Physiology Flashcards
Areas associated with the production of voluntary motion: (3)
- Primary motor cortex (precentral gyrus)
- Supplementary motor cortex
- Pre-motor cortex
Additionally, parts of the pre-frontal cortex and the parietal cortex contribute to voluntary motion as well.
A dorsal pathway leaving the occipital cortex and going to the parietal/frontal cortex enables us to:
Complete motor acts based on visual input.
This path allows you to play catch with your friends…
The ventral pathway relays info to the inferior temporal cortex and allows us to:
Process the visual image so that we can copy it if needed and name/recognize it.
Similar or related objects are all coded for in localized regions of the temporal lobe. There is a specialized area for recognizing faces.
When reaching for an object, there are 2 pathways:
Pathway 1: Where the object is located in space.
Pathway 2: Mapping the location of your arms in relation to the object.
Pathway 1
- Multiple areas within the parietal cortex receive the input from the occipital cortex: (4)
- End result:
- V6A
- PEc
- MIP (medial intraparietal area)
- VIP (ventral intraparietal area)
End result: The VIP creates a rough map of the space around you.
Pathway 1
- From the VIP (ventral intraparietal area), the info is sent to:
- End result:
F4 within the premotor cortex.
End result: F4 creates a detailed map of the space around you. Neurons here are particularly excited by proximity.
Pathway 2
- Within the parietal cortex, the initial processing is the same regions (V6A, PEc, AIP), but the info is instead sent to:
- End result:
F2 within the premotor cortex.
End result: F2 constructs a map similar to what we saw in F4, but it contains info about where you are in space.
To grasp an object, visual information is relayed to an area of the parietal cortex that is lateral to what was involved in creating the map of space when reaching for an object. This area is called the: (2)
- Anterior intraparietal area (AIP)
- PFG (parts of the inferior parietal cortex)
The AIP and PFG contain 3 sets of neurons:
- Visually dominant neurons fire when you see an object to grasp.
- Motor dominant neurons fire when grasping an object.
- Visuomotor neurons fire during either condition.
Unlike what we saw when reaching, the object has to be within your reach (not just any graspable object).
The AIP and PFG relay their info to:
What do these neurons encode?
F5 (premotor cortex area)
Encodes the GOAL of the action.
Neurons in F5 (premotor cortex) are involved in determining the ______ of the motor act
Intent
ANY motor action with the same intent activates the F5 neurons REGARDLESS of the physical specifics of the act (grasping top edge of cup vs. handle).
Premotor Cortex
Role of the ventral (lateral) regions (F4 and F5):
Integrate the sensory information required to complete the motion
Premotor Cortex
Role of the dorsal (medial) regions: (3)
- Determine whether it is appropriate to move.
- Identifies the intent of the motion.
- Determines what motion to produce.
2 divisions of the Supplementary motor cortex:
What is the role of each?
- Supplementary Motor Area (SMA) - postural control, multi-joint movements
- Pre-supplementary Motor Area (Pre-SMA) - plans complex motor actions.. active with the thought of motion, NOT with the actual motion
The Supplementary Motor Cortex has 3 main roles:
- Organize motor sequences
- Acquire motor skills
- Executive control (particularly the decision to switch actions/strategies)
Location of the primary motor cortex:
Precentral gyrus
T/F: Regions which do things requiring fine control have the most representation within each of these areas of the primary motor cortex (e.g., fingers, tongue).
TRUE
Cells in the primary motor cortex (precentral gyrus) are arranged in _______, and stimulation produces a ________ ________.
- column
- specific movement
T/F: If we’re in an area that controls a more general motion, stimulation may produce contraction of a GROUP of muscles (e.g., in your back).
TRUE
Only output is via _________ cells - located in one layer of the column (where the pyramidal tract gets its name).
-pyramidal
Layer _ receives sensory (afferent) input (muscle and joint proprioceptors, etc).
Layer 4
Layer _ becomes the output for the corticospinal (pyramidal) tract via pyramidal cells.
