NEUR2020 - QUIZ ONE

what is the orientation of the brain (above the brainstem)

1. dorsal → facing upwards (up axis at the top of our skull)

2. ventral → coming down (down axis towards our brain stem)

3. anterior → front forward where our face is

4. posterior → back backwards at the back of our skull

what is the orientation from the brainstem and below

1. anterior → up our body

2. posterior → down our body

3. ventral → coming out of our stomach

4. dorsal → going out our back

what is medial and lateral refer to

1. medial → things towards our midline (ie. our nose)

2. lateral → things for the outside (ie. our ears)

explain what we mean when we say we can use these orientations in a relative or absolute sense

our nose is medial in an absolute sense (it is actually in the middle of our face), but our eyes we would have to describe in a relative sense (ie. our eyes are lateral relative to our nose).

what is rostral and caudal

rostral (towards the head) and caudal (towards the tail)

what is proximal and distal

proximal (close to the main body mass) and distal(far from the main body mass)

according to a reference plane, what is the horizontal, frontal, and sagittal plane

• the horizontal plane → a flat line

• the frontal plane → goes down facing forward (like your face)

• sagittal plane → goes forward backwards (it cuts down like your praying)

what is an oblique plane and a cross section

• oblique plane → essentially any other odd direction that is not one of the main three planes

• cross section → a slice that runs orthogonal to the classic direction or movement of the structure (we don’t really get cross sections of the brain because there is not a typical direction of movement for the brain)

what are the two categories for research methods

1. structure → the structure of the brain (ie. what is the physical architecture that is in there). Tells us about the morphology or form of things (ie. CT scans)

2. function → what is the activity behind the skull, what is the brain actually doing (ie. EEG)

What does invasive mean in research methods

research methods can also be invasive (ie. puncture or incisions of the skin and denoting procedures or tests that require an insertion of an instrument into the body → single cell recordings and PET scans are an example) or non-invasive (ie. EEG) .

These can be both literal and also exist on a spectrum.

what does spatial (high or low )resolution mean

refers to the quality of the spacial information I get from the technique. How blurry or sharp is the measure is in space. How precisely can you determine where something is or occurred The more precise, higher the SR. Whether you need high or low SR is dependent on the question you are trying to determine.

Also how small a region in space can you resolve two locations, smaller the region higher the SR

what does temporal resolution (high or low) mean

how precise is my technique across time, can I narrow something down to a millisecond (ie. fMRI has low TR and EEG has high TR, and single cell recordings has super high TR). how blurry or sharp the measure is in time. How precisely can you determine when something happened, more precise higher TR

And also can be used to tell how small and interval of time 2 event occurred within each other, smaller the interval higher the TR).

what are behavioural response research methods

1. reaction times (ie. used with light detection)

2. detection thresholds (ie. used with sound)

3. stimulus discrimination

what is psychophysics

the scientific study of the relationship between stimuli (specified in physical terms) and the sensations and perceptions evoked by these stimuli. Commonly behavioural response research methods

what are some physiological response research methods

1. startle response (a reflex - ie. loud noise → blink) → this is a brainstem reflex for protection, an example of this is the fear-potentiated startle (when amplitude is increased when presented with a cue that has been previously paired with an aversive stimuli), this response measures fear conditioning

2. electrodermal activity (EDA) → you are measuring sympathetic nervous system activity. Called skin conductance responses (SCR) or galvanic skin response or electrodermal response (EDR). This is your flight or fight response. It acts as an index of autonomic activity (measure of emotional arousal). Skin momentarily becomes a better conductor.

3. pupilometry → expansion and dilation of the pupils can be used to measure sympathetic nervous system arousal

4. heart rate (and variability)

5. muscle tension

6. polygraph

what are damaging the brain studies

split into:

1. acquired brain injury

2. lesion studies

these studies are casual techniques

what are acquired brain injury studies

any brain damage after birth (ie. stroke, alcohol/drugs etc.)/ A good example of this is Patient Tan, he could only say ‘tan’. Autopsy revealed a large lesion in the posteriori inferior frontal gyrus (now known as Broca’s area which is linked to ability to express language)

what are lesion studies

removing or disabling a portion of the brain and observing the resulting behaviour (these are better than acquired brain injuries as you can choose which sections to look at).

