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PSYC2700D > 2: Neurocognition > Flashcards

2: Neurocognition Flashcards

1
Q

What is dissociation?

A

A disruption in one component of mental functioning but no impairment of another (e.g., HM)

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2
Q

What is long-term potentiation?

A
    • Changes in the ease at which two connected neurons will fire
    • Lasts a few hours, days, or weeks
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3
Q

What is consolidation?

A

– Long-term change over days, weeks, months, or years
–> Small Scale
LTP between individual neurons
–> Large Scale:
LTP changes in assemblies of neurons over long periods of time

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4
Q

What is the function of the thalamus?

A

– Gateway to the cortex: almost all sensory messages (except smell) pass through the thalamus.

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5
Q

What is the function of the corpus callosum?

A

Primary bridge for messages to cross to the left and right hemispheres

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6
Q

What is the myelin sheath?

A

– Insulator for the axon
– Gaps – called nodes of Ranvier
» Note: not all neuron have myelinated sheath
– Mainly on neurons that are long (e.g., periphery of nervous system)
» Myelinated neurons are white matter (myelin is fat)
– Most cortical neurons (cognition) are unmyelinated
»These form what we call “Gray Matter”

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7
Q

What is the action potential?

A
    • The change in electrical charge of a neuron from negative to positive
    • This charge propagates from the dendrites and down the axon.
    • Either a neuron fires or it does not
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8
Q

What is a synapse?

A
    • The region in which the axon terminals of one neuron and the dendrites of another come together
    • Convergence: many neurons may converge onto a single neuron
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9
Q

What are neurotransmitters?

A
    • The chemical substance released into the synapse between two neurons
    • Responsible for activating or inhibiting the next post- synaptic neuron
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10
Q

What is function of the hippocampus?

A

Implicated in storing new information in memory

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11
Q

What is the function of the amygdala?

A

Important for processing emotional qualities of information

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12
Q

What is the neocortex/cerebral cortex?

A

The top layer of the brain responsible for higher-level mental processes

  • -Frontal lobe
  • -Parietal lobe
  • -Occipital lobe
  • -Temporal lobe
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13
Q

What is contralaterality?

A

– Control of one side of the body is localized in the opposite-side cerebral hemisphere.
» The left hand, for instance, is largely under the control of the right hemisphere.

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14
Q

What are the hemispheric specialization?

A

Left hemisphere:
» language sounds, letters, words, speech, reading, writing, arithmetic, verbal memory, complex voluntary movement

Right Hemisphere:
» non-language sounds, geometric patterns, faces, nonverbal memory, prosody, narrative, inference, spatial processes, movements in spatial patterns.

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15
Q

What is the sensory and motor cortex?

A
    • Sensory cortex: processing of sensory information from throughout the body
    • Motor cortex: control of voluntary muscle movements
    • further localization of function within the sensory and motor cortices
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16
Q

What is the dorsal and ventral pathway?

A
    • Dorsal pathway: involved in “where” things are in space

- - Ventral pathway: Involved in “what” things are

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17
Q

What is a CT scan?

A

– Computerized-Axial Tomography; a bunch of X-rays that captures every layer/slice

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18
Q

What is an MRI scan?

A

– Gives clearer pictures of the structure of the brain

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19
Q

What is a single-cell recording?

A

Electrodes record the firing rate of individual cells

20
Q

What are Electrocephalograms (EEG)?

A

– Electrodes are attached to the scalp to record the patterns of brain waves.
– Event-Related Potentials
» The momentary changes in electrical impulses when a particular stimulus is presented

21
Q

What is transcranial magnetic stimulation (TMS)?

A
    • An electrical field is targeted over specific brain areas to stimulate nerve cells
    • This is a disruptive technique
22
Q

What is Positron Emission Tomography (PET)?

A
    • Image shows regions of the brain with heightened neural activity based on levels of blood flow.
    • radioactive isotope injected and detected by scanner
    • Cortical area(s) involved in the cognitive activity “light up”
23
Q

What is a functional MRI (fMRI)?

A
    • Similar to PET, but a more detailed image and does not involve a radioactive isotope
    • Measures metabolic rates in specific brain area change
    • Compare across different cognitive tasks
24
Q

What are other measures of brain activity?

A

– Lesions
» Used by Sperry
» The site and extent of the brain lesion are important guides to the kind of disruption that is observed.
– Direct Stimulation
» Pioneered by Penfield
» The patient in brain surgery remained conscious and small electrical charges were administered to the exposed brain, thus triggering small regions
– Special Populations
Groups of people who have known differences in brain function

25
Q

What is sensation?

A

Reception of stimulation from the environment and the encoding of it into the nervous system
Initial encoding into the nervous system

26
Q

What is perception?

A

Process of interpreting sensory information

27
Q

How are visual signals perceived?

A

– Rods/cones: the back layer of neurons stimulated by light, beginning the process of vision. The periphery (20+ degrees) are composed of mainly rods (so no colour vision)
120 M rods, 7 M cones
– Bipolar cells: Patterns of neural firing from rods/cones are passed on to a second layer, the bipolar cells, which collect the messages and move them along to a third layer, the ganglion cells
– Ganglion cells: Receive messages from the bipolar cells- the axons of the ganglion cells converge at the rear of the eye, forming the bundle of fibers that makes up the optic nerve
– Optic Nerve: Projects neural messages to visual cortex in occipital lobe

28
Q

What is the Fovea?

A

– The highly sensitive area of the retina responsible for precise, focused vision
» Covers about 1 to 2 degrees of visual field
– Most cones are in the fovea

29
Q

How is visual information compressed from the retina to the brain?

