Exam I (Revised) Flashcards

Question

Hyperpolarization

Answer 1

Cell becomes more negative, overshooting resting level At +40 mV, Na+ channels close and K+ channels open. As potassium exits axon, the cell begins to repolarize. The cell “undershoots” in which membrane potential dips lower than resting state (+40 mV —> -100 mV), known as hyperpolarization.

Answer 2

Ions flow into and out of the neuron under the forces of electricity (electrical, voltage) and concentration gradients (diffusion) Electrical: neuron maintains -70 mV relative to extracellular space Chemical: neuron will hold higher concentration of potassium inside and lower concentration of sodium inside relative to extracellular space

Answer 3

A transmembrane protein that moves ions across a plasma membrane against their concentration gradient through active transport Na+/K+ Pump: Removes 3 Na+ for every 2 K+ admitted

Answer 4

Electrical: neuron maintains -70 mV relative to extracellular space Chemical/concentration: neuron will hold higher concentration of potassium inside and lower concentration of sodium inside relative to extracellular space Neuron begins at rest (-70mV), maintaining life through an electrical and chemical disequilibrium (slightly negative inside relative to extracellular space)

Answer 5

Chemical: these open in response to a specific chemical stimulus (E.g: neurotransmitter, such as acetylcholine, or a hormone); these are specifically important a synapses Voltage: these open in response to a change in the membrane potential; these are important in conducting action potentials along axons

Answer 6

Small changes in voltage (about 1 mV)

Answer 7

The action potential spreads just far enough down membrane for neighboring voltage-gated channels to open up, causing the cycle to start again, moving progressively down axon (action potential propagation).

Answer 8

Jumping, AP regenerated at each node

Answer 9

When positive ions, such as potassium, flow out of cell or negatively charged ions, such as chloride, flow into cell, the neuron becomes hyperpolarized

Answer 10

When positive ions, such as sodium, flow into cell (slightly reducing the negativity, depolarizing it)

Answer 11

Small voltage changes are collected in dendrites and travel along dendritic membrane to soma, where all the branches come together Temporal: high frequency stimulation by one presynaptic neuron; signals arrive at soma at same time The total voltage of the cell is determined by the overall pattern of incoming signals (+EPSP, -IPSP)

Answer 12

Small voltage changes are collected in dendrites and travel along dendritic membrane to soma, where all the branches come together Spatial: simultaneous activation by many presynaptic neurons; signals arrive on different branches and converge at the soma The total voltage of the cell is determined by the overall pattern of incoming signals (+EPSP, -IPSP)

Answer 13

Transmit signals between neurons Exciting/inhibiting specific postsynaptic neurons

Answer 14

EPSP Excitatory neurotransmitter Opening of Na+

Answer 15

Excitatory neurotransmitter in the peripheral nervous system Excitatory neurotransmitter opening of Na+ Acetylcholine: facilitates learning and memory • affected in Alzheimer’s Disease

Answer 16

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

Answer 17

agonist: molecule that occupies receptor and activates antagonist: molecule that occupies receptor and blocks

Answer 18

agonist: molecule that occupies receptor and activates antagonist: molecule that occupies receptor and blocks

Answer 19

Function and pathology of the nervous system

Answer 20

Mechanisms of the nervous system - neuroanatomy - neurophysiology - neurochemistry

Answer 21

How the mind processes information

Answer 22

Axial/Transversal: top and bottom Sagittal: Side/side Coronal: front and back

Answer 23

(aka Axial) Top and bottom

Answer 24

Top and bottom

Answer 25

Side and side

Answer 26

Front and back

Answer 27

Electrical: Electrical impulses carry signals within a neuron, propagating down axon Chemical: Carry signals between neurons, crossing the synapse from presynaptic axon terminal to postsynaptic dendrite

Answer 28

``` Grey = border, cell bodies White = majority of middle, axons ```

Answer 29

``` Gyrus = top Sulcus = bottom ``` GS in alphabetical order, top to bottom Fundus is very bottom concavity

Answer 30

Concavity of gyrus/sulcus

Answer 31

Sulcus | Precentral gyrus = primary motor cortex

Answer 32

Boundary of motor and sensory cortices Separates frontal lobe from parietal lobe Separates primary motor cortex from primary somatosensory cortex

Answer 33

Sulcus | Postcentral gyrus = primary somatosensory cortex

Answer 34

Separates temporal lobe from frontal and parietal Insula buried deep within it

Answer 35

Separates frontal lobe from parietal lobe | Separates primary motor cortex from primary somatosensory cortex

Answer 36

Separates parietal and occipital sulci | Involved in planning

Answer 37

In parietal lobe, near superior edge of temporal lobe Angular is below supra, parietal lobe Transfers visual information to Wernickle's area, in order to make meaning from visually perceived words

Answer 38

Language perception and processing Supra is on top of angular, parietal lobe Lesion = aphasia (making sense of words)

Answer 39

Since gross anatomy is the study of brain anatomy at the visible level, I am assuming gross dissection is simply dissecting brain regions at the macroscopic level.

