CNS: The brain and spinal cord

PNS: Network of nerves that act as central communication link between CNS and the rest of the body (relay messages to muscles ot produce actual responses)

They receive, transmit, and integrate information

Sensory Neurons - take input from the environment and carry it toward the spinal cord/brain (they are the initial contact with the environment

Interneurons - Located in between sensory and motor neurons (make no direct contact with the external world)

Motor Neurons - Carry output or info from the spinal cord / brain towards areas of action (muscles, glands, etc.)

Greatly outnumber neurons, but don't directly communicate messages on their own

They remove waste, fill empty space, and help neurons to communicate efficiently (myelin sheath)

Dendrites - Fibers that extend outwards from a neuron and receive info from other neurons (the beginning of a neuron; receives info and carries to soma)

Soma - The cell body of a neuron (cell's metabolic center and where genetic material is stored)

Axon - Long tail-like part of a neuron that is the cell's transmitter (an action potential is sent down its axon towards other neurons)

Terminal buttons - Tiny swellings (vesicles/sacks) at the end of a neuron and the dendrite or cell body of another neuron

1. Action potential must be reached to fire a neuron (all or nothing response)

2. Once AP is receach, travels down entire axon to terminal buttons

3. Messages travel the same regardless of content or intensity as long as the AP is reached

The tiny electrical charge (-60 to -70 mV) between the inside and the outside of a resting neuron (in part because of large protein molecules making the membrane selectively permeable

Na+ and Cl- ions are outside of neuron

K+ is inside neuron

Maintained by sodium-potassium pump

Goes to about +40 to +50 mV at firing

Depolarization - moves the electrical potential of the cell from negative towards zero, and increases the changes of an AP (Na+ enters the cell from the opening of Na+ channels)

Hyperpolarization - the electrical potential of the cell becomes more negative, and the chances of an AP decrease (after K+ channels close, before sodium-potassium pump works again)

Repolarization - the electrical potential of the cell becomes more negative after an AP returning towards zero from being positive (Na+ channels close, K+ channels open and leaves the cell)

Excitatory - causes depolarization of membrane potential (NA+ enters cell) making AP more likely

Inhibitory - causes hyperpolarization of internal potential (K+ leaves cell) making AP less likely

1. AP reaches end of neuron and triggers the releases of neurotransmistters in vesicles

2. Neurotransmitters interact with other (postsynaptic) neurons' cell membranes

3. Receptor molecules determine if the neurotransmitter is excitatory or inhibitory, which would open or close certain ion channels

4. Reuptake of neurotransmitters occurs

Inhibitory; help dampen and stabilize communications in the brain and elsewhere

Schizophrenia (when too great)

Parkinson's (when too little)

Inhibitory; Affects sleep, dreaming, and general arousal

related to depression and OCD

PNS-->Autonomic NS --> Sympathetic NS (fight or flight)

                               --> Parasympathetic NS (Rest digest)

      --> Somatic NS

EEG - used to monitor gross electrical activity of brain; shows up in brain waves

CT scan - use of highly focused beams of X-rays to construct detailed anatomical maps of the living brian

PET - measuring how radioactive substances are absorbed in the brain; it can be used to detect how specific tasks activate certain areas of the living brain

MRI - device that uses magnetic fields and radio-wave pulses to construct detailed, three-dimensional images of the brain; "functional" MRIs can be used to map changes in blood oxygen use as a function of task activity

Broca's Area - controls speech

Central sulcus - divides frontal and parietal lobe; above tempoeral lobe

Occipital lobe - interpretation of eyesight

Temporal lobe - Hearing

Wernicke's Area - understanding/comprehension of words

- Primitive part of the brain that sits at the juncture point where the brain and spinal cord meet. Acts as basic life support system for body

Consists of metencephalon and myelencephalon

Metencephalon:

Pons - between medulla oblangata and mesencephalon and contains reticular formation which is sleep and arousal

Cerebellum (little brain) - has 2 hemispheres and is integral to motor functioning; helps smooth and coordinate movements (standing dancing)

Middle portion of the brain; structures here serve as neural relay stations and may help coordinate reactions to sensory events. Parts:

