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An imaginary line drawn through the center of the length of the central nervous system, from the bottom of the spinal cord to the front of the forebrain
With respect to the CNS (and neuraxis), located near or toward the head (Rostral).
With respect to the CNS (and neuraxis), located near or toward the tail (Caudal).
“Toward the beak”; with respect to the central nervous system, in a direction along the neuraxis toward the front of the face. (Anterior)
“Toward the tail”; with respect to the central nervous system, in a direction along the neuraxis away from the front of the face. (Posterior)
“Toward the back”; with respect to the central nervous system, in a direction perpendicular to the neuraxis toward the top of the head or the back.
“Toward the belly”; with respect to the central nervous system, in a direction perpendicular to the neuraxis toward the bottom of the skull or the front surface of the body.
The CNS is encased in bone: The brain is covered by the skull, and the spinal cord is encased by the vertebral column.
Peripheral Nervous System (PNS)
- Mass of neurons, glia, and other supporting cells
- Encased in a tough, bony skull and floating in a pool of cerebrospinal fluid.
- Chemically guarded by the blood–brain barrier.
- Receives approximately 20 percent of the blood flow from the heart, continuously
- The outermost layer of the meninges.
- It is thick, tough, and flexible but unstretchable
- Surrounds superior sagittal sinus vein
- Keeps brain from collapsing when we stand
- Closely attached to the brain and spinal cord, and following every surface convolution.
The smaller surface blood vessels of the brain and spinal cord are contained within this layer
Gap between the pia mater and arachnoid membrane filled with a liquid called cerebrospinal fluid (CSF).
The outer and inner layers (dura mater and pia mater) fuse and form a sheath that covers the spinal and cranial nerves and the peripheral ganglia of the PNS.
- A clear fluid that is extracted from the blood and resembles blood plasma, that fills the ventricular system of the brain and the subarachnoid space surrounding the brain and spinal cord.
- Reduces the shock to the central nervous system that would be caused by sudden head movement.
- Produced continuously.
- Total volume of CSF is approximately 125 ml, and the half-life is about 3 hours
- Located in the center of the telencephalon
- The ventricle located in the center of the diencephalon (down center of brain along midsagittal plane)
A bridge of neural tissue that crosses through the middle of the third ventricle.
A long tube that connects the third ventricle to the fourth ventricle, located in the center of the mesencephalon
The ventricle located between the cerebellum and the dorsal pons, in the center of the metencephalon
- Prduced by the choroid plexus of the lateral ventricles, flows into the third ventricle where more CSF is produced, then flows through the cerebral aqueduct to the fourth ventricle, where still more CSF is produced.
- The CSF leaves the fourth ventricle through small openings that connect with the subarachnoid space surrounding the brain.
- The CSF then flows through the subarachnoid space around the central nervous system, where it is reab- sorbed into the blood supply through the arachnoid granulations (pouch-shaped structures) that protrude into the superior sagittal sinus (a blood vessel that drains into the veins serving the brain)
When the walls of the ventricles expand due to an interruption in the flow of CSF (i.e. a brain tumor growing in the midbrain may push against the cerebral aqueduct, blocking its flow, or an infant may be born with a cerebral aqueduct that is too small to accommodate a normal flow of CSF.) This results in greatly increased pressure within the ventricles, because the choroid plexus continues to produce CSF.
Usually when one of the meninges is inflamed, they all are.These result in very quick and noticeable results. Changes nervous system function quickly.
-Cerebral aqueduct (Mesencephalo)
Neuron cell bodies predominate, giving a grayish tan appearance.
White matter (Beneath the cerebral cortex):
Millions of axons that connect the neurons of the cerebral cortex with those located elsewhere in the brain have a large concentration of myelin and gives this tissue an opaque white appearance
- outermost layer cerebral hemispheres
- consists mostly of glia and the cell bodies, dendrites, and interconnecting axons of neurons, making up gray matter.
