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Psych 275 > Chapter 7 > Flashcards

Chapter 7 Flashcards

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1
Q

fNIRS → functional near-infrared spectroscopy

A

Non invasive technique that gathers light transmitted through cortical tissue in to image oxygen consumption
→ form of optical tomography

Used on babies

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2
Q

Neuropsychology

A
  • Study of the relationships between brain function and behavior
  • emphasis on humans
  • origins: Paul Broca discovered the link between specific damage located in the left frontal lobe region and language difficulties
    -measuring brain and behavior includes noninvasive imaging, complex neuroanatomical measurement, and sophisticated behavioral analysis
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3
Q

Histological

A

Brains sectioned postmortem and tissue stained with different dyes (early 20th century)
→ microscopic study of tissue
→ dyes + chemicals made it easier to see shapes of neurons etc.

Contemporary techniques identify molecular, neurochemical, and morphological differences among neuronal types: how these differences contribute to behavior

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4
Q

Staining cerebral neurons

A

Light microscope: low mag. → No axons visible

Light microscope: high mag. → see soma, axon, and dendrites

Electron microscope → see synapses and synaptic vesicles

Multiphoton microscope → generate 3d map of living tissue

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5
Q

Modern day Methods of neural imaging

A
  • Prioritize greater resolution and specificity
  • visualize living tissue instead of dead
  • can visualize neutrons structures
  • visualize synapses in 3d detail
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6
Q

Temporal vs. Spacial resolution

A

Temporal: accuracy of now fast things are happening

Special: accuracy of structures in the brain and where everything is being activated

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7
Q

Behavioral neuroscience

A
  • Study of the biological basis of behavior
  • seeks to understand the brain-behavior relationships in humans and other animals

Major challenge is to develop methods for studying both normal and abnormal behavior

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8
Q

Ethology

A
  • The objective study of animal behavior, especially under natural conditions -
  • Animal learning and ethology provide the basis for modern behavioral neuroscience
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9
Q

Mirror-drawing task

A

Tests implicit memories: procedural and motor vs. Cognitive

Participants task is to trace between the two outlines of the star while looking only at their hand in a mirror. Crossing a line constitutes an error
↳ patient doesn’t nave recollection of learning task: implicit mem

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10
Q

Manipulating brain-behavior interactions

A
  • we can manipulate some aspect of brain function and see how behavior changes
    ↳ manipulation helps in developing hypotheses about how the brain affects behavior and then test the hypothesis
    ↳ manipulation helps in developing animal models of neurological and psychiatric disorders

Using techniques such as drugs and electrical stimulation to activate the brain and lesions to inactivate the brain
↳ animals can be manipulated using diets, social interaction, exercise, sensory stimulation, etc.

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11
Q

Brain lesions

A

First (and simplest) technique used for brain manipulation is to ablate ( or remove/destroy) tissue

Used to find location of memory in the brain → HM

HM: had debilitating seizures, so he underwent surgery to remove his hippocampus
↳ discovered hippocampus stores explicit memory’s (HM couldn’t store any new memories)

Seizures were cured → still had past memories stored elsewhere in brain: memory is not stored in one single place, increased removal of tissue = more memory loss → distributed throughout entire cortex

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12
Q

Stereotaxic apparatus

A
  • Surgical instrument used to target a specific part of the brain
  • allows the precise positioning of all brain regions relative to each other and to landmarks on the skull
  • used to destroy specific brain regions or to locate areas to inject drugs etc.
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13
Q

Compensations → Brain lesions

A

Neuroplastic ability to modify behavior from that used prior to the damage → try to reverse to previous state ( back to epilepsy etc)

To avoid compensation following permanent lesions, temporary and reversible lesion techniques are used
↳ regional cooling; prevents synaptic transmission
→ hollow metal coil placed next to brain structure
→ chilled fluid cools brain region to prevent synaptic transmission
- local administration of GABA agonist increases local inhibition

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14
Q

General Brain stimulation

A

Brain operates on both electrical and chemical energy → possible to selectively turn brain regions on or off by using electrical or chemical stimulation
↳ now we can use stereotactic instruments to place electrode or canulla in specific brain regions

Goal: enhancing or blocking neuronal activity and observing behavioral effects

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15
Q

Brain stimulation → rats

A

Rats with electrodes in the lateral hypothalamus eat ‘ whenever the stimulation is turned on

