Modules 3 & 5 and Lectures 5-9 Flashcards
Overall purpose of the nervous system?
Create behavior
Specialized cells of the nervous system and their purpose/functions?
Neurons - transmit electrical impulses throughout the body
Glial cells - helper cells assisting neurons in role as brain communicator, and provide structural support
What are Dendrites?
Extensions of membrane of cell body and receive chemical messages from many other neurons.
Cerebral cortex length?
2.5 feet long if stretched out fully. ‘Advanced brain’.
Which side of the brain has more neurons?
The left hemisphere with 186 million more
What is a neurotransmitter?
Chemicals released from end of axon that acts as message to other neurons and body parts. Binds with receptors.
Receptors
Built to receive chemical messages from transmitters. Are proteins embedded in the cell membrane
What happens to our nervous system as we learn new things and grow?
Dendrites spread and form new connections with different neurons
What is the soma and its function?
Cell body from which dendrites extend from. Responsible for metabolic processes of the cell and contains the cells organelles.
Name the order that the electrical impulse must travel through starting from where the neuron touches a dendrite and ending at the axon hillock
Terminal Buttons - edge of axon terminal where neurotransmitter exits.
Axon terminal - releases neurotransmitter after action potential is reached
Axon hillock - where soma and axon meet
What are vesicles?
Little bubbles at the terminal button that store neurotransmitter molecules
Why does electrical potential exist?
Because of ion concentration inside and outside of the cell
Where do hallucinations usually come from?
Left visual field
What does the LGN do?
Relays information for the sensory function of eyesight
Lowest anatomical part of the brain?
Medulla
Resting potential of a neuron?
-70.0 mV
Examples of neuroplasticity
Branching out of dendrites, increases in neurotransmitter and receptor numbers
What does stroke/injuries to Wernicke’s area affect?
Speech comprehension
What is a presynaptic neuron and how does it aid in neural communication?
It is the portion of the neuron (also called axon terminal) that releases the neurotransmitter into the synapse, this allows a cell to connect with another cell and send that electrical impulse.
What are postsynaptic neurons?
Dendrites that receive neurotransmitters from another neuron’s axon terminal
What is a synaptic cleft?
It is the space between neurons. Neurotransmitters go across this space to communicate to the next neuron.
What are differences between the synaptic cleft and synapse?
Synaptic cleft is terminology for the space between the end of the neuron that is releasing a neurotransmitter (axon terminal) and the end of the receiving neuron (usually a dendrite).
While the synapse, is a small fluid-filled gap between neurons into which neurotransmitters are released (dendrites extend from this structure)
Order of structures/processes that the neurotransmitter passes through?
Presynaptic neuron down into the axon terminal where they are stored in synaptic vesicles. Neurotransmitter eventually breaks the vesicle and passes through the synaptic cleft into the dendrites of the postsynaptic neuron
What is the Myelin Sheath and its purpose?
Protein and fatty substance that wraps around the axon to protect and increase speed of action potentials (electrical impulses)
Nodes of Ranvier
Gaps in the myelin that allow ions to enter into the axon and change the charge inside
What are the characteristics of the polarized cell?
Large number of negatively charged ions inside the cell cause the neuron to have a negative charge (-70.0 mV). Charge is far from 0 (neutral).
The effect of a polarized cell
Cell is at rest and will not release neurotransmitters
Depolarization and its characteristics
Moving away from the state of being polarized. More positive charged particles in cell.
More depolarized the more likely it is going to activate (action potential) and send neurotransmitter to message other neurons.
What elements affect the cell’s action potential?
Na+ into the cell gets closer to action potential. Pushing K+ out of cell gets closer to deactivating (lost + ions making neuron more negative and polarized.
Describe propagation
Na+ are lined up along the axon - electrical impulse continues in succession along the axon. Gated channels in each section “sense” the positive shift in voltage and open too, repeating rush of Na+.
Electrical impulses get sent to end of neuron.
Mechanism to turn off neurons (put them at rest)?
Opening of K+ channels brings neurons to resting potential. The ions rush OUT instead of IN like the Na+ ions do.
What is repolarization?
Na+ coming in triggers K+ leaving resulting in quick repolarization of neuron to negative resting potential. (Resets neuron)
True or false: A neuron may receive inputs from both excitatory and inhibitory neurotransmitters?
True
Different kinds of responses that neurotransmitters interacting with different classes of receptor proteins produce?
Inhibitory (hyperpolarization -) and excitatory (causing +)
4 factors influencing kinds of feelings, thoughts, and behaviors, neurotransmitters release?
Receptors they bind with, where they are released, timing of release, and activity of other neurons in the same network, manipulated by different chemicals as well.
How do drugs affect neural communication?
