Quiz 5 - Neuro 128

Which area of the brain is involved in producing movements?

Motor cortex

Explain topographic organization in the motor and visual areas of the brain

Motor cortex (homunculus) - areas that are used more/require more skilled movements are proportionally bigger In the visual cortex - when each LGN cell projects to V1, it maintains a spatially organized neural representation Topographic map - it is essentially a map of the visual world - also find that requires more processing like from the fovea requires more neural tissue

A tract is a bundle of axons in the CNS T/F

T

In v1 blob areas = color, p cells; while in v1 interblob areas = motion/form, M cells T/F

T

Interparietal area is for grasping T/F

T

Lateral interparietal are (LIP) is for eye movement T/F

T

Spinal cord neurons are important for executing movement T/F

T

The nasal projection crosses over but not the temporal projection T/F

T

The prefrontal cortex plans movements T/F

T

The primary motor cortex is topographically organized T/F

T

The spinal cord helps with voluntary and involuntary movement T/F

T

You cannot control reflexes T/F

T

What layers are Magnocellular?

Thalamus layers: 1-2

What layers are Parvocellular?

Thalamus layers: 3-6

Blindspot

area in which there are no photoreceptors

Rods

grayscale, night vision

Dorsal stream

how/where occipital lobe to parietal lobe

Which tract is involved in moving the limbs and digits?

lateral corticospinal tract

L cone

long wavelengths, orange/red

With visual form agnosia individuals suffer from:

loss of recognition but not retention of guidance

M cone

medium wavelengths, green

Efferent

neurons that carry info away from the CNS

Afferent

neurons that carry info toward the CNS

What is a functional column in the visual cortex that is maximally responsive to info coming from one eye called?

ocular-dominance column

S cone

short wavelengths, blue

Which tract is involved in moving muscles of the midline of the body?

ventral corticospinal tract

Ventral stream

what, striate cortex (V1) to the temporal lobe

The brainstem is important for which of the following?

- Species-typical movement and behavior - Contextual behavior - Movement linked to eating, drinking, posture, and balance

What are the 3 visual pathways? (visual info --> eye --> optic nerve --> optic chiasm --> optic tract into the brain)

1. Geniculostriate stream = M&p RGCs --> lateral geniculate nucleus --> striate system --> other visual cortical areas (retina to thalamus; conscious vision, pattern recognition) 2. Tectopulvinar system = M RGCs --> superior colliculus --> pulvinar --> other visual cortical areas (motion and spatial information, attention to movement) 3. Retinohypothalamic tract = pRGCs that go to the SCN (suprachiasmatic nucleus in hypothalamus) (photosensitive retinal ganglion cells respond to light directly do not go to thalamus, just SCn, they control the circadian clock

What is the primary neurotransmitter at the neuromuscular junction?

Acetylcholine

Which area of the brain is important for accuracy and timing of movements?

Cerebellum

How does info from the secondary somatosensory cortex contribute to the ventral stream?

Contributes info about object size and shape

What are some examples of damage that can occur in the visual pathways?

Cuts in optic tract, LGN, or V1 can result in homonymous heminopia = blindness of entire left or right visual field Quadrantopia = blindness of one quadrant of the visual field Scotoma = small blind spot caused by small lesion in visual cortex

motion and depth are not separated from color in the thalamus T/F

F

Electric stimulation of one part of the motor cortex shows movement in all areas mapped in the entire motor cortex T/F

F movement only in the area mapped in the specific part of motor cortex was stimulated

The motor homunculus shows equal representation of every body part that moves in the motor cortex T/F

F there is disproportionate representation (lips, toungue and hands have larger representation than other body parts_

In Cerebral Palsy movement and cognition are affected T/F

F Cognition is not affected

The motor neurons code for force but not direction of movement T/F

F They do both

Temporal lobe includes the fusiform face are (faces), parahippocampal place are (scenes) and lateral interparietal area (eye movements) T/F

F The last one is a part of the parietal lobe

Describe the geniculostriate pathway and the tectopulvinar pathway

Geniculostriate pathway = projections from the retina to the lateral geniculate nuclei to the visual cortex Tectopulvinar pathway = projections from the retina to the superior colliculus to the pulvinar (thalamus) to the parietal and temporal visual areas

Why are we limited to the visible spectrum?

Limitation in our photoreptor neurons detection capabilities

What are the 2 types of retinal ganglion cells?

Magnocellular x Parvocellular

Which area of the brain is involved in planning movements?

Prefrontal cortex

Which region of the brain is important for organization of movement sequences?

Premotor cortex

Why is rehabilitation after damage to the motor cortex important to rescue motor function?

Rehabilitation can make it so regions maintain their ratios of representation in the motor cortex, even if the lesion/injury remains

Correct order (vision)

Retinal ganglion cells, amacrine cells, bibolar cells, horizontal cells, cone/rod

Which is true of the Fovea?

Rod free, cones are most dense here

What is not a function of the motor cortex?

Sensing movement

Explain the hierarchical integration of coding visual information

The receptive fields of many retinal ganglion cells combine to form the receptive filed of a single LGN cell. The receptive fields of many LGN cells combine to form the receptive field of a single V1 cell.

Give examples of damage to object recognition (the what pathway) and visual action (the how pathway)

The what = visual form agnosia: inability to recognize objects or drawing of objects (ventral stream) The how = optic ataxia: deficit in the visual control of reaching and other movements (dorsal stream)

What is the primary visual cortex that receives input from the LGN?

V1

What type of information do dorsal-root ganglion neurons NOT sense?

Vibration

Tract

a bundle of axons in the CNS

Nerve

a bundle of axons in the PNS

Extensor

a muscle that moves (extends) the limb away from the trunk

Flexor

a muscle that moves (flexes) the limb towards the trunk

Cones

color and bright light