exam 2 Flashcards
if lesioned, subject will show memory deficits, this concludes that this is included in memory function
hippocampus
- part of the limbic system
- anatomical substrate for emotion
- includes the amygdala and hippocampus
limbic lobe
if lesioned, subject will show docility, tameness, placidity
this shows it is an excitatory structure
amygdala
if lesioned, subject will show rage
this shows it is an inhibitory structure
septum
- fornix
- mammillothalamic tract
- diffuse fibers
- cingulum
- stria terminalis
Papez’ circuit
gray matter
cerebral cortex
longitudinal fissure
divides cortex into symmetrical halves
central sucus
dorsal surface of cortex and somewhat posterior to the center
lateral fissure
runs posteriorly and dorsally on lateral surface
initiates voluntary movement, involved in motor coordination, abstract thinking, involved in speech
frontal lobe
subserves somesthesis, kinesthesis, and taste
parietal lobe
subserves audition and olfaction, involved in some memory functions
temporal lobe
subserves vision
occipital lobe
the study of differences among different types of cortical areas
architectonics
6 fundamental layers
neocortex
4 to 5 layers (cingulate cortex in limbic system)
transitional cortex
3 to 4 layers (i.e. hippocampus in limbic system)
paleocortex
6 layers, layers 2&4 are sensory, laters 5&6 are motor, 1&3 are association
neocortex
brodmann’s classification
numbers are assigned to brain areas and are associated with different functions
3,1,2 brodmann’s classification
primary sensory areas for taste, some thesis, and kinesthesis
5,7 brodmann’s classification
association areas for somesthesis and kinesthesis
4 brodmann’s classification
primary motor area, initiates voluntary movement
6 brodmann’s classification
premotor areas, initiates motor coordination
8 brodmann’s classification
frontal eye fields, motor area concerned with conscious movement of eyes
9-12 brodmann’s classification
areas involved in abstract thinking
41 brodmann’s classification
primary sensory area for hearing
42&43 brodmann’s classification
association areas for hearing
44 brodmann’s classification
primary speech area
17 (striate cortex) brodmann’s classification
primary visual cortex
18 & 19 brodmann’s classification
association visual areas
white matter
fiber tracts of the cerebral hemispheres (part of corpus striatum)
have their cell bodies in the cortex of one hemisphere and pass in a great white sheet to the other hemisphere
commissural fibers
connect one part of the cortex to another part of the in the same hemisphere
association fibers
radiate upward to the cortex from the thalamus and other subcortical areas (sensory)
afferent/corticopetal fibers
project downwards from the cortex to subcortical areas (motor)
efferent or corticofugal fibers
membranes surrounding entire CNS
meninges
thick, though, and protective
dura mater (outer)
thin weblike sheet of tissue
arachnoid mater
thin and delicate (inner)
pia mater
space between arachnoid mater and Pia mater, filled with cerebrospinal fluid
subarachnoid space
within the brain and spinal fluid
the ventricular system
two ventricles _______ _____, are four in each hemisphere
lateral ventricles
the lateral ventricles connect with each other and with the ____ ____ located in midline in the thalamus and hypothalamus
third ventricle
the third ventricle is connected with the ____ ____ which is contained in pons and medulla
fourth ventricle
the fourth ventricle joins to the _____ ____ that runs the length of the spinal cord
central canal
cerebrospinal fluid is manufactured in a _____ ____ which is found in the ventricles
choroid plexus
lateral ventricles, third ventricles, fourth ventricles, central canal
routes of circulation of cerebrospinal fluid (lateral ventricles)
subarachnoid space, down posterior surface of spinal cord, up anterior surface of spinal cord, arachnoid villi, absorbed into venous sinuses of the brain
ventricles
loss of motor ability
paralysis
loss of sensory ability
anesthesia
distortion of sensory ability, tingling and burning sensation
paresthesia
loss of ability to walk in a skilled manner, due to destruction of the gracilis and cuneate tracts, a sensory problem
locomotor ataxia
polio
destroys motor ability, damage to ventral horn in the spinal cord
polio at a higher level in the CNS is bulbar polio (medulla)
disease of the lateral corticospinal tract, destroying voluntary movement, demyelinating disease
aka lou gehrigs disease
amyotrophic lateral sclerosis
demyelinating disease involving several tracts (sensory and/or motor)
multiple sclerosis
shingles
disease of lateral horn of spinal cord, inflammation of dorsal root of nerve, goes from dorsal root into lateral horn, characterized by tenderness of the skin and skin eruptions, caused by a virus
parkinsons disease
disorder characterized by muscle tremors that occur when the person attempts to hold their hand still, due to deficiency of dopamine in basal ganglia
neurodegenerative disease that is characterized by profound personality changes and intellectual impairment, including memory loss (affects frontal Cortex and hippocampus)
alzheimers disease
outside of the cell, beta amyloid (with Alzheimers)
plaques
inside of cell, tangles (with Alzheimers)
tau