Layer 5
T/F: Compared to the sensory cortex, motor cortex has expanded layer 5 and compressed layers 2, 3, and 4.
TRUE
There appears to be 2 sets of neurons in each column:
- One set STARTS the movement
- The other set MAINTAINS the movement
There are also 2 types of columns:
- One supports the onset and offset of motion in the agonist muscle
- The other set supports the onset and offset of motion in the antagonist muscle
T/F: Neighboring columns control related motions, NOT neighboring muscles.
TRUE
Roles of the cerebellum: (4)
- Sequence complex actions
- Correct force/direction
- Balance and eye movements
- Learning of complex actions
Functional divisions of the cerebellum: (3)
- Spinocerebellum
- Cerebrocerebellum
- Vestibulocerebellum
2 regions of the spinocerebellum and their roles:
- Central - postural control
- Either side of the vermis - force and direction
Roles of the cerebrocerebellum (lateral regions of cerebellum): (2)
- Plan complex motions
- Sequence motions
Roles of vestibulocerebellum: (2)
- Balance and eye movements
- Being planned in the future, not necessarily what’s happening at that moment
Outputs from cerebellum are via the ____ __________ ______.
-deep cerebellar nuclei
Deep cerebellar nuclei: (4)
- Dentate nucleus
- Fastigial nucleus
- Globose
- Emboliformis
Note: The globose and emboliformis nuclei are sometimes lumped together as the ____________ nucleus.
-interpositus
Job of Vermis (spinocerebellum):
Control of axial musculature and posture
Inputs to Vermis (spinocerebellum): (3)
- Vestibular
- Visual and auditory
- Efferent copy (what the motor neurons are telling the muscle to do)
Outputs from Vermis (spinocerebellum): (3)
- Interpositus
- Fastigial nucleus
- To Rubrospinal tract via red nucleus
Functions of spinocerebellum (region lateral to the vermis): (2)
- Control of the force and direction of motion… if damaged, intention tremor will result
- Controlling ballistic movements
Inputs to spinocerebellum: (2)
- Efferent copy (what brain thinks is happening) via the ventral spinocerebellar tract
- Muscle afferents* (muscle spindle, Golgi tendon, etc…) via the dorsal spinocerebellar tract
Outputs from spinocerebellum: (3)
- Interpositus (Globose and Emboliformis)
- To rubrospinal tract
Functions of the cerebrocerebellum: (2)
Sequencing - especially of rapid learned movements (playing the piano)
- Planning the sequence
- The timing of the movements within the sequence
T/F: The neurons of the cerebrocerebellum are concerned with what WILL be happening, NOT what IS happening.
TRUE
Inputs to cerebrocerebellum: (1+)
Cerebral cortex (all)
- Primary motor area
- Premotor area
- Supplementary motor cortex
- Somatosensory
Outputs from cerebrocerebellum: (2)
- Dentate
- back to cortex through the ventral lateral nucleus of the thalamus
Function of vestibulocerebellum (flocculonodular region):
-Controls eye movement and balance, particularly in future*
Effect of lesions on vestibulocerebellum…
At rest:
In motion:
At rest: balance well
In motion: have trouble maintaining balance
Input to vestibulocerebellum:
Vestibular apparatus (direct or indirect) CN VIII (vestibulocochlear N.)
Output from vestibulocerebellum:
Fastigial nucleus to Vestibular nuclei to either ascending or descending tracts
Together, the putamen and the caudate nucleus are called the ________.
striatum (also includes the accumbens, but it’s not involved in motor control)
The ________ receives the inputs to the basal ganglia.
striatum
The nucleus within the striatum that is most heavily involved in motor control:
Putamen
Nigrostriatal dopaminergic system
From:
To:
Effects:
From: substantia nigra pars compacta (SNPC)
To: striatum
Effects: D1 (+), D2 (–)
Intrastriatal cholinergic system Location: From: To: Effect:
Location: between nuclei of the striatum
From: neurons of striatum
To: synapse on other neurons of striatum
Effect: excitatory
Striatonigral GABA-ergic pathway "The Direct Pathway" From: To: (2) Effect: Leads to:
From: striatum (putamen + caudate nucleus)
To: substantia nigra pars reticularis (SNPR) and internal segment of globus pallidus (GPi)
Effect: inhibitory
Leads to: initiation of movement
Information leaves the basal ganglia via the ____ and ___.
- SNPR
- GPi
The SNPR and GPi axons project to the ________ and release ____.
- thalamus
- GABA
Nuclei of basal ganglia: (4)
- Substantia nigra (pars compacta & pars reticulata)
- Striatum (caudate and putamen)
- Globus pallidus (internal/external segments)
- Subthalamic nucleus
Neurotransmitter systems of the basal ganglia: (3)
- Dopamine
- Cholinergic
- GABA-ergic
Inputs into basal ganglia received by: (1)
Outputs sent to: (2)
Inputs: substantia nigra pars compacta relays to striatum
Outputs: globus pallidus (internal segment) and substantia nigra pars reticulata send axons to thalamus
-When activated, release GABA at synapses in thalamus… inhibition of thalamus
Basal ganglia
What they do:
How:
What they do: control beginning and the end of the movement
How: inhibition and disinhibition (withdrawal of that inhibition)
-Major dz’s of basal ganglia cause their symptoms by either removing this inhibition (Huntington’s Chorea) or by removing the brakes on the inhibition (Parkinson dz)
The inputs into the striatum include: (6)
- Cortex (all) - via corticostriate track by using EAA
- Centromedian nucleus of thalamus - EAA
- Pars compacta of substantia nigra (SNPC) - dopaminergic input, tonically active**, provides background excitation to striatum
- Within caudate and putamen- two diff sets of neurons
- The Direct Path: direct connection to output nuclei of basal ganglia, D1 receptors, input from SNPC is excitatory
- The Indirect Path: connect indirectly to output nuclei of basal ganglia, D2 receptors, input from SNPC is inhibitory*
“The Direct Pathway”
- To activate, ____ sends dopamine to striatum.
- Dopamine binds (D1/D2) receptors.
- Axons release ____ in GPi and SNPR.
- By inhibiting the SNPR and GPi, (more/less) GABA is released in the thalamus. The thalamus is then free to excite the cortex, allowing the initiation of movement.
- SNPC
- D1 receptors
- GABA
- LESS GABA in thalamus… allows movement
“The Indirect Pathway”
Input from the SNPC is (excitatory/inhibitory) to the striatal neurons that are part of the indirect pathway due to the (D1/D2) receptors
- inhibitory
- D2
T/F: To ACTIVATE the indirect pathway, we must use input from the cortex and the intrastriatal pathway.
TRUE
“The Indirect Pathway”
The striatal neurons synapse on the ___ (GABA) - by activating the striatal neurons, we release (more/less) GABA. Activity in the GPe is (increased/decreased)
- GPe
- MORE
- decreased
“The Indirect Pathway”
The neurons of the GPe synapse in the ___________ _______. Since GPe neurons are less active, there is (more/less) inhibition of the subthalamic nucleus.
- subthalamic nucleus
- LESS inhibition (disinhibition)
“The Indirect Pathway”
Neurons from the subthalamic nucleus synapse in the ____. Since they’re active (less inhibited), (more/less) EAA are released in the SNPR.
- SNPR
- MORE EAA released
The effect of the direct pathway is to:
INHIBIT the neurons in the GPi and SNPR
The effect of the indirect pathway is to:
EXCITE the neurons of the GPi and SNPR
The limbic system is now recognized to control: (2)
- Emotional behavior
- Motivational drives
Anatomy of the limbic system: (7)
- Hypothalamus
- Paraolfactory areas
- Thalamus
- Basal ganglia
- Hippocampus
- Amygdala
- Limbic cortex
- Key player
- Emotional experience
- Physiological responses* (connection to ANS)
Hypothalamus
- Relay sensory info for emotional processing
- Anterior nucleus of ________ - Role in Papez circuit
Thalamus
- Nucleus accumbens - role in pleasure
- Putamen - role in disgust
Basal ganglia
- Role in learning/memory
- Part of Papez circuit (probably tied to memory)
Hippocampus
-Long recognized for its role in creating emotion, particularly fear
Amygdala
- Mostly paleocortex - 3 cell layers, some parts have 6 cell layers
- *Many of the neurons show after-discharge - allows for persistence of emotion
Limbic (cingulate) cortex
- Postulates a single anatomical substrate that encodes all emotional functioning
- Allows for separation of perception/expression of emotion as distinct from the experience of the emotion
- E.g., Papez circuit
Model #1: Single System
- All emotions are generated/experienced as opposing pairs (happy vs. sad; anger vs placid)
- Often hemispheric (L vs R) to give the opposing emotion
- Same anatomical substrate used on both sides
Model #2: Dual System
- Uses interoceptors* to detect internal environment
- Input of the interoceptors to the limbic system
- Info sent to limbic system (hypothalamus?)
- Emotional interpretation base on these inputs
Model #3: Physiological responses as emotion
- Postulates certain “basic” emotions that are common across cultures/species (fear, anger, disgust, happiness, sadness)
- Each of these is controlled by separate* neural substrates that are then integrated by other parts of the limbic system and interpreted as emotion
Model #4: Multi-System
The Papez Circuit:
- Sensory info / emotional stimulus…
- ________…
- ____________ and ______
The Papez Circuit:
- Sensory info / emotional stimulus…
- Thalamus…
- Hypothalamus and cortex
In the Papez Circuit, where does the info go from the hypothalamus? (3)
-Anterior thalamus… Cingulate cortex… Hippocampus… then back to Hypothalamus
In the Papez Circuit, where does the info go from the cortex? (3)
-Standard sensory processing, then to the appropriate association cortex, then to anterior cingulate cortex
One of the major roles of the hypothalamus in Papez circuit is to:
Control autonomic outflow, particularly balance between parasymp and sympathetic
-Crucial for generating the physiological response* of the emotions- changes in heart rate, blood flow, blood pressure…
In Papez circuit:
- Controls sensory inputs to cortex
- Provide the sensory input with access to emotion circuits
Thalamus
Cingulate cortex role in the Papez circuit:
To coordinate and interpret* the inputs from the other parts of the circuit
Role of hippocampus in the Papez circuit:
Creation of memories of that emotional event (highly emotional events are highly memorable)
Important consideration from lecture: READ BACK
Regardless of which theory “works,” it appears that the neural circuits for recognizing emotion in others are also involved in producing that emotion in ourselves.
-E.g., If a psych pt cannot recognize disgust, he/she cannot be disgusted.
TQ:
Describe the mirror neuron system.
These neurons fire when you do something (smile) and when you see someone else do that same action.
-Give us the ability to identify emotions in other people’s face
Two kinds of fear:
- Innate (unconditioned)
- Learned (conditioned)
- Fear that requires no experience
- In animals, associated with olfactory cues*
Innate (unconditioned) fears
- Learned from experience
- In humans, the experience can be indirect* (watching someone else experience a frightening thing)
Learned (conditioned)
- Processing and recognition of social cues related to fear
- Emotional conditioning in response to fear
- Memory
Amygdala
Emotional conditioning in response to fear… 2 pathways:
- Direct thalamo-amygdaloid (early response)
- Indirect thalamo-cortical-amygdaloid (late responses)
Learned (conditioned) fear input arrives at the:
Lateral nucleus of the amygdala
Role of the lateral nucleus of the amygdala:
Integrates the inputs (e.g., the pairing of sound and an electric shock)
-Makes it a single event
The paired information from the lateral nucleus of the amygdala is then sent to the:
Basal and intercalated nuclei of the amygdala for additional processing.
Information from the lateral, basal, and intercalated nuclei is sent to the:
Central nucleus of the amygdala
Which decides what responses are required and relays info appropriately
Hypothalamus
-Generates physiological responses
In the individual with damage to the amygdala, fear (is/is NOT) perceived, therefore conditioning related to fear (does/does NOT) occur.
In the individual with damage to the amygdala, fear is NOT perceived, therefore conditioning related to fear does NOT occur.
Anatomical substrate: lower sector of the anterior cingulate cortex*
Sadness
Anatomical substrate:
- Lateral portion of posterior hypothalamus
- Dorsal midbrain
- Entorhinal cortex
Avoidance
short term vs. long term differences
- Anatomical substrate: insular cortex / putamen
- Damage (including Huntington’s dz) abolishes**
Disgust
- Anatomical substrate: amygdala
- Requires dopaminergic input acting at D2 receptors*
Anger / Rage
Inhibition of anger/rage requires: (3)
- Neocortex
- Ventromedial hypothalamic nuclei
- Septal nuclei
Anterior cingulate cortex functionally divided into 2 regions:
- Ventral - affective
- Dorsal - cognitive
Roles of anterior cingulate cortex (ventral division) in emotion: (3)
Ventral division:
- Integration of visceral, attentional, and emotional input
- Regulation of affect ** - particularly top-down control (“controlling our emotions”)
- Conflict detection - what new info has the power to change how I’m feeling
The pre-frontal cortex has two divisions:
- Ventromedial prefrontal cortex (receives input from amygdala, hippocampus, temporal visual association area, dorsolateral prefrontal cortex (the other division))
- Dorsolateral prefrontal cortex (receives input from motor area, including basal ganglia, pre- and supplementary motor cortex; cingulate cortex and performance monitoring; several cortical association areas)
Three roles of pre-frontal (ventromedial division) cortex:
Ventromedial division:
- Reward processing (orbitofrontal)
- Integration of bodily signals (ventromedial prefrontal cortex) - the “gut feeling”
- Top-down regulation (with anterior cingulate) - esp towards delayed gratification
The ventral tegmental area (VTA) receives excitatory input from: (3)
- Lateral hypothalamus (orexin)
- Prefrontal cortex (EAA)
- Laterodorsal tegmental nucleus (ACh)
Excitatory inputs into the nucleus accumbens (NAc) include: (3)
- Medial prefrontal cortex (EAA)
- Amygdala (EAA)
- Hippocampus (EAA)
In order to produce pleasure, we must (activate/inhibit) VTA, (activate/inhibit) NAc, and (incr/decr) GABA in the prefrontal cortex.
In order to produce pleasure, we must ACTIVATE VTA, INHIBIT NAc, and DECREASE GABA in the prefrontal cortex.
In order to inhibit pleasure, we (activate/inhibit) NAc, and (incr/decr) GABA in the prefrontal cortex.
In order to inhibit pleasure, we ACTIVATE NAc, and INCREASE GABA in the prefrontal cortex.
Opioid inputs into the VTA inhibit GABA interneurons, which have what effect on dopamine levels in the nucleus accumbens?
Inhibiting GABA interneurons in the VTA will increase dopamine in the NAc.
What makes drugs most addictive in terms of their action on the nucleus accumbens?
The most addictive drugs turn on the dopaminergic input to the nucleus accumbens or replicate its effects.
Drugs that activate G protein coupled receptors: (2)
- Opiates (Gi subtype)
- Cannabis - CB1/CB2 - anandamide ligand
Drugs that act on ligand-gated channels: (4)
- Benzodiazepines (GABA(A), also reduces action of EAA at non-NMDA receptors)
- Nicotine (agonist at nicotinic ACh receptors, opens Na+ channel)
- PCP (antagonist at NMDA receptors, blocks Ca++ channel)
- Ethanol (incr GABA receptor function, decr NMDA receptor function)
Drugs that impact re-uptake mechanisms: (3)
- Cocaine (inhibits dopamine re-uptake mechs)
- Amphetamines (reverse transport of dopamine)
- Ecstasy (dopamine leaves neuron)
Effect of drugs in the pleasure/reward systems: Opiates: Cocaine: Amphetamines: Nicotine: Cannabinoids *PCP: Ethanol:
Opiates: activate opiate systems
Cocaine: increases amt of dopamine present at synapses in the nucleus accumbens (incr VTA dopaminergic neurons)
Amphetamines: (same as above)
Nicotine: activates nicotinic AChR on VTA neurons»_space; increases dopamine release
Cannabinoids: act directly on CB1 receptors in NAc
PCP: disrupt EAA inputs to the NAc
Ethanol: activate opioid inputs to the VTA and NAc, disrupt EAA inputs to the NAc…same as PCP
All lead to sensation of euphoria in the individual taking the drug.