- conscious mind: motor, sensory, perception, cognition, and association areas
- Contain sulci (small grooves), fissures (large grooves), and gyri (bulges between adjacent sulci or fissures)
- receives visual information
- located at the back of the brain, on the inner surfaces of the cerebral hemispheres—primarily on the upper and lower banks of the calcarine fissure (A fissure located in the occipital lobe on the medial surface of the brain; most of the primary visual cortex is located along its upper and lower banks)
primary auditory cortex
primary somatosensory cortex
Normally hidden from view by the frontal and temporal lobes, receives information concerning taste.
primary motor cortex
Primary sensory and motor cortex occupy only a small part of the cerebral cortex. The rest accomplishes perceiving, learning/remembering, planning, & acting in association areas
- Central sulcus (separates frontal from parietal lobe) provides dividing line b/w rostral (involved in movement-related activities, such as planning and executing behaviors) and caudal regions (involved in perceiving and learning of the cerebral cortex)
Motor Association Cortex (akaPre-Motor Cortex)
- Rostral (in front of) the primary motor cortex. This region controls the primary motor cortex; thus, it directly controls behavior by organizing the movements that you’re going to do.
- Each primary sensory area of the cerebral cortex sends information to these adjacent regions
- Analyze the information received from the primary sensory cortex (perception, and memories)
- Region closest to the primary visual cortex analyzes visual information and stores visual memories.
- Regions far from the primary sensory areas receive information from more than one sensory system; thus, make it possible to integrate information
- left hemisphere analyzes information - the extraction of elements that make up the whole of an experience, recognizes serial events and controls sequences of behavior. verbal activities, such as talking, understanding speech, reading, and writing
- right hemisphere is specialized for synthesis, putting isolated elements together to perceive things as a whole. (ability to draw sketches (especially of 3D objects), read maps, and construct complex objects out of smaller elements
a large band of axons that connects corresponding parts of the cerebral cortex of the left and right hemispheres
- The neocortex includes the cerebral cortex that covers most of the surface of the cerebral hemispheres (including the frontal, parietal, occipital, and temporal lobes)
- The limbic cortex, is located around the medial edge of the cerebral hemispheres. The cingulate gyrus is an important region of the limbic cortex.
a set of interconnected brain structures formed a circuit whose primary function is emotion, memory, motivation, and sense of smell
-the limbic cortex, the hippocampus and the amygdala (“almond”), located next to the lateral ventricle in the temporal lobe.
- Acts to inhibit emotions. Tells us if we hate/like things, that we should stop liking things (tells us to stop if we’re eating too much chocolate).
- Processes both social and physical pain
- Sexual drive, feeding behavior (primitive drives)
This part helps you think about what you’re going to. Is right beside motor skills so that you can then execute.
The more powerful your inferior frontal is, means you have better control over your impulsivity.
Dopamine being at too high of levels in this area – found in gamblers.
Involved in Theory of Mind (religion)
Motor cortex controlling face and throat is right behind this area.
This is a very vulnerable part of the brain, common problem area for strokes.
Can lose separate languages if you learn languages differently.
Voices/music heard by schizophrenics.
Causes visual hallucinations. Right next to occipital lobe, processes what you are looking at. Recognizes what you’re seeing.
Integrates the sensory systems into a single “world view” that is unique for each person.
Integrates sensory systems. Vision, hearing, touch, all come together and seem seamless.
Inherited abnormal neuronal connections in the inferior prefrontal cortex may underlie an increased risk of developing stimulant drug dependence.
- Bottom of brain, hovers at top of nasal cavity.
Blood comes from heart through internal carotid artery.
Humans also get small amount thru vertebral artery (dogs and cats get much more thru here)
Circle of willis – allows blood to flow from one side of brain to next.
Then divides into Posterior Cerebral Artery, Anterior Cerebral Artery, and Middle Cerebral Artery (most associated with clogs and problems bc biggest)
Hemorrhagic – weakening in wall, blood bleeds out.
Emotional disturbances – like bipolar disorder can be detected by observing the cingulate gyrus.
