BIO 208 FINAL
The nervous system plans a movement in terms of its...
-Goal rather than the effector, e.g. hand or foot, used to accomplish the task. -This process requires a coordinate system transformation.
Why study the brain? part two
-Increasing Prevalence of Brain Disorders e.g. Alzheimer's Disease (increased cost and funding peak from 2010-2050 estimated) -Alzheimers in top 5 expensive diseases
What Do Living Systems Need To Do To Stay Alive?
-Respiration, Maintain Optimal Temp, Nutrition, Water, Reproduce -f You Collect Food And Water Instead Of Waiting For It To Come To You You Need A Brain So That You Can Move
A Brain Is For Movement...
-Sea Squirts -Larval tunicates attach to rocks and mature into adults. -As sessile creatures, they digest almost their entire nervous and sensory systems and spend their time extracting plankton that they pump through their gut.
Spinal cord:
-Segmental Reflexes: Processing of sensory input ascending to the brain -processing of motor output from the brain destined for the muscles
Gross anatomy of the brain:
-Specific brain regions, e.g., cerebellum, cerebral cortex, pons -Can be observed without a microscope
SYMPATHEIC VS PARASYMPATHETIC NERVOUS SYSTEM
-Sympathetic system is activated for short lasting, high energy tasks such as escape ("wide eyed with fear"); -Parasympathetics are activated in tasks that involve body maintenance. These 2 regulatory systems are coordinated via supraspinal controls, e.g., cells in the medulla oblongata and the hypothalamus according to the needs of the body.
A brain is 2% of...
-The body's weight, but consumes 20% of its energy. -This is like having a house in which 20% of the electricity goes to keep the night light running
Attention is a neural process by...
-Which you enhance your perception of certain stimuli relative to other stimuli in the environment -e.g., you ignore activity of the crowd and focus your attention on catching the ball.
Alzheimers aging...
-aging is the strongest predictor (40 mil americans are over the age of 65, 80 mil americans predicted to be over by 65 by 2040). -diagnosis accelerating (5 million+ americans currently diagnosed)
Rotational degrees of freedom are...
-pitch -roll -yaw
Translational degrees of freedom are...
-up/down (Y) -left/right (X) -backward/forward (Z)
Movement is a parallel process. It involves the..
.Basal Ganglia & Cerebellum
Flow of information in the cerebral cortex: Gray/White Matter
1) Gray matter (cell bodies) is on surface of cortex and is where neural processing takes place 2) White matter (myelinated axons) is in the interior of the cortex, and is where axons connecting different sub regions are located
What's Involved in Catching A Ball? (4 functions)
1. See the ball and follow it with your eyes. 2. Prepare to make the movement. 3. Adjust your posture before making the movement. 4. Execute the movement. A. Create a signal to start your planned arm movement to catch the ball
What's Involved in Catching A Ball? Function one and Two
1. See the ball and follow it with your eyes. (Sensory & Motor). Focus your attention on the ball and ignore other objects in the visual environment; move your eyes to stay with the target 2. Prepare to make the movement. (Goal Directed Behavior) What is your objective in making the movement?
What's Involved in Catching A Ball? 3 functions
1.See the ball and follow it with your eyes. 2.Prepare to make the movement. 3.Adjust your posture before making the movement. Prepare to maintain your equilibrium with changes in the center-of-gravity.
Changing the angle of your elbow and shoulder the same amount produces...
A curved movement of your hand.
Wernicke demonstrated...
A more posterior region in the left cortex associated with language comprehension rather than speaking or writing This is the motor output of the language center.
Galvani and Volta discovered...
Bioelectricity in the late 1700s Studying the ability of various electrical stimulation procedures to cause the muscles of a dead frog to contract.
The brain must transform the body's joint coordinate system determined by its...
Effector organ, e.g., a hand or a foot, into the Cartesian coordinates of the real world where the ball is going to arrive. In addition, the brain must solve the too many degrees of freedom problem.
Cerebral hemispheres:
Cerebral cortex (outer layer) Hippocampus (memory) Amygdala (control of emotional responses) Basal ganglia (regulation of motor performance)
The initial processing of input from different sensory systems is represented in unique regions of the...
Cerebral cortex: Vision: occipital cortex Somatosensory: parietal cortex (postcentral gyrus) Audition: temporal cortex Taste and smell: temporal cortex Motor: parietal cortex (precentral gyrus)
Postganglionic cells are...
Close to the target tissue (heart, etc.)
Hindbrain (Medulla oblongata)
Continuation of spinal cord Maintains wakefulness and alertness, contains reflex centers (cardiac center, vasomotor center, respiratory rhythmicity center)
Medulla oblongata:
Control of heart rate, breathing, etc.