A
    • Only fraction of light waves reach retina
    • One cone synapses with one bipolar cell. In contrast, in peripheral vision, tens to hundreds of rods converge on a single bipolar cell (120M rods reduced down to about only 1M ganglion cells)
    • Such convergence results in a loss of information because a bipolar cell cannot “know” which of its many rods triggered it
30
Q

How do the eyes transmit visual information to the brain?

A
    • contralaterality principle: each eye transmits to both hemispheres, however each half of the retina gathers information from the contralateral visual field
    • The left half of the retina in each eye receives images from the right visual field and the right half of each retina receives images from the left visual field
    • Thus, the right visual field projects to the left half of the retina in both eyes, and this is then transmitted to the left hemisphere. Similarly, stimuli in the left visual field project to the right half of both retinas, and are then sent to the right hemisphere.
31
Q

What are saccades?

A
    • Movement of the eyes from one fixation point to another
    • Jerky & variable: 25ms – 175 ms
    • Nothing “seen” during a saccade
32
Q

What are fixations?

A
    • Eyes pause to foveate and gather visual information
    • For the most part we take in visual information only during a fixation. It is almost as if we are blind during the actual saccade (if the eye did encode information during the saccade, we’d see a smear)
33
Q

What is sensory memory?

A
    • allows the sensation of a visual pattern, sound, or touch to linger for a brief moment after the sensory stimulation is over
    • the information that is being held within ourSensory Memory appears to be unprocessed (not making any sense of it. It has to be processed for it to move to short term memory)
34
Q

How does information accumulate in sensory memory?

A
    • Information accumulates over time (50ms)

- - Not “all-or-none”

35
Q

What is visual persistence?

A

– The apparent persistence of a visual stimulus beyond its physical duration

36
Q

How did Eriksen & Collins study the duration of visual persistence (iconic SM)?

A

– superimposed dot patterns
– delay varied: 0 to 500 ms
@ 0 ms delay > 1 pattern, see letters (VOH)
@ ~ 75 ms > 2 patterns, but perceive letters
@ > 250 ms > 2 patterns, no letters
– Visual SM lasts for a short period of time: about between 250ms – 500ms

37
Q

What was Sperling’s Whole Report Procedure and what was the problem?

A
    • participants had to report all items in the display
    • Only able to report ~ 3 of 9 items
    • Problem with whole report technique; working short-term memory rather than sensory-memory because maybe all the items got into sensory memory but because it fades away so quickly you don’t get the chance to report them all
38
Q

What was Sperling’s Partial-Report Technique

A
  • -Subjects saw three rows of letters flashed on a screen for just 1/20 of a second. A tone following the exposure signalled which row of letters the subject should report to the experimenter.
    • If interval short between the tone and presentation, then close to 100% accurate however their accuracy steadily declined as the delay of the tone increased to one second. Why? Because the memory trace in the visual sensory store decays in about 1/4 (250ms) of a second
    • Conclude: capacity of visual SM is very large
39
Q

How is information coded in sensory memory?

A

– Can select items from display based on:
> Location
> Colour
> Even angles/line versus circles
– However, cannot select based on higher-level features
> e.g., not able to select based on letters vs. digits (meaning sensory memory deals with primitive features so cannot categorize based on letters or numbers)
– Conclude: Information in SM is pre-categorical, not semantic

40
Q

How can information in SM be erased?

A
    • Originally thought that information in SM simply decayed over time
    • But, turns out that information can be erased from SM through interference; forgetting caused by the effects of intervening stimulation or mental processing
    • this is called masking; the partial or complete obscuring of one stimulus (the target) by another (the masker)
    • Masking occurs because we can’t keep different sensory information to integrate cause all this sensory information will overlap and blur out everything
41
Q

How did Averbach and Coriell study interference?

A
    • presented a display of two rows of letters, eight letters per row, for 50 ms. A blank white postexposure field, varying in duration, followed the display and was itself followed by a partial report cue
    • The bar marker was just above (or below) the position of the to-be-reported letter, and the circle marker surrounded the position where the to-be-reported letter had just been
    • With the bar marker, the results that were similar to those obtained by Sperling, such as higher performance with short delays of the cues
    • With the circle marker, accuracy was lower than with the bar marker, especially when the target letter resembled the circle marker (for instance, when the letter c had been shown at that position).
    • These results suggest that the circle had in some way disrupted the memory trace for the letter in that position
    • Thus, a later visual stimulus interfered with the memory for the prior stimulus at that location (called backwards masking)
42
Q

What are the different types of masking?

A
    • Backward Masking: when Target followed by Mask
    • Forward Masking: when Mask before the Target
    • Energy; such as a flash of light; affect peripheral (early)
    • Pattern ; has features (information) and is central & interrupts processing of features
    • Masking is strongest with energy masks when it happens at the same time as the stimulus
43
Q

What are the different visual fields you can use with masking?

A

Monocular: target & mask to one eye Binocular: target & mask to both eyes Dichoptic: target to one eye, mask to other eye

44
Q

What type of visual field can you use with energy masking?

A

– Occurs with mono & binocular, not with dichoptic

45
Q

What type of visual field can you use with pattern masking?

A

Is effective with all, even dichoptic

46
Q

What does masking suggest and why does it happen?

A
    • Shows that features coded in SM (not just energy)
    • Processing in SM is NOT passive, but dynamic
    • Masking arases information to allow for next event to be cleanly encoded into SM

PSYC2700D (8 decks)

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