The skin senses (Surface of body conditions)

Proprioception (Information about limb and body position and movement)

Interoceptive System (Sensations in our internal organs)

Head position and movement (known as the vestibular sense)

Vestibular System sends projections to the cerebellum and the brain stem.

Found in Inner Ear

Called the semiciruclar canals, the utricle, and saccule

Touch, Warmth, Cold, Pain

General Receptors: 

1) Free Nerve Endings - processes at the ends of neurons that detect warmth, cold, and pain 

2) Encapsulated Receptors - More complex structures enclosed in a membrane to detect touch

Segments of the body that are served by spinal nerves. One dermatone to one spinal or cranial nerve.

Neruons (Spinal or cranial) cross from one side of the body to the other side of the brain -- this makes it so that touch on the right is processed in the left hemisphere and vice versa. 

Body Sense ---(Spinal & Cranial Nerves)-----> Thalamus

Thalamus -----(Body Sense Neurons)------> Somatosensory Cortex

Body sense information enters the spinal cord via spinal nerves or brain via cranial nerves and travels to the thalamus. From the thalamus it then goes up body sense nurons to the somatosensory cortex located in the parietal lobes

Some cortical neurons have receptive fields on the skin and processing is hierarchical

Includes a variety of energy forms

-Gamma rays are at one extreme of frequency

-The visable part of the spectrum accounts for only 1/70 of the range

Used to describe light

Wavelength is the distance the oscillating energy travels before it reverses direction

Visible light ranges in wavelength from 300nm to 800 nm

At the back of the eye

Contains two main types of light-sensitive photoreceptors - Rods and Cones

Contains photopigment which breaks down in the presence of light -- Specifically, Rods contain Rhodospin which is extremely sensitive to light

Rods work well in dim light and poor in bright light.

They distinguish only different levels of light.

In terms of receptive fields:

-Many rods to each ganglion cell = even more enhanced sensitivity to light

-Numerous in the periphery, absent in the center (fova)

Contain Photopigment which breaks down in the presence of light. Specifically, cones contain iodopsin which requires bright light to function.

Cones work well in daylight and nonfunctional in dime light

Three types of iodopsin allow the cones to distnguish among different wavelengths

In relation to receptive fields:

-Few cones to each ganglion cell

-Each cone has it's own ganglion cell = visual acuity (the ability to distinguish details).

-Cones are numerous in the center (fovea) and decrease towards the periphery.

Cells that the cones and rods connect to.

Photoreceptors (Rods and Cones) are most active in the darkness -- Sodium and Calcium channels are open and the receptor is depolarized, causing it to release glutamate which inhibits the bipolar cells.

Cells that bipolar cells connect to

When light strikes the photopigment (in the rods and cones), sodium and calcium channels close and reduce glutamate release.

This causes bipolar cells to release more transmitter which increases the firing rate in the ganglion cells.

Area of the retina from which a ganglion cell (or any other cell in visual system) recieves its input 

Receptive field of cones are small

Receptive field of Rods are larger

No receptors where the optic nerve exits the eye

Where the two optic nerves join (for a short distance) just in front of the pitutiary gland.

Located in the thalamus and where the first synapse the axons from the ganglion cells that form the optic nerves will connect with.

Axons of retinal ganglion cells that have joined together and pass out of each eye

The part of the environemtn that is being registered on the retina.

Information from the left visual field is detected by the right half of each retina and transmitted to the right hemisphere.

Vice Versa: Image in the right visual field wil be detected by the left half of each retina and projected to the left hemisphere.

Optic Nerves (Axons of retinal ganglion cells) pass out of each eye exiting at the blind spot and joining momentarily at the optic chaism. 

At the optic chaism, the nerves or bundle of axons from the nasal sides of the eyes cross to the other side and go to the opposite visual cortex by way of the Lateral Geniculate Nuclei (LGN) in the thalamus.

Neurons from the outside (temporal side) DO NOT cross over at the optic chaism, but stay on the same side and head towards the same side visual cortex by way of the LGN in the thalamus.