Answer 40

Silver staining reveals the entirety of one neuron but not all neurons in total

Answer 41

Aniline dye dark blue staining reveals every cell body in total picture, allowing an estimate of total

Answer 42

The cerebral cortex is made up of 6 cortical layers Layer 4: Main input layer, receives input from thalamus (V1) Layer 2/3: Send info to higher levels of cortex [feed-forward] (V2 --> V4) Layer 5/6: Send feedback projections to earlier levels of cortex [feedback] and project to thalamus [feed-forward] or other subcortical structures - Cell bodies located layer have dendrites that extend to another layer - Many project to the neurons in the layer(s) above and below (in addition to many already sending ff and fb projections) - Neurons "stacked" on top of one another forming cortical columns LAYER 4 = MAIN INPUT LAYER LAYER 5 = MAIN OUTPUT LAYER

Answer 43

Striate Cortex Band of myelinated neurons, forming a thick white stripe in cross-sectional views of the cortex lining the calcarine fissure. Fundus of the calcarine sulcus of the occipital lobe Composed of axons bringing visual information into the layer 4 of visual cortex

Answer 44

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

Answer 45

Ways of examining circuitry Using heat map Myelination DTI - white matter tracts

Answer 46

Spatially adjacent stimuli on sensory receptor surfaces are represented in adjacent positions in cortex

Answer 47

From the 3D reality, lower area visual neurons form a visual image on the retina such that neighboring regions of visual space are represented by neighboring regions of neurons 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 So everything in the primary visual cortex is “flipped” with respect to the visual field

Answer 48

Tones close to each other in terms of frequency are represented in topologically neighboring regions in the brain

Answer 49

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

Answer 50

Brain is divided into different subsections according to function.

Answer 51

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

Answer 52

Fixation or visual fixation is the maintaining of the visual gaze on a single location

Answer 53

The particular region of a visual field in which the onset of a particular stimulus will drive the firing of a correlated neuron

Answer 54

Neurons from primary motor cortex have a preference for the orientation of movements Broadly tuned, very little specificity

Answer 55

Frequency coding As the frequency or rate of action potentials (or "spike firing") increases action potentials/time

Answer 56

Used to characterize the responses of sensory neurons to external stimuli Orientation can be decoded by changes and spike rates Offers a way to describe the preferences a neuron reacts to A neuron's role is to encode the stimulus at the tuning curve peak, because high firing rates are the neuron's most distinct responses

Answer 57

Summation of input from thousands of units firing | "wisdom of the masses"

Answer 58

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

Answer 59

Discovery that brain blood supply pulsates From his findings that these pulsations change during mental activity, he inferred that during mental activities blood flow increases to the brain. Brain diverts more blood to that part of brain during mental processing Brainin balancing device: Mosso reasoned his volunteer's brain would have to process the sound, requiring more blood, making it weigh more, which would tip the scale toward the head's side. According to his manuscripts, that's exactly what happened.

Answer 60

Injected with tracer, pick up on distribution | Localization of brain activity

Answer 61

Structural imaging | Uses magnetic field and radio frequency

Answer 62

BOLD blood oxygen level dependent Blood level = correlate for brain activity Blood oxygen-level dependent Neural correlate for brain activity Hemodynamic signal driven by metabolic need of cell

Answer 63

Blood oxygen-level dependent Neural correlate for brain activity Hemodynamic signal driven by metabolic need of cell

Answer 64

Hemodynamic 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

Answer 65

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

Answer 66

Neuron firing

Answer 67

Exitocins: chemicals that overstimulate neuron receptor Overexciting neurons causing tissue damage and cell death

Answer 68

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 or even nervous tissue death

Answer 69

Cooling | Reversible

Answer 70

INHIBITORY NEUROTRANSMITTER Hyperpolarizes neurons and drastically reduce probability of firing They inactivate neuronal cell bodies, where the receptors are located and NOT passing axons. When an inhibitory NT activates the receptor site, it causes additional potassium channels to open which may cause potassium ions to flow out of the cell and if additional positively charged potassium ions flow out of the cell, the inside of the cell will become more negative. In other words, inhibitory neurotransmitters cause an opening of ligand-gated potassium ion channels which leads to a local hyperpolarization (more negative than normal). This is known as a Inhibitory Postsynaptic Potential (IPSP) because it’s going to be LESS likely to throw off an action potential. ex: GABA and Glycline, or GABA agonists

