firing and a toilet…
Like a neuron, a toilet operates on an all - or - none principle . It always flushes with the same intensity, no matter how much force you apply to the handle.
Q: So how can we tell the difference between a love tap and a punch??
A: Because the NUMBER of neurons that fire depend on the intensity of the stimulation. So, the intensity is based on how many neurons fire. They all fire at the same intensity.

11. synapse
The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
Synaptic gap – tiny gap
Air kisses
Neurons send info through synaptic gap with neurotransmitters

12. neurotransmitters
Chemical messengers that cross the synaptic gap between neurons
Bind to receptor sites – fit like a lock and key
Ions flow in - a neuron’s readiness to fire
Excitatory
Inhibitory
Reuptake – a neurotransmitter’s reabsorption by the sending neuron
Get sucked back up and used in next message

13. neurotransmitters
Each pathway uses different neurotransmitters, each neurotransmitter has a different function
===================================
Take 15ish minutes and complete your neurotransmitters chart with a partner. Explain each neurotransmitter’s function as well as provide an example for the malfunction

14. How drugs effect neurotransmitters
Many drugs mimic the neurotransmitter
Agonist vs. antagonist
Agonist – excitatory – increases effect of neurotransmitter (mimics)
Opiate drugs
Glutamate
Amphetamines
Antagonist – inhibitory – slow down the effect of neurotransmitter (destroy connections or block them)
Botox – smooth wrinkles by paralyzing underlying facial muscles
GABA
Alcohol

15. Agonist mimics neurotransmitter Antagonist blocks Neurotransmitter
molecule
Receiving cell
membrane
Receptor site on
receiving neuron
Agonist mimics
neurotransmitter
Antagonist
blocks

16. The nervous system
Body’s speedy, electrochemical communication network consisting of all nerve cells of PNS and CNS
2 parts
Central Nervous System
Peripheral Nervous System
The nervous system uses 3 types of neurons
1. sensory
2. interneurons
3. motor neurons

18. THE NERVOUS SYSTEM
Nerves – bundled axons that form neural “cables” connecting the CNS with muscles, glands, and sense organs
3 types of neurons
1. sensory – carry incoming info from body’s tissues and sensory receptors to brain and spinal cord
MILLIONS
AFFERENT
2. interneurons – communication that takes place internally and intervene between sensory input and motor output
BILLIONS
3. motor neurons – carry outgoing info from brain and spinal cord (CNS) – muscles/glands
EFFERENT

20. THE NERVOUS SYSTEM – CNS & PNS
CNS – brain and spinal cord
Body’s decision maker
Spine connects PNS to brain
Reflex – simple, automatic response to a sensory stimulus, such as the knee-jerk response
PNS – the sensory and motor neurons that connect the CNS to the rest of the body
Responsible for gathering info and sending CNS decisions

21. PERIPHERAL NERVOUS SYSTEM
SOMATIC NERVOUS SYSTEM
Control’s the body’s skeletal muscles - voluntary
aka skeletal nervous system
Bell rings at the end of class – SNS reports to brain – carries instructions back – triggering your body to rise from your seat
AUTONOMIC NERVOUS SYSTEM
Controls our glands and the muscles of our internal organs, influencing such functions as heartbeat, digestion, and hormones
Autopilot – operates on its own – autonomously

22. Autonomic nervous system
SYMPATHETIC NERVOUS SYSTEM
*arouses the body
*mobilizes its energy in stressful situations
*accelerated heartbeat
*raise blood pressure
*slows digestion
PARASYMPATHETIC NERVOUS SYSTEM
*calms the body
*conserves its energy
*decreased heartbeat
*lowering blood sugar

24. TOOLS OF DISCOVERY
THE BRAIN

25. Tools of Discovery Manipulating the brain – Clinical Observations
Lesions
electromagnetic charges
chemical and magnetic stimulation
Clinical Observations
- looking at damaged brains
Recording Electrical Activity EEG ( electroencephslogram)
an amplified recording of the waves of electrical activity that sweep across the brain’s surface

26. Tools of Discovery Neuroimaging- CT (Computed tomography) Scan-
X- Ray photographs
PET (Positron emission tomography) Scan
Looks at sugar glucose to determine brain activity
“HOT SPOTS”
MRI- (Magnetic Resonance Imaging)
generated images that distinguish among different types of soft tissue; allows us to see structures within the brain.