The effect of dopamine release is to (incr/decr) GABA release in the prefrontal cortex, allowing reward pathways to be active.
Increase dopamine release from the VTA»_space;
Decreased GABA release from NAc onto prefrontal cortex»_space;
Sensation of pleasure
Opioids function to (incr/decr) dopamine release from the VTA. What does this lead to?
Opioids function to INCREASE dopamine release from the VTA»_space;
Increased dopamine in NAc»_space;
Decreased GABA in NAc»_space;
Pleasure
A series of changes in the pre-and post-synaptic neurons of a synapse, which leads to increased response to the released NT.
- Increase in response must last for hours after stimulation
- Change gene transcription / translation
- Permanently alters synaptic structure
This is known as:
Long-term potentiation
Changes in the anatomy and physiology of synapses assoc w/ learning.
This is known as:
Synaptic plasticity
By increasing the action of dopamine in the NAc, ________ is produced.
By increasing the action of dopamine in the NAc, EUPHORIA is produced.
____ ____ ____________ has been demonstrated in VTA dopaminergic neurons in response to cocaine and nicotine.
LONG TERM POTENTIATION has been demonstrated in VTA dopaminergic neurons in response to cocaine and nicotine.
One major thing that occurs as a result of long-term changes in neurons from addictive drugs is the induction of:
CREB
cAMP response element binding protein
What does CREB do to produce effects of drugs?
CREB increases the production of dynorphin (opioid, binds to kappa receptors) within the NAc.
The NAc also send GABAnergic and dynorphin-ergic input back to the VTA. What is the effect of this?
The increase in dynorphin release from the NAc turns off the input from the VTA, reducing the effect of the drugs. Part of the desensitization process that occurs with drug addiction.
Activation of CREB within the _____ ________ and the ______________ ____ are assoc with what?
Activation of CREB within the LOCUS CERULEUS and the PERIAQUEDUCTAL GREY is assoc with PHYSICAL DEPENDENCE on the drugs.
- A long term response to drug addiction (longer than CREB)
- Also a regulator of transcription
delta-FosB
What is the role of delta-FosB and where does it act?
Role: leads to production of proteins that are responsible for the remodeling of the dendrites that occurs with addiction
Location: NAc
Role of outer ear in hearing:
Funnel the sound waves into ear
Role of middle ear in hearing:
Impedance matching – the sound wave has been moving through air, but now it moves in liquid/water
Role of inner ear in hearing:
Cochlea* converts the sound waves into action potentials
The scala vestibuli and the scala tympani are continuous, fluid-filled compartments. The fluid inside is _________.
The scala vestibuli and the scala tympani are continuous, fluid-filled compartments. The fluid inside is PERILYMPH.
Perilymph is most similar to ECF in terms of ion balance. What is expected in terms of Na+ and K+?
High Na+
Low K+
The scala media (between the scala vestibuli and scala tympani) is created by what 2 membranes?
- Reissner’s membrane (top)
- Basilar membrane (bottom)
The fluid inside the scala media is _________.
The fluid inside the scala media is ENDOLYMPH.
Contrary to the ion balance in perilymph, endolymph is most similar to ICF. What is the ion balance in endolymph?