Answer 71

Brain damage common in specific area Orbitofrontal and anterior temporal Holbourn Orbitofrontal and Anterior Temporal Contusions

Answer 72

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

Answer 73

A “single dissociation”: a single dissociation happens when a patient has an impaired competence X but a normal (or a less impaired) competence Y A "double dissociation": a pattern of results in which damage to area A affects performance on task X, but not on task Y; whereas damage to area B affects performance on task Y, but not on task X. 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

Answer 74

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.

Answer 75

- Visual stimuli is inverted top to bottom and flipped left to right when projected to retina - Information in left visual field is detected by right sides of eyes (left nasal, right temporal) and processed by right LGN/hemisphere - Information in right visual field is detected by left sides of eyes (left temporal, right nasal) and processed by left LGN/hemisphere - Information leaves the eye by way of the optic nerve - Optic nerves cross at optic chiasm (nerves from temporal side remain lateral, nerves on nasal side cross over) - After optic chiasm, axons are called optic tracts - Optic tracts terminates at lateral geniculate nuclei, the visual part of the thalamus that functions as the primary relay system for visual processing - Axons from the LGN fan out through optic radiations, myelinated fibres between the thalamus and primary visual cortex

Answer 76

Region of the retina most densely packed with photoreceptors, and thus supporting highest resolution vision Center of eye

Answer 77

The part of the brain where the optic nerves partially cross

Answer 78

Receives a major sensory input from the retina Visual part of thalamus, primary relay nucleus for visual processing Left LGN receives right visual input from left sides of eyes Right LGN receives left visual input from right sides of eye The LGN is the main central connection for the optic nerve to the occipital lobe, particularly the primary visual cortex

Answer 79

Myelinated fibers between the thalamus and primary visual cortex (V1)

Answer 80

Contralateral Nasal Retina Contra = opposite side

Answer 81

Ipsilateral Temporal Retina Ipsi = same side

Answer 82

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

Answer 83

MAGNOCELLULAR NEURONS - receive input from larger retinal ganglion cells (larger receptive field) - input from LGN layers 1,2 and output to top of V1 layer 4 - Magnocellular layers of LGN: detection of motion and location (bigger picture); larger receptive field M retinal ganglion cells (RGCs) sample larger space, have larger receptive field and do not carry color specific information; faster axonal conduction velocities; project to orientation-selective V1 areas; good temporal resolution PARVOCELLULAR NEURONS - receive input from smaller retinal ganglion cells (smaller receptive field) - input from LGN layers 3-6, output to lower of V1 layer 4 Input from small retinal ganglion cells Smaller receptive field Parvocellular neurons in LGN project to color-selective blobs in V1; good spatial resolution Detection of color and form (finer details)

Answer 84

Where the primary visual cortex (V1) is concentrated

Answer 85

Simple cells in V1 respond preferentially to specific orientations, and complex cells can signal the termination of lines

Answer 86

Hubel and Weisel's perpendicular penetrations found that neurons within the same cortical column responded to the exact same orientation Parallel penetrations found that adjacent columns tended to be tuned to slightly rotated orientations A hypothesized grid of orientation columns that, together, represented every possible orientation that could fall within a receptive field. Represent - Stereo (depth) - Color - Line orientation

Answer 87

1. Stereo (depth) 2. Color 3. Line (edge) orientation Separate cortical channels for the processing of form, color, movement and depth of visual stimuli Color and form = P pathways Depth and movement = M pathways

Answer 88

Can only view one quarter of the visual field

Answer 89

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

Answer 90

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

Answer 91

Our senses precisely, and accurately, reflect the physical world. They provide us with a true, complete, and accurate representation. J.J. Gibson (Cornell) Direct Perception

Answer 92

There is no inherent organization to the world, but rather, our brain organizes our perceptions, and we therefore believe the world is, itself, organized. Gestalt

Answer 93

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

Answer 94

Magnocellular layers of LGN: detection of motion and location (bigger picture) input from large retinal ganglion cells larger receptive field MT has a columnar architecture of direction selectivity for visual motion perception, area IT has a columnar architecture of complex shape/feature selectivity for object recognition.

Answer 95

Some V1 cells are also direction selective meaning that they respond strongly to oriented lines/bars/edges moving in a preferred direction MT has a columnar architecture of direction selectivity for visual motion perception, area IT has a columnar architecture of complex shape/feature selectivity for object recognition.

