PSY 223 Intro Cog Exam 1 Flashcards

Question

Reversible animal lesions temporal resolution and spatial resolution - good or bad In humans

Answer 1

Animals: more invasive and more common pharmacological inactivation - block synaptic transmission cryogenic depression (cooling) optogenetic imaging - control neuronal function Good spatial resolution Good temporal resolution In humans TMS

Answer 2

Creates reversible lesions in humans by creating a magnetic field that influences electrical properties of the brain - not an indirect measure of brain activity because it temporarily damages brain tissue (i.e., creates a lesion) Creates a magnetic field in a specific area of the brain - magnetic field influences electrical activity, i.e. inhibits of the activity, in a specific area of the brain Can assess cognitive function while the brain area is temporarily lesioned Generally good spatial resolution: can have as good spatial resolution as fMRI → where in the brain that stimulation is being applied and what activity was like with and without the lesion Generally good temporal resolution: can have as good temporal resolution as EEG Can assess lesions to multiple brain regions in the same participant (double dissociation) Single dissociation: affecting only one area of function

Answer 3

“translation” of external, environmental stimuli into changes in neuronal signaling

Answer 4

“neural processes that correspond most closely to the concept of detection”

Answer 5

internal experience of the external world

Answer 6

Input signal → Transduction → Bottom-up processing: Integration across inputs → Top-down processing: Using pre-existing knowledge and context

Answer 7

Photoreceptors: where transduction takes place for vision translate light into neuronal signal Rods: receptors for low light (night time) - Low acuity (spatial resolution) Cones: receptors for high light intensity and different wavelengths (color) Cones and color - High acuity (spatial resolution) Photoreceptor doesn't just respond to light anywhere it depends on the location so on or off like photoreceptors respond to light in a particular part of space A photoreceptor does not respond to light regardless of where the light is located with respect to the visual field

Answer 8

Receptive field: Sensory stimulus that induces maximal changes in a neuron’s membrane potential Intuition: Bipolar cell needs input from several photoreceptors across space in the brain (spatial summation)

Answer 9

Off-center In center no light and On-center light in middle ON-center bipolar cells are depolarized by small spot stimuli positioned in the receptive field center. OFF-center bipolar cells are hyperpolarized by the same stimuli. Both types are repolarized by light stimulation of the peripheral receptive field outside the center

Answer 10

Simple Cell: Detects points of light in a single orientation in a certain part of the visual field relies on spatial summation from several LGN neurons with on-center receptive fields in slightly different visual locations Complex cell: detect long bar of light in a single orientation in a certain part of the visual field - relies on spatial summation from several simple cells, so responsive to light in a larger area than simple cells

Answer 11

Fovea / central retina: more densely populated with cones Rods are more towards the periphery Blind spot: at the optic disk, where the optic nerve fibers leave the eye - no photoreceptors Visual field: “total area in which objects can be seen in the side (peripheral) vision as you focus your eyes on a central point”

Answer 12

Pigmented epithelium (back of eye) Photoreceptors - rods and cones Bipolar cells Ganglion cells (light) Light goes back of eye to photoreceptors

Answer 13

Retinogeniculate Visual Pathway: conveys visuals info from retina to LGN(thalamus) → optic chiasm: where some nerve fibers cross from the left and right eyes => each side of the brain has visual information from the contralateral (opposite) visual hemifield

Answer 14

Once leave retina → optic nerve, optic chiasm, LGN, V1 or Primary visual cortex Primary somatosensory cortex or V1 or primary visual cortex

Answer 15

spatial relationships preserved from retina - mapping of visual input from the retina to neurons

Answer 16

Visual information presented near the center of the visual field is represented by larger areas of cortex, i.e. the majority of neurons in V1 have receptive fields from the center of the visual field (fovea). Thus, this central information is “magnified” → The number of neurons in the visual cortex responsible for processing the visual stimulus of a given size varies as a function of the location of the stimulus in the visual field.