27. PET SCAN

28. Lower Level Brain Structure

29. Lower Brain Lower Brain-
performs life saving operations freeing the higher brain regions to think, dream, memorize..
We are unaware of most of its functions

30. Lower Level Brain Structure The Brainstem
where spinal cord enters the skull
Crossover point for nerves
responsible for automatic survival functions
Medulla- Heartbeat and breathing

31. Lower Level Brain Structure The Brainstem
3. Reticular Formation-
Filter and relay station
Controls arousal
4. Thalamus-
Sensory input station, except smell
Receives higher brains replies
Controls electrical cycles. Slows during sleep; speeds up while awake

32. Lower Level Brain Structure The Brainstem
5. The Cerebellum
Coordinates voluntary movements
Balancing, walking……….
Nonverbal voluntary movement
6. Pons
Regulates sleep

33. The Limbic System

34. The Limbic System
associated with emotions such as fear and aggression and drives such as those for food and sex
includes the hippocampus, amygdala, and hypothalamus.

35. The Limbic System Processes memory Forms new memories
1. Hippocampus-
Processes memory
Forms new memories
2. Amygdala-
Aggression and fear

36. The Limbic System directs several maintenance activities
3. Hypothalamus-
Controls pituitary gland (hormones)
directs several maintenance activities
eating
drinking
body temperature
Triggers autonomic nervous system
Pleasure Center
Reward Deficiency Syndrome- alcoholism, binge drinking, drug abuse

37. The Cerebral Cortex
Thin layer covering your cerebral hemispheres- wrinkly thing
Neural cells
Controls body and info
The bigger the better

38. Structure and Functions
The Cerebral Cortex
Structure and Functions
Each hemisphere is divided up into 4 lobes
Frontal
Occipital
Temporal
Parietal
Glial Cells- -
neural nannies
Support the 22 billion nerve cells

40. The Cerebral Cortex Motor Cortex- outgoing messages to the body
1. Frontal Lobe- speaking, muscle movement, making plans, judgments
Motor Cortex- outgoing messages to the body

41. The Cerebral Cortex
2.Parietal Lobe- sensory cortex
Sensory Cortex-registers and processes body sensations
Receives info from skin receptors
More sensitive= bigger area
3.Occipital Lobe- receives visual from opposite sides

42. The Cerebral Cortex
4.Temporal Lobes- receive auditory simulation from opposite sides
Don’t need real sounds

43. Functional MRI scan of the visual cortex activated by light shown in the subject’s eyes

44. Auditory
cortex
Visual

45. The Cerebral Cortex Association Areas-
areas of the cerebral cortex that are not involved in primary motor or sensory functions
involved in higher mental functions such as learning, remembering, thinking, and speaking

46. Association areas Aphasia Broca’s Area Wernicke’s Area
impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding)
Broca’s Area
an area of the left frontal lobe that directs the muscle movements involved in speech
Wernicke’s Area
an area of the left temporal lobe involved in language comprehension
Angular Gyrus-auditory sounds

47. The Cerebral Cortex
Brain activity when hearing, seeing, and speaking words

48. Brain Reorganization
Plasticity- neural tissue can reorganize in response to damage
Orgasm in foot
Most plastic when young

49. Our Divided Brain Corpus Callosum largest bundle of neural fibers
connects the two brain hemispheres
carries messages between the hemispheres
Corpus callosum

50. Split Brain
a condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them
“alien hand syndrome”

52. Hemispheric Differences
Specialization
Each hemisphere has its own specialties
Most people are stronger in one hemisphere
Left- logical, verbal, sequential
Right- emotional, expressive, better at spatial relations

53. Handedness 90% right handed Percentage of left-handedness Age in years
The percentage of
lefties sharply
declines with age
Age in years
14% 12 10 8 6 4 2
Percentage of
left-handedness

54. Neural and Hormonal Systems
Endocrine System
the body’s “slow” chemical communication system
a set of glands that secrete hormones into the bloodstream

55. Endocrine System Hormones
chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another
Growth, reproduction, metabolism, mood………

56. Endocrine System Adrenal Glands
a pair of endocrine glands just above the kidneys
secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress
Increases heart beat, blood pressure, blood sugar….. Gives us energy

57. Endocrine System Pituitary Gland
under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands
Master gland

58. Other Hormones/Glands
Pineal Gland-
Produces melatonin
regulates circadian rhythms
Seasonal Affective disorder
2. Thyroid-
Maintains metabolic activities
Lack of thyronixe= mental retardation in children
3. Pancreas-
releases insulin and glucagon which regulates blood sugar

59. Other Hormones /Glands
4. Gonads-
Testis and Ovaries
Release estrogen and testosterone

60. Half a brain Split brain Left or right Pituitary Gland Concussions
Pituitary Gland
Split brain
Left or right  
Concussions
football-concussions