Caused by the separation between the eyes

More distant objects cast their image toward the nasal (inside) side of the retina

Closer objects case their image toward the temporal (outside) part of the retina

In the visual cortex, different nuerons fire depending on the image's displacement on the two retinas, providing information about the object's distance.

The anterior parietal cortex combines this depth info. with info. about the object's shape and location to provide 3D location of objects.

Visual info. travels from the retina to the brain in the parvocellular system.

System is specialized for discrimination of fine detail and discimination of color

     -This is because the receptive fields are circular, small, and color opponent

Parvocellular ganglion cells located mostly in the fovea

Visual info. travels from the retina to the brain in the magnocellular system

Ganglion cells located mostly in the periphery

Magnocellular system is specialized for brightness contrast and for movement

     -This is because they have larger circular receptive fields that are brightness opponent and respond only briefly to stimulation.

Dominated by the Parvocellular system

Concerned with color perception & Object Recognition

     -Projects to the inferior temporal cortext, providing object recognition

Is the visual "what" processor

Ventral Stream Path: Visual Cortex----> V1, V2 & V4 ----> Inferior temporal cortex---->Prefrontal Cortex (for managing information in memory & integrating information about the body and about objects while planning movements)

People with damage to the ventral stream can see objects, reach for them, and walk around them, but cannot identify the objects.

Dominated by the magnocellular system

Concerned with movement and location of objects in space

     -Projects to the posterior parietal area, which provides location of objects in space.

Visual "where" processor

Dorsal Stream path is: Visual Cortex --->V5/MT & MST ----> Posterior Parietal ----> Prefrontal Cortex (Used for managing information in memory and integrating information about the body and objects while planning movements)

People with damange to the dorsal stream can identify objects, but they have trouble orienting their gaze toward objects, reaching accurately, and shaping their hands to grasp and object using visual cues.

Damage to the inferior temporal cortex

Impaired ability to recognize objects

Damage to the inferior temporal cortex

Inability to visually recognize familar faces

Does not involve memory -- people can be identified by speech or mannerisms.

The posterior parietal cortex combines input from visual, auditory, and somatosensory areas to help locate objects in space and orient body to the environment...

Damage impairs abilities such as reaching for objects

It also produces neglect

Patient ignores visual, touch, and auditory stimulation on the side opposite the injury.

Usually results from injury in the right hemisphere

NOT due to any visual processing defect, but defect in attention

Symptoms can be seen in drawings, which lack detail on the left side.

How the brain combines info. from different areas into a whole 

It is suggested this combinging or "binding" might occur in:

1) part of the superior temporal gyrus-it recieves info. from both dorsal and ventral streams.

2) part of the pareital cortex, where damage causes neglect

3) in frontal areas where both streams converage

They are the pain receptors.

Sensitive to stimulation that begin near levels that damage tissue.

When certian free nerve endings are stimulated by intense pressure, temperature, damange to tissue, or various chemicals.

released when intense stimulation occurs.

Referred to as "inflammatory soup"

1) Sharp pain right after injury has occured -- transmitted by large, myelinated A-delta fibers

2) Delayed, longer lasting dull pain -- transmitted by small, unmyelinated fibers

Glutamate

Substance P -- for intense pain stimulation

Through the thalamus to the

somatosensory cortex to

areas that process emotional aspects of pain.

Local anesthetics

General anesthetics

Common pain medications like aspirin

Morphine and opiate drugs for intense pain

They block sodium channels in the pain neurons and reduce their ability to fire.

Reduce inflammation by suppresing prostaglandin synthesis

Endorphins

Gate control theory

They are both neurotransmitter and hormone

they act as opiate receptors in many parts of the nervous system.

-inescapable shock

-physical stress

-acupuncture

-vaginal stimulation (most likely linked to childbirth)

-placebo administration

Hypnosis

Acupuncture near the pain site.

Proposed by Melzack and Wall

Theory of a circuit invovled in internal pain relief:

-Pressure triggers an inhibitory message that closes a neural "gate" in the pain pathway

-Brain determines whether gate is open or closed.

Pain causes the release of endorphins from the gray matter in the brain stem.

This inhibits the release of substance P, closing the pain "gate" in the spinal cord.

