Neuroscience

1. Neuroscience Chemicals and the Brain Crash Course video

2. Everything psychological is simultaneously biological! • Your every idea, mood or urge is a biological happening!!!! • Without your body, you are nobody! • Biological Psychologists study the links between biological activity and psychological events.

3. PHRENOLOGY • Invented by Franz Gall in the early 1800’s. • A theory that claimed that bumps on the skull could reveal our mental abilities and character traits. • Phrenology focused the attention that various regions of the brain have particular, specific functions.

5. Neuron • a nerve cell • the basic building block of the nervous system -our bodies information system is built from 100 billion of interconnected cells called neurons. -many different types of neurons, but all are composed in the same way. • Glial Cells • cells in the nervous system that support, nourish, and protect neurons

6. Dendrites (Greek for tree) Are the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body. They receive information from other nerve cells and send it through the soma or cell body to the:

7. Axon • (Greek for axle) • the extension of a neuron, (long fiber) ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands (senders). At the end of the axon are thousands of terminal buttons.

8. The area where the axon ends, in the terminal buttons just before the synapse, is filled with small containers that look like bubbles..calledvesicles. • Inside the vesicles are thousands of chemical messengers called neurotransmitters.

9. Myelin [MY-uh-lin] Sheath • a layer of fatty cells segmentally encasing the fibers of many neurons (insulating the axons) • enables vastly greater transmission speed of neural impulses • Multiple Sclerosis, a disease in which the myelin sheath degenerates, which results in a slowing of communication to the muscles and loss of muscle control. MS video

10. Synapse [SIN-aps] • (means junction point) • The space between the axon tip of the sending neuron and the dendrite of the receiving neuron • tiny gap at this junction is called the synaptic gap or cleft • Neurons work by electricity. Electricity will not go over a space, so it stops. “Lets talk about the Synapse”

11. Structure of a Neuron

12. Neural Communication

13. Neurotransmitters • chemical messengers that traverse the synaptic gaps between neurons • when released by the sending neuron, neuro-transmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse • If the message is for arm movement, the vesicles only release neurotransmitters involved in the movement circuit. • There are dozens of different neurotransmitters.

14. Neurotransmitters

15. Neurotransmitters • Acetylcholine [ah-seat-el-KO-leen](Ach) • most common, best understood • a neurotransmitter that, among its functions, triggers muscle contraction • is involved in memory (a shortage of causes Alzheimer’s Disease) • Endorphins [en-DOR-fins] • “morphine within” • natural, opiate like neurotransmitters • linked to pain control and to pleasure

16. Dopamine- • Involved in the control of bodily movements, learning, attention, & emotion. • Shortage causes Parkinson’s disease • Excessive dopamine linked with schizophrenia Seratonin Affects mood, hunger, sleep and arousal

17. Dopamine Pathways Neural Communication Serotonin Pathways

18. Neural Communication Neural communication refers to how the neurons relay messages to each other. It is referred to an electrochemical reaction. Neurons are surrounded by fluid. The fluid inside a neuron contains negative charged atoms, called ions, ( - ) from the fluid located outside the neuron, which has positive charged ions (+).

19. The neural membrane only allows certain ions through the membrane. Positively charged sodium and potassium ions and negatively charged chloride ions flow back and forth across the cell membrane, but they do not cross at the same rate. The difference in the flow leads to a higher concentration of negatively charged ions inside the cell.

20. Positive ions will flow into the neuron if not stopped or pumped out by the membrane. This is called the electrical potential, which is measured in millivolts. • The resting potential is the neuron’s usual charge, which is –70 millivolts. • When the resting potential has changed enough, about +10mv, the membrane changes and this is called the action potential.

21. A neuron fires an impulse, when it receives signals from sense receptors…the impulse is called • Action Potential • a neural impulse; a brief electrical charge that travels down an axon, each tripping the next (depolarization) • generated by the movement of positively charged ions (atoms) in and out of channels in the axon’s membrane. • The speed at which an action potential travels the axon ranges from 2 to 250 mph.

22. Refractory Period- a resting pause, when the neuron pumps the positively charged ions back outside…then it can fire again. • Excitatory-signal to send the message • Inhibitory-signal to stop the message • Threshold -the level of stimulation required to trigger a neural impulse • Agonist-excite by mimicking particular neurotransmitters or block their reuptake. • Antagonists-inhibit a neurotransmitter’s release or block its effect.

23. The neuron’s reaction is an “all or none response.” Neurons either fire or they don’t. (like a gun) HW Assignment: How is the action potential neuron like flushing a toilet? orlike using a camera?

