brain cognition Flashcards
optogenetics
how photoreceptor proteins could control neuroactivity
angiography
clinical imaging method used to evaluate the circulatory sytem in the brain nd diagnose disruptions in circulation
cerebral vascular accidents
strokes, occur when blood flow in the brain is suddenly disrupted
degenerative disorders
huntingtons disease, progressive diseases like parkinsons and alzheimers
double dissociation
whether two cognitive fucntions are independent of each other
deep brain stimulation
electrodes are implanted in the basal ganglia. Continuous electrical signals that stimulate neural activity
knockout procedures
developing genetically altered animals
computed tomography (CT or CAT)
allows for the reconstruction of threedimensional space from compressed two dimensional images.
diffusion tensor imaging
can offer info about anatomical connectivity between regions of the anatomical structure of the axon tracts that form the brains white matter
retinotopic
in vision topographic representations. cell activity within a retinotopic map correlates with the location of the stimulus
multiunit recording
recordings made in many neurons simultaneously
EEG
when populations of neurons are actie together they produce electrical potentials large enough to be measued by non invasive electrodes that have been placed on the scalp
event related potential
the evoked responses that are caused by an the variations in the brains electrical activity due to a external stimulus or response
time frequency analysis
the fact that the amplitude (power) of a wave in different frequency regions varies over the course of processing
MEG (magneto encephalography)
technique related to ERP. the electrical current associated with synaptic activity produces small magnetic fields that are perpendicular to the current
electrocortogram
similar to eeg except the electrodes are placed directly on the surface of the brain either outside the udra or beneath it
MRI (magnetic resonance imaging)
produce high resolution images of soft tissue. exploits magnetic properties of atoms that mae up organic tissue
DTI (diffusion tensor imaging)
measures the density and motion of water contained in the axons
PET (positron emission tomorgraphy)
measures local variations in cerebral blood flow that are correlated with mental acitivity. radioactive substance introduced into bloodstream
voxels
regions of neurons
BOLD blood oxygen level dependent effect
the fmri detectors measure the ratio of oxygenated to deoxygenated hemoglobin.
block design experiment
recorded neural activity is integrated over a ‘block’ of time during which thent either is pres enteda stimulus r performs a task
event related design
neural activation is compared between experimental and control scanning phases
glial cells
nonneural cells that serve various functions in the nervous sytem. providing structural support and electrical inslation to neurons and modulating neuronal activity.
soma
cell membrane encases the cell body. contains metabolic machiery that maintains the neuron
cytoplasm
salty intracellular fluid that is made up of combi of ions ; potassium sodium chloride and calcium and proteins
dendrites
branching extensions of the neuron that receive inputs from other neurons
spines
little knobs attached by small necks to the surface of the dendiretes where the dendrites receive inputs from other neurons
axon
single process that extends from the cell body
synapse
specialized structure where two neurons come into close contact so that chemical or electrical signals can be passed from one cell to the nect
axon collaterals
can transmit signals to more than one cell
nodes of ranvier
allong the length of the axons there are evenly spaced gaps in the myelin.
neuronal signaling
neurons receive evluate and transmit information
presynaptic
when their axon makes a connection onto other neurons
postsynaptic
when other neurons make connection into their dendrites
resting membrane potential
the voltage difference acros the neuronal membrane in the resting state is typically -70mV
neuronal membrane
bilayer of fatty lipid molecules that seperates the cytoplasm from the extracellular millieu
ion channels
proteins with a pore through their centers and they alow certain ions to flow down their concentradion gradients
ion pumps
use energy to actively transport ions across the membrane against their concentration gradients ; from regions of low concentration to regions of higher concentration
permeability
the extent to which a particular ion can cross the membrane through a given ion channel
gated ion channels
ion channels that are capable of changing their permeability for a particular ion, they open or close based on changes in nearby transmembrane voltage, or as a response to chemical or physical stimuli
nongated ion channels
ion channels that are unregulated and hence always allow the associated ion to pass through
electrical gradient
because each K+ ion carries one unit of positive charge out of the neuron as it moves across the membrane.
electrochemical equillibriu
when the force of the concentration gradient pushing K out through the K+ channels is equal to the force of the electrical gradient driving K+ in.
