neuro exam three

three main components of vision

sensory transduction

early visual processing

cortical processing and perception

where does sensory transduction happen

retina

what is sensory transduction

transforming physical energy into neural energy, something the brain can understand

What is the physical energy (sensory stimulus) that our eyes transduce

Light

What makes up the structure of the eye?

Retina, cornea, lens, rods, and cones

How does light work?

Most of the light that we see is reflected, and when it passes through things is refracted

What is wavelength?

determination of color

what is brightness

amplitude/intensity of light

How does light enter the eye?

It goes through the cornea to the pupil to the lens to the retina

What does the cornea do?

It protects outer covering and refracts light

what is the pupil?

It is a hole in the center of the iris which controls light entry

what are lens?

They reflect light dynamically and change to adjust focal distance

what is the retina?

It is neural tissue in the back of the eyeball that can transduce light to electrical signal

what is the optic disc?

A hole in the retina where optic nerve leaves

most light you see is

visible light

area where vision is sharpest

fovea

primary visual cortex location

occipital lobe

what is the fovea

Point of central focus

What is the optic nerve?

It is a bundle of nerves that transmit sensory information

what are the two types of photo receptors that the retina has?

rods and cones

what are rods

"Night vision" sensitive to low light, but do not see color; brightness

What are cones?

"day vision" require bright light to see both color and fine details

What is the trichromatic theory of color?

We have three types of cones for colors

What are S cones?

They are sensitive to short wavelength; blue and violet

what are M cones

Sensitive to medium wavelength; yellow, and green

what are L cones?

Sensitive to long wavelength; red and orange

what forms the optic nerve

ganglion cellsaxons

why do we have a blind spot

bc there are no photoreceptors in the back of the eye

what is the optic chaism

where the optic nerve fibers cross before the LGN

basic route for the visual pathway into the brain

retina, optic nerve, thalamus (LGN), primary visual cortex

at all levels of processing, we use cues like what to understand aspects of the stimulus

firing rate, firing pattern, which neurons are active

what 2 major processing streams originate in primary visual cortex

ventral stream and dorsal stream

what is ventral stream

identifying objects

what is the dorsal stream

assessing the location of objects and guiding out movement toward them

what is optic ataxia

difficulty using vision to reach and grasp for objects

info used to locate objects and detect their motion is sent to

dorsal stream

info necessary to detect, identify, and use color and shape information is sent to

ventral stream

what is a specalized hotspot that determines “who am i looking at?”

fusiform face area FFA

what is feature detection from the V1

detects lines, edges, movement, and orientation

what is retinotopic mapping

brain keeps a map of the visual field

4 types of biological rhythms

circadian, ultraidian, infradian, cirannual

what is circadian

rhythms that last abt 24 hours

what is ultradian

less than 24 hours

what is infradian

more than 24 hours

cirannual

yearly

what kind of biological rhythm is body temp

circadian

what kind of biological rhythm is sleep cycle

ultradian

what kind of biological rhythm is menstrual cycle

infradian

what kind of biological rhythm is migration

circannual

syncing to environment (light)

entrainment

a shift in the timing of circadian rhythms

phase shift

zeitgeber

external cue (light)

internal clock without cues (light)

free-running

where and what is our master clock

SCN, in the hypothalamus and right above the optic chiasm

what are iprgcs

photoreceptors that regulate non image forming functions like our internal clock and sleep

pathway for circadian rhythms

light > retina > SCN > pineal gland > melatonin

what is melanopsin

in iprgcs, they detect blue light and send signals to the scn

how does melatonin come into play

with blue light, melatonin goes down and SCN is activated

how does adenosine work

builds up during the day, makes you sleepy

hypothalamus with sleep

scn within hypothalamus

brainstem in sleep

control transitions between wake/sleep

thalamus for sleep

sensory relat between senses and cortex. very active during rem

pineal gland in sleep

receives signals from scn to produce melatonin

basal forebrain in sleep

promotes sleep and wakefulness

amygdala in sleep

emotional processing; active during rem

hypothalamus in dreaming

basic drives and arousal

pfc in dreams

off, no logic

visual cortex in dreams

hallucinations

how does the scn work as a clock

inside every cell, there are clock genes that make protein and break down at night

define chronotypes

ones natural sleep/activity pattern

stages of sleep

NREM stages 1-3 and then REM sleep

what is NREM sleep stage one

very light sleep, drifting off

what is nrem stage 2

light sleep, where u spend most of the night, sleep spindles

nrem stage 3

deep sleep or slow wave sleep; most restorative

what is rem sleep

brain is very active, eyes more, we are in muscle paralysis, vivid dreams, mostly second half of night

REM vs SWS

active brain, vivid dreams, vs deep sleep, delta waves

delta brainwave

slow

alpha and beta brainwaves

faster; while awake

what do iprgcs do

detect blue light

what is active while dreaming

amygdala, hypothalamus, visual areas

what is inactive during dreaming

prefrontal cortex

what happens if you destroy the scn

rhythms become disorganized, not synced to 24 hour days

what is microsleep

brief, uncontrollable sleep episodes in seconds

what are alpha waves

relaxed

when do we see theta waves

light sleep

when do we see detla waves

deep sleep

when do we see beta waves

awake/rem

elderly with sleep

frequent awakenings an reduction in stage three bc of dementia

brain development for sleep

critters born further developed than human babies sleep less

energy conservation for sleep

lower metabolic demands

niche adaptation for sleep

sequestering for saferty

physical restoration for sleep

breaking down and cleaning waste for the day

memory consolidation for sleep

sws for declarative memory, rem is important for memory

what is brainwashing

change in the brains extracellular space between sleep and waking states may drive the clearance of toxins

most common sleep disorders in kids

night terrors, bedwetting, sleepwalking

insomnia

inadequate, non-restorative sleep

what is narcolepsy

sudden sleep attacks

what is sleep apnea

breathing stops

functions of fear, anger, and disgust

escape, attack, avoid

expressions of emotion evolve from behaviors that indicate what

an animal is likely do next