an abnormal proliferation of glial cells and meninges cells
tumor
blockage of flow of cerebrospinal fluid
hydrocephalus
disturbance in shape and tone of muscle
dystrophy
progressive muscular weakness, lymphocytes produce antibodies that attack receptors on muscle cells at the neuromuscular junction, thus the nerve impulses are blocked
myasthenia gravis
potentials in neurons are measured by
micro electrode recordings from the cell
a difference of electrical charge on 2 sides of the membrane
polarization
recorded from axon
resting potential
large negative protein ions
anions (a-)
potassium ions
k+
positive change on the outside of the membrane is due to the presence of
sodium ions
negative charge on the inside of the membrane is due to the presence of
potassium ions
na+ rush in
k+ already inside
large anions on inside can’t get out
cl- on outside
action potenttial
k+ diffuse out
na+ are pushed out and k+ are pulled back in
this process if regulated by na pump
resting potential
depolarization
reverse of polarization
repolarization
action potential summarizes
increase in excitability as the neuron moves towards threshold1`
period of latent addition
no stimulus, no matter how great, is capable of stimulating as a response`
absolute refractory period
a stronger than normal stimulus is capable of exciting a response
relative refractory period
conduction of nerves impulses along an axon is _______, action potentials do not grow weaker as they travel along the membrane
nondecremental
an axon fires completely or not at all (doesn’t apply to dendrites and cell body)
all or none law
the propagation of inaction potential from node to node of myelinated fibers
saltatory conduction
when axons reach their final destinations, they typically branch into a number of fine collaterals at the end in small swellings called terminal buttons
the buttons represent the end of the axon and it is at these small swellings that information is transferred from one cell to another
neural communications
synapses imposes a delay in the transmission process (delay of 0.5msec)
inhibition of transmission, as well as excitation, can occur at the synapse
inhibitory and excitatory conditions at the synapse may persist over relatively long time periods
synaptic transmission
found in presynaptic terminals they are sites where neurotransmitters are synthesized, stored, and released
synaptic vesicles
depolarization of membrane allows entry of ca+
ca++ causes vesicles to fuse with plasma membrane
neurotransmitter released
neurotransmitter binds to receptor, na+ gates open (depolarization)
summary of synaptic transmission
the potential that arises in the somatodendritic structure is called a _______ _____
this requires a specific excitant (neurotransmitter)
a graded potential that can build up with excitation arriving simultaneously from different axon terminals
postsynaptic potential
the combined influences of many neurotransmitter releases at different locations on the postsynaptic membrane at a particular moment in time
spatial summations
repeated excitation, the combined effects of neurotransmitter release over time
temporal summation
the neurotransmitter makes the dendrites and cell body of the postsynaptic cell more permeable to positively charged sodium ions
the result is partial depolarization/graded potential
excitatory postsynaptic potential (epsp)
the neurotransmitter hyper polarizes the dendrites and cell body of the postsynaptic cell
its now more difficult to stimulate the postsynaptic cell
inhibitory postsynaptic potential (ipsp)
stimulate or inhibit the dendrites and cell body of another neuron
taken back into the axon from which it was liberated
be inactivated in a reaction analyzed by an enzyme
fate of a neurotransmitter
bind to their own neuron’s transmitter molecules
located on the presynaptic membrane
their usual function is to monitor number of transmitter molecules in the synapse to reduce subsequent release when they are low
autoreceptor
one electrode placed over the brain area
one electrode is placed over the ear lobe (for grounding)
monopolar recording
on electrode is placed over the brain area
one electrode is placed over another brain area
bipolar recording
1/2-4 cps
characteristic of deep sleep of slow wave sleep
delta waves
4-7 cps
found in young children, in the adult its like the twilight state, which is experienced fleetingly upon waking or drifting off into sleep
theta waves
8-12 cps
characteristic of relaxed wakefulness
alpha waves
13-30 cps
characteristic of alert, wakeful state, found in one stage of sleep REM, or paradoxical sleep which is associated with dreaming
beta waves
40+ cps
associated with highest state of focus
gamma waves
acetylcholine
- biosynthesis: choline acetyltransferase
- degradation:
acetylcholinesterase
catecholamines (CA)
- DA,NE, E
- biosynthesis: tyrosine hydroxylase
l-dopa: aromatic amino acid decarboxylase
DA: dopamine-beta-hydroxylase
NE: phenylethanolmine-N-methyl transferase
-degradation:
monoamine oxidase (MAO)
serotonin
- biosynthesis: tryptophan hydroxylase, aromatic amino acid decarboxylase
-degradation:
monoamine oxidase (MAO)
gama aminobutyric acid (GABA)- inhibitory neurotransmitter
- biosynthesis: glutamic acid decarboxylase
- degradation:
GABA transaminase