The endorphine circuit is activated by the cingulate cortex during placebo administration, and by the amygdala during fear.

Pain that persists after healing has occured

Involves Neuropathic pain, which is caused by damange to the CNS or PNS

There are genes that can increase susceptibility to chronic pain

During chronic pain, several changes occur in the PNS and CNS including loss of gray matter equivalent to aging 10-20 years.

Nociceptive pain invovles activation of the pain receptors, while Neuropathic pain is caused by damage to the CNS or PNS.

Neuropathic pain (chronic pain) persists after Nociceptive pain is gone.

80%-90% of amputees experience phantom in the missing limb.

Doidge reports 95% of amputees report phantom pain that lasts a lifetime.

Neurons from other body areas incade the area that normally recieves input from the missing limb.

Ex: When areas of the upper arm are touched, they might stimulate phantom pain in a missing hand.

Functional Prosthesis or the mirror box illusion reverses the cortical reorganization and provides pain relief.

How does the mirror box effect work?

-It activates mirror neurons in the area that once served the missing limb.

-This activity is interpreted as real touch and movement, and this stimules reorganization

To set in motion

Refers to the factors that initiate, sustain, and direct behaviors

Instinct

Drive Theory

Incentive Theory

Arousal Theory

A complex behavior that is automatic and unlearned, and occurs in all members of a species

Instincts account for few if any behaviors in humans.

Ex: Maternal behavior

The body maintains homeostasis (equilibrium) inn its systems

Departure from homeostatis produces an aroused condition (drive) that impells the individual to engage in action to return to homeostasis.

People are motivated by external stimuli (incentives), not just internal needs

Incentives can include money, grades, the smell of food.

People behavior in ways that keep them at their preferred level of arousal.

Factors into things like sensation seeking. -- If they function at a high level arousal, they will behavior in away that keeps them there.

Homestatic drives are a "control system" that maintains conditions around a set point.

Include

Temperature Regulation

Thirst

Hunger

Taste

Cannot regulate body temperature internally

Regulate body temperature by dialating or constricting blood vessels, adjusting metabolism, sweating, etc.

Warm and cold senstive cells in "preoptic area" of the hypothalamus get input from the blood and skin

The preoptic area initiates temperature regulating responses

In the hypothalamus

recieves input from blood and skin about temperature and initiates regulating responses.

Osmotic Thirst - Thirst of the cells

Hypovolemic Thirst - Thirst of the blood, caused by extracellular water loss

Our cells are made of ____% water.

Occurs when fluid INSIDE the cells are decreases.

This decrease occurs because the blood is more concentrated ususally do to food intake w/o water.

Because of this, the bloodstream draws water from the cells to dilute it, making the cells Osmotically Thirsty.

Process: Hypothalamus detects the loss due to the OVLT (near 3rd ventricle) ---> OLVT signals Median Preoptic Nucleus in the hypothalamus to initate drinking.

Occurs when the blood volume drops due to loss of extracellular water.

Caused by Diarrhea, sweating, vomiting, or loss of blood.

Process: Lowered blood volume detected in heart and kidneys

Heart talks to the vagus nerve--> vagus nerve talks to the nucleus of the solitary tract in the Medulla and the Median preoptic nucleus in the hypothalmus

Kidneys release hormone renin --> renin increases production of angiotensin II ---> which stimulates subfornical organ --> signals the median preoptic nucleus in the hypothalamus

Physiological - growth spurts, high energy days, stress

Psychological - Eating disorders, body image, depression

A homostatic drive that produces behavior to provide energy for fuel that maintains body temperature and material needed for growth and repair.

Naturally sweet foods = nutrition

Salty foods = ions for neural transmission

Sour foods = spoiled

Bitter foods = toxic

Umami taste = select protiens

The taste bud receptors send signals to the insula which is in the frontal lobes and then to the Nucleus of the Solitary Tract (NST) in the medulla.

Think Frontal then Medulla

Preference for the flavor of a food that contains a needed nutrient.

Not to be confused with distraction of tasty, high-calorie foods not found in nature.

Begins in the mouth - saliva enzyme starts the breakdown of food.

