Exam I Flashcards Preview

Cognition and the Brain > Exam I > Flashcards

Flashcards in Exam I Deck (124):
1

Early goal of neuroscience

map the brain by characterizing the effects of damage and disease

2

Task-based analysis

Can characterize the precise nature of deficits
Limitation: not useful for normal mental activity

3

Gold standard for understanding critical structures for brain function

Lesioning; causation not correlational

4

Baddeley & Hitch Model

***

5

Phrenology

Gall
by touching skull, you can make assessments on personality
PRESUMPTION --> brain would be bigger/smaller ; (convexities/concavities) depending on the functions you possess

6

Localization

localization: different aspects of brain function are governed by, and therefore localizable to different centers of the brain

7

Mass Action

brain function distributed throughout the cortex

8

Pierre Flourens

critic of phrenology (Gall's localization)
would lesion animals in localized spots; failed to find evidence of localization (cerebral cortex)

EQUIPOTENTIALITY:

9

Equipotentiality

Pierre Flourens
any given piece of cortical tissue had potential to support any brain function

overtime, animals with experimental damage recovered without repair to damaged tissue itself, assumed other parts could take over

10

Evidence for localization

Gall "phrenology"
Paul Broca "tan"
John Hughlings Jackson "jacksonian march"

11

Evidence for mass action

Pierre Flourens "equipotentiality" animal lesions

12

Jacksonian March

John Hughlings Jackson
noticed there was a specific sequence of body parts that correlate with seizure activity traveling along motor cortex

13

Paul Broca

tan
language production
left frontal cortex

14

Factor that advanced brain studies

aseptic surgery

15

Method of learning a great deal about neural function

studying morphology from brain tissue under microscope

16

Camilo Golgi

developed a silver stain that allowed for visualization of individual neurons

BELIEVED brain was a continuous mass of tissue with a common cytoplasm

Synctyium

17

Santiago Ramon y Cajal

Neural Doctrine: nervous system made up of individual neurons

18

Neuron Doctrine

Ramon y Cajal
nervous system made up of individual neurons

19

Fritzch and Hitzig

reported that electrical stimulation in anterior part of dog's frontal lobe produced movement in opposite side of body

part of body affected varied systematically with positioning of electrode

supported Jackson's somotropic organization

20

Describe the process of neuronal communication

electrical-chemical transmission

(1) electrical impulses carry signals along axon
(2) chemical transmitters carry signals between neurons across synapse

21

Describe neuronal communication

Describe

22

PSP Summation

postsynaptic potential summation -- EPSPs and IPSPs integrate spatially and temporally at the axon hillock

their summation determines signal

IPSP: hyperpolarization, cell further away from threshold, less likely to fire
EPSP: depolarization, generates action potential

23

Glutamate

EPSP
excitatory neurotransmitter
opening of Na+

24

GABA

IPSP
inhibitory neurotransmitter
influx of Cl- ions, hyperpolarizing cell /orK+

25

Acetylcholine

excitatory neurotransmitter
opening of Na+

Acetylcholine: facilitates learning and memory
• affected in Alzheimer’s Disease

26

Excitatory NTs

glutamate, acetylcholine

27

Inhibitory NTs

GABA, glycine

28

Neuromodulators

modulate activity in large regions rather than
strictly exciting/inhibiting specific postsynaptic neurons

dopamine, norepinephrine, serotonin

29

Neurotransmitters

transmitting signals between neurons

exciting/inhibiting specific postsynaptic neurons

30

Norepinephrine

Norepinphrine: enhances vigilance & preparation for action

31

Dopamine

facilitates movement, reinforces behaviors,
helps keep information in short-term (working) memory
• affected in Parkinson’s Disease (low), schizophrenia (high)

32

Serotonin

inhibits some behaviors; lots of other effects
• affected in Depression

33

Agonist

fully activates the receptor that it binds to

34

Antagonist

binds to a receptor but does not activate and can block the activity of other agonists