Mesencephalon consists of 2 parts

Tectum: neural relays; help coordinate rectiosn to sensory events

Tegmentum:

Reticular formation -for sleep and attention

Substantia nigra - release dopamine (Parkinsons)

Telencephalon - composed of three things

Cerbral cortex- for reasoning  and solving problems

4 lobes

Frontal: planning decisions, brocas

Parietal: top middle of brain, touch temp pain

Temporal: Sides aspect speech and auditorry (Wernicke)

Occipital: visual processing

Basal ganglia - control of movement

Limbic system - motivational and emotional and memory

Diencephalon 2 parts

Thalamus - relay station thought to be important gathering point for input from senses

Hypothalamus - Thought to play a role in regulation and various motivation activities (eating drinking sex)

Main network of neurons that connect left and right hemisphere

split brain patients occur due to agenesis of CC, usualy for people with epilepsy (report what you see on right side of screen)

Right hemisphere - for spatial ability, emotional processing, judging time

Left hemisphere- language abilities

network of glands that use blood stream rather than neurons to send chemical messages (in form of hormones) that regulate growth and other internal functions

Regulated by hypothalmus and pituitary gland

One part of the spectrum of all electromagnetic energy; has 3 main properties:

Wavelength: corresponds to the physical distance from one energy cycle to the next; changes here are usually experienced as changes in hue (color)

Intensity: The amplitude; determined by the amount of light falling on an object; changes are experienced as increases or decreases in brightness

Purity: determined by the wavelengths present, and can influence the saturation of perceived colors

Cornea - protective outer layer

Pupil - hole in a ring of the iris

Lens - clear, flexible piece of tissue that sits behind the pupil

Retina - the thin layer of tissue that covers the back of the eye and contains the light-sensitive receptor cells for vision (cells here receive input from rods)

The process by which external messages are translated into the internal brain language

Light strikes the retina, where light-sensitive cells react to light by creating neural impulses

Rods - receptor cells in retina, located mainly around the sides; highly sensitive and active in dim light

Cones - receptor cells (ganglion) in the central point of the retina; operate best when light levels are high, and primarily responsible for the ability to sense color; processing fine detail

Substance that chemically reacts to light and is contained by rods and cones

-These break down in bright light, regenerate after time in low light, causing dark adaption

1. Neural messages travel to brain via optic nerve

1a. Splits at the optic chiasm - where the information travels into the separate hemispheres of the brain

1b. Information from the right visual field goes to the left hemisphere; information from the left visual field goes to the right hemisphere

2. Most of the information travels to LGN in the thalamus

From LGN, messages are relayed to parts of occipital lobe that process vision ("visual cortex")

Visual cortex picks out and identifies features

Trichromatic -  proposes that color information is extracted by comparing the relative activations of three different types of cone receptors

-there are 3 types of cones in retina, each maximally sensitive to one range of wavelengths (wavelengths of blue, green, and red)

-colors are sensed by comparing the amount of activation coming from them (most a mix:orange)

-Certain kinds of colorblindness result from having wrong kind of photopigment in cones

Opponent Process - Cells in the visual pathway increase their activation levels (respond positively) to one color and decrease their activation levels (respond negatively) to another

-Why does yellow seem like primary color?

Proximity - elements that are close to each other are seen as being part of the same object (3 groups of dots rather than one collection

Similarity - Items sharing physical properties are put into the same set (rows of X's and rows of O's rather than mixed-object columns)

Closure - Figures with gaps or small missing parts of the border are seen as complete (whole circle rather than broke)

Good continuation - lines that are interrupted are seen as continuously flowing (road intersection)

Common fate - Things moving together in same direction are seen as a group

Proposed by Biederman that people recognize objects perpetually via smaller components called geons (simple geometric forms)

Size constancy - the perceived size of the object remains constant even though the actual size of the reflected image is changing with distance

-perceived size

-perceived distance

-retinal image

Shape constancy - Shape can be recognized as it moves in space (ex: door opening)

-We do this by making assumptions that allow us to guess, for example, about relative distances of objects

Ames Room Illusion - misshapen room, perceived as normal because of the assumption that rooms are rectangular