Next, stomach - food is mixed with hydrochloric acid and pepsin to further breakdown food

     -Most of this process happens in the small

      intestine (Duodenum - initial 25 cm)

Produts of digestion (Glucose, amino acids, fatty acids, and glycerol) are absorbed thorugh the intestinal walls

The nutrients are then taken to the liver by the hepatic portal vein

Glucose

Amino acids

fatty acids

glycerol

Absorbative phase

Fasting Phase

During this phase, the body uses the nutrients arriving from digestive system

In away, this is like the "Full" phase, or getting to "Full" phase. When the parasympathetic system is activated, it is all about calming the body down, using what's available to satiate systems.

Increase in glucose turns on the Parasympathetic system which releases insulin -- In the parasympathetic system (cells outside of the CNS), this insulin turns on glucose transporters which carry glucose to the cells.

In the brain/CNS, insulin is not needed, so CNS cells get direct/priority access to glucose.

Nutrients can also be stored during this phase

     -Glucose turns to glycogen in the liver and

      muscles

     -Excess glucose is converted to fats and

      stored in adipose tissue

During this phase, glucose levels have fallen and the body must rely on stored nutrients.

This is like the "hungry phase" when the sympathetic nervous system is activated, the body starts moving to get what it needs.

The sympathetic nervous system causes release of glucagon, which turns livers glycogen to glucose

This glucose gets sent only to the brain because insulin levels are low.

Glucagon, secreted by the pancreas, breaks down fat and fatty acids (used by muscles and organs)  and glycerol (converted to glucose for the brain)

The lateral hypothalamus - initates eating and controls aspects of feeding and metabolic responses

Parventricular Nucleus - controls metabolic functions

A glucose Deficit - Glucoprivic Hunger

A fatty acids deficit - Lipoprivic Hunger

Ghrelin - released when the stomach empties

Glucoprivic - Glucose deficit

Lipoprivic - Fatty Acid deficit

The signals are carried by the vagus nerve to the NST (Nucleus of the Solitary Tract) in the medulla then to the arcuate nucleus, which is in the hypothalamus -- it is the nutrient regulator.

The Arcuate Nucleus in the hypothalamus.

Ghrelin is released when the stomach empties.

It signals hunger when it reaches the NST (Neculus of the solitary tract) via the blood stream

The NST talks diretly to the arcuate nucleus in the hypothalamus

The arcuate nucleus sends neurons to the lateral hypothalamus and the PVN.

Stretch or volume receptors in the stomach signal meal size.

Stomach and intenstines release certian peptides in response to types of food -- some of these peptides act as signals to the brain

---The best known of these petides is cholecystokinin (CCK) -- released as food passes into the duodenum (first 25 cm. of the small intestine)

---------CCK detets fats and aids in fat digestion by causing the gall bladder to release bile

---------CCK stimulates the vagus nerve, which stimulates the NST, which talks to the hypothalamus that tells us to quit eating.

Little is known about satiation, but it invovles the mouth, stomach, and intestinal factors. 

It involves arousal and satiation

Involves hormonal control

controlled by specific areas of the brain

Does nto fit the pattern of a homeostatic tissue need

Individuals do not require sex for survival

but SPECIES require sex and reporduction to survive

Excitement phase

Plateau phase

Orgasm

Resolution

Period of arousal and preparation for intercourse

Increased heart rate, blood pressure, and muscle tension -- Males become erect, women clitoris swells, breasts swell

Increase in sexual arousal levels off

Preparation for orgasms - women secrete lubrication, males testes rise in preparation for ejaculation

Rhythmic contractions occur in the vagina and those in the penis are accompanied by ejaculation.

follows as arousal decreases and the body returns to its previous state

Males have a refractory period during the resolution phase whre they cannot become aroused or ejaculate again (this varies with age and across life span)

Females do not have a refractory period and can become aroused again during the resolution

Attraction - but this varies from human to human and within the same individual over time.

Brain Structures - the amygdala which is involved in emotions -- connected to past experiences & plasticity

Hormones

Class of hormones responsible for a number of male characteristics (Testosterone is part of the Androgen class)

Testosterone levels go up on evenings for men after they have had sex, but down for both parties when they have not.