Responses involving multiple sensory modalities are...
Coordinated through interconnections throughout the brain, not necessarily restricted to the sensory regions
Paul Broca demonstrated...
Damage in left frontal lobe post mortem: Broca's area.
Little information on connectivity between...
Different regions and its contribution to function & No information about the cellular constituents of the brain
Initial discoveries of localization of function in the brain came from study of individuals with...
Disease or trauma. There were initial attempts to correlate function with "bumps" on the skull
Catching a ball involves the...
ENTIRE BRAIN
Midbrain:
Eye movements; coordination of visual and auditory functions
Different brain regions can be....
Grossly identified with specific functions e.g., visual sensory, auditory sensory, motor, autonomic
The medial cerebral cortex:
Hippocampus; amygdala; cingulate gyrus; corpus callosum.These structures mediate complex functions such as memory (hippocampus); emotion (amygdala); as well as coordination of both sides of the brain (corpus callosum).
To determine where you want your hand to be to catch the ball, you must identify...
How many independent variables (degrees of freedom) are necessary to specify the location of your hand in space.
Parietal And Frontal Cortex Are...
Important In Attention
Right parietal area of brain is...
Important for attention evoked by an external event -e.g., an unexpected visual stimulus.
Right frontal area of brain is...
Important for attention necessary to concentrate on a task -e.g., studying for a test.
The brain is a 3-dimensional structure that requires sections...
In all 3 planes to be adequately visualized (Coronal, Horizontal, Sagittal)
Using Cartesian coordinates, any point...
In space can be specified by its X, Y, and Z coordinates.
Parasympathetic preganglionic cells are...
In the brain
3 degrees-of-freedom are necessary to specify the...
translational components of the goal.
Sympathetic preganglionic cells are...
In the spinal cord and exit via the ventral root. Post ganglionic cells are close to the spinal cord in sympathetic chain.
Pons:
Information about movement from cerebral cortex to cerebellum
The visual system has several stages. The visual image comes...
Into the eyeballs and is initially processed by the retina.
Damage to the frontal lobe indicates...
Its role in determining behavioral parameters such as personality.
Our body, is not in Cartesian coordinates (X, Y, & Z), it is in...
Joint coordinates. Because changes in joint angles are the basis for our movements, the brain must transform Cartesian coordinates of the world outside our bodies into joint coordinates to move to a point in the real world.
More complex functions such as language tend to be represented unilaterally in the cerebral cortex...
Left brain: language, verbal, analytical thinking Right brain: non verbal, intuitive thinking Generally left and right brain function together via the corpus callosum linking left and right cortices
Electrical stimulation of the brain reveals...
Localization of function
Many axons pass through the...
Midbrain, e.g., the descending corticospinal axons (motor), the ascending medial lemniscus (somatosensory).
To execute a movement you must first start the movement and then...
Monitor the movement using proprioception to compare the actual movement with the expected movement, the brain's 'model' of the movement.
Frontal lobe (and regions of the other lobes not representing primary sensory inputs) mediate...
More complex functions such as language, executive function, decision making, personality, etc.
Cerebellum:
Motor coordination; motor memory
When you reach out to catch the ball, your center-of-gravity...
Moves forward. To avoid falling forward when you reach out, you need to contract your back and leg muscles before reaching out.
Shifting Between Cartesian and Joint Coordinates Involves...
Nonlinearities
See the ball and follow it with your eyes. Sensory & Motor: Focus your attention...
On the ball and ignore other objects in the visual environment.
Proprioception is...
Our sense of our body's movement and position in space.
Movement is a ______ process...
Parallel process. It begins at several places in the brain at about the same time.
Both sympathetic and parasympathetic nervous system have...
Preganglionic and post ganglionic fibers.
The midbrain contains cells responsible for...
Processing visual (superior colliculus), auditory (inferior colliculus) information. It also is responsible for motor behavior, most directly eye movements (e.g., oculomotor nucleus) and also limb and head movements (red nucleus).
Every time a muscle contracts or stretches and every time a limb moves at a joint...
Proprioceptive receptors send information to the brain to tell it about the movement.
When we move voluntarily, the massive amount of sensory information from the movement...
Rarely reaches consciousness.
3 degrees of freedom are necessary to specify the...
Rotational components of the goal.
Your body must set _______ degrees of freedom to specify where hand must be to catch the ball
SIX
Comparison of Somatic and Autonomic Nervous Systems
SNS: conscious and subconscious control over skeletal muscles ANS: controls VISCERAL functions largely outside of our awareness.
Which side is sympathetic and parasympathetic nervous system of the AUTONOMIC NERVOUS SYSTEM?