Self-stimulation: given the opportunity, rats will press a lever to obtain the current → stimulation affects a neural circuit involving both eating and pleasure

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16
Q

Deep-brain stimulation

A

Electrodes implanted in the brain stimulate a targeted area with a low-voltage electrical current to facilitate behavior

Used for Parkinson disease, depression,OCD, etc.
↳ DBS to the Globus pallidus in the basal ganglia of Parkinson patients makes movements smoother

Invasive: holes must be drilled into the skull to attach the electrode in the brain

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17
Q

Transcranial magnetic stimulation (TMS)

A

Procedure in which a magnetic coil is placed over the skull to stimulate the underlying brain

↳ High voltage current passed through the coil produces a rapid increase and subsequent decrease in the magnetic field around the coil → The magnetic field easily passes through the skull and causes a population of neutrons in the cerebral cortex to depolarize and fire

Used either to induce behavior or to disrupt ongoing behavior

Non-invasive

Motor cortex stimulation: induces body movements
Visual cortex stimulation: participant sees phosphenes

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18
Q

Drug manipulations

A

Drugs can pass into bloodstream and enter brain through indwelling cannula → allows direct application of drugs to specific brain structures

Drugs influence activity of specific neurons in specific brain regions

Drugs wear off → makes it possible to study drug effects on learned behaviors

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19
Q

Synthetic Biology

A

Design and construction of biological devices, systems, and machines not found in nature → process of altering specific functions

Techniques include inserting or deleting a genetic sequence into the genome of a living organism

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20
Q

CRISPR method ( clustered regularly interspaced short palindromic repeats)

A

Alter sequence of DNA within nucleus

Cuts DNA in any cell → used to silence genes by cutting out those regions in the DNA → DNA repair can be tailored to insert a new sequence to replace previous one

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21
Q

Optogenetics

A

Transgenic technique that combines genetics and light to control targeted cells in living tissue
↳ Based discovery that light can activate proteins

Protiens that occur naturally can be inserted into cells

Fiber-optic light delivered to selected brain regions → all neurons exposed to light respond immediately

22
Q

Opsins → photorecptive proteins

A

Protiens derived from microorganisms → combine light-sensitive domain with ion channel

Channelrhodopsin-2 (ChR2) → blue light
→when expressed in Neuron, ion channels open and depolarize Neuron = excitation → render cell optimal for firing

Halorhodopsin (NpHR) → green-yellow light
→ activates chloride pump, hyperpolarizing Neuron = inhibition → lower ability for cell to fire

23
Q

Benefits of optogenetics

A

great potential for research

High spatial and temporal resolution

Ion channels can be placed into specific cell lines and turned on and off on Ms time scales

24
Q

Measuring Brain electrical activity

A

4 major techniques:
Single-cell recording → must go into single cell
Electroencephalography (EEG)
Event-related potentials (ERP) → within EEG category
Magnetoencephalography (MEG) → picks up magnetic fields instead of electrical dipoles

Brain always electrically active even when comatose

25
Q

Recording action potentials from single cells

A

Measuring single-neuron AP’s with fine electrodes:
Electrodes placed next to cells (extracellular recording) or inside them (intracellular recording)

Extracellular recording techniques make it possible to distinguish activity of up to 40 neurons at once

Intracellular recording allows study and recording of a single neurons electrical activity

26
Q

Single-cell recording

A

Used to discover ‘place cells’ → code the spatial location of the animal and contribute to a spatial map of the world in the brain

Showed neurons in the rat and mouse hippocampus vigorously fired when an animal was n a specific place in the environment

27
Q

EEG: recording graded potentials

A

measures the summed graded potentials from thousands of neurons → excitatory and inhibitory

Reveals features of the brains electrical activity
↳ changes as behavior changes
↳recorded from cortex: displays rhythmical patterns
↳ living brains electrical activity is never silent

Pyramidal cells → outer edge of cortex

28
Q

EEG and sleep

A

Activity from EEG can help uncover now perception works → stimuli vs. EEG reaction

Awake or excited: shorter length shorter amplitude
Relaxed, eyes closed: Alpha rhythms generated
Drowsy: slowed frequency, increased amplitude
Asleep: slower, higher amplitude waves
Deep sleep: even slower and higher amp.

