The Nervous System The big picture: gathers and processes information, responds to stimuli, and coordinates the workings of different cells

The Nervous The Nervous SystemSystem

The big picture: gathers and The big picture: gathers and processes information, responds processes information, responds to stimuli, and coordinates the to stimuli, and coordinates the workings of different cells.workings of different cells.

The Central Nervous The Central Nervous SystemSystem

Consists of the brain and spinal cord, Consists of the brain and spinal cord, receives processes, interprets, and receives processes, interprets, and stores sensory information. *Nose touchstores sensory information. *Nose touch

1.1. Spinal reflexes are automatic and require no Spinal reflexes are automatic and require no conscious effort. Ex. Knee-jerk or finger on conscious effort. Ex. Knee-jerk or finger on stovestove

2.2. The neural circuitry underlying a reflex is a The neural circuitry underlying a reflex is a reflex arc.reflex arc.sensory neuron >interneuron (w/in the sensory neuron >interneuron (w/in the spinal cord)>motor neuronspinal cord)>motor neuron

Ex. Scottie: C-5 spinal cord injury. No way for Ex. Scottie: C-5 spinal cord injury. No way for sensory info to reach his brain.sensory info to reach his brain.

The Peripheral Nervous The Peripheral Nervous SystemSystem

Consists of all parts of the nervous Consists of all parts of the nervous system other than the brain and system other than the brain and spinal cord. It handles the central spinal cord. It handles the central nervous system’s input and nervous system’s input and output.*Shoulder, elbow, finger output.*Shoulder, elbow, finger touchtouch

1.1. Sensory nerves carry messages from Sensory nerves carry messages from receptors to the brain.receptors to the brain.

2.2. Motor nerves carry messages from the Motor nerves carry messages from the central nervous system to muscles, central nervous system to muscles, glands, and internal organs.*dollar dropglands, and internal organs.*dollar drop

PNS con’tPNS con’t

3. The peripheral nervous system is divided 3. The peripheral nervous system is divided into the skeletal (somatic) and autonomic into the skeletal (somatic) and autonomic branches.branches. A. The skeletal (somatic) nervous system controls A. The skeletal (somatic) nervous system controls

skeletal muscles and permits voluntary action. skeletal muscles and permits voluntary action. *knee/slap*knee/slap

B. The autonomic nervous system regulates blood B. The autonomic nervous system regulates blood vessels, glands, and internal organs. *stop your vessels, glands, and internal organs. *stop your heartbeat! Like automatic pilot.heartbeat! Like automatic pilot.

C. Although biofeedback can help people control C. Although biofeedback can help people control voluntary responses, it is not clear whether they voluntary responses, it is not clear whether they can learn to control autonomic responses directly.can learn to control autonomic responses directly.

PNS con’tPNS con’t

4. The autonomic nervous system is 4. The autonomic nervous system is divided into opposing sympathetic and divided into opposing sympathetic and parasympathetic branches; both are parasympathetic branches; both are involved in emotion and stress.involved in emotion and stress. A. The sympathetic nervous system A. The sympathetic nervous system

mobilizes the body for action and mobilizes the body for action and increases energy output. *meeting a increases energy output. *meeting a mountain lionmountain lion

B. The parasympathetic nervous system B. The parasympathetic nervous system conserves energy and helps the body store conserves energy and helps the body store it. Calms/conserves. Decrease heartbeat!it. Calms/conserves. Decrease heartbeat!

Communication in the Communication in the Nervous System: The Nuts Nervous System: The Nuts

and Boltsand Bolts Neurons, or nerve cells, are the basic Neurons, or nerve cells, are the basic

units of the nervous system, which are units of the nervous system, which are held in place and nourished by glial cells. held in place and nourished by glial cells. They specialize in communication.They specialize in communication. A. The structure of the NeuronA. The structure of the Neuron

1. The neuron has three main parts: a cell body, 1. The neuron has three main parts: a cell body, dendrites, and an axon.dendrites, and an axon.

