the nervous system- central and peripheralcreyes/classes/chapt4slides_triune.pdf · the nervous...

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The nervous system- central and peripheral Neurons Neuron Communication Chemical messengers Inside the brain Parts of the brain Split Brain Patients

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Brain Spinal cord A collection of neurons and supportive tissue running from the base of the brain down the center of the back. Actually and extension of the brain.

Protected by spinal column

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Dendrites Receive information from other neurons and transmit toward the cell body Cell body Keeps the neuron alive and determines whether it will fire Axon Extending fiber that conducts impulses away from the cell body and transmits to other cells.

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Which part of a neuron is tree-like or “branchy”? A.  Dendrites

B.  The axon

C.  The cell body

D.  The nucleus

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Which part of a neuron is tree-like or “branchy”? A. Dendrites

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Axon terminals release neurotransmitters.

Neurotransmitter enters synapse.

Neurotransmitter binds to receptors that it fits.

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A brief change in electrical voltage that occurs between the inside and outside of an axon when a neuron is stimulated.

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Chemical released by a transmitting neuron at the synapse and capable of affecting the activity of a receiving neuron

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Serotonin-sleep/dreaming, moods, eating Dopamine- reward/motivation/ movement, learning, emotion, possibly response to novelty Acetylcholine (Ach), muscle action, memory Norepinephrine- (once called adrenaline) heart rate, alertness, learning (GABA)-inhibitory, low levels may be responsible for some seizures. GABA agonists used to treat anxiety disorders, Benzodiazapenes (e.g. Valium) and Alcohol also acts on GABA

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Endocrine glands release hormones into the bloodstream…

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…Hormones regulate growth, metabolism, sexual development and behavior, and other functions.

Melatonin

Regulates daily biological rhythms

Adrenal hormones

Involved in emotions and stress

Cortisol, epinephrine, and norepinephrine

Sex hormones

Regulate development and functioning of reproductive organs

Androgens, estrogens, and progesterone

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1. Researchers study brains that have experienced disease or injury. 2. Some Animal Studies Involves damaging and removing sections

of animals’ brains and observing the effects. 3. EEG 4. TMS 5. PET 6. MRI

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A recording of neural activity detected by needle electrodes

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Involves delivering a large current through a wire coil on a person’s head

Can be used to Produce motor responses Temporarily inactivate an area of the brain Treat depression

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Active areas have increased blood flow.

Sensors detect radioactivity.

Different tasks show distinct activity patterns. Diagnose abnormalities or just learn about normal brain

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A method for analyzing biochemical changes in the brain as they occur, using injections of a glucose-like substance containing a radioactive element

Magnetic fields align certain ions and compounds.

When field is removed, these molecules release energy as radio waves.

Computer calculates tissue density from radio waves.

Provides nice clear 3D images

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Method for studying body and brain tissue

Brain stem Cerebellum Thalamus Hypothalamus and pituitary gland Amygdala Hippocampus Cerebrum and lobes of the cerebral cortex

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Pons & Medulla Basic survival functions; such as breathing, vomiting, swallowing, and orgasm. Reticular activating system Arouses the cerebral cortex (general alertness) and screens incoming information that is projected to the cerebral cortex.

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Regulates movement and balance Involved in remembering simple motor skills and acquired reflexes. e.g. riding a bicycle

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The thalamus Relays sensory messages to the cerebral cortex

Includes all sensory messages except those from olfactory bulb

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Hypothalamus and pituitary gland Involved in emotions and drives vital to survival Fear, hunger, thirst, and reproduction Regulates autonomic nervous system Pituitary gland Small endocrine gland which releases hormones and regulates other endocrine glands

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The amygdala Responsible for Initial regulation of emotion Initial emotional response to sensory information

Plays important role in Mediating anxiety and depression Emotional memory

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The hippocampus Responsible for Storage of new information in memory

Comparing sensory information with what the brain expects about the world

Enabling us to form spatial memories for navigating the environment

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The neocortex-Human

Subcortical-Mammal

Cerebellum, Hypthalamus ,spinal cord etc- Reptile Brain

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Reptilian - instinct, physiology

Paleo&mammalian*(limbic)*&*emo/ons*

Neo-mammalian (neocortex) - thinking, cognition

The triune brain model has become a widely-used way of thinking about the overall functional organization of the brain.�

In this view the brain developed over the course of vertebrate evolution into a three-layered organ, where these layers retain of the separateness of their different evolutionary origins despite being highly interconnected.�

The oldest layer of the brain is called the reptilian brain, composed of the brainstem -- the structures that dominate in the brains of snakes and lizards.�

The mammalian brain is layered over the reptilian brain, it consists primarily of a system of brain parts called the limbic system, sometimes referred to as the Papez circuit. The limbic system plays a major role in human emotion. �

The neocortex or primate brain is the most recent addition to our brain. It consists of a wrinkled covering of the cerebral hemisphere which has mushroomed in primates and humans as compared to other mammals. �

Gives brain it’s distinctive wrinkled appearance. The phenomenal site of ALL thinking/thoughts, detailed perceptions, consciousness, culture, and communication. In short, everything that makes us human. Two hemispheres connected by the corpus callosum.

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Occipital lobe visual information, visual cortex Parietal lobes - somatosensory cortex And sense of touch, larger areas for more sensitive areas such as fingers and faces. Interesting cases of “hemineglect” Temporal lobes language perception, auditory cortex, emotion and memory too Frontal lobes All planning, also most complex and creative thinking, language. Emotional regulation and complex motor movements such as dance, sports, and playing an instrument.

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Omar bumps his head and is suddenly unable to see, although the doctor says there is nothing wrong with her eyes? Which part of his brain did Omar damage? A.  The amygdala

B.  The hippocampus

C.  The occipital lobe of the cortex

D.  The parietal lobe of the cortex

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Omar bumps his head and is suddenly unable to see, although the doctor says there is nothing wrong with his eyes? Which part of his brain did Omar damage? C.   The occipital lobe of the cortex

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Gage was a railroad construction foreman An 1848 explosion forced a steel tamping rod through his head Others said he was “no longer Gage” Lost his job, worked as a sideshow exhibit

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Millions of myelinated axons connecting the brain’s hemispheres

Provides a pathway for communication

If surgically severed to treat epilepsy, hemispheres cannot communicate directly

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Subjects were presented information to one or the other side of their brains.

Patients identified verbally the pictures to the right (e.g., boy’s face). Right side goes to left brain, the verbal side.

BUT, When patients were asked to POINT to the face seen, the patients pointed to the left (man’s) picture.

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Research on split-brain patients shows us that…

1.  Nearly all right-handed and the majority of left-handed individuals process language mainly in the left hemisphere.

2.  Many researchers believe in left-hemisphere dominance because cognitive skills originate here.

3.  Others insist right-hemisphere is just as important for spatial visual problem solving, art & music appreciation and is more intuitive.

4. The two hemispheres are more allies than opposites

“I used to think that the brain was the most wonderful organ in my body. Then I realized…… well, look what's telling me this!”-Emo Phillips, Actor & Comedian