Low Na+
High K+
(Most similar to ICF***)
*The composition of endolymph has a significant effect on the transduction of sound waves into APs
The ________ transmit and amplify the sound waves from the tympanic membrane to the oval window of the cochlea.
The OSSICLES transmit and amplify the sound waves from the tympanic membrane to the oval window of the cochlea.
In the inner ear, the impact of the stapes on the oval window causes:
The basilar membrane to vibrate at the same frequency of the sound.
HIGH frequency (short wavelength) sounds cause the maximum vibration of the basilar membrane where on the cochlea with respect to the oval window?
Closest to the oval window
near the base of the basilar membrane
LOW frequency (long wavelength) sounds cause the maximum vibration of the basilar membrane where on the cochlea with respect to the oval window?
Farthest away from the oval window
towards the helicotrema, at the tip of the basilar membrane
Each hair cell involved in hearing is composed of a distinct arrangement of shorter ___________ that increase in length.
Each hair cell involved in hearing is composed of a distinct arrangement of shorter STEREOCILIA that increase in length. (These are not true cilia.)
Each stereocilia is connected to another at the top by an extracellular filamentous protein. This protein filament is known as the ___ ____.
Each stereocilia is connected to another at the top by an extracellular filamentous protein. This protein filament is known as the TIP LINK.
During development there’s a single true cilium called the __________.
During development there’s a single true cilium called the KINOCILIUM.
-The kinocilium is the tallest of the ‘hairs’ on the hair cell. Degenerates beginning around the time of birth, i.e., not a crucial part of the transduction mechanism
When sound causes the basilar membrane to vibrate, the connections between the basilar membrane and the tectorial membrane cause the tectorial membrane to:
Move!
As a result of the movement of the tectorial membrane, what happens to the hair cells?
The hair cells bend!
If the stereocilia are bent towards where the kinocilium used to be, the hair cell (depolarizes/hyperpolarizes). What kind of channels open?
If the stereocilia are bent towards where the kinocilium used to be, the hair cell DEPOLARIZES.
K+ channels open»_space; depolarization
If the stereocilia are bent away from where the kinocilium used to be, the hair cell (depolarizes/hyperpolarizes).
If the stereocilia are bent away from where the kinocilium used to be, the hair cell HYPERPOLARIZES.
Due to the composition of the endolymph, K+ (enters/leaves) the hair cells and cause it to depolarize. Ca++ is also involved.
Due to the composition of the endolymph, K+ ENTERS the hair cells and cause it to depolarize. Ca++ is also involved.
2 parallel paths in the cochlear nucleus and their roles:
- Ventral path: starts processing of temporal and spectral features of the sound
- Dorsal path: integrates the acoustic info with somatosensory information for localizing the sound
The MEDIAL superior olive generates a map of the intra-aural ____ differences (how the sound arrived at the two ears differently…)
The MEDIAL superior olive generates a map of the intra-aural TIME differences (how the sound arrived at the two ears differently…)
The LATERAL superior olive generates a map of the intra-aural _________ differences (how the sound arrived at the two ears differently…)
The LATERAL superior olive generates a map of the intra-aural INTENSITY differences (how the sound arrived at the two ears differently…)
The ____ and _________ differences are crucial info in determining where a sound originated from.
The TIME and INTENSITY differences are crucial info in determining where a sound originated from.
The inferior colliculus suppresses info related to ______ (they interfere with location) and arrives at a final estimation of the sound location on the horizon.
The inferior colliculus suppresses info related to ECHOES (they interfere with location) and arrives at a final estimation of the sound location on the horizon.
The superior colliculus takes the location data from the inferior colliculus and adds ________ ______ to create the spatial map of the sounds location.
The superior colliculus takes the location data from the inferior colliculus and adds VERTICAL HEIGHT to create the spatial map of the sounds location.
The primary auditory cortex (A1) has a tonotopic representation of the sounds — more rostral areas are activated by (high/low) frequencies, while caudal areas receive info about (high/low) frequencies.
Rostral areas activated by LOW frequency sounds.
Caudal areas activated by HIGH frequency sounds.