peptides that play a role in neurotransmission are referred to as ______
among the most interesting of these are the endorphins
frequently referred to as endogenous opiates
neuropeptides
- produce and release ACH
- motor neurons which innervate striated (skeletal) muscles
- central nervous system
- preganglionic parasympathetic fibers
- postganglionic parasympathetic fibers
- preganglionic sympathetic fibers
cholinergic fibers
- produce and release noriphenephrine
- postganglionic sympathetic fibers
-CNS
noradrenergic fibers
- produce and release epinephrine
- CNS
adrenergic fibers
- produce and release dopamine
- CNS
dopaminergic fibers
- produce and release serotonin (5-HT)
- CNS
serotonergic fibers
- produce and release GABA
- CNS
gabaergic fibers
- synthesis
- storage in synaptic vessicles
- breakdown of any neurotransmitter leaking from the vessicle
- exocytosis
- inhibitory feedback via autoreceptors
- activation of postsynaptic receptors
- deactivation of reuptake or enzymatic degradation
steps in neurotransmitter action
- drugs that mimic or enhance the activity of a neurotransmitter
- drugs increase the synthesis of neurotransmitter molecules (increasing the amount of precursor)
- drug increases the number of neurotransmitter molecules by destroying degrading enzymes
- drug increases release of neurotransmitter molecules form terminal buttons
- drug binds to auto receptors and blocks their inhibitory effect on neurotransmitter release
- drug binds to postsynaptic receptors and either activates them or increases the effect of them on neurotransmitter molecules
- drug blocks activators of neurotransmitter molecules by blocking degradation or reuptake
drug agonists
- drugs that block activity of a neurotransmitter
- deug blocks synthesis of neurotransmitter molecules (destroying synthesizing enzymes)
- drug causes neurotransmitter molecules to leak from vesicles and be destroyed by degrading enzymes
- drug blocks release of transmitters from terminal buttons
- drug activates auto receptor and inhibits neurotransmitter release
- drug is a receptor blocker, binds to the postynspatic receptors, and blocks effect of neurotransmitter
drug antagonist
barbiturates
ethyl alcohol (ethanol)
halcion
ambien (most commonly prescribed)
sedative-hypnotics
benzodiazepines
libirum
valium
xanax
enhance inhibitory effects of GABA
busiprone
antianxiety drugs
caffeine- ne stimulant
nicotine- ach receptor stimulant
amphetamine- inhibitor of NE and DA reuptake and increased release of NE and DA
cocaine- inhibitor of NE and DA reuptake and increased release of NE and DA
stimulants
lysergic acid diethyl amide (LSD)- 5-ht agonist
psilocybin (found in certain mushrooms)- 5-ht agonist
mescaline (type of cactus, peyote)- structural resemblance to NE (also some 5-ht agonistic actions)
phencyclidine (PCP)- opioid receptor agonist, high dose of PCP can enhance seroterngic activity, partially by inhibiting 5-HT reuptake
psychotomimetics, psychedelics, and hallucinogens
- cannaboid receptors are widely distributed in the brain, but the pattern is uneven
- depending upon concentration, this can either enhance or inhibit release of various neurotransmitters
- changes in hippocampal operations are probably responsible for the distortions in memory and cognitive performance
tetrahydrocannabinol (THC) (marijuana, psychotomimetic, psychedelics, and hallucinogens)
-antipsychotic drugs/antischizophrenic drugs
- chlorpromazine- da receptor/blocker
- clozapine- da receptor blocker
psychotherapeutic drugs
- antidepressants
- inhibitors of NE reuptake (norepinephrine reuptake inhibitors: reboxetine)
- inhibitors of 5-HT (SSRIs: prozac)
- inhibitors of both serotonin and norepinephrine (SNRIs: Cymbalta)
- mood stabilizing drugs: lithium carbonate
antidepressants (psychotherapeutic drugs)
- aspirin
- opiates (morphine, heroine, fentanyl)
analgesic drugs (painkillers)
- the least amount of physical energy that can be perceived (50%) of the time
absolute threshold
the least amount of physical energy that can be perceived as being different from a standard (50%) of the time
there is always a standard to compare it to
differential threshold
maximum energy sensed (increasing stimulus energy does not increase the sensation)
terminal threshold
a study of the relationship between physical energy and experience
psychophysics
wavelength, intensity
light stimulus
color or hue
light experience
frequency, intensity
sound stimulus
pitch, noise
sound experience
experimenter (_E) presents randomly varying intensities of the stimulus
method of constant stimuli
the subject (_S) varies the intensity of the stimulus themselves
method of adjustment
the experimenter starts well above threshold and gradually decrease the intensity of a stimulus in a series of steps, then E starts well below the threshold and gradually increases the intensity of a stimulus in a series off steps
method of limits (staircase method)
(change in intensity/original intensity)= constant
- if original intensity if too low, not much bust be added to detect a difference, the original intensity is high, a great deal must be added to detect a difference Weber’s law holds up well for original low and medium intensities, breaks down at a high original intensities because differential threshold has been reached