Cingulate gyrus is not as big or thick in people who suffer from bipolar disorder (trouble controlling emotion)
Tumor pressing against cingulate cortex – hypersexual nun.
Impulsivity – disorder with cingulate cortex.
-Top of spinal column, switchboard of brain.
Projects outward, out of thalamus to rest of brain to wake you up.
Immature Thalamus = ADHD
Hearing, then speaking it (mirroring)
Allows you to mimic and learn language.
Allows you to read out loud
Help us move better. We can move without it but this perfects it.
Motor skills that are learned and stored in cerebellum (performing repetitive motor skills like signing your name or swinging a bat/golf club).
Glucose is the brain’s primary source of energy and most of it is used to maintain a resting membrane potential – critical for neuronal function.
Neurons use a lot of DNA - Large nuclei
2 most glucose dependent cells in body are neurons and cancer cells.
Lots of mitochondria, neurons don’t have ability to store energy.
Important component to blood-brain barrier.
Astrocytes conduct nutrients from the blood to the neurons and transport waste products away to the blood and CSF. Live b/w blood vessels and neurons. Fatty substance so polar things must be transported.
Fill and cover surfaces of blood vessels. Very dense. 10-15 astrocytes for every neuron. Non-overlapping. Each astrocyte occupies a distinct volume (domain) with very little or no overlap with the volumes (domains) occupied by other astrocytes.
95% of all tumors are from glia.
Glia tumors are common and form as spheres or gather around an artery or something. Don’t go far, concentrated. Grow very slowly, don’t really spread. Glia/astrocytes are the only brain cells that form cancer.
Phagocytosis of synaptic structures during postnatal development, phagocytosis of newborn neurons during adult neurogenesis, active remodeling of the perisynaptic environment and release of soluble factors in the mature and aging brain. Influence neuronal plasticity and function, may be regulated by sensory experience. Help synapses form and disappear. Test to see if anything is wrong. If they sense anything is wrong they can initiate an immune response. Protection and recovery.
have a complete array of proteins floating on their surface that allow them to attach to the pre-synaptic membrane and be prepared to eject their contents.
Synapse on soma (cell body) – much more influential than those on dendrites.
Can be on spine or dendritic shafts
Can be on another axon.
Could have millions synapses attached to one neuron.
A Transmitter - important for paying attention – glucose and mitochondria needed to produce acetylcholine
A primary neurotransmitter secreted by efferent axons of the PNS.
All muscular movement is accomplished by the release of acetylcholine.
ACh is also found in the basal ganglia of the autonomic nervous system and at the target organs of the parasympathetic branch of the ANS.
Making the connection larger and larger by “using” it.
Usage can eventually make 2 connections.
You can sever the connections for things you don’t want to remember.
More “plastic” when you have less connections (youth), but inefficient.Adult brains are more efficient, but less flexible.
voluntary eye movemnts
Related to visual Memory
studies of groups of subjects who have been exposed to the conditions of interest in the real world. Not true experiments because confounding variables are not controlled.
the outermost layer of the cerebral hemispheres.
Chronic brain damage resulting from repeated concussion, often found in boxers and football players. Typical Symptoms: Slurred Speech, Awkward gait, Slowed thought processes, lack of emotional and behavioral control.
advance form of syphilis that effects the spinal cord, leads to lose of sensation to the bottom of the feet. Individual ends up walking funny
Patient stands upright and closes eyes, if they fall then there is something wrong with the cerebellum.
Tumor in Basolateral Amygdala
Threadlike structure containing genes in the nucleus of each cell. Occur in match pairs.
destruction of brain tissue either naturally or experimentally.
The acetylcholinergic neurons located in the dorsolateral pons play a role in REM sleep.
Those located in the basal forebrain are involved in activating the cerebral cortex and facilitating learning, especially perceptual learning.
Those located in the medial septum control the elec- trical rhythms of the hippocampus and modulate its functions, which include the formation of particular kinds of memories
Choline, a substance derived from glucose from the breakdown of lipids, and acetate, the anion found in vinegar, also called acetic acid.