Answer 17

Matching representations of organized sensory input to stored representations in memory Involves bottom-up processes (e.g. integrating lower level features) and top-down processes (e.g. knowledge, expectations, context)

Answer 18

Dorsal: “where” (where in space are these features located?) determining the location of an object Ventral: “what” (what do these features comprise?) determining the identity of an object Inferior temporal cortex (IT) and the “what” pathway - Matching representations of organized sensory input to stored representations in memory - Involves bottom-up processes (e.g. integrating lower level features) and top-down processes (e.g. knowledge, expectations, context)

Answer 19

1) Where does it end? Object representations may assemble from “primitives” - Hierarchical processing in visual system 2) Feature Matching – object constancy: Object is viewed as constant, despite changes in visual input - M in different sizes is still an M 3) Feature Matching – object composition: Many objects are composed of the same collection of features - R and P (vertical line and left facing curve) 4) Aperture Problem: integrate information from early visual brain regions into a coherent picture across larger regions of visual field 5) Relative color: what color are you seeing with solution V4

Answer 20

Distributed coding: An object is “coded” not with APs from one neuron, but is distributed across several active neurons. Population coding: Representation of a stimulus by the pattern of firing of a large number of neurons Sparse coding: Representation of a stimulus by a pattern of firing of only a small group of neurons, with the majority of neurons remaining silent

Answer 21

Similarity/Proximity: link alike items together 1) similarity: visual elements that are similar (e.g. same color) are likely to be grouped together 2) proximity: visual elements that are close together are likely to be part of the same object Continuity/Closure: link items with missing pieces 3) continuity: edges are grouped together to avoid interruptions 4) closure: missing parts of an object are “filled in”

Answer 22

Top-down processing

Answer 23

Motion processing in region MT thanks to spatial summation Neurons firing AP in response to light

Answer 24

Egocentric localization: representation of space in a body or self-centered coordinate system; representation of space centered around one’s own location Hemispatial Neglect: reduced awareness of stimuli on one side of space, even though there may be no sensory loss (what they are paying attention to so like only half of side - not a not seeing thing) - neglect information on one half (hemi) of one’s space - commonly on the opposite (contralateral) side to the parietal lobe lesion - only ate food on the right side of her plate - when looking at her left hand, she thought it was the doctor’s hand - spoke about weakness on the right side of her body, even though this weakness was much more pronounced on the left side of her body

Answer 25

Representation of space in an environment-centered coordinate system; representation of space with respect to the environment Place cells in the hippocampus: In a given environment, a place cell fires action potentials in a specific but objective place, i.e. independent of how the animal approaches it Across cells, much of a given environment can be represented

Answer 26

Audition: Sound = changes in (oscillatory) air pressure - Transduced occurs in the cochlea (inner ear) - goes from air to fluid. Transduction occurs in the cochlea via the inner hair cells on the basilar membrane swaying back and forth - hair cells moving at oscillation rate so by pitch Somatosensation: sensory receptors in the peripheral nervous system Vision: Photoreceptors

Answer 27

Audition: Hair cells in cochlea Somatosensation: Receptive field: Sensory stimulus that induces maximal changes in a neuron’s membrane potential correspond to different parts of the body - size and sensitivity vary by, body part, receptor type Merkel and Meissner and Pacinian Vision: Retina rods and cones

Answer 28

Audition: primary auditory cortex (A1) Somatosensation: primary somatosensory cortex (S1) = postcentral gyrus Vision: primary visual cortex (V1)

Answer 29

Audition: Volley principle (100-4000 Hz): a group of neurons (“volley”) encodes the frequency, because no one neuron can fire action potentials quickly enough on its own Somatosensation: Somatotopy: Different parts of S1 correspond to somatosensation in different body parts Vision: Right eyes to LEFT LGN: visual info from the right half of the visual field of each eye is transmitted to the left side of the brain. Basically, optic nerve fibers from the RIGHT eye carry info from the right visual field to the left LGN→ LEFT BRAIN. Left Eye to RIGHT LGN: opposite of above