35

brain orientations

dorsal: top
ventral: bottom

anterior: front
posterior: back
rostral: front
caudal: back

medial: middle
lateral: side

36

Electrochemical communication

electrical signal propagated down axon, converted to chemical signal and transmitted across synapse

37

3 basic neuronal components

soma, dendrites, axon

38

Evolution of brain morphology

computational power of brain increased over time...more wrinkled and compacted to fit (gyrations)

optimally shaped to minimize connection distance between distant groups of neurons

39

Gray v. White matter
location in brain

gray matter=border=glial cells (cell bodies)
white matter=majority, middle=axons

40

Brain slicing

axial: top and bottom
sagittal: side and side
coronal: front and back

41

gyrus and sulcus

gyrus: top
sulcus: bottom

42

4 lobes of brain

FPOT
frontal: executive functioning
parietal: perception, making sense of world
occipital: vision
temporal: memory

43

central sulcus

separates frontal and parietal lobe, deep groove
separates motor and sensory cortex

44

precentral sulcus

primary motor cortex

45

postcentral sulcus

somatosensory cortex

46

sylvian fissure

separates parietal and temporal lobes
insula buried within it

47

line of Gennari

white
primary visual cortex

48

Brodmann

cytoarchitectonic
52 layers, based on cell morphology, density, and layering

49

Cytoarchitect

Brodmann
52 layers, based on cell morphology, density, and layering

50

Golgi stain

everything on neuron in all of its glory but not all neurons in total

51

Nissi stain

every cell body in total picture, can estimate how many total total

52

Cortical layers

six cortical layers

53

Striate v. motor cortex

STRIATE CORTEX - visual, line of genarri
Superficial
Upper
Middle
Deep

MOTOR CORTEX -
superficial
upper
deep

54

Layers: input v. output

layer 4: main input layer
layer 5: main output layer

Different functional areas show different pattern of layering and cell types

55

Brain area mapping

heat map = brain activation
DTI = white matter tracts along axons

56

Human connectome project

aims to provide an unparalleled compilation of neural data, an interface to graphically navigate this data and the opportunity to achieve never before realized conclusions about the living human brain

57

Brain dictionary

interactive map showing which brain areas respond to hearing different words
---> just tied to English language?
--> conceptual or semantic?

58

Topographic Functional Brain Organization

structure correlates to function

59

Retinotopic mapping

visual areas organize by retinotopic mapping, forming a 2D representation of the visual image formed on the retina in such a way that neighboring regions of the image are represented by neighboring regions of the visual area

radioactive glucose injected into bloodstream, developed map of retina produced by brain

adjacent neurons of the LGN project to adjacent neurons in primary visual cortex

60

tonotropy

tones close to each other in terms of frequency are represented in topologically neighbouring regions in the brain

61

Cortical homunculus

a distorted representation of the human body, based on a neurological "map" of the areas and proportions of the human brain dedicated to processing motor function

discrimination ability --> more neurons coding for adjacent areas

62

corpus collosum

largest bundle of myelinated axons
carries millions of axons from one hemisphere to the other

63

foveal vision

center of your gaze

64

Retinotopic organization

concave shape of retina on back of eyeball means anything perceived below the point of fixation will be projected onto upper retina, and left projected to right

adjacent neurons of the LGN project to adjacent neurons in primary visual cortex

everything in the primary visual cortex is “flipped” with respect to the visual field

65

Electrophysiology

measures the electrical activity of neurons, and, in particular, action potential activity

Hubel and Weisel - a neuron responded with bursts of action potentials in given angle
orientation selectivity of V1 neurons

rate coding
tuning curve

66

Retinotopic Receptive Fields

A single neuron in visual cortex is not responsive to all stimuli. Shape, color, orientation, contrast, movement...