Answer 96

Parahippocampal place area (PPA) Encoding and recognition of environmental scenes Inferior temporo-occipital cortex

Answer 97

Fusiform face area (FFA) Inferior temporal cortex (IT) Codes for faces

Answer 98

Areas outside of V1 but that V1 projects to

Answer 99

Center of gaze

Answer 100

SPIKES = electrical, EEG, HIGH temporal resolution BOLD = hemodynamics, PET/fMRI, HIGH spatial resolution

Answer 101

Imply a proportional relationship between fMRI response and average firing rate

Answer 102

- oxygenated hemoglobin and deoxygenated hemoglobin have different magnetic profiles - neuronal activity creates increased need for blood to that area --> this results in an increased hemodynamic response (rapid delivery of blood to active neuronal tissue) - this HR serves as a proxy for neural activity - baseline is subtracted from changed values - time lag (neural activity....fMRI bold signal evoked)

Answer 103

The rapid delivery of blood to active neural tissue Serves as a proxy for neural activity

Answer 104

right temporal parietal damage failure to be aware of one side of space

Answer 105

Carries visual information from eye until optic chasm

Answer 106

After chiasm, axons are called optic tract

Answer 107

Contralateral nasal retina | Ipsilateral temporal retina

Answer 108

Neuron located near the inner surface (the ganglion cell layer) of the retina of the eye Also compose optic nerves, etc.

Answer 109

Cortical magnification = disproportionate representation of high-acuity portions of a sensory system Cortical representation of the fovea, with its many more columns of neurons, covers a large area relative to the cortical representation of the periphery, with its relatively fewer columns of neurons 80% of V1 is devoted to processing information from the central 10% of the retina The fovea is the region of the retina most densely packed with photoreceptors, and thus supporting highest resolution vision

Answer 110

In V1, receptive fields are smallest at regions receiving input from the fovea, and largest at regions receiving input from the periphery

Answer 111

Discovered orientation selectivity of V1 neurons Found that neurons responded preferentially to orientations A neuron responded with bursts of action potentials in given angle

Answer 112

Orientation selectivity allows for the detection of edges, direction selectivity necessary for motion

Answer 113

Pinwheel Orientation-insensitive blob at the center and several “petals” made up of orientation-selective columns of neurons emanating from it

Answer 114

During refractory period (when cell unable to generate AP) Na+/K+ pump expels 3NA+ ions for every 2K+ ions admitted, returning cell to resting state (-100 mV —> -70 mV)

Answer 115

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.

Answer 116

glutamate, acetylcholine

Answer 117

GABA, glycine

Answer 118

Neuronal Communication Neuron begins at rest (-70mV), maintaining life through an electrical and chemical disequilibrium (slightly negative inside relative to extracellular space) - Electrical: neuron maintains -70 mV relative to extracellular space - Chemical: neuron will hold higher concentration of potassium inside and lower concentration of sodium inside relative to extracellular space Small voltage changes are collected in dendrites and travel along dendritic membrane to soma, where all the branches come together - Temporal: high frequency stimulation by one presynaptic neuron; signals arrive at soma at same time - Spatial: simultaneous activation by many presynaptic neurons; signals arrive on different branches and converge at the soma - The total voltage of the cell is determined by the overall pattern of incoming signals (+EPSP, -IPSP) If the number of EPSPs is much higher than number of IPSPs, the cell will depolarize. If threshold level is reached (-55mV), an action potential will be initiated by axon hillock. Na+ leaks into axon (-70 mV —> -55 mV) Na+ voltage gated ion channel opens, allowing sodium to flow into axon (-55mV —> +40 mV) At +40 mV, Na+ channels close and K+ channels open. As potassium exits axon, the cell begins to repolarize. The cell “undershoots” in which membrane potential dips lower than resting state (+40 mV —> -100 mV), known as hyperpolarization. The action potential spreads just far enough down membrane for neighboring voltage-gated channels to open up, causing the cycle to start again, moving progressively down axon (action potential propagation). During refractory period (when cell unable to generate AP) Na+/K+ pump expels 3NA+ ions for every 2K+ ions admitted, returning cell to resting state (-100 mV —> -70 mV) Action potential propagates down axon until it reaches axon terminal. As the signal begins to reach the presynaptic terminal, Ca++ voltage-gated channels open, flooding Ca++ ions into cell. The influx of Ca+ ions acts as the signal for signal-mediated exocytosis of vesicles containing neurotransmitters. Neurotransmitters diffuse across the synaptic space, binding to receptors on postsynaptic neuron.