- Processing of complex sounds (e.g., music)
- Identification of sound (naming)
- Speech
Auditory Association Cortex
______ acceleration is motion that occurs in either the horizontal or vertical plane.
LINEAR acceleration is motion that occurs in either the horizontal or vertical plane.
_______ acceleration requires rotation around one or more planes.
ANGULAR acceleration requires rotation around one or more planes.
Acceleration in these different planes is detected by the ____________ ______ (anterior, horizontal, and posterior), the _______, and the _______.
Acceleration in these different planes is detected by the SEMICIRCULAR CANALS, the UTRICLE, and the SACCULE.
Just like in the cochlea, _________ (high K+) is inside the semicircular canals, the utricle, and the saccule. _________ surrounds the vestibular apparatus.
Just like in the cochlea, ENDOLYMPH (high K+) is inside the semicircular canals, the utricle, and the saccule. PERILYMPH surrounds the vestibular apparatus.
The _______ is best situated to detect LINEAR MOTION occurring on the HORIZONTAL PLANE.
The UTRICLE is best situated to detect LINEAR MOTION occurring on the HORIZONTAL PLANE.
The _______ is best positioned for vertical (up and down) accelerations.
The SACCULE is best positioned for vertical (up and down) accelerations.
The turning (spinning) motion is best detected by the __________ (aka lateral) canals…
The turning motion is best detected by the HORIZONTAL (aka lateral) canals…
Falling (or being thrown backwards) maximally activates the _________ semicircular canal.
Falling (or being thrown backwards) maximally activates the POSTERIOR semicircular canal.
Falling FORWARDS maximally activated the ________ semicircular canal.
Falling FORWARDS maximally activated the ANTERIOR semicircular canal.
The process of activating the different vestibular organs is similar to what we saw in the cochlea – movement of hair cells in one direction is excitatory, movement in the opposite direction is inhibitory. In the SEMICIRCULAR CANAL, the _______ is specialized for this process.
The process of activating the different vestibular organs is similar to what we saw in the cochlea – movement of hair cells in one direction is excitatory, movement in the opposite direction is inhibitory. In the SEMICIRCULAR CANAL, the AMPULLA is specialized for this process.
The process of activating the different vestibular organs is similar to what we saw in the cochlea – movement of hair cells in one direction is excitatory, movement in the opposite direction is inhibitory. In the UTRICLE and SACCULE (the otolith organs), the ______ is specialized for this purpose.
The process of activating the different vestibular organs is similar to what we saw in the cochlea – movement of hair cells in one direction is excitatory, movement in the opposite direction is inhibitory. In the UTRICLE and SACCULE (the otolith organs), the MACULA is specialized for this purpose.
What is the process in all cases of motion? (3)
Motion moves endolymph»_space;
Bending of the hair cells»_space;
Initiation of APs
If I fall forward, my eyes move (up/down).
If I fall backwards, my eyes move (up/down).
If I fall forward, my eyes move UP.
If I fall backwards, my eyes move DOWN.
If the anterior semicircular canal is active (falling forward), which muscle in the eye is activated and which is inhibited?
Fall forward:
- Anterior semicircular canal activated
- Eyes move UP
- Superior rectus muscle activated
- Inferior rectus muscle inhibited
If the posterior semicircular canal is active (falling backwards), which muscle in the eye is activated and which is inhibited?
Fall backwards:
- Posterior semicircular canal activated
- Eyes move DOWN
- Superior oblique muscle activated
- Inferior oblique muscle inhibited
If the horizontal (lateral) semicircular canal is active, which muscle is activated and which is inhibited in the ipsilateral eye to the rotation? What about the contralateral eye?
Ipsilateral eye to rotation:
- Medial rectus muscle is activated
- Lateral rectus muscle is inhibited
Contralateral eye to rotation:
- Lateral rectus activated
- Medial rectus inhibited
The vast majority of the cortical and cerebellar involvement in the vestibulo-optic reflexes is to:
Suppress the reflex to allow for voluntary motion.
