Brain Functions Exam 1

Front 1

Concentration of ions (K/Na/Ca/Cl)

Back 1

Out:In

K/ 1:20

Na/ 10:1

Ca/ 10000:1

Cl/ 12:1

Front 2

Pacinian Corpuscle

Back 2

Sense vibration

Front 3

Ruffini Endings

Back 3

Responds to skin stretch

Front 4

Free nerve endings

Back 4

Pain and temperature

Front 5

Meissner's Corpuscle

Back 5

Flutter and stroking movements

Front 6

Merkel Receptors

Back 6

Sense steady pressure and texture

Front 7

Mechanoreceptors

Adaptation & Receptive field

Back 7

Front 8

Diameter of 4 axons thickness

Back 8

group 1: Aalpha:

13-20 micrometers/ 80-120 m/s

used for proprrioception

group 2: Abeta:

6-12 micrometers/ 35-75 m/s

used for mechanoreceptors

group 3: Adelta:

1-5 micrometers/ 5-30 m/s

used for pain/temperature

group 4: C:

0.2-1.5 micrometers/ 0.5-2 m/s

used in temperature, pain, itch

Front 9

Dorsal Column-Medial Lemniscal Pathway?

Back 9

This is the major route for touch and proprioceptive sensations ascend to the cortex

Front 10

Lemniscus?

Back 10

Means a band of white nerve fibers in the brain

Front 11

Damage to posterior parietal cortex

Back 11

(association area essential for perception of spatial perception of sensation)

leads to Tactile Agnosia: can't recognized objects by feeling them

Front 12

Retinal cells

Back 12

Front 13

Retinal Layers

Back 13

Front 14

Cellular pigmented epithelium

Back 14

Front 15

Phototransduction in Rods

Back 15

Depolarization in the dark: dark current (cGMP-gated Na+ channel)

Hyperpolarization in the light

Rhodopsin: Opsin + Retinal

Opsins are receptors that activate by light causing a conformational change on Retinal (11-cis to all-trans)

Front 16

3 Opsins in Cones

Back 16

Red, green and blue

Front 17

What NT is secreted in the dark

Back 17

Glutamate as a result of depolarization of cells in the dark

go on to depolarize IPL of bipolar cell, then OPL of them onto ganglion cells which generate an AP

Front 18

2 kinds of Bipolar cells

Back 18

ON: respond to Glutamate by hyperpolarizing (light ON at the center)

,so depolarized when light is on

OFF: respond to Glutamate by hyperpolarizing (light OFF from the center)

,so depolarized when light is off

Front 19

Example of direct and indirect pathways

Back 19

Front 20

Retinal Processing picture

Back 20

"PhBAG"

Photoreceptors -> (Horizontal) -> Bipolar -> Amacrine -> Ganglion

Front 21

Purpose of on/off ganglion cells

Back 21

Detect differences in illumination in a receptive field

Front 22

Best stimuli for an on/off ganglion cell

Back 22

light/dark center pattern

(They are sensitive and responsive to contrast!)

Front 23

integration of presynaptic inhibition

Back 23

Front 24

3 major types of great ape ganglion cells

Back 24

P (Parvo) - Type: 90%

M (Magno) - Type: 5%

nonM-nonP (K-type): 5%

some P and K type cells are color-sensitive ganglion cells

(color-opponent center-surround receptive field)

Front 25

Mechanoreceptors

Back 25

Front 26

M-type cells

Back 26

-Lack of color opponency

-do not send color info to brain

-large receptive field

-respond and adapt fast

*motion detection, but low-resolution image

Front 27

P-type cells

Back 27

-color-opponency

-sends color info to brain

-response has no adaptation

-conduction speed is slower than M-type

*Object shape and color detection, with detailed images

Front 28

K-type cells

Back 28

-color-opponency

-sends color info to brain

-contributes to color vision

*physiological properties not yet clear

Front 29

Parallel Processing

Back 29

Simultaneous input from 2 eyes

for depth and distance

info about light and dark (On/Off ggl. cells)

different receptive fields and properties of retinal ggl cells (M/P/K type)

Front 30

Nonthalamic Targets of the optic tract (3)

Back 30

Hypothalamus: biological rhythms like sleep and wakefulness

Midbrain's pretectum: size of the pupil

Midbrain's Sup. Colliculus: visual reflexes, tracking, or reading left to right for example

Front 31

Superior colliculus

Back 31

receives 10% of optic fibers, and is involved in Saccadic eye movements and attention

Front 32

2 visual systems

Back 32

Primitive

(eye and head movements, reaching hands and other simple behaviors)

Mammalian

(Speech and thinking in words: consciousness, and other complex behaviors)

Front 33

damage to each visual system

Back 33

to primitive: person is not aware of vision

to mammalian: abolishes perception

Front 34

Segregation of eye input by ganglion cell types in LGN

Back 34

Front 35

Receptive fields of LGN

Back 35

Front 36

Retinotopy

Back 36

Map of the visual field onto a target structure:

Retina -> LGN -> striate cortex

perception here is related to the brains interpretation of distributions of neural activity, not a snapshot of reality

Front 37

Gen features of cerebral cortex

Back 37

Front 38

Anatomy of striate cortex

Back 38

Front 39

Simple Cells

Back 39

analyze shape, are orientation-selective, but not very sensitive to color

Front 40

Complex cells

Back 40

detect movement and not color regardless of position in the receptive field

Front 41

Hypercomplex cells

Back 41

Has stopping properties in larger receptive fields

Front 42

Dorsal stream

Back 42

Part of interconnected systems in the visual cortex involved in perception of spatial locations, visual disparity (depth) and movement

Front 43

Ventral stream

Back 43

anatomical pathway for perception of form and color

Front 44

Damage in the MST

(of dorsal stream)

Back 44

leads to "snapshot vision" of motion perception

Front 45

Magnocellular LGN neurons project to

Back 45

layer IVC-alpha

Front 46

Parvocellular LGN neurons project to

Back 46

layer IVC-beta

Front 47

Koniocellular LGN axons bypass

Back 47

layer IV to make synapses in layers II and III

Front 48

basis of stereopsis

Back 48

-binocular disparities for depth perception

-layer IVC innervates binocular neurons in superficial layers

Front 49

What are receptive fields of the striate cortex

Back 49

-input of K cells to II, III

(Koniocellular in LGN)

-input of M cells to IVC-alpha

(Magnocellular in LGN)

-input of P cells to IVC-beta

(Parvocellular in LGN)

Front 50

Cortical receptive fields physiology

Back 50

Layer IVCalpha: insensitive to the wavelength

Layer IVCbeta: center-surround color opponency

Outside IVC: not center-surround

(found upon Hubel and Wiesel's work in the 60's that won them a nobel prize in 1981)

Front 51

Orientation selectivity

Back 51

orientation-selective neurons where layers II to VI have the same orientation selectivity for vertical outlines

Front 52

What is the great impact of Hubel and Wiesel to neurobiology?

Back 52

1) ocular dominance columns

2) describing how visual signals are processed by the brain to generate edge detectors, motion detectors, stereoscopic depth detectors and color detectors: building blocks of the visual scene

(Detection of lines or bars of the simple cell)

Front 53

Direction selectivity

Back 53

some neurons fire AP's more strongly to a bar moving to one specific direction

Front 54

Simple cell picture

Back 54

Front 55

Hypercomplex cells

Back 55

exhibit end stopping properties:

when a cells response increases as a stimulus expands to fill the receptive field, and then responds less when the stimulus exceeds the size of the receptive field

Front 56

3 classes of cells in V1

Back 56

building blocks of the visual scene:

simple cells (line/bar/edge detectors)

complex cells (orientation detectors)

hypercomplex cells (patterns/length/corners/angle detectors)

Front 57

Color blobs of the striate cortex

Back 57

are cytochrome oxidase mitochondrial enzyme in cell metabolism, which receive input from K-cells of the LGN for color as well as some P and M LGN neurons

Front 58

Blob cells

Back 58

-are color detectors (light wavelength-sensitive)

-monocular, no orientation, no direction selectivity

Front 59

***3 parallel pathways to visual cortex

Back 59

Front 60

A cortical module

Back 60

2 by 2 block in V1 of striate cortex containing ocular dominance columns, orientation columns, and color blobs to fully analyze a portion of the visual field

Front 61

Steps of hearing

Back 61

Front 62

Dorsal Stream

Back 62

A system of interconnected regions of visual cortex involved in the perception of spatial locations, visual disparity (depth) and movement, beginning with the striate cortex (primary) and ending with the posterior parietal cortex by way of extrastriate cortex.

Receiving projections mostly from M-cell pathway

Front 63

Ventral Stream

Back 63

A system of interconnected regions of the visual cortex involved in the perception of form (3D object) amd color, beginning with the striate cortex and ending with the inferior temporal cortex by way of the extrastriate cortex.

Receiving projections mostly from P cell and blob pathways

Front 64

receiving projections of dorsal stream

Back 64

Mostly from M cell pathwaya

Front 65

receiving projections of ventral stream

Back 65

mostly from P cell and blob pathways

Front 66

Achromatopsia

Back 66

caused by damage to area V4 (part of Ventral stream)

leading to partial or complete loss of color vision as well as shapes of objects (color cone receptors in the retina are normal)

Front 67

Area IT

Back 67

is the major output of V4 and responds to a wide variety of colors and abstract shapes, like faces and hands

Front 68

damage to ventral stream

Back 68

leads to inability to recognize objects. faces, textures or colors.

although they can still perceive movement

so can see form from motion, so patients with this visual agnosia can recognize their friends by the way they walk

Front 69

"Where" and "What" streams

Back 69

Where: dorsal stream (M-ovement)

What: ventral stream (P-erception)