Alter our experiences by acting like a neurotransmitter or stopping neurotransmitter from finding the receptor site.
What are agonists in relation to endogenous (naturally produced in the body) neurotransmitters?
Chemicals from outside of body that mimic action of neurotransmitters.
Antagonists in relation to endogenous neurotransmitters
Chemicals that comes from outside of body to shut off the receptors
What is Botox?
Contains poison stopping release of neurotransmitter acetylcholine, preventing muscle contractions. Muscles in face cannot contract.
What are oligodendrocytes?
Glial cells that wrap the myelin insulation around axons in the central nervous system. They speed up communication in the central nervous system. (Schwann cells are the same in the nervous system
What are 3 different types of glial cells?
Astrocytes - help get nutrition. Maintain balance of charged particles
Microglia - clean debris and help get rid of germs
Oligodendrocytes - wrap the myelin insulation around axons in central nervous system
What are the implications of a neurodegenerative disease?
Neurons dying over time resulting in loss of particular ability
Efferents vs Afferents
Axons that carry signals away from the CNS vs Axons carrying towards
Definition of neuroplasticity
Ability of neurons and their networks to change
What is the neocortex?
Outer part of brain, with bumps (gyri) and valleys (sulci) responsible for all the high-level processing info
Medulla and its function
Part of brain closest to spinal cord that helps regulate life functions like breathing and heart rate and reflexes
CNS and what it consists of
Gray matter (neurons and glia) and white matter (bundles of myelinated axons)
Gray matter vs white matter and their functions
Gray- local processing of info
White - helps different areas of the brain share information by connecting neurons via dendrites
In regards to the nervous system, what is the somatic division?
It is of the body, and controls movement of torso, head, and limbs. Nerves that control skeletal muscles
Autonomic division in nervous system?
Controls the more automatic functions of the body
In the automatic division there are parasympathetic and sympathetic nervous systems. Compare the two
Sympathetic - excitatory system. Increases heart rate and breathing. Can be nervous/frightened
Parasympathetic - calms heart rate, helps with recovery. Become sexually aroused
In the brain, what are the medulla and pons’ function?
Sustaining basic life functions.
Specific function of the pons
Helps regulate arousal (excitement/energy) and serve as bridge for tracts from upper brain to lower brain/spinal cord
What is the reticular activating system (RAS)?
Network of cells in pons and medulla regulating level of awareness and alertness in humans
What is the main role of the prefrontal cortex?
Make decisions
Main role of limbic system?
Regulate emotions, endocrine activity, and forming emotional memories
Amygdala and its main function
More active when we are under threat, and activates fear response
Hippocampus and its main role
Neurons and glia that act as gateway for forming new memories
Cingulate Gyrus
Activates when we find something to be unpleasant or disgusting
What are the Basal Ganglia?
Interconnected groups of neurons near base of brain that help us learn movements and coordinate movement patterns
What are 3 neuronal circuits the basil ganglia consists of?
Dorsal striatum - close to neocortex playing a central role in coordinating movement (caudate nucleus and putamen)
Ventral Striatum - close to neocortex playing a central role in coordinating movement
(substantia nigra - dark substance sending inhibitory signals to thalamus to coordinate sensory info with motor plans)
and subthalamic nucleus (below the thalamus
Globus Pallidus - pale globe playing role of inhibiting circuits in thalamus to control how sensory info is coordinated with movement
What is the cerebellum?
Two-lobed (wrinkled) part of brain posterior to brainstem helping coordinate movements and problem-solving
3 major divisions of cerebellum
Spinocerebellar - match sensory input with moto plans to fine-tune movement patterns
Vestibulocerebellar - process info from inner ear to aid posture and balance
Cerebrocerebellar - manage connection with pons and thalamus to adjust timing and planning of movements
What kind of axons first synapse in the thalamus?
Spinal and cranial nerves that carry impulses from eyes, ears, skin, muscles, and joints
Humans and their neocortex’s vs that in animals
Humans have a thicker neocortex
3 distinct features of neocortex
Gyri (ridges), sulci (valleys), and fissures (space between lobes)
Remembering grandparent’s cooking smells when you see their house can be an example of activity in what area of the cortex?
Association cortex
What lobes are primarily responsible for decision making and movement?
Frontal lobes
What cortex receives input from all parts of the cerebral cortex?
Prefrontal cortex
vmPFC (ventromedial prefrontal cortex) vs DLPFC (dorsolateral prefrontal cortex)
Modulate behavior based on fear vs maintain info in our working memory and change how we do things depending on task we want to complete
What would happen if parietal lobes got damaged?
Not able to navigate space or misinterpret sensation from our left side.
What is the temporal lobe responsible for?
Memories
What is a lesion?