Acetyl is made from sugars from diet, Choline also comes from diet, sugars and lecithin.
Cholinergic neurons project to brain regions with functions like...
In raphe nuclei and project everywhere in the brain.
Turn Off Serotonergic Neurons in the Raphe Nuclei by Stimulating 5HT-1A Receptors. LSD is a direct agonist for postsynaptic 5-HT2A receptors in the forebrain. MDMA is both a noradrenergic and a serotonergic agonist
A remarkable, rare condition where an individual has multimodal perceptual experiences from a unimodal sensory event. The ability of hallucinogens to induce synesthesia may be related to their ability to influence serotonergic control over the frontal lobes.
For some people their inherited tendency to depression may be linked to the absence of a single brain protein (p11) associated with a specific serotonin receptor.
Deficits in p11 are associated with increased depressive-like behavior, and increases in p11 can be linked to antidepressant effects.
Depression in Parkinson Disease may be due to reduced serotonergic function.
The more religious, the less receptors. The less religious, the more receptors.
Less receptors = more anxiety and depression
Block reptake of serotonin, more serotonin will be produced and available making you more alert or something.
Same with dopamine (done with cocaine or amphetamines), will make you happier.
Find GABA and its receptors everywhere, very common in brain. Responsible for IPSPs.
produced from glutamic acid
Very effective anxiolytics, or “anxiety-dissolving” drugs, a class of tranquilizing drugs that bind to a second site on the GABA receptor. Produces sedative, anxiolytic, muscle relaxant, anticonvulsant and cognition-impairing effects.
Barbiturates bind to a third site.Alcohol also binds to GABA. These promote activity of GABA and act as agonists
transmitter critical in creating and destroying neural synapses
Could be related to the cause of schizophrenia via alterations in Dysbindin.Dysbindin mutations in schizophrenics may alter plasticity
PCP blocks the Glutamate Receptor
Amphetamines, Cocaine, Opiates, Marijuana, PCP, Caffeine, Sex, Alcohol, Barbiturates, Chocolate, Nicotine, Foods
Prefrontal Cortex results in powerful release of dopamine. Impulsive. Makes you like things a lot (like chocolate).
Nucleus accumbens fights with prefrontal cortex (should I get the cake or no)
Brain makes its own marijuana (and can make many other psychoactive compounds) called anandamide – made of fats, similar to fats. Shape is similar to that of THC. Similar effects when eating lots of fats
Calcium channel inactivation: less calcium enters sensory neurons
2. Sensory neuron releases less NT
3. Motor neuron releases less NT
Action is lessened
1. Harmful affect is followed by stimulus.
2. Sensory neuron releases NT
3. Facilitating interneurons release serotonin, causing sensory neuron to release increased amounts of NT
4. Motor neuron releases increased amounts of NT
5. Action is stronger
Serotonin creates long chain reaction (long term changes in neuron). Acetylcholine just opens a channel (short term)
Brain stem + cerebellum activated during classical conditioning.
Cerebellum is very important for CC because it has loop of neurons that correct your (motor) behavior for you w/o you noticing.
Ventral striatum and parts of thalamus also important
Someone who learns quickly has huge amount of activation in cerebellum
-Example of classical conditioning
-Combines spatial learning (hippocampus) and fear (amygdala)
Positive reinforcement: Get candy every time you raise your hand in class
Neg. reinforcement: If you get perfect attendance, you don’t have to turn in a homework assignment
Punishment: if you don’t come to class I’m giving you 300 hw assignments
The hippocampus forms a virtual map of your current space.
As the environment moves, the place cell adjusts accordingly.
Hippocampus “place cells” fire whenever the rat traverses a particular location.
Subiculum “head direction cells” fire whenever the rat’s head faces in a certain direction.
Entorhinal “grid cells” fire at the vertices of a regular, repeating grid that covers the entire space.
A neuron becomes connected (or a connection improves) with another neuron after repeated activation and activation gets easier
•Can have more receptors, channels, dendritic spines
Hippocampus is most common area to study LTP (memory)
When weak synapses become strengthened by being stimulated along with strong synapses at approximately the same time.