2. The cell body keeps the neuron alive and 2. The cell body keeps the neuron alive and determines whether it should send a message to determines whether it should send a message to other neurons; the dendrites of a neuron receive other neurons; the dendrites of a neuron receive messages from other neurons and send them to the messages from other neurons and send them to the cell body; the axon transmits messages away from cell body; the axon transmits messages away from the cell body to other neurons, muscles, or glands.the cell body to other neurons, muscles, or glands.

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B. The Cerebral Cortex: The B. The Cerebral Cortex: The Brain’s Thinking CapBrain’s Thinking Cap

1. The cortex contains three-fourths of all the cells in the human 1. The cortex contains three-fourths of all the cells in the human brain. More cortex in humans…we aren’t on autopilot!brain. More cortex in humans…we aren’t on autopilot!

2. The 2. The occipital lobesoccipital lobes contain the visual cortex, where visual contain the visual cortex, where visual processing occurs. processing occurs.

3. The 3. The parietal lobesparietal lobes contain the sensory cortex, where contain the sensory cortex, where information about pain, touch, and temperature is processed.information about pain, touch, and temperature is processed.

4. The 4. The temporal lobestemporal lobes are involved in memory, perception, are involved in memory, perception, emotion, and language comprehension, and they contain the emotion, and language comprehension, and they contain the auditory cortex, which processes sound. auditory cortex, which processes sound.

5. The 5. The frontal lobesfrontal lobes are involved in judgment, planning, creating, are involved in judgment, planning, creating, and initiating, and they contain the motor cortex, which and initiating, and they contain the motor cortex, which produces voluntary movement.produces voluntary movement.

*head pointing*head pointing

The Motor Cortex – con’tThe Motor Cortex – con’t

6. Those areas of 6. Those areas of

the body requiringthe body requiring

precise control precise control

(fingers, mouth, (fingers, mouth, etc.) etc.)

take up the most take up the most

cortical space. cortical space.

The Cerebral Cortex – The Cerebral Cortex – con’tcon’t

7. Damage to the 7. Damage to the

frontal lobes may frontal lobes may

dramatically alter dramatically alter

personality. personality.

(Phinias Gage)(Phinias Gage)

The Cerebral Cortex – The Cerebral Cortex – con’tcon’t

8. The association 8. The association cortex is the site cortex is the site of higher mental of higher mental processes. 10% processes. 10% of our brain myth.of our brain myth.

A Question of DominanceA Question of Dominance1.1. Nearly all right-handed people and a majority of Nearly all right-handed people and a majority of

left-handers process language mainly in the left left-handers process language mainly in the left hemisphere, which also seems to be dominant in hemisphere, which also seems to be dominant in logical, symbolic, and sequential tasks.logical, symbolic, and sequential tasks.

2.2. The right hemisphere is superior in visual-The right hemisphere is superior in visual-spatial ability and facial recognition. It is also spatial ability and facial recognition. It is also involved increasing and appreciating art and involved increasing and appreciating art and music, and seems to have some language ability.music, and seems to have some language ability.

3.3. Although some popular programs promise to Although some popular programs promise to enhance one or the other of your hemisphere’s enhance one or the other of your hemisphere’s abilities, in most real-life activities, the two abilities, in most real-life activities, the two hemispheres cooperate naturally with each hemispheres cooperate naturally with each contributing to our effectiveness. contributing to our effectiveness.

*which side of the brain are you accessing? *which side of the brain are you accessing?

Which is your dominate Which is your dominate side?side?

Left HemisphereLeft Hemisphere *Step by stem *Step by stem

reasoning of info.reasoning of info. LanguageLanguage ListeningListening WritingWriting ReadingReading Mathematical Mathematical

calculationscalculations

Right HemisphereRight Hemisphere *Visual/Spatial *Visual/Spatial

informationinformation Recognize complex Recognize complex

patterns $ drawingspatterns $ drawings Aptitude for musicAptitude for music Expression & Expression &

recognition of emotionrecognition of emotion Recognizing facesRecognizing faces Solving spatial Solving spatial

relationship problemsrelationship problems Symbolic reasoningSymbolic reasoning Artistic activityArtistic activity

Eavesdropping on the Eavesdropping on the BrainBrain

Progress in understanding the brain Progress in understanding the brain depends on studies of brain damage, depends on studies of brain damage, investigations that stimulate brain investigations that stimulate brain centers, and studies in which brain centers, and studies in which brain activity is measured, for example by activity is measured, for example by means of the …means of the …

1. Electroencephalogram (EEG)-traces 1. Electroencephalogram (EEG)-traces electrical brainwaves. Ex how the electrical brainwaves. Ex how the brain responds to sound or sight. brain responds to sound or sight.