Ponzo Illusion - the linear perspective cue-converging parallel lings- tricks the brain into thinking that the horizontal line near the top of the display is farther away, when actually same size

Muller-Lyer Illusion - based on the assumption that converging lines are corners; depth cues cause perceptual errors

Mechanical energy requiring a medium such as air or water to move

-Caused by a vibrating stimulus

- Vibrations sent to the cochlea

- Hair cells (auditory receptor cells) on basilar membrane send signals to brain

1. Sound enters the auditory canal and causes tympanic membrane to vibrate in a pattern that is then transmitted through three small bones in middle ear to oval window

2. Vibrating fluid in oval window causes fluid in cochlea to be displaced, which moves basilar membrane

3. Auditory nerve - Transmits messages from the hair cells on auditory cortex

Place theory - The idea that the location of the hair cells activated by the movement of the basilar membrane underlies the perception of pitch

Frequency theory - the idea that pitch is determined partly by the frequency of neural impulses traveling up the auditory pathway (coming from hair cells)

- High-frequency sounds are coded with colleys of firing

ability to sense the position and movement of ones body parts

-many systems are involved

-nerve impulses travel to the somatosensory cortex

The ability to sense changes in acceleration or posture

-inner ear organs contribute

--Semicircular canals

--Vestibular sacs - organs of the inner ear that contain receptors thought to be primarily responsible for balance

Absolute threshold - the intensity level at which people detect the stimulus 50% of the time

Signal detection technique - A technique used to determine the ability of someoen to detect thepresence of stimulus (varies)

Principle stating that the ability to notice a difference in the magnitude of two stimuli is a constant proportion of the size of the standard stimulus

-Psychologically, the more intense a stiumulu is to begin with, the more intense it will need to become for one to notice a change

Different auditory messages are presented separately and simultaneously to each ear. The subject's tast is to repeat aloud one message while ignoring other

-Unattended message: little is remembered

complex disorder of attention characterized by tendency to ignore things that appear on one soide of the body (usually left)

-result from damage to right parietal

-Reading only one side of page

Ex: cant see difference between 2 houses but would rather live in not burned one

psychological disorder marked by difficulties in concentrating or in sustaining attention for extended periods; can be associated with hyperactivity

-treatable with medication/training

-possible causes

--anxiety

--depression

--ODD

Circadian - biological activities that rise and fall in accordance with 24 hour cycle (regular daily transition from waking to sleep)

Biological clocks - brain structures that schedule rhythmic variations in bodily functions by triggering them at appropriate times (environment syncs these)

EEG's - device that monitors electrical activity in the brain

-Reveals regular, cyclic changes in brain activity during sleep

-Sleep cycles about every 90 minutes, 4-5 times

Stage 1: Theta waves appear

-Light sleep; person may claim to be awake

Stage 2: sleep spindles (short bursts of activity that interrupt theta waves), K complexes (sudden, sharp, intermittent wave forms - ex: loud noises)

Stage 3 and 4: Delta activity (characterized by sychronized slow waves)

- Very deep sleep; nonresponsive to most stimuli and slow to awake

Stage of sleep characterized by rapid eye movements, low amplitude, irregular EEG patters, resembling those of a waking brain

-associated with dreaming

-begins 70-90 minutes into sleep cycle

Manifest content - actual symbols of dream

Latent - true psychological meaning of dream symbols

Idea that dreams represent the brain's attempt to make sense of the random patterns of neural activity generated during sleep

-Other posibilities

--Problem solving and threats from environment

Insomnia - chronic condition marked by difficulty maintaining or initiating sleep (drugs, stress, alchohol)

Hypersomnia - marked with excessive sleepiness (sleep apnea (wake up gasping for breath))

Narcolepsy - rare sleep disorder characterized by sudden extreme sleepiness

Cataplexy - sudden and transient episode of loss of muscle tone (often from emotions) affect 70% of narcoleptics

Nightmares - fright during REM

Night terror - Awake sudden state of panic

Sleepwalkign - occurs in non REM sleep

drugs that affect behavior and mental processes through alterations of conscious awareness

- work mainly by changing communication channels of neurons

--may mimic neurotransmitters