67

Angelo Mosso

discovery that brain blood supply pulsates

brain diverts more blood to that part of brain during mental processing

68

PET

injected with tracer, pick up on distribution
localization of brain activity

69

MRI

Structural imaging
uses magnetic field and radio frequency

70

fMRI

BOLD blood oxygen level dependent

blood level = correlate for brain activity

71

Hemodynamics

Haemodynamic response (HR) allows the rapid delivery of blood to active neuronal tissues

fMRI imaging technique used to measure the haemodynamic response of the brain in relation to the neural activities

slow compared to direct neural recordings

72

BOLD versus spikes

SPIKES = electrical, EEG, HIGH temporal

BOLD = hemodynamics, PET/fMRI, HIGH spatial

73

Lesion options

tissue removal
tissue destruction
reversible lesions

74

tissue removal

+precise
-non-reversible

75

tissue destruction

exitocins: chemicals that overstimulate neuron receptor

76

Why was trauma site not random?

Shaken Jello Mold Inside Skull
Holbourn
Orbitofrontal and Anterior Temporal Contusions

77

Hemineglect

right temporal parietal damage

78

Visual Pathways

dorsal = where
ventral = what

79

V1 hypercolumns

1. Stereo
2. Color
3. Line (edge) orientation

80

Draw nueron

Draw

81

Electrochemical gradient

The active transport of ions across the cell membrane causes an electrical gradient to build up across this membrane. The number of positively charged ions outside the cell is usually greater than the number of positively charged ions in the cytosol (neg inside)

difference in charges creates voltage; voltage across membrane =membrane potential

there are less positive ions inside the cell, the inside of the cell is negative compared to outside the cell. This resulting membrane potential favors the movement of positively charged ions (cations) into the cell, and the movement of negative ions (anions) out of the cell. So, there are two forces that drive the diffusion of ions across the plasma membrane—a chemical force (the ions' concentration gradient), and an electrical force (the effect of the membrane potential on the ions’ movement). These two forces working together are called an electrochemical gradient.

82

Electrochemical gradient

The active transport of ions across the cell membrane causes an electrical gradient to build up across this membrane. The number of positively charged ions outside the cell is usually greater than the number of positively charged ions in the cytosol (neg inside)

difference in charges creates voltage; voltage across membrane =membrane potential

neg inside, pos outside
mem potential favors outflux of positive ions in, and neg ions out

a chemical force (the ions' concentration gradient), and an electrical force (the effect of the membrane potential on the ions’ movement). These two forces working together are called an electrochemical gradient.

83

Voltage gated channel
Chemical gated channel

***

84

Regenerative spike

opens Na+ and Ca+ voltage gated channels
depolarization
EPSP summation

85

temporal v. spatial summation

spatial: simultaneous activation by many presynaptic neurons

temporal: high frequency stimulation by one presynaptic neuron

86

Neurology
Neuroscience
Cognitive psychology

Neurology: Function and pathology of the nervous system

Neuroscience: Mechanisms of the nervous system, includes neuroanatomy, neurochem, neurophysiology

Cognitive psychology: How the mind processes information

87

fundus

concavity of gyrus/sulcus

88

Fixation point

the point that directly stimulates the fovea of the retina

89

rate coding

# of action potentials/time

the differences in spiking frequency from different stimuli

measuring the number of these spikes that occur during a set period of time

orientation can be decoded by changes and spike rates (tuning curve)

90

temporal coding

When precise spike timing or high-frequency firing-rate fluctuations are found to carry information

91

rate coding

# of action potentials/time

the differences in spiking frequency from different stimuli

measuring the number of these spikes that occur during a set period of time

orientation can be decoded by changes and spike rates (tuning curve)

92

Ways of examining circuitry

brain activation - heat map
myelination
dti - white matter tracts

93

Movement field

(neurons from primary motor cortex have a preference for the orientation of movements)

broadly tuned, very little specificity

94

Ways of examining circuitry

brain activation - heat map
myelination
dti - white matter tracts

95

Receptive field

relationship between visual stimulus and neural firing induces a metabolic demand

96

tuning curve

orientation can be decoded by changes and spike rates

way to describe the preferences a neuron reacts to

97

Population coding

summation of input from thousands of units firing
"wisdom of the masses"