weber’s law (utilized with differential threshold)
immediate impression that senses make on the brain the process of detecting the presence of stimuli
sensation
higher-order processing of integrating, recognizing, and interpreting complex patterns one sensations
perception
conversion of physical energy into nerve impulses (occurs at sensory receptors)
(eye tranduces light into nerve impulses, and ear traduces sound into nerve impulses)
transduction
- 1826, Johannes muller published “specific nerve energies”, explaining how nerve fibers code sensory stimuli
- greeks used to assume that given stimulus impressed its characteristic directly onto brain
- muller noted gross sensory quality depends on which nerve is stimulated, not how
- not the stimulus that determines gross sensory quality, but rather the receptors and neurons activated by stimulus
law of specific nerve energies
the receptor system is most sensitive, it requires least a mount of energy
- for eye/vision, this is light
adequate stimulus
the organism will respond, but it requires a great deal of energy
- for eye/vision, this is pressure on the eyeball, electric shock, and mechanical irritation
inadequate stimulus
the sensory receptors generate a specific pattern of neural activity
allows for nervous system to construct a representation of the physical world, this message contains information about stimuli in the physical environment
coding
- subserve pain, warm, cold, some touch (diffuse light touch)
unspecialized neurons (free nerve endings)
subserve vision and olfaction
specialized neurons
subserve auction, balance, taste, specific light touch, pressure, and kinesthesis
specialized epithelial cell- neuron combinations
decrease in a réponse of the receptor and a decrease in the perceived intensity of a stimulus resulting from a constant rate of stimulation, caused by receptor fatigue
- olfaction and taste adapt most readily
adaptation
loss of attention to a stimulus caused by repetition or lack of novelty
habituation
a feedback mechanism from the brain to the receptors, inhibiting incoming sensory information
sensory gating
- recording electrode was placed on the auditory nerve of a cat
- a noise was sounded, auditory nerve responded
- next, a rat was placed in the box with the cat, noise was sounded, auditory nerve did not respond, rat was removed from the box, noise was sounded, auditory nerve responded
experiment of Hernandez-peon
occur when the receptors continue to respond after the stimulus ceases acting on them
afterimages
usually results from brief, intense stimulation
positive afterimages
result from prolonged, moderate stimulation
negative afterimages
smaller chamber in from of the lens, contains aqueous humor
aqueous chamber
larger chamber behind the lens containing vitreous humor
vitreous chamber
the outermost layer of the eye, contains a translucent front called the cornea
sclera layer
prevents escape of light from the eye and contains blood vessels
choroid layer
contains receptors for vision, innermost layer
the retina,
outside of the eyeball, moves the eyeball
extrinsic muscles
inside of eyeball, controls the lens (ciliary muscles) and pupil (iris)
intrinsic muscle
the first group is a row of primary receptor neurons which ar responsive to light
rods and cones- specialized neurons
bipolar neurons bring impulses to the neurons of the _____ _____
ganglion cells
light– cornea– aqueous humor– lens– vitreous humor– ganglion cells– bipolar cells– receptors– transduction
receptors- bipolar cells- ganglion cells- to the brain
pathway of light and transduction
pick up information from receptor cells and spread effects to several bipolar cells
horizontal cells
pick up information from bipolar cells and spread effects to several ganglion cells
amacrine cells
concentrated in the central part of the back of the retina and become sparser in the periphery
cones
more numerous in the periphery and absent in the center of the retina
rods
the part of the retina centered behind the lens is the _____ ____ or yellow spot
macula lutea
the ____ ____ is the center of the macula lutea
the area of the sharpest vision
the bipolar and ganglion cells are drawn aside as an oblique angle so the cones ar more directly exposed to the light rays
fovea centralis
- functions at night
- low illumination
- don’t see color
- most sensitive in the greenish part of the spectrum
- most numerous in periphery
- much convergence
duplicity theory of rods
- functions during the day
- high illumination
- see color
- most sensitive in yellowish spectrum
- most numerous in central retina
- create point-to-point connection (greater visual acuity)
duplicity theory of cones
all variations of light may be specific in terms of 2 variables ____ and ___
wavelength and intensity
the unit commonly employed for designation of wavelength is ______
millimicron
the vertebrate eye is sensitive to wavelengths between ____ and ____ millimicrons
380 and 760
this depends on the size of the pupil through which light enters the eye
the size of the pupil depends on this
the narrower the aperture, the sharper the focus of the retinal image
focus is best when illumination is high and pupil is constricted
retinal illumination