Women are most likely to initiate sex in the middle of their cycle, when Estrogens and Androgens (like Testosterone) are at their peak.

A class of hormones responsible for a number of female characteristics and functions

Removal of the gonads (testes or overies) removes the major source of sex hormones

results in loss of sexual motivation in both sexes.

Castration with drugs can be elected by male prisoners to control aggression and sexual predation.

Medial Preoptic Area of the Hypothalamus (MPOA) -- mostly for men -- more important in performance than sexual motivation

Medial Amygdala in the temporal lobe -- involved in sexual behavior, aggression, and emotions -- stimulation of this area causes release in Dopamine

Ventromedial hypothalamus - activity increases during copulation. Is important for receptivity to male advances.

Pareventricular nucleus - important for performance

Sexually dimorphic nucleus, located in the MPOA, male sexual activity is related to its size and size is dependent on prenatal exposure to testosterone.

Dopamine - involved in sexual motivation for both sexes, critical for performance in males

   (drugs that increase DA increase sexual acitivty.

    DA produces erections, ejaculation, and

    subsequent loss of erection and refractoriness)

Serotonin -

---Ejaculation is accompanied by increases in serotonin in the lateral hypothalmus

---contributes to the refractory period

--- Drugs that increase serotonin impair sexual ability in men and women.

The generation and understanding of written, spoken, and gestural communication

Broca's area was discovered in 1861 - studied a stroke patient with injury in the frontal area.

Often reffered to as nonfluent aphasia

Classic Broca: Understand speech, and what they want to say, but cannot SPEAK it -- not really about meaning comprehension, but grammatical comprehension.

Symptoms of aphasia:

-Nonfluent speech (one word terms, telegraphic speech)

-Anomia, or trouble finding words

-articulation problems (inflections might be the same, but can't string a sentence together)

-lack of grammatical, or function, words

Reading and writing are impaired as much as speech.

Comprehension is impaired when the meaning depends on grammatical words

Wernicke's area in the posterior left termporal lobe

The aphasia is about language production and meaning comprehension -- grammatical comprehension is ok in that tone, inflection, pauses etc. are ok, but not meaning to the words. THey have a hard time making meaning of what other people say.

Trouble understanding spoken and written language

Often called "receptive aphasia" but this is misleading because patient has as much trouble producing language as undestanding it.

Speech is often fluent, but meaningless--word salad -- Person is often unaware their speech is not making sense.

An model to explain how Broca's and Wernicke's interact to produce language

Answering a spoken question:

Auditotry cortex --> Wernicke's Area--> Broca's area

- Broca's then communicates with the facial area of the motor cortext to produce speech

Reading Outloud:

Visual information transformed into auditory form in the angular gyrus, then:

Angular Gyrus-->Wernicke's Area-->Broca's Area

Model is generally accurate, but oversimplified.

The right hemisphere can usually take over language functions

Language control is more likely to shift into bordering areas of the left hemisphere.

The ability for these other areas to take language functions over may be due to their normal participation. Broca's and Werenicke's are huge areas, but they are not the only ones.

Contributed by the right hemisphere to speech

It is the use of intonation, emphasis, and rhythm to convey meaning.

Prosody - use of intonation, emphasis, and rhythm to convey meaning

Important in understanding information from language that is not specifically communicated by the meaning of the words. (Meta communication)

--When meaing must be inferred from an entire discourse

--when the meaning is figurative rather than literal, as in the moral of a story

The inability to read and write

probably due to disruption of pathways in the angular gyrus.

These pathways connect the visual projection area with the auditory and visual association areas in the temporal and parietal lobes.

Impairment of reading

Can be acquired through damange, but more often developmental

The left planum temporale, where Wernicke's area is located, is USUALLY larger than on the right, but in dyslxics it is larger on the right or equal in size.

Neurons in the left planum temporale lack orderly arrangement and some have migrated to the outermost layer

The most reliably identifed genes are invovles in neuron gudiance and migration -- which effects neurons getting where they need to go during development.

