Learn: UMD NEUR200 Exam 2

Charles Scott Sherrington

coined the term synapse to describe the specialized gap that existed between neurons

Action potential along sensory or motor axons are at about?

40m/s (10 to 100 meters per second)

Synaptic Delay

Occurs where one neuron communicates with another

Graded Potential

May be either depolarizations (excitatory) or hyperpolarizations (inhibitory)

Excitatory Synapses (EPSP)

Temporary graded depolarization of postsynaptic membrane.

Caused by the entraced of sodium ions into the cell. Makes the cell more likely to fire an action potential

inhibitory postsynaptic potential (IPSP)

Temporary graded hyperpolarization of postsynaptic membrane. Caused by the exit of potassium ions outside the cell or chloride ions (negative charges) inside. It increases the negative charge within the neuron. This will make the cell less likely to fire an action potential

Spatial Summation

Synaptic inputs from separate locations combine their effects on a neuron. Summation over space. Synaptic inputs from separate locations combine their effects on a neuron

Temporal Summation

Repeated stimuli within a brief time have a cumulative effect. Even though the threshold in the postsynaptic neuron decays over time, it can be combined within a second excitation. When the combination exceed the threshold, produce an action potential. Temporal summation and spatial summation can occur together.

spontaneous firing rate

a periodic production of action potentials even without synaptic input. Ongoing activity in the absence of a task or simulation. Ongoing brain activity may be important for perception. The perception of a weak stimulus for example. will depend on both the phase and amplitude of spontaneous activity.

ESPSs increase or decrease the frequency of action potentials above the spontaneous rate?

The ESPSs increase. Whereas the IPSPs decrease it

neural synchronization

- Brain waves from different regions will synchronize (network communication)

- Synchronized activity of neurons can give rise to oscillations

Coherent Waves

Waves that have the same frequency, speed and have a constant phase relationship. More memory, attention, consciousness, and synchronized activity.

What triggers synaptic vesicle exocytosis in neurons?

Ca2+

Iontropic

effects vision and hearing.

.

True

Metabotropic

Initiate metabolic reaction a second messenger communicates to many areas within the cell

TRUE or FALSE: Metabotropic effects are SLOW and COMPLEX

True

Monoamines

Modified amino acids

Dopamine

Voluntary movement, learning, and feelings of pleasure

Mesocortical

Learning and memory: Ventral tegmental area -> Prefrontal Cortex

Mesolimbic

Reward and addiction: Ventral tegmental area -> Nucleus Accumbens

Nigrostriatal

Ganglia movement/Parkinsons: Substantia nigra -> Basal Ganglia

Norepinephrine

Alpha and Beta waves: Energy, arousal, mood, depression, and anxiety.

Main Synthesizer: Locus Coeruleus

PNS: adrenal cortex

Serotonin

Sleep, wakefulness, mood

Main Synthesizer: Raphe Nuclei

SSRIs

Used to treat depression and inhibit the reuptake of serotonin

Glutamate

Most important excitatory neurotransmitter

Receptors: AMPA and NMDA

Psychosis and Excitatory

GABA

Inhibitory postsynaptic potentials influx of chloride (Cl-)

Alcohol increases GABA and decreases Glutamate

Acetylcholine

Hippocampus. Nucleus basalis of Meynert, msucles, memory and attention. (Alzheimer's Disease)

Old people have less acetylcholine

Proliferation

Production of new cells. 28 weeks of gestation

Overproliferation

Magalencephaly (Some cases come along with Autism)

Reduced Proliferation

microencephaly (Smaller brain, cognitive disabilities)

Migration

Chemicals guide neuron migration until ADULTHOOD

-Deficit in chemicals lead to decreased brain size and axon growth

-Environmental factors during pregnancy can contribute

Differentiation

Cells change into a specialized type of neuron.

Axon and dendrites are formed

Axons grow first, Dendrites start forming after migration when neurons reach their destination

Myelination

Continues gradually through adolescence and adulthood

-Impaired adult myelination in the prefrontal cortex of socially isolated mice

Synaptogenesis

neurons form synapses with other neurons, discard old ones.

Synaptic Pruning

Stimulating Environment

enhances sprouting of axons and dendrites in many species

What is the best ways to maintain intellectual vigor in old age?

Physical Activity

Combined adult _______ and ______ mimic exercise effects on cognition in an Alzheimer's mouse model

neurogenesis, BDNF

Blind people use what cortex to help identify what they feel?

Occipital Cortex

TRUE or FALSE: Practicing music reorganized the brain to maximize performance of that skill

True

Spinal Cord

Communicates with the sense organs and muscles

Each segment of the spinal cord sends sensory information to the brain and receives motor commands from the brain.

Hindbrain

Disconnection of hindbrain from the rest of the brain is a vegetative state

Consciousness is affected

Midbrain

Important for operant movements

Superior vision and inferior colliculus hearing

Thamalus

Relay station for sensory information

Hypothalamus

Important for motivated behaviors (Sleep, eating, sex) thermoregulation

Pituitary Gland

Hormones

Basal Ganglia

They can learn simple sequences of movements

Animals learn to feed themselves

Behaviors are more biologically adaptive

Animals can learn without cortex

Cortex: Intention

The animal is more pro active

Skilled movements and sequences

cortex allows us to extend the usefulness of learned behaviors to new situations.

Solve problems, make plans

Layers

Input and Output

Columns

Interaction (function)

middle cortical layers (layer IV)

- input zone of sensory analysis

- temporal, occipital, and parietal

- sensory areas have a larger layer IV

Layers V and VI

Output zone

Sends axons to other cortical and brain areas

Motor areas has a large layer V and a small layer VI

Superficial Layers

Receive inputs from other cortical areas and integrate them with inputs from layer IV

Columns or modules

Most interactions between neurons take place vertically. Less interaction takes place with cells more than a couple of millimeters on either side.

Neurons within a column are functionally similar

These modules are apparent in primary sensory regions and less apparent in the association or motor areas of the cortex

Types of energy and transduction

Vision, Audition, Touch, Smell and Taste

Vision

Light, electromagnetic energy

Audition

Pressure changes in the air

Touch

Pressure changes in the skin

Smell and Taste

Chemicals

Transduction

The receptors transform energy on a different type of energy (electrical energy)

Transduction occurs in the receptors

Retina

Neural tissue that receives light

-Contains 2 types of receptors: Cones and Rods

Fovea

Small area specialized for acute, detailed vision

Periphery

Has better sensitivity to dim light

Cones

Mostly in the fovea (good with details)

Rods

In the periphery (good with intense light)

geniculostriate pathway

pattern, color, motion recognition

Visual-form agnosia

Inability to recognize objects

tectopulvinar pathway

tectum-midbrain: superior colliculus, thalamus pulvinar nucelus and parietal lobe

-Spatial location of objects

Visual ataxia

Inability to recognize where objects are located

V1

primary visual cortex

V2

4th intercostal space to the left of the sternum

V4

Color vision

V5 (Middle Temporal Lobe)

Important to perceive objects in motion

Damaged: objects at rest are perceived, but when they move they vanish

Ventral Stream

Closer to belly

The "WHAT" pathway, toward the temporal cortex to determine an objects identity EX: Face blindness

Dorsal Stream

Closer to back

The "WHERE" and "HOW" pathway, toward the parietal cortex to determine an object's location. Also information about how to direct action with regard to a stimulus.

Fusiform Face Area (FFA)

Face analysis

extrastriate body area (EBA)

Body Analysis

Superior temporal sulcus (STS)

Biological motion

parahippocampal place area (PPA)

Scenes (indoor and outdoor places; landmarks)

Parietal Reach Region

Visually guided reach (helps us know where objects are and how to reach them)

Hemianopia

Blindness of half visual field (right or left) because of damage on left or right V1

Blindsight or cortical blindness

Sometimes people with anopsia or hemianopsia respond to the stimuli that they don't consciously see (specific characteristics of the stimulus such as movement can help)

Cortical color blindness

Damage to the V4 area, imagery and memory are affected too

Agnosia

Problems to recognize the line drawings of objects (can recognize the object, but not a drawing of it)

apperceptive agnosia

Cannot copy an object

Cannot see objects, but knows a chair is a chair

Simultagnosia

inability to perceive more than one object at a time

Associative Agnosia

inability to recognize an object despite its apparent perception

Can copy an object but cannot recognize

Can see but cannot understand what they are, lack of memory

Prosopagnia

Difficulty recognizing familiar faces

Bilateral damage of fusiform area (right hemisphere)

Alexia

AKA word blindness

Inability to read

Damage of left fusiform area and affects word recognition

They can read letter by letter

They can use motion (tracing the letters) to read

Stimulants used to treat ADHD

increases dopamine in the synapse by inhibiting the reuptake of dopamine

Most ADHD medications...

inhibit the reuptake of dopamine

Monoamines include

Serotonin, dopamine, and noradrenaline

Benzodiazepines can increase the influx of ______ ions as it happens with alcohol and GABA

Chloride