Answer 30

Audition: superior olive (combine ears) - Sound localization in the horizontal plane Somatosensation: crosses sides at medulla Vision: opposite side of brain at the optic chiasm

Answer 31

Frequency (oscillations per second): perceived as pitch

Answer 32

High Pitch = High frequency Base of cochlea Low Pitch = Low frequency Apex of cochlea

Answer 33

height of signal Intensity/amplitude: perceived as loudness

Answer 34

Low frequencies (below 100 Hz): A neuron fires an action potential at a particular phase for a certain frequency (e.g. peak), so its timing is in sync with the wave Volley principle (100-4000 Hz): a group of neurons (“volley”) encodes the frequency, because no one neuron can fire action potentials quickly enough on its own Tonotopy (100-20000 Hz): sound causes maximum vibration for hair cells at one location on the basilar membrane in the cochlea, which varies in width and height

Answer 35

1.mechanoreceptors: receptive to mechanical forces, such as pressure, texture, vibration, stretch 2.thermoreceptors: receptive to heat and cold 3.nociceptors: receptive to sensory processes signaling (risk of) tissue damage, which can trigger pain response

Answer 36

1.location of the body part it covers 2.size of the body part it covers 3.the type of stimulus it is sensitive to 4.for frequency-sensitive mechanoreceptors, the optimal frequency of vibration

Answer 37

important to account for adaptation: “decreased response to a stimulus as a result of recent exposure to it”

Answer 38

Horizontal: Relies on the differential timing of information from the left and right ears Vertical: Relies on reflections from the pinna

Answer 39

More nerves go to the cochlea from the brainstem than from the cochlea to the brainstem

Answer 40

Superior olive: Sound localization in the horizontal plane Pinna: Sound localization in the vertical plane

Answer 41

Audition – act, sense or power of hearing sound Sound- series of pressure waves in air (or other medium)

Answer 42

Sound corresponds to changes in air pressure Sound is transduced via vibrations in the inner hair cells on the basilar membrane of the cochlea Different frequencies of sound (pitch) and loudness (amplitude) are encoded based on the properties of the inner hair cells

Answer 43

Different parts of M1 correspond to planning and control of movements in different body parts Like S1, each side of brain corresponds to the contralateral side of the body Like S1, not consistent with anatomical order or size However, not the same mapping as S1

Answer 44

Neurons in M1 are active prior to a movement, during motor preparation Individual neurons in M1 fire the most action potentials during planning of movement of a particular body part AND movement of that body part in a specific direction Number of AP varies with movement - across neurons diff rate at which they fire AP but each neuron has a different body part with a specific body part Vector has direction and and magnitude Translate neuronal activity into a vector: direction = direction with greatest response rate magnitude = response rate Population coding

Answer 45

Exist in motor cortex regions outside of M1, including premotor cortex Fire the most action potentials in response to 1) a specific action or set of actions performed by the self or 2) the same (set of) action(s) as in 1, but performed by another Some seem to fire more action potentials in response to specific actions performed by another; some respond to a wider range of actions These actions usually consist of a series of individual movements Hypothesized roles beyond motor movement remain controversial

Answer 46

Cerebellum: Motor coordination motor sequences requiring precise aim and timing fine-tuning of movements

Answer 47

Basal ganglia: Regulating motor activity, such as starting and stopping action

Answer 48

most active just before a rapid series of movements e.g. push, turn, then pull a mechanical key, playing piano or guitar

Answer 49

primarily active during preparations for a movement (e.g. grab a cup) somewhat active during the actual movement

Answer 50

Neurons in a region of M1 will fire the most action potentials when planning the movement of a specific body part An individual neuron within a region of M1 will fire the most action potentials when planning the movement of a specific body part in a specific direction - each neuron diff direction of movement Recording from multiple neurons at once, it is possible to predict the planned motor movement of a body part

Answer 51

somatosensory Motor