Auditory: Trouble detecting the frequency and amplitude changes that distinguish letter sounds

and

Visual-perceptual: words are read backward, mirror-image letters, b and d are confused, words appear to move around on the page.

Dyslexia involves deficience in auditory and visual magnocellular cells.

The major problem is an impairment of phoneme processing -- so sounds embedded in words (PH, EH, DA) Book vs. Cook vs. Look, hard to distinguish the Bo, Co, Lo

The deficiet in hearing the spoke word leads to deficits in decoding and encoding words, which leads to struggles writing them later on.

fMRI indicates the problem is in an auditory word analysis area, not in the area that recognizes words by their visual form.

Language acquisition device (universal to all languages), which is a part of the brain that is dedicated to learning and producing language.

Biological mechanisms make language acquisition easy Ex: Speaking and signing children follow the same sequences in learning language

The interpretation is that language has co-opted areas specialized for abilities that language requires. (like Broca's or Werenicke's. These are needed to produce language, so acquiring language has become part of their function)

Brain is innately well fitted for creating and learning language

Evidence:

-The left hemisphere is dominate for language in 90% of right-handed people and most left-handed

-Broca's is larger and the lateral fissure and planum temporale are longer on the left than on the right

-Even newborns show left-hemisphere response to speech.

-Sign language activates the left hemisphere, even in individuals deaf from birth.

The ability to reason, to understand, and to profit from experience.

The measure of intelligence - how it is expressed

Binet was one of the first, verbal and performance IQ. Was focused on children. 

1916, Lewis Terman adapted Binet's test for English speaking kids. Developed the Standford Binet

100 is the average and always has been. 70 or 2 standard deviations below is the mean associated with learning disabilities or mental "retardation" 2 standard above is for the gifted.

School performance

Job performance

Income

Socioeconomic Level

If intelligence is a single capability or a collection of several independent abilities.

Claim that intelligence is a single, unitary capability which is usualy called the general factor, or g.

Intelligence is made up of several mental abilities that are more or less independent of each other

Catell - Believed intelligence is too big for just g. Crystalized intelligence, fluid intelligence

Gardner - Was purist of splitters. Defines intelligence as a distinct sets of processing operations that permit individuals to solve problems, and create products. He dismissed idea of g completely.  - 8 different intelligences that have a biological bases :Math, logical, linguistic, music, intrapersonal, interpersonal, kinesthetic, spatial

Is important to biology of intelligence.

Ratio for humans is one of the highest

ratio for males is slightly higher than females

--womens brains may be more efficient, having a higher ratio of gray to white matter.

--Perhaps males' brains are larger because their spatial ability requires greater capacity

Brain size accounts for 11% of the variance in human intelligence.

The volume of gray matter, esp. in frontal areas.

The volume of white matter.

A thicker cortex

Smaller and more tightly packed processing modules (columns)

Contributes to improved processing efficiency

IQ scores are correlated with reaction time and nerve conduction velocity

Enhanced Myelination

Faster transfer from a limited STM to a LT storage

Use of less energy while engaging in tasks.

Linguistic

Logical-Mathematical

Spatial

--suggests our brains are not ony hardwired for language. but math and spatial abilities as well.

Language - Left frontal and temporal lobes

Depends on the right parietal lobe structures

Mathmatical performance engages in two areas:

Calcuations and arithmetic facts involve the left frontal area

Estimation and use of visual-spatial representation involve the parietal lobes

Both areas, in many math tasks, are usually active.

Intelligence has a heritability of _____ and concordance rates _____ with genetic similarity.

50%

Increase

This is only for intelligence as measured by an IQ test. Got to accept that IQ test IS what defines intelligence.

Working Memory

Processing Speed

Choice Reaction time

Brain Volume (90% heritable)

White Matter (88% heritable)

Gray matter (82% heritable)

APSP Gene - major determinant of brain size

PACAP precursor gene - plays a role in neural signaling and neurogenesis.

at least 150 candidate genes.

IQ correlated 1.76 with the incidence of infectious disease??

SES - children adopted from impoverished homes into middle class homes increase as much as 16 IQ points.