excitatory postsynaptic potentials EPSPs
at synapses on the neuron dendrites cause ionic currents to flow in the volume of the cell body
electrotonic conduction
passive current conduction. diminishes with distance from its origin (the synapse)
action potential
rapid depolarization and repolarization of a small region in the membrane caused by the opening and closing of ion channels
voltage gated ion channels
e a class of transmembrane proteins that form ion channels that are activated by changes in the electrical membrane potential near the channel.
spike triggering zone
initiates the action potential in the axon hillock allng the axon
depolarized membrane potential
membrane moves from its resting potential of about -70 mV to -55 mV (threshold)
equillibrium potential
particular voltage at which there is no net flux of ions
hyperpolarization stage
is a change in a cell’s membrane potential that makes it more negative. … Hyperpolarization is often caused by efflux of K+ (a cation) through K+ channels, or influx of Cl– (an anion) through Cl– channels
refractory period
a period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation.
saltatory conduction
is the propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials
synaptic cleft
gap between neurons at the synapse
vesicles
is a large structure within a cell, or extracellular, consisting of liquid enclosed by a lipid bilayer.
isopotential
have the same electrical potential
glial cells
surround neurons and provide support for and insulation between them
microglial cells
a specialised population of macrophages that are found in the central nervous system (CNS). They remove damaged neurons and infections and are important for maintaining the health of the CNS.
neural circuits
groups of interconnected neurons that process specific kinds of info
neural systems
for ex. the visual system is composed of many dfferent neural circuits organised in both hierarchical and parallel processing streams to enable vision
peripheral nervous system
nerves and ganglia
autonomic nervous system
involved in controlling the involuntary action of smooth muscles the heart and various glands
sympathetic system
increases heart rate, prepares body for action
parasympathetic system
slows heart rate, stimulates digestion, in general helps body with functions to maintainthe body
central nervous system
brain and spinal cord
nucleus
compact arrangememnt of nerve celll bodies and their connections ranging from hundreds to millions of neurons. located througout the brain and spinal cord
cerebral cortex
outer layer of the brain
gray matter
composed of neuronal cell bodies
white matter
consists of axons and glial cells
medulla
essential for life. providing sensory and motor innervtions to the face neck abdomen and throat. controls respirtion heart rate and arousal
pons
connection between brain and cerebellum. important for some eye movements as wella s those of the face and mouth. responsible for REM
cerebellum
clings to brainstem at level of the pons, critical for maintainging posture, walking and perforing coordinated movements
hypothalamus
controls functions necessary for maintaining normal state of the body
cytoarchitectonics
uses the microanatomy of cells and their organization to subdivide the cortex
neocortex
cortex that contains six cortical layers or that passed through a developmental stage involving six cortical layers. includes areas like primary sensory and motor cortex and association cortex
acuity
how good we are at distinguishing among stimuli within a sensory modality
oval window
door to the fluid filled cochlea
cochlea
critical auditory structure of inner ear
tonotopy
the arrangement of the hair cells along the cochlear canal form a tonotopic map
interaural time
difference in when a sound reaches each of the two ears
optic chiasm
crossover place in the brain rom the optic nerves
receptive field of the neuron
most visual neurons only respond when a stimulus is presented in a specific region of space
retinotopic maps
topographic representations
rhodopsin
light sensitive receptor protein, enables vision in low light conditions
m pathway
magnocellular, parasol cells, initial analysis of movement of visual image
p pathway
parvocellular, midget cells, analysis of fine strucuture and color vision
ocular dominance columns
are stripes of neurons in the visual cortex of humans that respond preferentially to input from one eye or the other.