REM: noticed after a while, sleep looked like person was awake → when dreaming, EEG reflects waking patterns

29
Q

Event related potentials (ERP’s)

A

Largely the graded potentials on dendrites that sensory stimulus triggers

Complex electroencephalographic waveforms are related in time to a specific event

To counter noise effects, the stimulus is presented repeatedly and recorded responses are averaged

30
Q

Detecting ERP’s

A

In averaging process for auditory ERP→ tone is presented at time 0, and EEG activity in response is recorded

After many successive presentations of the tone, EEG wave sequence develops distinctive shape
↳ becomes very clear after 100 responses are averaged

Positive and negative waves that appear at different times after the stimulus presentation are used for analyses

31
Q

Advantages and disadvantages of EEG

A

Non invasive → not penetrating brain/skull
Cost effective → commercially available EEG’s
Can record hundreds of sites
High temporal resolution → tell changes in very short time frame

Poor spatial resolution
Can’t record deep brain regions → only cortical events result in firing of pyramidal cells

32
Q

Magnetoencephalography (MEG)

A

Neural activity has electrical field and produces a magnetic field→spatial resolution = good

Magnetic potentials are recorded from detectors placed outside the skull
→ permit 3D localization of cell groups generating measured field
→ Higher resolution than ERP

High cost

33
Q

Anatomical imaging techniques

A

Only shows structure (no functioning levels)
→ CT scans, MRI, DTI, MRS, etc.

fMRI → Brain functioning and imaging
MRI → just structure/location

34
Q

Computed tomography (CT scan)

A

Xray beams passed through brain at many different angles → creates many images

Images are combined with mathematical techniques to create 3D image of brain

Dense skull forms white border→ gray matter and white matter density does not differ enough to distinguish between two: cortex and white matter shows up as homogenous gray

Ventricles can be visualized because fluid in them is far LESS dense → darker image
→ Major fissures in cortex also rendered darker

35
Q

Magnetic Resonance imaging (MRI)

A

Produces a static, 3d, brain image by passing strong magnetic field through brain → followed by a radio wave → then measures radiation emitted from Hydrogen atoms

Increased demand of blood flow due to increased activity→ measure radiation from H atoms in the blood

36
Q

Diffusion tensor imaging (DTI)

A

Defects directional movement of H2O molecules to image nerve fiber pathways

Used to delineate abnormalities in neural pathways ↳ find connective pathways

37
Q

Magnetic resonance spectroscopy (MRS)

A

MRI method: uses hydrogen proton signal to determine the concentration of brain metabolites

Useful in detecting persisting abnormalities in brain metabolism in disorders such as concussion → using MRS you can find agents of infectious disease, metabolic disease, etc.

38
Q

Functional Brain imaging

A

When brain region is active, the amount of blood, oxygen, and glucose flowing to the region increases

Possible to infer changes in brain activity by measuring blood flow OR levels of the bloods constituents, such as oxygen, glucose, and iron

39
Q

Functional magnetic Resonance imaging (fMRI)

A

Active neurons use more oxygen → increase blood carbon dioxide levels, which signal blood vessels to dilate, increasing blood flow and bringing more oxygen to the area
↳ oxygen levels in activated brain area increases

Changes in oxygen content in blood alters the magnetic properties of the water in blood
→ oxygen rich hemoglobin = less magnetic than oxygen-poor hemoglobin

MRI could accurately match these changes in magnetic properties to specific brain locations

fMRI allows good spatial resolution on brain activity’s source

40
Q

Advantages and disadvantages of fMRI

A

Dense blood vessel supply to cerebral cortex allows for a spatial resolution of fMRI on the order of 1 mm

Changes in blood flow take 1/3 second
→ poorer temporal resolution relative to EEG

Extremely restrictive to subject

Must stay motionless

41
Q

Functional near-infrared spectroscopy (fNIRS)

→ long card: explain how it works, why, and drawbacks/benefits

A

Form of optical tomography → functional

Technique operates on principal that object can be reconstructed by gathering light transmitted through it

Reflected infrared light is used to determine blood flow because oxygen-rich hemoglobin and oxygen-poor hemoglobin differ in absorption spectra

Different levels of blood flow = different levels of activity → light absorption changes based on O2 consumption