Still, children's IQs are more highly correlated with IQ of biological parents than adoptive parents and this increases over time.

Perhaps not as motivated to perform tasks such as memorizing words.

When tested on content that was meaningful to them (television shows and conversations) decline was moderate

Confounding results with the Flynn effect - 35 year longitudinal study showed less decline.

Performance loss is usually related to reduced speed, and processing speed acounts for 99% of age-related differences in working memory

loss of coordination in default mode network--represents preparedness for action

Through practice, diet, improved self-esteem, and possibly increased GABA

Those who maintain performance recruit additional brain areas during tasks

Neuroplasticity - novel environment exposure will stimulate synaptic growth.

Limitation in intelletual functioning and in adaptive behavior originating before the age of 18.

Trying to be uniformly defined as having non-adaptive behavior or struggles in

Conceptual skills - communication, time, money

Social Skills - social responsiblity, capacity to form relationships with other people

Practical skills - daily living skills, work, and travel.

1-3% of u. s. population considered intellectually disabled.

--45% of those find it impossible to determine the cause or if it was genetic.

IQ below 70

Difficulty meeting routine needs like self-care

Combination of genetic and environmental

Environmental = disease during infancy, prenatal exposure to viruses, and maternal alcoholism.

IQ 50-70

85%

Can graudate, able to hold jobs, have families

May require extra level of support especially during stressful circumstances, but it is within their capabilities.

More people with mild come from Racial minorities and lower SES

IQ 35-49

10% of population of intellectual disabilities

Typically diagnosed in preschool years and usually show organic cause for their delay.

Can achieve to 2nd or 3rd grade level.

With consistent support they can hold jobs and function in the community.

Many people with downs and Fragile X fall into this category.

IQ 20-34

4% of population

Cognitive, Motor, and Ambulatory problems and poor communication.

Usually require specialized cared throughout their whole lives.

IQ Below 20

1%

Significant deficits in motor, cognitive, communication, eating, etc. 

Require significant support to functioning.

Ability to form new memories after damage to the hippocampus or impaired hippocampal formation.

Memories of the past are lost - usually right before a traumatic surgery/event.

Involves short-term memory, long term memory, and long-lasting memory

During consolidation, the brain forms a more or less permanent physical representation of a memory.

Brain stores information temporarily in the hippocampal formation

Over time, memory is progressively transferred to cortical areas - usually stored where the information they are based on was processed.

Memories are nto stored in a single area, nor is each memory distributed throughout the brain

Ex: verbal memories are stored in the left frontal lobe, Memories sounds activate auditory areas, spatial memories in parietal lobe.

Retrieval is the process of accessing stored memories

Glutamate is required (for consolidation as well)

--Blocking glutamate receptors for 7 days following learning prevents memory from being consolidated.

--Blocking them during testing interferes with retrieval.

Prefrontal area is believed to direct the search strategy required for retrieval.

Involves learning that results in memories of facts, people, and events, which a person can verbalize.

HM would improve in tasks over time, but couldn't remember having every done the task -- Declaritive Memory

Memories for behaviors.

Result from procedural (skill) learning, emotional learning, and stimulus-response condititiong.

Subtypes:

Episodic - Memory for events (factual)

Autobiographical - Info about yourself

Spatial - Location of individual and objects in space.

Hippocampi

Amygdala - strengths declarative memories about emotional events.

Memory for both pleasant and aversive stimuli is related to the amount of activity in the amygdala while viewing material.

THe amygdala - emotional learning

could explain why a person might have an emotional response resulting from an unremembered experience.

Provides a temporary "register" for information while it is being used.

The Brain and WM:

-Cells in prefrontal cortex continue to fire during a delay, even in spite of a distracting stimulus, thus assisting working memory.

-Prefrontal cortex acts as a working memory central executive

----manages behavioral strategies and decision making

----directs the neural traffic in WM

-----Coordinates activity involved in perception and response.

The increase in synaptic strength that occurs when presynaptic and postsynaptic neurons are both activated.

Lasts for hours in tissue culture and months in lab animals.