amblyopia
lazy eye
receptive field tuning
a neuron will only respond to a stimulus within its receptive field if that stimulus has certain characteristics
cortical column/hypercolumn
is a group of neurons in the cortex of the brain that can be successively penetrated by a probe inserted perpendicularly to the cortical surface, and which have nearly identical receptive fields
view dependent frame of reference
people have a cornucopia of speciic representations in memory; we simply need to match a stimulus to a stored representation
view invariant frame of reference
perceptual system extracts structural info about the components of an object and the relationship between these components
repetition suppression effect
hypothesized to indicate increased neural efficiency ; the neural response to the stimulus is more efficient and perhaps faster when the pattern has been recently activated
central sulcus
divides the frontal lobe from the parietal lobe
sylvian (lateral) fissure
seperates the temporal lobe from the frontal and parietal lobe
insula
located between temporal and frontal lobe ad is an island of folded cortex hidden deep in the lateral sulcus
prefrontal cortex
more complex aspects of planning, organizing, and executing behaviour tasks that require integration of info over time
parietal lobe
receives sensory info from the outside world, sensory info from within the body and info from memory and integrates it
thalamus
sensory info about touch pain temp sense and limb proprioception is received via receptor cells on the skin and converted to neuronal impulses that are conducted to the spinal cord and then to the somatosensory relays of the thalamus
somatotopy
the mapping of specific parts of the body to areas of the cortex
association cortex
portion of the neocortex that is neither sensory nor motor cortex . receives and integrates inputs from many cortical areas, language, abstract thinking
cognitive control
cognitiive processes that permit us to perform more complex aspects of behaviour
perseveration
patients may persist in a response even fter being told that it is incorrect
utilization behaviour
extreme dependency on prototypical responses for guiding behaviour
goal oriented actions
based on the assessment of an expected reward or value and the knwledge that there is a causal relationship between the action and reward
habit
an action that is no longer under the control of a reward, but is stimulus driven
recency memory
the ability to organize and segregate the timing or order of events in memory
astrocytes
large and round forms which surround neurons, makes contact with blood. Blood brain barrier. CNS
microglial
come into play when tissue is damaged. devour and remove damaged cells in CNS
oligodendrocytes
structure which forms myelin. in peripheral nervous system
schwann cells
create myelin with wrapping their cellmembranes aroudn the axon. increases the speeds of action potentials
convergence
axons from the input neurons can originate from widely distributed origins / if a theoretical concept can be proven with many different neuroscientific techniques, then it is highly likely true
divergence
a single neuron can project to multiple target neurons in different regions
dura matter
the outer membrante (thick) which has a rigid organization of neurons
commissures
when axons travel to the other hemisphere
dorsal horn
contains sensory neurons and interneurons
ventral horn
contains large motor neurons
inferior
below another part
superior
above another part
proximal
located close to the point of origin or attachment
distal
located more distant from the point of origin
ipsilateral
on the same side of the body
contralateral
on teh opposite side of the body
coronal plane
plane that shows brain structures as seen from the front
sagital plane
a plane that shows brain structures as seen fro the side
horizontal plane
a plane that shows brian structure as seen from above
superior colliculi
specialized for seeing
inferior colliculi
specialized for hearing
vestibulo
includes balance, coordination of eye movement while moving
spino
includes poly sensory integration and flexible control of moving limbs
neo
plannign of movement, higher mental functions and time perception
lateral hypothalamus
stimulates hunger
ventromedial hypothalamus
suppresses hunger
internal transformations
sensory signals can activate a memory of a stimulus.
retino-cortical expansion
visual info from the central part of the visual field is projected on a bigger part of the primary visual cortex, in comparison the the peripheral visual fields
achromatopsia
caused by lesions that encompass V4. report seeing colour as a bland palette of dirty shades of grey
akinetopsia
selective loss of motion perception
visual agnosia
when people see objects, but not make sense of them
optic ataxia
people can recognize objects but cannot use visual info to guide their actions
apperceptive agnosia
problems with object recognition regarding bjects with limited stimulus (outlines of objects or unusual perspective)
integrative agnosia
problems with integrating features into parts or parts of an object into a whole
associative agnosia
can perceive objects but cannot understand or assign meaning to the objects
prosapognosia
impairments in face recognition
phospholipid bilayer
cell membrane
ligand
excitatory neurotransmitter
spatial summation
epsp’s and ipsp’s from different locations happening at the same time summate to larger depolarizations
temporal summation
epsp’s arriving shortly after one another at the same location summate to larger depolarizations
hodgkin-huxley cycle
the inflow of Na+ causes further opening of voltage gated Na+ channels, causing more depolarization, causing more channels to open
complementarity
precision in time, precision in space, one/many neurons measured, direct vs indirect measurements of the brain
high temporal resolution
precise in time
low spatial resolution
imprecise in space
graded potentials
small depolarisation/hyperpolarisations in membrane voltage
local field potentials
if a large number of neurons produces graded potentials at the same time