Area in the brain where neurons have died.
What is the Wernicke’s area?
Important area for processing language
5 parts of the forebrain
Amygdala
Cerebellum
Hypothalamus
Hippocampus
Thalamus
Damage to the basal ganglia (releases dopamine) causes Parkinson’s, what does that mean?
Uncontrollable movements (shaking, lack of balance etc.)
What divides the cerebrum into two parts?
Corpus callosum
What is Aphasia and its two types?
Damage to communication part of the brain.
Wernicke’s area - (temporal lobe) comprehensions of words, word salad
Broca’s area - production of words, can’t find words
What is Agnosia?
Can’t identify similar objects
Prosopagnosia?
Inability to identify faces
What is unilateral neglect syndrome?
Usually unaware of any problem.
Role of occipital lobes
Primarily concerned with processing light stimuli
In regards to the endocrine system, what does the hypothalamus do?
Regulates production of hormones by endocrine system, giving it an integral role in governing important bodily functions
What happens if one has chronic stress?
Neurons on the hypothalamus become active more often. Pituitary gland then tells the adrenal gland to produce more cortisol (stress hormone)
What decade was the staining method invented?
1990s by Martin Chalfie
Hans Berger in 1924 and his creation
EEG method allowing us to record directly from clusters of electrical activity in the brain.
Describe bottom-up processing
Neural process that starts with the physical message or sensations
Describe top-down processing
Occurs when you combine incoming neural messages with our understanding of the world to interpret info in such a way that has value.
What did the psychologist Gestalt believe?
Believed we are born with specific, predisposed, ways of organizing information so that it has utility
Figure-ground principle
Focusing on one input of information. Ex. Focusing on communicating with a person at a party with loud music in the background.
What are the 5 Gestalt principles of organization?
Proximity - objects grouped together
Similarity - physical similarities
Closure - people perceive whole objects even when part of that info in missing
Continuation - if lines cross over each other people still tend to see continuous flowing lines
Common fate - objects moving together will be grouped together
What percentage does the cortex play in the role of visual interpretation?
20%
What amount of electromagnetic radiation can the human eye perceive?
400-700 nm of light
What is accommodation in relation to the lens?
Process in which lens changes shape to bring objects into focus on the retina
Myopia vs. hyperopia
Nearsightedness vs farsightedness
What are photoreceptors?
Where light is transduced into cellular activity. Last time message is in the form of electromagnetic energy. After passing through this area the image will be composed of patterns of neural firing.
Two special kinds of photosensitive cells
Rods - responsive to low levels of light. Used for night vision. Found in periphery of retina
Cones - responsive to bright lighting conditions. Communicates info about acuity and color
How many layers of cells must light travel to to reach the photoreceptors?
7
Diffuse bipolar cells vs midget bipolar cells in the bipolar layer of retina
Receive signals from rods and send messages to large ganglion cells
VS
Receive signals and send messages to small ganglion cells
What is the optic chiasm?
X-shaped structure where optic nerves from each eye cross before the message is sent to the thalamus
Lateral Geniculate Nucleus (LGN) and its function
Organized into 6 sublayers of the thalamus that process and organizes visual organization
What is the visual striate cortex?
Location in occipital lobe where visual info is organized
Retinotopic Organization
Spatial organization of info stored in the retina as it is processed through the LGN and striate cortex
Who were Hubel and Wiesel (1962) and what did they discover?
They discovered feature detectors.
Simple cell - cells in VSC that respond to lines of specific orientation.
Complex Cell - Cells in VSC responding to lines of specific orientation that are in motion
Where does information gathered from the visual cortex go?
Down the ventral stream (WHAT stream) to temporal lobe, over to dorsal stream (WHERE stream) to parietal lobe.
Steps that allow the light/visual images to be processed?
Pt. 1 Light Waves
Pt. 2 Light enters through cornea to pupil, to retina, which is back of eye where photoreceptors are stored
Pt. 3 Photoreceptors are the rods and cones. When light hits these a signal is sent to the brain.
Pt. 4 Action potentials are sent along optic nerve where they cross at the optic chiasm
Pt. 5 Info sent into the LGN and processed in its 6 sublayers
Pt. 6 Info then sent to VSC and retinotopically organized in patter we experience info
Different wavelengths and their colours
Long (L cone) - red
Medium (M cone) - greens
Short (S cone) - blues
What is the fovea?
Portion of retina directly behind the pupil. Contains large concentration of cones and no rods.
Describe the Trichromatic Theory
Proposes that color info is identified by comparing activation of different cones
What is it called when cells respond equally to 2 photopigments and the brain can’t differentiate between them?
Color blindness
What are the 2 kinds of depth cues?
Monocular and Binocular (comparing images from both eyes) Depth Cues
List the 6 types of monocular depth cues
Occlusion - image partially blocking other image
Relative Height - objects closer to horizon appear farther away
Relative size - two equal sized objects, one is farther away so will take up a smaller portion in retina
Perspective Convergence - parallel lines move into distance and seem to converge together
Familiar Size - we judge distance based on our knowledge of that object’s size
Atmospheric Perspective - objects appear hazy and have a blue tint.
List the 6 types of monocular depth cues
Occlusion - image partially blocking other image
Relative Height - objects closer to horizon appear farther away
Relative size - two equal sized objects, one is farther away so will take up a smaller portion in retina
Perspective Convergence - parallel lines move into distance and seem to converge together
Familiar Size - we judge distance based on our knowledge of that object’s size
Atmospheric Perspective - objects appear hazy and have a blue tint.
Limit for decibels and damage to human ears
100 dB
Describe the process of sound entering the ear
- Enters through the pinna and filters sound towards the tympanic membrane (eardrum).
- Energy is transferred to 3 smallest bones of body, the ossicles (malleus, incus, and stapes)
- Stapes is connected to oval window which transfers the vibrations to bony sound process, the cochlea.
- There it is transferred into neural language the brain can understand
Term for tissue inside the cochlea where hair cells are located
Basilar membrane
When does transduction occur?
Vibrations against oval window cause fluid inside cochlea to move
Place theory VS Frequency Theory
Understand pitch because of LOCATION VS RATE of cellular firing on the basilar membrane
Where are components of sound organized?
Medial Geniculate nucleus of thalamus
Tonotopic organization
Spatial organization of basilar membrane maintained through auditory pathway
Process of sound through the Auditory Pathway
Pt. 1 Funnel sound waves to middle ear. From outer ear to pinna into ear canal
Pt. 2 Sound goes into tympanic membrane into the ossicles (malleus, incus, stapes). Stapes connects to oval window which connects to inner ear.
Pt. 3 Pressures of vibrations of oval window cause fluid of inner ear to move (in cochlea). In the cochlea the hair cells in the basilar membrane move and is recorded to be sent to the brain
Pt. 4 In the auditory cortex is the primary sensory processing area in the brain
3 ways to help localize sound
Binaural cues - requires comparison between info from both ears
Interaural time differences - arrival of time of sound in each ear
Interaural level differences - sound wave is loud in one ear but get less intense as it is absorbed in the other ear
What are the 3 basic components of production of speech?
Respiration from lungs, vocal chords, and vocal tract
How many sounds do we produce a second in casual speech?
10-15 seconds
What is the olfactory mucosa and what does it contain?
Nostrils with the cilia hair cells. It contains olfactory receptor neurons
Where do the ORNs send signals to?
Glomeruli in the olfactory bulb
Papillae definition
Little bumps on our tongue (tastebuds)
5 basic tastes we use in conjunction with smell to evaluate food.
Sweet, salty, bitter, sour, umami
4 categories of papillae
- Filiform - over entire surface of tongue
- Fungiform - look like little mushrooms
- Foliate - little folds
- Circumvallate - back of tongue in little mounds.
What does the orbitofrontal cortex do?
Region of brain that analyzes both taste and smell
Location in the frontal lobe where touch and motion are processed
Somatosensory cortex
Mechanoreceptors
Receptors in the skin that sense different kinds of pressure
What are Merkel receptors?
Fire continuously as long as skin is making contact with an object.
What are Meissner corpuscle receptors?
Fire when skin first encounters the stimulus and when it is removed
Ruffini Cylinder vs Pacinian Corpuscle
Interprets stretching of the skin VS feels vibrations and texture
What is sensory homunculus?
Visual depiction of what our bodies would look like if they were built in proportion to their representation on the cortex.
Nociceptors
Detect pain and send a signal to our brains
Gate- control theory of pain (Melzack and Wall 1965-95
Suggest impulses that indicate painful stimuli can be blocked in the spinal cord by signals sent from brain
Process of receiving pain signals
Small fibers (S-fibers) fire to painful stimuli. Transmission cell (T-cell) activate in response to S-fibers. Intensity depends on the T-cell. Large fibers (L-fibers) send signals to the brain that are NOT painful, inhibiting the activation of T-cells. Decreasing perception of pain
Congenital Analgesia
Rare conditions where someone is unable to experience pain
Kinesthetic vs Vestibular Sense
Spatial awareness and how to move accordingly VS sense of balance from the vestibular sacs
Structures in the inner ear that sense changes in acceleration and rotation of the head.
Semicircular Canals
Absolute vs Difference Threshold
Level of intensity required to create a conscious experience 50% of the time VS smallest amount a particular stimulus required for a difference in magnitude to be detected.