Mostly in the hippocampus, but appears characteristic of much of neural tissue.

decrease in strength of synapses that occurs when stimulation of presynaptic neurons is insufficient to activate postsynaptic cells.

--The way the brain modifies or clears memories to make room for new information

Trains of low frequency stimulation produce LTD

occurs when a weak synapse and a strong synapse on the same postsynaptic neuron are active simultaneously, resulting in strengthing of the weak synapse

Think of classical conditioning. Weak stimulus (weak neuron) with a strong stimulus (Strong neuron) soon, the weak stimulus/neuron becomes strong.

Theta activity (4 to 7 hz)

Theta activity occurs in the hippocampus during novel situations

Peaks of theta waves produces LTP

Troughts of theta waves suppresses LTP

Glutamate activates AMPA receptors, but NMDA receptors are bocked by magnesium ions.

First few pulses of stimulution partially depolarize the membrane and dislodge the magnesium ions.

Further stimulation activates NMDA receptor, depolarizing the membrane.

Calcium influx activates CaMKII, an enzyme required for strengthing the synapse.

LTP induction is followed by gene activation and silencing, which affects the synthesis of protiens

Gene activation, Siliencing, and synthesis of protiens al result in functional changes in the synapse and the growth of new connections.

Increased numbers of dendritic spines

Enlargement or splitting of existing spines

transport of additional AMPA receptors into the spines further increases postsynaptic strength.

Dopamine release unmasks previously silent synapses and initiates growth of new synapses.

Neurogenesis increases in the hippocampus.  -- new neurons are more likely to participate in learning.

Eliminates useless memories.

Involves new learing.

requires activation of NMDA receptors

Forgetting is an active biological process which appears to be adaptive.-- May precent the saturation of synapses.

when retrieved, it must be reconsolidated.

During that time, electroshock and drugs that interfere with protein synthesis can disrupt the memory.

Also a chance to refine and correct errors in memories.

Can also result in recall of false memories.

Loss of synapses and NMDA in hippocampal circuits -- leads to LTP impairment and slower learning.

Myelin loss

Substantial cell loss in basal forebrain region (in monkeys)

Prefrontal deficits, which interfere with learning.

Plaques - clumps of amyloid (protein) that cluster among axon terminals and interfere with neural transmission

Neurofibrillary tangles - Abnormal acumulations of the protein tau inside neurons.

--Tangles are associated with the death of brain cells.

Temporal and frontal lobes

Gyri are reudced in size, sulci and ventricles are enlarged

Hippocampus is effectively isolated from the rest of the brain.

Drugs:

3 Acetylcholinesterase inhibitors

1 Memantine - moderate to severe symptoms

They limit neurons' sensitivity to glutamate (Excess glutamate kills cells by excitotoxicity)

Induce an immune response to amyloid

--Injecting amyloid clears plaques but did not affect cognition

--Injecting immunoglobulin removed plagues and produced mental improvement.

Implant genes for nerve growth factor -- increased brain metabolism and reduced cog. loss by 84%

--

App - Amyloid precursor protein

Chromosome 21 - because individuals with Downs have plaques and tangles.

ApoE4 about 50% of cases -- late onset (over 60)

Batteries of physical, neurological, and cognitive tests.

Brain scans -- PET scans detect plaques

Markers in skin, blood, and Cerebrospinal fluid can diagnoise 5-6 years in advance with 90-100% accuracy.

Another form of demetia with brain deteroriation almost always caused by chronic alcholoism

Results from a thiamine deficiency (alcohol consumes it and reduces absorbtion in the stomach)

Most profound symptom is anterograde amnesia, but can have severe retrograde amnesia as well.

Usually amnesia for declarative memories, nondeclarative memory remains in tact.

Size reductions in the mammillary bodies and the medial thalamus

Structural and functional abnormalities in the frontal lobes.

Thiamine therapy can relieve the symptoms somewhat, but damage is irreversible.

Fabricate stories and facts to make up for thos missing their memories.

depends on abnormal activity in the frontal lobes -- usually have lesions there

They have more trouble than nonconfabulating patients in suppressing irrelevant information they have learned earlier

May be due to an inability to distinguish between current reality and earlier memories.