Some neighbouring tissue lesions and functions are inadvertently attributed to the target structure that are actually carried out by the neighbouring tissue. Sometimes a portion remains as well as some function, making it inaccurate.

what are the three type of lesions

There are three types of lesions: Aspiration lesion (sucking up part of the brain with a needle tube), Radio frequency lesions (heat up a needle and burn tissue you don’t want), and knife cuts. Lesion studies are rarely administered with 100% accuracy.

what are some stimulating/disrupting activity methods

• these are causal methods and include:

1. tDCS

2. drug blocks

3. cryogenic block

4. TMS

explain tDCS

small current between anode (+) and cathode (-), transiently disrupt neural activity. Neurons under anode become depolarised (more likely to fire), neurons under cathode become hyper-polarised (less likely to fire). Changes in behavioural performance is generally; anodal improves, cathodal hinders.

explain drug blocks and cryogenic blocks

Drug blocks → injection of local anaesthetics (ie. WADA test used prior to ablative surgery, determine lateralisation of vital functions (ie. speech). Inject left or right internal carotid then assess.)

cryogenic block → Cryoprobe cools neurons near tip so they stop firing (virtual lesions). This is invasive. It looks like a metal rod.

explain TMS (Transcranial Magnetic Stimulation)

single magnetic pulses are applied to specific locations on the scalp at specific times during a behavioural task; or repetitively prior to task performance (rTMS used in clinics for depression and neuropathic pain). Magnetic activity causes neurons to fire → focal stimulation, cognitive or behavioural consequences are then observed. This permits causal inference about the necessity of a specific brain region for performing a given task.

There are two different effects you may have: stimulation effects (ie. motor or visual activation), disruption effects (synchronised discharge interferes with normal activity, timing is important here (ie. disrupt letter recognition).

what are recording associated activity methods

• provide correlational information, and include:

1. magneto-encephalography (MEG)

2. electro-encephalography (EEG)

what is MEG

measuring electric fields at the scalp. Electric currents generates small magnetic fields. Has a very high temporal resolution, relativity direct measure of activity. However, it is not good for subcortical (ie. brainstem), it is hard to model sources, and has very expensive equipment.

what is electro-encephalography (EEG)

electrical activity generates electric fields which can be measured. Scalp measures gross electrical activity of the brain. Sum of electrical events → action potentials, postsynaptic potentials, muscle activity etc. Measured electrical activity correlates with underlying neural activity.

what are the key waveforms in EEG

The idiosyncratic waveforms associated with different states of consciousness → relaxed (alpha, 8-12Hz), deep sleep (delta, <4Hz), focused (beta, 16-31 Hz).

what are Event related potentials (ERPS)

related to EEG, measuring the sum electrical activity. These are waveforms that accompany an event (onset of a stimulus or response - evoked). Time is locked to the event. Small signals embedded in noise - so average lots of trials to clean and extract signal. This is best for time course of events rather than location

Note that name peaks are based on polarity (N is negative and P is positive) → however N is up).

what are typical ERP peaks

1. sensory processes within less than 100 milliseconds (ms)

2. 100ms modulated by attention → N100 and P100 selective attention

3. N200 → mismatch negativity → stimulus physically deviates from previous (ie. cat cat cat dog cat cat)

4. P300 → attended stimulus appears (supposed to look for a black dot and it suddenly appears)

5. P400 → unexpected stimulus (surprise)

what are some advantages of EEG

1. high temporal resolution

2. measure of activity

3. no drugs, tracers etc. non invasive

4. relatively low cost

what are some disadvantages of EEG

1. low spatial resolution

2. poor activity for below superficial layers

3. low signal to noise and signals are easily contaminated → need lots of trials and lots of subjects, therefore it is time consuming

what are some brain imaging techniques

• provide correlational information and includes:

1. positron emission tomography (PET)

2. magnetic resonance imaging (MRI)

3. diffusion tensor imaging (DTI)

4. functional magnetic resonance imaging (fMRI)

what are PET scans

radioactive tracer coupled to biologically active molecule. Inject a radioactive isotope into the body and the isotope is taken up by active portions of the brain but not broken down (accumulates). Note, radioactivity is short lived (less than 3 hours commonly). PET scans measure metabolism because it looks at glucose intake by the brain with the radioisotope.

what is DTI

this is a variation of MRI. Measures density and motion of water molecules - restricted movement along axon fibres. Measures diffusion anisotropy.

what is MRI

hydrogen atoms line up in a strong magnetic field. We perturb atoms with a RF pulse, atoms return to lined up positions and emit EMR that can be detected. Strength of the EMR from a small region reflects the density of H atoms in that small region. Additional magnetic fields permit 3D imaging. This has a high spatial resolution structural imaging.

what is fMRI

measures neural activity (indirectly). Makes use of and looks at Neurovascular coupling → coordinated response to brain activation involving local capillary dilation and a transitory surge in the flow of oxygenated, glucose-containing blood across the neurovascular unit, thereby replenishing ATP used in neurotransmission. Shows what regions of the brain were more active as they had a higher blood density (BOLD) (as more active neurons were located there → neurons needs oxygen and thus, blood).