Biological tissue (brain) can absorb light → properties of tissue determine how MUCH light is absorbed

By measuring bloods light absorption→ can also measure average oxygen consumption (like fMRI)

In fNIRS, an array of optical transmitter and receiver pairs are fitted across scalp

Overview: changes in tissue (blood flow) → tissue becomes swollen → sensor that emits light bounces MORE light → longer time to reach detector = more activity

Easy to hook up and can record short periods of activation → good temporal resolution

Light doesn’t penetrate deeper brain tissue → restricted to cortex

Spatial resolution poorer than fMRI

42
Q

Position emission tomography (PET)

A

Indirect way to measure changes in blood flow by measuring changes in the uptake of compounds such as oxygen or glucose

Used to analyze the metabolic activity of neurons

Radioactive molecules are injected into the bloodstream → foreign isotope flows with blood to activated area

Radioactive isotope oxygen-15 are very unstable
↳ break down in just a few minutes: relatively safe

Radioactive 15O molecules release tiny positively charged subatomic particles known as positrons

Positrons are attracted to negatively charged electrons in brain → collision of 2 particles causes release of energy (photons)

Energy leaves the head at the speed of light which is detected by PET camera → can target source of energy release

43
Q

Advantages of PET

A

Can detect decay of hundreds of radiochemicals and allows mapping of a wide range of brain changes and conditions

Can detect relative amounts of a given NT, the density of receptors, and metabolic activities associated with learning, brain poisoning, and degenerative processes

Widely used to study cognitive function

44
Q

Measures of Brain and behavior → Chemical and genetic

A

Neurons are regulated by genes that encode the synthesis of particular proteins within cells

Genes control the cells production of chemicals within the nucleus
↳ changes that happen within cell can change genes and chemicals → changes behavior

Brain contains a wide mixture of chemicals
↳ abnormalities in these chemicals leads to disruptions in behavior
↳ low serotonin production correlated with depression

45
Q

Microdialysis

A

Technique used to determine the chemical constituents of extracellular fluid

Catheter with semipermeable placed in brain → fluid flows in and passes along membrane → diffusion drives passage of molecules across membrane →fluid with molecules exits brain in tubes and collected for analysis

46
Q

Measuring genes in brain and behavior

A

Ability to relate the alleles of specific genes to behaviors

Met allele: associated with 11% reduction in hippocampal volume and poorer memory for specific events → episodic memory (associated with high incidence of dementia later in life)

Val allele: carriers have better episodic memory but higher incidence of anxiety disorders

Two alleles produce different phenotypes: they influence brain structure/function differently

47
Q

Epigenetics

A

Genes expressed differently in response to environment and experience

Epigenetic changes can persist throughout a lifetime and even across multiple generations

Wide range of experimental factors → chronic stress, trauma, drugs, culture, and disease: cumulative experiences affect how genes work

Epigenetic changes may be related to better stroke recovery

48
Q

Compare neuroscience research methods

A

Some focus on Morphology → structure in postmortem tissue

Some focus on ways neurons generate electrical activity in relationship to behavior →EEG

Some focus on functional changes in brain activity during specific types of cognitive processing →PET and fMRI

Considerations:
- Temporal resolution (how quickly the measurement or image is obtained)
- Spatial resolution: how accurate localization is in the brain
- degree of invasiveness

49
Q

Examples of comparing neuroscience research methods

A

Studying audition → study using EEG: high temporal resolution as response to sound happens quickly

Studying tumor → use CT or MRI or fMRI: good spatial resolution to localize where injury is

PET→ disadvantage: radioactive tracer must be made in own lab and administered immediately (very unstable: expensive)

EEG → cheap and good temporal resolution

50
Q

Kyoto SHR rat

A

Proposed as a good model for ADHD research

Known abnormalities in prefrontal dopaminergic supply that correlate with behavioral abnormalities such as hyperactivity

DA agonists such as methylphenidate (ritalin) can reverse behavioral abnormalities → both children with ADHD and in SHR rats

51
Q

Canadian Council on Animal Care

A

Only use animals if it promises to contribute and develop helpful knowledge

Optimal care → neglect can skew results

Use of animals is public and justified

Use only if demonstrated there is no other method that will work

Psych 275 (6 decks)

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