24. Cell body end of axon Direction of neural impulse: toward axon terminals Neural Communication

25. The Nervous System • Nervous System • the body’s speedy, electrochemical communication system • consists of all the nerve cells of the peripheral and central nervous systems • Central Nervous System (CNS) • the brain and spinal cord • Peripheral Nervous System (PNS) • the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

26. Nervous system Peripheral Central (brain and spinal cord) Autonomic (controls self-regulated action of internal organs and glands) Somatic or Skeletal (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming) The Nervous System

27. Three Types of Neurons • that carry information throughout the nervous system: • Sensory Neurons(Afferent) • neurons that carry incoming information from the sense receptors to the brain & spinal cord (CNS) • Interneurons • CNS neurons that internally communicate and intervene between the sensory inputs and motor outputs • Motor Neurons (Efferent) • carry outgoing information from the CNS to muscles and glands

28. The sensory & motor axons carrying the PNS information are bundled into electrical cables called: • Nerves • neural “cables” containing many axons • part of the peripheral nervous system • connect the central nervous system with muscles, glands, and sense organs

29. The Peripheral Nervous System • Somatic Nervous System • the division of the peripheral nervous system that controls the body’s skeletal muscles, composed of sensory & motor nerves. • Controls our voluntary movements & reflexes.

30. The Nervous System • Autonomic Nervous System • the autonomic control system of the body (the peripheral nervous system) It regulates breathing, heartbeat & digestion. It sometimes can be overridden by the brain. It is a dual system composed of:

31. Sympathetic Nervous System • division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations, slows digestion. Raises blood sugar & pressure, heart rate, dilates eyes. Gets body ready for “fight or flight”

32. Parasympathetic Nervous System • division of the autonomic nervous system that calms the body, conserving its energy • It decreases your heartbeat, lowers your blood sugar and pressure. These two systems work together to keep us in balance.

33. The Nervous System

34. The Nervous System

35. Brain Sensory neuron (incoming information) Interneuron Motor neuron (outgoing information) Muscle Spinal cord Skin receptors The Nervous System • Reflex • a simple, automatic, inborn response to a sensory stimulus

36. Neurons in the brain connect with one another to form networks Inputs Outputs The brain learns by modifying certain connections in response to feedback The Nervous System • Neural Networks • interconnected neural cells • with experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results • computer simulations of neural networks show analogous learning

37. Methods Used in Studying The Brain • Accidents In 1848, a railroad worker named Phineas Gage was involved in an accident that damaged the front part of his brain. Gage’s doctor took detailed notes documenting the brain damage and about Gage’s behavior & personality changes. Before the accident, Gage was a nice guy, after the accident he was highly emotional and impulsive.

38. 2. Lesion is the removal or destruction of part of the brain. a brain lesion is a naturally or experimentally caused destruction of brain tissue • Frontal lobotomies

39. 3. Electroencephalogram (EEG) • an amplified recording of the waves of electrical activity that sweep across the brain’s surface • these waves are measured by electrodes placed on the scalp

40. CT (computed tomography) Scan • a series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; also called CAT scan • It creates a 3-D image of brain’s structure. Does not show function or activity. • PET (positron emission tomography) Scan • a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task • MRI (magnetic resonance imaging) • a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain, not function

41. MRI Scan

42. PET Scan

43. The Cerebral Cortex • Functional MRI scan shows the visual cortex activated as the subject looks at faces

44. Three regions of the brain • 1. the forebrain -most recently evolved section • 2. the midbrain • -contains the upper part of the brain stem • 3. the hindbrain • -consists of structures in top part of the spinal cord, most of the brain stem.

45. The Hindbrain • Brainstem • the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull • responsible for automatic survival functions • Medulla [muh-DUL-uh] • base of the brainstem, attaches to spinal cord • controls heartbeat and breathing

46. The Brain • Reticular Formation (Reticular Activating System) • a nerve network in the brainstem that plays an important role in controlling arousal & sleep. • Involved in controlling muscle reflexes, breathing & perception.

47. The Brain

48. The Brain • Cerebellum [sehr-uh-BELL-um] • the “little brain” attached to the rear of the brainstem • it helps coordinate voluntary movement and balance

49. The Midbrain • A segment of the brainstem located between the hindbrain & forebrain, containing the reticular formation-regulating sleep & arousal.

50. The Forebrain • Thalamus [THAL-uh-muss] • the brain’s sensory switchboard, located on top of the brainstem • it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla