1st L Flashcards
Explain the method of Techniques of functional neuroimaging in
neuroscience
— they are 3 methods :
1-Positron emission tomography (PET)- This technique is based on the introduction of radioactive substances into the bloodstream.
2-Single-photon emission computed tomography/ This is a recording technique that’s similar to the previous one. However, it uses gamma radiation.
3- Functional magnetic resonance. This is an MRI where, at the same time, some cognitive activity is carried out. It’s based on the fact that the neurons involved in a mental process will need more energy and therefore more oxygen from the blood.
Explain the Electorphysiological methods of diagnosis
1-Electroencephalogram. It measures the electrical power of the brain.
In addition, it also measures the type of wave and frequency in which it’s functioning.
2-Electromyogram. It evaluates the electric activity of the muscles. It’s used for the exploration of the peripheral nerves.
3-Electroculogram. It measures the electrical muscle recording of the eyes and the sleep phases.
Explain the Techniques of cerebral stimulation
• These techniques allow brain activity to be influenced by two types of stimuli:
1-Magnetic. With transcranial magnetic stimulation, a current
is safely induced in the brain. This induction is achieved by a flow of current
that passes through a coil and generates a magnetic field.
2- Electrical: This uses a low-intensity current by means of electrodes on the scalp. As a result, the induction causes changes in the excitability of the neurons of the cortex
Explain the sensitivity DF and types :
-DF : the ability of the body to perceive irritations coming from the environment or from its own tissues and organs.
—-Types :
1- Overall :
1.1 : superficial (extraceptive ) Ex : painful and temperature
1.2 Deep ( proprioceptive ) Ex: muscular- Articular , vibration
2-Complex :
2.1 interceptive: caused by irritation of the receptors of internal organs
3-Special type :ex , vesion , hearing
- Chemical: taste , and semll
Explain the General somatosensory pathway dorsal column -medial lemniscus pathway
-A somatosensory pathway will typically have three neurons: first-order, second-order, and third-order
1-The first-order neuron is a type of pseudounipolar neuron and always has its cell body in the dorsal root ganglion spinal nerve with a
peripheral axon innervating
touch mechanoreceptors and a central axon synapsing on the second-order neuron.
—NB! : If the somatosensory pathway is in parts of the head or neck not covered by the cervical nerves,
the first-order neuron will be the trigeminal nerve ganglia or the ganglia of other sensory cranial nerves)
Explain Spinothalamic tract
- (the first order neuron)
is a type os pseudo unipolar neuron and it always has a cell body located in the dorsal root ganglion of spinal nerve with
1- peripheral axon innervating pain and temp.
2- central axon enters dorsal horn of spinal cord where they synapses with 2nd order neuron
ANTERIOR SPINOTHALAMIC TRACT
after entering the dorsal horn it synapses with the ( the 2nd order neuron ) this synapse occurs in “nucleus proprius”
then the 2on DECUSSATE via the white commissure then it ascends and SYNAPSES in the thalamus “ventral posteriolateral nucleus”
via lissauer’s tract
LATERAL SPINOTHALAMIC TRACT
also DECUSSATE to the other side via anterior white commissure(usually occurs 1-2 spinal nerve segments above point of entry) and to the anterolateral corner of spinal cord hence it becomes parts of anterolateral system and synapse in thalamus via VPL nucleus
then the majority goes to postcentral gyrus to synapses with 3rd cortical layer
and some goes to parietal lobes , projection of awareness
note it forms spinal leminscus
Explain Auerbach’s Flatau’s law
-the law concerning the eccentric
position of the long spinal tracts: The greater the length of the fibres in the spinal cord the
closer they are situated to the periphery.
Explain types of Sensitivity pain
1-) local - at the site of direct irritation of pain receptors
2-) irradiating - associated with the spread of pain impulses beyond the zone of irritation (forexample, with pulpitis, pain can cover the entire zone of innervation of the trigeminal nerve);
3-) projection - the pain sensation does not coincide with the site of irritation, but occurs distally to it (for example, when the posterior spinal root is stimulated, pain occurs at adistance in the corresponding segment of hte body in the dermatome, myotome, sclerotome of the same name);
4-) reflected -can be considered as a variant of projection pain [for example, diseases of the internal organs,
painoccurs in a certain part ofthe body (Zakharyin-Ged zones), the innervation of which is provided by the same segment of the spinal cord].
Explain disorders : Sympathalgia , Neuralgia
1- Sympathalgia : is a burning pain with difficulty localization of the pain, because of irritation of sympathetic vegetative structures
2-Neuralgia is manifested by brief paroxysms (usually within 2 minutes), but the pain is perceived as sharp, shooting, piercing, burning, electriclike. Trigger zones provoke pain attacks.
explain (sensitive disturbances) types
– they are 3 types :
1- peripheral : they have 3 types also
1.1 NERUAL TYPE :
area innervated by affected nerve followed by sensory loss involving all sensory functions (mononneuropathy)
1.2 PLEXOPATHY
is a disorder of network of nerves in the brachial or lumbosacral plexus
symptoms : pain, ms weakness and numbness
1.3 POLINEYRIOPATHY
simultaneous malfuction of many peripheral nerves throughout the body due to infection , toxins , drugs , cancers , diabetes , autoimmune disorders , and other disorders cause peripheral nerves malfuncation \
2- segmental :
SEGMENTAL OR RADICAL - SEGMENTAL
- within areas innervated by respective nerve roots followed by sensory loss involving all sensory functions
-cause : damage of (spinal ganglion , post root , post horn , ant white spike )
3-OTHERS : its 5 types :
3.1 CONDUCTIVE
sensory loss below the lesion level ( pos or lateral columns of spinal nerves )
3.2 ALTERNATING HEMIANETHETHESIA
has ipsilateral “same side” 5th cranial nerve and contralateral to trunk & extremities of body sensory disturbances
ex . thalamus damage can lead to contralateral thalamic pain syndrome that involve one sided burning or aching sensation
3.3 CORTICAL
in case of damage , anesthesia or hypoesthesia of all types of sensitivity occurs in corresponding ( depending on location of lesion ) parts of body from the opposite side
3.4 COMPLITE DAMAGE
sensory loss depending on the damage area , inability to assess stimulus intensity and location
3.5 IRRITATION
parethesia occurs in the ares corresponding to the irritated areas of the cortex
ex. sensitive jackson seizure
explain SENSTION ABNORMALITIES
SENSTION ABNORMALITIES
1- hyperesthesia : abnormal increase sensitivity to stimuli sense
2- hypoesthesia or numbness : is common side effect of various medical conditions that abnormal decrease sensitivity to stimuli sense
note : lack of sensitivity usually resulting from denervation referred as ANETHESIA
3- parethesia : abnormal sensation of skin ( tingling , pricking , chilling , burning, numbness ) with no apparent physical cause , it can be transient or chronic and may have many underlying causes , usually painless and can occur anywhere in body but usually arms and legs
note : the most familiar kind of it known as “ pins & needles” after having a limb fall asleep and less uncommon insects crawling on the skin
4- allodynia : pain caused by stimulus that doesn’t usually elicit pain ex. sunburn or coldburn