Prefrontal – decides what is worth remembering.
Thalamus helps with sensory cues
Brain stem cues feed into all systems
Normally, glutamate and glycine bind to NMDA receptor which allows calcium ions to enter the neuron. Alcohol is an uncompetitive antagonist of the NMDA channel and blocks NMDA channel so calcium can no longer enter the neuron. Hinders LTP and results in alcohol-induced memory impairments
Affects Hippocampus + medial temporal first. Then spreads, especially to prefrontal cortex
Plaque build up (normal brain gets rid of plaque)
One-third of adult hippocampal neurons are renewed during a lifetime = 1400 new neurons per day.
This turnover rate is not different between men and women and declines only modestly with age.
Because the hippocampus automatically encodes all experience, then Neurogenesis a decaying process continually clears memories from the hippocampus.
The stem cells that give rise to the cells of the brain.
During the first phase of development, progenitor cells in the ventricular zone (VZ), located just outside the wall of the neural tube, divide, making new progenitor cells and increasing the size of the VZ. Some progenitor cells migrate a short distance away from the ventricular zone, where they continue to divide into more progenitor cells and establish the subventricular zone (SVZ).
The first brain cells produced through asymmetrical division. The cell bodies of radial glia remain close to the wall of the neural tube, in the VZ and SVZ, but they extend fibers radially outward from the VZ. These fibers end in cuplike feet that attach to the pia mater, located at the outer surface of what becomes the cerebral cortex. As the cortex becomes thicker, the fibers of the radial glia grow longer and maintain their connec- tions with the pia mater
The laminar architecture is built up progressively in an inside-out sequence, so that cells contributing to outside formed superficial layers are born later and migrate through earlier formed layers on their migration route from the ventricular zone.
Mouse = 5 hours, 9 cycles
Rat = 6 hours, 10 cycles
Monkey = 20 hours, 18 cycles
Man = 22.4 hours, 20 cycles
All organisms 1st form central sulcus and motor and sensory. Motor front, sensory back - pattern in all species. We organize our brains the same way as birds
The disadvantage is that small unilateral lesions from strokes of cancers produce big deficits in function.
Neurons that are not needed can be pruned by excessive glutamate or undergo programmed cell death – called apoptosis
can remain intact after injury and help guide the regrowing nerve axon to the correct site of action.
Neurons attached to muscle are damaged, muscle degenerates (atrophies).
With some physical therapy, the neurons and muscle will regrow.
The presence of stem cells. Stem cells originate in the proliferative zone throughout life and are guided on their migration by glia.
and antidepressant drugs stimulate their production. Anything that impairs stem cell neurogenesis = depression (ex. Pregnancy, being overweight)
The use of growth factors and transplants are attempting to overcome these problems.
Cortical folding abnormalities in low- and high-functioning autism. Cortical shape abnormalities in restricted regions of parietal and frontal cortex may reflect abnormal patterns of connectivity that underlie cognitive impairments.
Frontal lobe (broca's area) problems
decline in the function of acetylcholine in the right fusiform gyrus that may underlie impaired social functioning and facial attention.
Natural biorhythm is closer to 25 hrs for 95% of us. Easier to stay up than go to bed early.
measures the consequences of the movement of ions across neural membranes.
The movement of ions in a conducting fluid induces voltage potential shifts that can be monitored at the surface of the scalp.
projections from Thalamus slow the neuronal activity and EEG.
All we really need at the end of the day is rest for the body.
Sleep allows synaptic plasticity leading to improved memory.
Memory formation and destruction is the only proposed explanation for sleep that justifies shutting down consciousness
To fully process information gathered throughout the day, the brain must me shut down
With age, SWS decreases somewhat while REM % decreases significantly.
Brainstem controls sleep (where serotonin and norepinephrine originate). If the connections severed that allow these NT to enter the brain, you will enter a coma. But if severed under medulla, you will live, will just be paralyzed.