98

Cognitive subtraction

The idea behind cognitive subtraction is that, by comparing the activity of the brain in a task that utilizes a particular cognitive component (e.g. the visual lexicon) to the activity of the brain in a baseline task that does not, it is possible to infer which regions are specialized for this particular cognitive component

fMRI and PET

99

fMRI designs

blocked - segregate diff cog processes into diff time periods
event-related

100

action potentials v. postsynaptic activity

local field potential (LFP) : summation of post-synaptic potentials
multi-unit activity (MUA) : action potential spikes

found BOLD signals more correlated to LFP

logothetis

101

exitocins

chemicals that overstimulate neuron receptor

nerve cells are damaged or killed by excessive stimulation

102

channel blockers

block action potential conduction. Only type that can affect fibers

103

inhibitory neurotransmitter

hyperpolarize neurons and drastically reduce probability of firing. Inactivate neuronal cell bodies, where the receptors are located and NOT passing axons

104

Neurotoxin

Neurotoxins are toxins that are poisonous or destructive to nerve tissue through inhibition

By inhibiting the ability for neurons to perform their expected intracellular functions, or pass a signal to a neighboring cell, neurotoxins can induce systemic nervous system arrest as in the case of botulinum toxin,[13] or even nervous tissue death

105

contusion

orbitofrontal and anterior temporal
Holbourn

106

neuropsychology

Neuropsychology is the study of the structure and function of the brain as they relate to specific psychological processes and behaviours

107

TMS

measure activity and function of specific brain circuits in humans

connection between the primary motor cortex and a muscle to evaluate damage from stroke

coil magnetic field is used to cause electric current to flow in a small region of the brain via electromagnetic induction.

108

single dissociation
double dissociation

single -manipulation leaves one cognitive function (say, A) intact whilst severing another (say, B). This indicates the functions A and B are at least partially independent.

double-

"establishing a single dissociation between two functions provides limited and potentially misleading information, whereas a double dissociation can better demonstrate that the two functions are localized in different areas of the brain

109

magnocellular v. parvocellular

Parvocellular: good spatial resolution
The top four are parvocellular layers
receive input from small ganglion cells

Magnocellular: good temporal resolution
LGN cells receive inputs from (large) ganglion cells
bottom 2 layers

110

Contralateral retina
Ispilateral retina

ipsi=same side
contra=opposite side

111

Center-surround receptive field

There are two types of retinal ganglion cells: "on-center" and "off-center"

on-center cell is stimulated when the center of its receptive field is exposed to light, and is inhibited when the surround is exposed to light

Off-center/surround cells stimulated when surround is exposed to light, inhibited in center

112

Simple cell
Complex cell

simple- responds primarily to oriented edges and gratings (bars of particular orientations), tuned to different frequencies and orientations

no center/surround in complex

113

Hypercolumns

set of columns that are responsive to all lines of all orientations from a particular region in the visual field and viewed by both eyes

ocular dominance columns (LRLR) bringing together alternations creates depth perception

orientation columns (pinwheel like structure)

114

Quadranopsia

only one quarter of the visual field

115

Hemianopsia

decreased vision or blindness (anopsia) in half the visual field

116

Scotoma

a partial loss of vision or a blind spot in an otherwise normal visual field

117

Binocular Rivalry

phenomenon of visual perception in which perception alternates between different images presented to each eye

118

Motion selectivity
Direction selectivity

*

119

PPA

parahippocampal place area (PPA)

encoding and recognition of environmental scenes

inferior temporo-occipital cortex

120

FFA

Inferior temporal cortex (IT)
codes for faces

121

Extrastriate cortex

sensitive to motion

122

loss of visual field: variations

Quadranopsia - 1/4
Hemianopsia - half of visual field
Scotoma - spot

123

Scientific Reading

for binocular vision,
what neurons are uniquely tied to perception, not merely picking up retinal image

124

critique of BOLD

logothetis

local field potential (LFP) : summation of post-synaptic potentials
multi-unit activity (MUA) : action potential spikes

found BOLD signals more correlated to LFP