Active neurons → blood flow increases bring oxyhemoglobin. Oxyhemoglobin increase greater than oxygen consumption increase so increased oxy to deoxy in veins. Note that oxy and deoxy have different magentic properties. So less deoxy relative to oxy → MR signal increased intensity (BOLD; blood oxygen level dependent contrast).

what are some advantages of fMRI

1. compared to PET → no tracers, better temporal and spatial resolution, faster acquisition

2. no known health risks

3. structural and functional information in the same image

4. 3D images of activity over the whole brain

what are some disadvantages of fMRI

1. low temporal resolution

2. indirect measure of neuronal activity → correlated by relationship between BOLD and neural activity complex and variable

3. 2-3 seconds to create an image

4. not causal

what are the two systems the nervous system is split into

1. central nervous system (CNS) → inside skull, includes brain and spinal cored

2. peripheral nervous system (PNS) → located outside of the skull and spine, transmits information to and from the CNS.

• the two systems work and communicate together

difference between afferent and efferent

the afferent division brings information in, the efferent division acts upon that information.

two divisions of the PNS and their functions

1. somatic nervous system (voluntary interaction with environment and the organism, muscle and nerves, sensory information in, motor information out) → contains afferent nerves (sensory information from the environment to CNS) and efferent nerves (motor from CNS out to the environment)

2. autonomic nervous system (regulates the body’s internal state, it is an unconscious regulator, informations in from organs and out to organs from brain) → contains afferent (from internal organs) and efferent (to internal organs). It is also split into the sympathetic and parasympathetic nervous system (both of which are efferent)

the two different types of efferent nerves within the autonomic nervous system

1. sympathetic → stimulate (wind things up, organise energy in threatening situations)

2. parasympathetic → winds things down and conserves energy

• organs receive inputs from both sympathetic and parasympathetic systems.

where do two PNS systems project from within the body and the consequence of this

• the parasympathetic system projects from the brain and the lower back region (sacral region), and the sympathetic system projects from the chest region (thoracic) and mid lower back (lumbar).

• Because of this innervation (ie. when the sympathetic nervous system is activated, the organs located around it will be affected first etc.), the effects follow a systematic pattern

what are the 12 different types of cranial nerves and where are they located

• the cranial nerves are on the underside of the brain. And we refer to them in roman numerals (1-12). They are as follows:

1. olfactory nerves (smell) → I

2. optic (sight) → II

3. occulomotor (eye movement, pupil constriction) → III

4. trochlear (eye movement) → IV

5. trigeminal (facial sensations, chewing) → V

6. abducens (eye movement) → VI

7. facial (facial expression; taste - front 2/3 of tongue) → VI

8. auditory/vestibulocohlear nerve (hearing, balance) → VII

9. glossopharyngeal (taste - back 1/3 of tongue, swallowing) → IX

10. vagus (parasympathetic control of heart, lungs, and digestive tract) → X

11. spinal accessory (neck, shoulders, head) → XI

12. hypoglossal (tongue movement) → XII

what are glial cells

glial cells have only become known recently. However, they are crucial to the communicative functions of the brain.

glial cells are hugely important in support and communications, and they outnumber neurons 10:1

they facilitate saltatory conduction, myellination, regeneration (neuroplasticity), communication (by helping the neuron jump down the axon rather than going bit by bit), and reduction of inflammation

what are glial cells in the CNS called

oligodendrocyte

what are glial cells in the PNS called

schwann cell

what are the four main types of neurons

1. unipolar neuron (one direction, afferent neurons) → they are sensory neurons that transfer information from receptor cells to higher nerve cells

2. bipolar neuron (two directions, two poles) → connecting adjacent cells, typically in sensory system

3. multipolar neuron (many poles coming out of the cell body) → transfer information between cells within a single structure, they can collect information from many cells, often in the spinal cord

4. multipolar interneuron → connecting adjacent cells

what is the structure of the nerves along the spinal cord

nerves join the spinal cord in pairs and 31 locations along the length of the spine. Nerves split as they approach the spine into the dorsal root and the ventral root

how are the neurons arranged within the spinal cord

• the unipolar afferent neurons join the dorsal horn → both somatic (skeletal/sensory) and autonomic (internal organs) systems

• the multipolar efferent neurons have their cell bodies in the ventral root. Their axons project out to somatic and autonomic systems

what are the 5 major divisions that the fetal brain (neural tube) develops into

1. forebrain → telencephalon (cerebral hemispheres), diencephalon

2. midbrain → mesencephalon

3. hindbrain → metencephalon

4. spinal cord → myelencephalon (medulla), spinal cord

what are the physical and chemical structures that protect the brain

1. physical protection from mechanical injury → skull, meninges (dura mater, pia mater, arachnoid), and cerebrospinal fluid )CSF)

2. chemical protection (maintaining chemical balance) → the blood brain barrier (tightly packed cells along the blood vessel walls of the CNS prevent entry of many large molecules)

what is comprised in the first line of defence in the brain

the first line of defence is the meninges (dura, arachnoid, and pia), ventricles and cerebrovascular fluid

note: dura meaning hard, pia meaning soft

what is the choroid plexus

the choroid plexus produce cerebrospinal fluid (CSF) and this fluid serves a very important function, which it to cushion the brain. these plexus sit in the ventricles. When this fluid gets out it drains out of the sinus (if this drainage is blocked, this causes hydrocephalus)

what do cysts in the choroid plexus cause

cysts in the choroid plexus (or in the ventricles that hold them) can cause blockage of the CSF flow. This is problematic for an adult brain as the bones have hardened so they cannot expand to let the fluid through in time, so you get pressure building up and brain tissue has no where to go. Causing hydrocephalus.

what is within the myelencephalon and its purpose

medulla → this is primarily composed of axonal tracts carrying information from the brain to the body and back. It has vital functions such as heart rate and breathing. It contains a portion of reticular formation (net-like formation). This has a role in arousal.

what is within the metencephalon

• in the metencephalon, it is composed of many tracts of nerves and contains a portion of the reticular formation, specifically, you have:

1. pons → vital functions relay centre

2. cerebellum → sensory and motor control; cognitive learning; implicit memory → also involved in retrieval. People with cerebella problems (ie. stroke) of have a gait imbalance (they need a wider gait)

what is within the mesencephalon

• in the mesencephalon (midbrain) you have:

1. tectum → superior and inferior colliculi (responsible for visual and auditory orienting of attention, respectively.)

2. tegmentum → portion below tectum → periaqueductal grey matter and Substantia Nigra.

what is within the diencephalon

• in the diencephalon you have:

1. thalamus, relay station for sensory information → this is split into three sections → lateral geniculate nucleus (first synapse after the optic nerve leaves the eye, visual information relay), medial geniculate nucleus (auditory information relay), and ventro posterior nucleus (sensorimotor information relay)

2. hypothalamus → just below the thalamus, controls pituitary gland (growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, prolactin, follicle stimulating hormone, luteinizing hormone)

what is within the telencephalon

• in the telencephalon (and cerebral cortex) you have:

1. sulci (fissures) → longitudinal and central

2. gyri → precentral (sensory cortex) gyrus and postcentral (motor cortex) gyrus, and superior temporal gyrus.

3. neocortex → layered sheet of tissue, folds in on itself, increased surface area. these have stellate and pyramidal neurons

• from a coronal aspect you have; fissures, commisures (ie. corpus callosum as it is a joining bundle of fibres), and ventricles

what is the pituitary gland

this is a midline structure under the hypothalamus, in sells turcica, it it involved in lactation, stress, growth and reproduction, and blood pressure

it is prone to forming tumours

what is the limbic system

the limbic system is involved with affect (emotion) such as fighting, fleeing, feeding, and reproduction.

what is the basal ganglia

the basal ganglia are the connections between the striatum (putamen and tail of caudate) and the substantia nigra. They are involved in voluntary movement/movement initiation; smooth movement; movement timing. Parkinson’s disease is associated. with degeneration of this pathway.

what are the two main cell types the neocortex is composed of

1. pyramidal cells → large bodies, multipolar, long axon goes down and inward through layers

2. stellate cells → small star shaped, short, no axons, transmit information laterally

how many different layers do the neocortex have

the neocortex has 6 different layers (1-VI)

each layer differs in relative concentration of stellate and pyramidal cells in the relative size and concentration of cell bodies (eg. layer IV is thick in sensory areas; layer V mainly pyramidal cells with long axons in motor areas).

what is the corpus callosum

the 2 hemispheres of the brain are connected by the corpus callosum, which links together homotopic areas (same hemisphere to same hemisphere information) of the cortices as the primary means of communication.

what are commisurotomies (split brain)

the removal of the corpus callosum usually to treat epilepsy. Thus, the consequence is to reduce seizures.

There is very little behavioural consequence. However, the experimental consequence is that sensory information presented to one hemisphere is not available to guide behaviour in the other hemisphere.

what does split brain cause in terms of the visual field

information from one hemisphere does not flow to the other because of surgery. the two hemispheres process information in a different way (ie. left is sequential (words) and right is holistic (pictures)).

Patient cannot name of describe visual stimuli presented to the right hemisphere, because the information is not made available to the left/language hemisphere. But knowledge about the stimuli is still present in the right hemisphere (non-verbal techniques can elicit it).

this is to do with visual field and visual information → the visual field of the left side goes to the right hemisphere and vice versa

what are the three glial cells of the CNS

1. oligodendrocytes

2. astrocytes

3. microglia

function of the oligodendrocytes

extensions (wrap around the axon) rich in myelin create myeline sheaths in CNS. Extensions get pruned off (apoptosis) and turned into the myelinating oligdendrocyte

function of the astrocytes (star-shaped)

largest, role is in structural integrity and for creating a blood-brain barrier (seal off capillaries). Important function in sensing pH levels in the blood and communicating this to the brain. They also boost recovery after damage (eg. stroke) and sustaining capillary function/regeneration and neuronal function.

function of the microglia

small, they are important in response to injury or disease (anti-inflammatory response, scoop up pathogens). Rapidly activate to stop pathogens, eliminate excess neurotransmitters. Mainly involved in inflammation effects/process.

what is the purpose of the nodes of ranvier

help with transmission of information → the oligodendrocyte covers the node of ranvier and feels the information passing through there and this guides its actions.

The impulses jump from node of ranvier to node of ranvier as it travels down the axon and the oligodendrocyte picks up this information.

what happens when the nodes of ranvier are damaged and what disease does this cause

transmission does not happen well/the oligodendrocyte cannot pick up this information (therefore it has damaged myelin), this can causes multiple sclerosis. It is an acute, inflammatory autoimmune disease. Not a homogenous diseases, it happens in more females than males.

what are the symptoms of multiple sclerosis

1. visual → blurred and double vision, nystagmus, ‘flashes’

2. motor → weakness of muscles, slurred speech, muscle wastage, poor posture, tics

3. sensory → numbness, tingling, pain

4. coordination and balance

5. cognitive → short and long term memory, forgetfulness, slowed recall

what are the three disorders you can get from the process myelination itself

1. frontal lobe astrocytoma → when astrocytes go cancerous.

2. temporal lobe glioblastoma multiforme

3. acoustic schwannoma → arising in the acoustics nerve.

glial cells are the cause of damage. Gliomas are the most common (40-50% of all brain tumours). They are relatively fast growing, arising from any type of glial cells, hence, gliomas, astrocytomas, and oligodendroglicomas. These disorders are:

what are the typical structures in a neuron

dendrites bring in information from connecting neuron.

Ribosomes (the speckles) and endoplasmic reticulum to generate proteins - in this case, the neurotransmitters.

Mitochondria is used for energy release.

The golgi complex is used to package proteins (neurotransmitters into vesicles).

The synaptic vesicles contain the neurotransmitters.

Microtubules transport the packaged neurotransmitters down the axon (the vesicles travel down them).

Myelin is used to protect the axon and promote transmission down the axon.

what happens when we get neuronal degenration

this causes neuropathological changes associated with Alzheimers Dementia.

This is cerebral atrophy, caused by neuronal death, whereby the external surface of the brain with widened sulci and narrowed gyri, mostly over the frontal and parietal regions.

what are some early symptoms of Alzheimer’s

1. olfactory (anosmia) → lack of ability to smell

2. emotion regulation

3. anxiety/mood

• later changes include:

1. poor new learning

2. changed personality

3. language deficits

what are the three main brain structural indicators of Alzheimers

1. amyloid plaques

2. neurofibrillary tangles

3. Lewy bodies

where are the neurofibrillary tangles and amyloid plaques located

the neurofibrillary tangles are inside the cell, and the Amyloid plaques are outside the cell and it is thought they cause transmission blockage.

what are amyloid plaques

• Plaques are referred to as ‘cellular trash’ and are mostly found in areas where there are many synapses. The synapses then degenerate as they cannot communicate.

• plaques contain an amino acid peptide protein core: beta-amyloid. Mostly in frontal and temporal regions and around hippocampus

what are neurofibrillary tangles

neurofibrillary tangles look like twisted ropes within swollen cell body. They consist of ‘tau’ proteins that accumulate, creating tangles through the brain (layers III and IV of the cortex)

what are Lewy bodies

These are the most characteristic marker of idiopathic Parkinson’s Disease and Lewy body dementia (they are a non-specific indicatory of cell pathology). They are laminated, oesinophilic, cytoplasmic inclusions, 7-20nm in diameter.

what is the role of inflammation and Alzheimer’s

inflammation could be a central mechanism to Alzheimer’s disease (more inflammation could drive plaques and tangles in the brain) → however now, the role of illnesses, viruses, and bacterial infections, and the benefits medicine, vaccinations → this lowers inflammations over time.

what are the three phases of neuronal communication

1. collection and integration of signal at the membrane (membrane potentials) → resting state of a neuron is -70mV (we call this polarised).

2. transmission of signal along the axon → through conduction in myelinated axons

3. transmission of signal from the axon terminals

what is the absolute refractory period

absolute refractory period is when the cell cannot be driven to do anything else. And relative refractory is when the cell cannot be driven to do anything unless there is something more exciting going on.

what is the importance of excitatory and inhibitory potentials

excitatory and inhibitory potentials are very important to push the potential along to the next neuron

what is an excitatory and inhibitory potential

excitatory potentials is when the stimulus causes the potential to burst forth and the inhibitory potential is when the stimulus causes the potential to be withheld.

where do the transmission of signals take place

in the myelinated axons

how are signals transmitted via conduction

it takes forth through saltatory conduction. This is passive conduction (instant and decremental - loses power as it passes along each sheath of myeline) along each myelin segment to the next node of Ranvier.

New action potential generated at each node. Instant conduction along myelin segments results in faster conduction than in un-myelinated axons. Having the myelin sheath around it makes the conduction go faster

what kind of relationship do the myelin and axon potentials hold

there is a dynamic relationship between the myelin and the axon potentials. The two help each other out. Axon potentials/signals promote myelination. This is shown through tetanus toxin which was injected and inhibited vesicle (neurotransmitter) release. This then cause myelination to retract.

what are the three parts of the synapse

1. presynaptic terminal → with vesicles containing neurotransmitters. And receptors for re-uptake

2. junction/gap/synaptic cleft → where the neurotransmitters ‘float’ briefly after release (cannot float for a long time)

3. post-synaptic terminal → with receptors for the neurotransmitters (these are going to cause either an excitatory (impulse that goes down the axon) or inhibitory (nothing will happen) potential)

what are the two basic types of neurotransmitter molecules at the synapse

small and large

what are the small neurotransmitter molecules

small molecules (amino acids, monoamines, acetylcholine (ACh), unconventional neurotransmitters - soluble gases and endocannbinoids)→ synthesised in cytoplasm of the terminal button, packaged in vesicles by the Golgi complex, vesicles stored in clusters next to pre-synaptic membrane, waiting for the trigger to be released.

what are the large neurotransmitter molecules

large molecules → all neuropeptides, assembled in the cell body by ribosomes, packaged by Golgi complex, transported to the axon terminal via microtubules.

what are the different types of amino acid small neurotransmitter molecules

1. Glutamate → most prevalent excitatory neurotransmitter in the CNS

2. GABA → synthesised from glutamate, most prevalent inhibitory neurotransmitter in the CNS

3. Aspartate and glycine

usually found at fast-acting directed synapses in the CNS

what are the types of monoamine small neurotransmitter molecules

1. catecholamines → synthesised from tyrosine (ie. dopamine, norepinephrine, epinephrine)

2. indolamines → synthesised from tryptophan (ie. serotonin and melatonin)

effects tend to be diffuse → non-directed.

what is an agonist and an example

agonist can be used to speed up the process (increase or facilitate activity because they have the same lock and key model as the neurotransmitter)

L-dopa increases synthesis of dopamine, and nicotine stimulates ACh receptors. therefore it is an agonist

what is an antagonist and an example

antagonists can be used to slow the process down (decrease or inhibit activity as it blocks the lock and key model).

PCPA inhibits the synthesis of serotonin, and reserpine prevents storage of monoamines in vesicles, therefore they are antagonists.