Eavesdropping on the Brain Eavesdropping on the Brain – con’t – con’t

2. positron-emission tomography (PET 2. positron-emission tomography (PET scan) –shows consumption of sugar scan) –shows consumption of sugar (glucose) as needed for brain activity.(glucose) as needed for brain activity.

In men who had ADHD, PET scans showed that they In men who had ADHD, PET scans showed that they processed a memory task in visual areas in the occipital processed a memory task in visual areas in the occipital lobe of the brain, as indicated by the yellow spots in the left lobe of the brain, as indicated by the yellow spots in the left image. Non-ADHD men used the temporal and frontal image. Non-ADHD men used the temporal and frontal

lobes, shown at rightlobes, shown at right


3. Magnetic resonance imaging (MRI) – 3. Magnetic resonance imaging (MRI) – uses magnetic fields & radar waves to uses magnetic fields & radar waves to distinguish between different types of distinguish between different types of soft tissue. soft tissue.

(Brain Structure)(Brain Structure)

MRI’S give detailed volumetric measurements of specific regions of the brain.MRI’S give detailed volumetric measurements of specific regions of the brain.

The volumetric measurements of the caudate nucleus indicate a The volumetric measurements of the caudate nucleus indicate a smaller right caudate smaller right caudate nucleus in ADHDnucleus in ADHD boys in comparison to normal boys boys in comparison to normal boys

Extensive and time consuming measurements of the head and body of the caudate Extensive and time consuming measurements of the head and body of the caudate nucleus and the frontal lobes have supported their role in ADHDnucleus and the frontal lobes have supported their role in ADHD


4. Computed tomograph (CT) – takes x-4. Computed tomograph (CT) – takes x-ray photographs that can reveal brain ray photographs that can reveal brain damage. damage.

The top picture shows a The top picture shows a newborn with newborn with hydrocephalus prior to its hydrocephalus prior to its treatment. The darker treatment. The darker gray is CSF and the gray is CSF and the lighter gray rim around it lighter gray rim around it is brain. The bottom is brain. The bottom picture is the same child picture is the same child three and a half months three and a half months later, after he was later, after he was shunted. Note how much shunted. Note how much smaller the fluid spaces smaller the fluid spaces (dark gray) are and the (dark gray) are and the dramatic expansion of the dramatic expansion of the brain into the space brain into the space created by removing the created by removing the excess CSF. excess CSF.


5. Single Photon Emission Computed 5. Single Photon Emission Computed Tomography (SPECT) - Measures Tomography (SPECT) - Measures blood flow and brain metabolism by blood flow and brain metabolism by monitoring photons emitted by iodine-monitoring photons emitted by iodine-labeled monoamine and diamine labeled monoamine and diamine tracers carried in the blood to the tracers carried in the blood to the brain. brain.

Guess what disorder these SPECT Guess what disorder these SPECT images reveal.images reveal.

NormalNormal ADHD-Attention Deficit ADHD-Attention Deficit Hyperactivity DisorderHyperactivity Disorder

When methylphenidate (Ritalin) was administered to ADHD children, its effect showed up as a redistribution of blood flow in the brain, methylphenidate appeared to increase the level of function of the under-perfused regions at the striatum, posterior periventricular region and to a lesser extent the frontal lobes. This normalization allowed the clutter of irrelevant messages to be screened out and was seen as a reduction in blood flow to the vision and hearing areas. This filtering of irrelevant distraction suppresses reflex responses and helps concentration.


NormalNormal Anxiety/panic DisorderAnxiety/panic Disorder


NormalNormal Bipolar DisorderBipolar Disorder


NormalNormal DepressionDepression

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The Nervous System The big picture: gathers and processes information, responds to stimuli, and coordinates the workings of different cells