Neur200 Exam 2

Presynaptic neurons

send the signals

Postsynaptic neurons

receive the signals

Sherrington

Experiment w/ dogs, synaptic delay (speed in reflex arc slows down = 15 m/s bc of chemical communication), won noble prize, one of the first to use “synapse”

Synaptic delay

gaps between neurons slows down the rate of firing

Excitatory Postsynaptic Potential (EPSP)

temporary depolarization of POSTsynaptic membrane, makes cells more likely to fire, caused by increase of Na+

Inhibitory Postsynaptic Potential (IPSP)

temporary hyperpolarization of POSTsynaptic membrane, K+ leaves or Cl- enters, makes the cell less likely to fire

Spatial Summation

multiple neurons combine their inputs from several locations, help depolarize + get to threshold

Temporal Summation

repeated stimuli to make a cumulative effect, postsynaptic signal decays over time, so keep it going to increase longevity

Spontaneous Firing Rate

periodic production of APs even w/out synaptic inputs, ongoing activity w/out a task, EPSP will increase frequency of APs, IPSP will decrease it

Neural Synchronization

brain waves from different areas will match up, network communication, synchronized waves/oscillations

Calcium response to APs

Calcium channels open in the axon terminals, Ca2+ enters the neuron, triggering protein (SNAREs) that lead to exocytosis

Ionotopic Receptors

vision and hearing, neurotransmitter binds to receptor and opens a channel, effects are fast

Metabotropic Receptors

pain + attention + emotion, initiate metabolic reaction, needs second messenger, slower b/c the extra messenger but lasts longer

Monoamines

modified amino acids

Types of Monoamines

dopamine, norepinephrine/noradrenaline, serotonin

Dopamine

movements - parkinsons’s

reward, motivation, cognitive control - adhd

psychosis - hallucinations

Dopamine drugs

antipsychotics, stimulants, recreational drugs

Norepinephrine/Noradrenaline

main synthesizer (Locus coerclus + adrenal gland)

energy, arousal, mood - anxiety, depression

Serotonin

main synthesizer (Raphe nuclei)

sleep + wakefulness

mood - depression

highest when awake

Serotonin drugs

SSRIs, TCAs, MAOIs

Types of Amino Acids

glutamate, GABA, acetylcholine

Glutamate

receptors: AMPA + NMDA - psychosis + excitoxicity

GABA

receptors: GABAA, GABAB, GABAC

inhibitory postsynaptic potentials = influx of Cl-

GABA Drugs

benzodiazepines

Acetylcholine

receptors: nicotinic + muscarinic

Nucleus basalis of Meynert

muscles

memory + attention - alzheimer’s

Spinal Cord

communicates w/ sense organs + muscles (reflexes)

sends sensory info to brain, receives motor info from brain

after injury: stem cells, glial cells, neurotrophic factor, electrical stimulation

BDNF

brain chemical neurotrophic factor

mimic exercise effects on cognition along w/ adult neurogenesis

Hindbrain (myelencephalon + metencephalon)

postural support

medulla, pons, cerebellum, Locus coerelus, Raphe nuclei

Medulla

vital functions, breathing, heart rate

Pons

bridge

connections between many diff areas

Cerebellum

motor coordination

disconnect = vegetative state

Locus coerelus

norepinephrine/noradrenaline production

Raphe Nuclei

serotonin production

Midbrain (mesencephalon)

spontaneous behaviors + operant behaviors (instincts)

superior + inferior colliculi, ventral tegmental area, substantia nigra

Superior colliculi

vision

Inferior colliculi

hearing

Ventral tegmental area (VTA)

dopamine production

Substantia Nigra (SN)

dopamine production

Diencephalon (Tectum, motivation)

thalamus, hypothalamus, pituitary gland

Thalamus

directs incoming sensory info to correct part of cortex

Hypothalamus

motivated behaviors

sleep, eating, sex, 4 fs

Pituitary Gland

hormones

Telencephalon

limbic system, basal ganglia, cortex

Limbic system

hippocampus, cingulate gyrus, olfactory bulb, amygdala

emotion, learning, memory

Basal ganglia (self-maintenance)

help us do system of automatic movements, can learn w/out cortex

caudate nucleus, putamen, globus pallidus, substantia nigra

Cortex (control and intention)

intention, convulsions, skilled movements and sequences, solve new problems + make plans

Cortical Layers

input + output

middle (IV): input zone of sensory analysis

V + VI: output zone; send axons to other cortical brain areas (motor areas)

superficial areas (II + III): receive inputs from other cortical areas and integrate them w/ inputs from IV

Cortical columns

interaction

neurons w/ same column function similarly (respond to a particular stimulus)

neurons communicate more vertically than horizontally

ex: ocular dominance - ipsilateral vs. contralateral

Hubel and Wiesel

kitten experiment

affected their visual cortex development and function

shared the Nobel Prize

discoveries about information processing in the visual system

Types of Energy

each type of receptor is specialized

vision: light

audition: pressure changes in the air

touch: pressure changes in the skin

smell + taste: chemicals

Transduction

energy transforming (occurs in receptors)

Retina

neural tissue that receives light

contains cones + rods

Fovea

small area specialized for acute, detailed vision

lots of cones

Periphery

has better sensitivity to dim light

mostly rods

Geniculostriate Pathway

pattern, color, motion recognition (thalamus)

eyes to cortex

Tectopulvinar Pathway (tectum + midbrain)

identifying spatial location of objects, unconscious

retina - superior colliculus (tectum) - pulvinar (thalamus) - parietal + temporal areas

V1

straite cortex/primary visual cortex

signals travel to other areas in cortex for processing

V4

color vision

color blindness if damaged

V5

middle temporal (MT), perceive objects in motion

akineptosia if damaged

Ventral Stream

the “what” pathway

determine an object’s identity

temporal lobe

FFA, EBA, STS, PPA

if messed up: can see, but doesn’t know what it is

Fusiform Face Area (FFA)

face analysis

Estrastriate Body Area (EBA)

body analysis

Superior Temporal Sulcus (STS)

biological motion (body movement)

Parahippocampal Place Area (PPA)

scenes (indoor + outdoor places; landmark)

Dorsal Stream

the “where” or “how”

parietal lobe

if messed up: can see + know what it is, but can’t tell where it is

Parietal Reach Region

visually guided reach

Visual Agnosias

inability to recognize visual info

Apperceptive

can’t copy an object

Associative agnosia

can copy object, but can’t identify it

Prosopagnosia

can’t recognize faces

Alexia

word blindness → can’t read

Hemianopia/hemianopsia

blindness of half visual field b/c of damage in left or right V1

Simultagnosia/Balint’s syndrome

can’t perceive two items at once, spatial attention

Visual Ataxia

inability to recognize location of objects

Too little synaptic pruning =

autism

Too much synaptic pruning =

schizophrenia

Fine tuning by experience

use it or lose it

stimulating environment enhances sprouting of dendrites and axons

Mesocortical

ventral tegmental area < - > prefrontal cortex

Mesolimbic (reward pathway)

ventral tegmental area < - > nucleus accumbens

Nigrostriatal

substantia nigra < - > basal ganglia (straitum)

Dopamine pathways

mesocortical, mesolimbic, nigrostraital, tuberoinfundibular

Motor Cortical Layers

V and VI

Sensory Cortical Layers

IV

Input Cortical Layers

II and III

If dopamine + norepinephrine/noradrenaline increase…

then serotonin decreases