SYMPATHETIC: LEFT PARASYMPATHETIC: RIGHT
Gross Brain Structure Can be visualized in the living Human Brain Through...
Schematic and MRI (magnetic resonance imaging) picture
What's Involved in Catching A Ball? Function Two
See the ball and follow it with your eyes. -Sensory & Motor
What's Involved in Catching A Ball? Function one
See the ball and follow it with your eyes. -Sensory information
The neurons in the retina...
Send information to the visual area of the thalamus.
The visual area of the thalamus...
Sends information to visual cortex where the brain identifies the object as a ball and locates it in the world.
Stimulation of the somatosensory cortex elicits...
Sensations associated with touching the skin-e.g., a wind blowing across the hand.
How Many degrees of freedom in moving your arm?
Shoulder = 4 degrees-of-freedom Elbow = 2 degrees-of-freedom Wrist = 2 degrees of freedom Fingers = at least 2 degrees-of-freedom (There are 10 degrees of freedom to specify a 6 degree of freedom goal. Too many degrees of freedom is over completeness).
Over completeness is equivalent to...
Solving for X in the equation 7 = X + Y
Converting between coordinate systems usually involves...
Some distortion.
In the mid 1800s Frisch and Hitzig...
Stimulated the cortical surface electrically Demonstrated a region associated with contralateral limb movements in anesthetized animals-concept of motor cortex.
Paul Broca studied...
Stroke patients in the 1860s who could not speak grammatically or write sentences but could understand speech, speak isolated words, could sing a melody.
Studies of individuals with memory loss reveals the role of...
The hippocampus.
PARASYMPATHETIC POST VS PREGANGLIONIC CELLS
Tend to oppose one another e.g., sympathetic speeds the heart, dilates the pupil; parasympathetic slows the heart, constricts the pupil. Preganglionic cells use acetylcholine as transmitter; postganglionic cells use either acetylcholine (parasympathetics) or noradrenaline (sympathetics).
Diencephalon:
Thalamus-gateway of sensory information to cerebral cortex Hypothalamus-control of autonomic function
The advantage to excess degrees of freedom is...
The ability to go around obstacles. You could pick up the coffee cup even if it was behind the laptop.
When you move your hand in a straight line in front of your body...
The angle of your elbow changes much less than the angle of your shoulder
Visual System Example: In the ventral stream of visual processing...
The brain identifies the object as a basketball rather than as a football.
Visual System Example: In the dorsal stream of visual processing...
The brain locates the basketball and determines how fast it's moving.
When the proprioceptive feedback from the movement matches the expected sensory feedback...
The brain's model, proprioceptive signals don't reach consciousness. When a movement is unexpected, proprioception reaches consciousness
The Red Nucleus has extensive connections with...
The cerebellum, basal ganglia and the spinal cord.
Our sensation during movement is the difference between...
The expected sensory consequences of a movement and the actual sensory signals from the movement.
The term midbrain refers to its location between...
The forebrain and the hindbrain (Medulla Oblongata).
(Why adjust posture before movement?) The body's center-of-gravity is...
The point where all forces acting on the body are balanced.
Penfield demonstrated that electrical stimulation of...
The temporal cortex (in patients undergoing brain surgery for epilepsy) evoked previous conscious experiences suggesting a unique role for the temporal cortex in memory storage.
Top Down: _____________ Bottom up: ____________
Top Down: gross anatomy Bottom up: microscopic anatomy
Unexpected vs. Expected Movement: Eye twitches are...
Unexpected and we feel like they are a very large movement. Spontaneous blinks are much larger eyelid movements, but we don't notice them.
Sensory and motor cortical projections are...
Unilateral involving the other side of the body
Stimulation of visual cortex elicits...
Visual sensations known as phosphenes.
Your Brain Is Estimating The...
Weight Of The Object Before You Catch It
Neural mechanisms for 2-point discrimination also involves
With lateral inhibition, the zone of excitation is diminished which increases the chance of 2 stimuli activating different population of sensory cells in the somatosensory cortex.
There is an enormous amount of sensory input caused by movements, e.g., reaching your arms out to catch the ball. The brain creates...
a "model" of the sensory signals it expects from the movement
Primary Motor Cortex has...
a Map of the CONTRALATERAL (opposite) Side of the Body
Why study the brain? part one
cost of brain disorders in 2014: -alzheimers + other brain disease (243 billion) -chronic back pain, stroke, brain injury, migraine, epilepsy -these numbers do NOT include the cost of BLINDNESS (139 billion) and MENTAL DISORDERS (193 billion)
The autonomic nervous system is under control of...
structures in the medulla oblongata.
