Applied Neuroscience SG

What is the primary excitatory neurotransmitter used in the CNS?

Glutamate

What is the primary inhibitory neurotransmitter used in the CNS?

GABA

What are the primary neuromodulators used in the CNS? What is their purpose?

Dopamine (SNc) & serotonin (brainstem) -- facilitate or inhibit subsequent firing of neurons

R vs. L hemisphere damage: cautious and disorganized BUT aware of impairment (behavioral)

Left (dominant)

R vs. L hemisphere damage: impulsive, poor judgment, poor insight, unrealistic, safety risk (behavioral)

Right (nondominant)

R vs. L hemisphere damage: disorganized, processing delay, highly distractible (intellectual)

Left (dominant)

R vs. L hemisphere damage: difficulty w/ abstract reasoning and synthesizing, rigidity of thought, memory impairment related to perception (intellectual)

Right (nondominant)

R vs. L hemisphere damage: difficulty perceiving emotions & expressing (-) emotions

Right (nondominant)

R vs. L hemisphere damage: difficulty expressing (+) emotions

Left (dominant)

R vs. L hemisphere damage: task performance fluctuations

Right (nondominant)

R vs. L hemisphere damage: aphasias, apraxia, and impairments in analytic functions

Left (dominant)

R vs. L hemisphere damage: hemineglect, impairments in complex visual-spatial abilities

Right (nondominant)

R vs. L hemisphere damage: severe personality or emotional changes, difficulty w/ constructional ability, impaired geographic orientation

Right (nondominant)

R vs. L hemisphere function: language

Left (damage --> aphasias)

R vs. L hemisphere function: skilled motor function (aka praxis)

Left (damage --> apraxia)

R vs. L hemisphere function: sequential & analytic abilities (arithmetic, music, and sense of direction)

Left (damage --> impairments in analytics)

R vs. L hemisphere function: visual analysis and spatial attention

Right (damage --> impairment in complex visual-spatial abilities, hemineglect)

R vs. L hemisphere function: perception

Right

R vs. L hemisphere function: prosody (emotion conveyed by tone)

Right (damage --> severe personality or emotional changes--irritability, apathy, psychosis, delusional)

R vs. L hemisphere function: ability to estimate quantity and correctly line up columns of #s, novice or complex musical pieces, finding one's way by overall sense of spatial orientation

Right (damage --> difficulty w/ constructional ability, impaired geographic orientation)

__________ (type of neglect): ignore visual, tactile, auditory $ on neglected side

Sensory neglect (tested w/ sensory extinction)

__________ (type of neglect): perform fewer movements on neglected side

Motor neglect (tested w/ motor extinction)

__________ (type of neglect): tactile & crossed response, cancellation task, and/or clock test

Combined sensory and motor neglect

__________ (type of neglect): do not recognize their arm/leg on the neglected side of the body belongs to them

Conceptual--anosognosia

___________ (lobe): functions in executive function (decision making, judgment), cognition, and motor

Frontal

___________ (lobe): functions in sensation and perception

Parietal

___________ (lobe): functions in auditory/hearing, memory, interpretation of speech, & olfaction

Temporal

___________ (lobe): functions in vision

Occipital

___________ (lobe-ish): involves a compilation of specialized regions that deal w/ homeostasis, olfaction, memory, and emotion

Limbic system

Which Brodmann areas are a part of the frontal lobe?

Prefrontal association cortex, frontal eye fields, supplemental motor cortex (supplemental eye field, premotor cortex), precentral gyrus/primary motor cortex, Broca's area

Which Brodmann areas are a part of the parietal lobe?

Postcentral gyrus/primary somatosensory cortex & secondary and tertiary association/somatosensory association/parietal-temporal-occipital cortex

Which Brodmann areas are a part of the occipital lobe?

Primary visual cortex & secondary and tertiary visual cortex

Which Brodmann areas are a part of the temporal lobe?

Visual inferotemporal cortex, primary and secondary auditory cortex/Heschl's gyrus, higher-order auditory cortex/Wernicke's area, primary olfactory cortex

Which Brodmann area is a part of multiple lobes?

Limbic cortex/ cingulate gyrus/ parahippocampal gyrus

_________ are ependymal cells @ lateral ventricles that produce CSF fluid

Choroid plexus

The lateral ventricles consist of 4 connected regions: frontal horn - _________ lobe, body - __________ & __________ lobes, occipital horn - _________ lobe, & temporal horn - ___________ temporal lobe

Frontal horn - frontal lobe

Body - frontal & parietal lobes

Occipital horn - occipital lobe

Temporal horn - temporal lobe

From the lateral ventricles, CSF flows through the ____________ to reach the third ventricle

Foramen of Monro

From the third ventricle @ the diencephalon (thalamus), CSF flows through the ___________ to reach the fourth ventricle

Cerebral aqueduct/ aqueduct of Slyvius

From the fourth ventricle @ pons, cerebellum, medulla, CSF flows through the ____________ or ___________ to reach the central canal OR subarachnoid space

Foramen of Luedke & Magendie

How does CSF return to the bloodstream?

Arachnoid granulations

Structure: epidural space

Middle meningeal artery

Structure: dura mater

Venous sinuses

Structure: subdural space

Bridging veins

Structure: subarachnoid space

Major vessels & CSF

___________ hematoma/hemorrhage is associated w/ a lucid interval during rapid bleeding --> fast deterioration w/ compression of tissue --> death

Epidural

___________ hematoma/hemorrhage shows up as a white, biconvex lens on imaging

Epidural

___________ hematoma/hemorrhage is associated w/ slow, oozing --> headache, cognition, unsteady gait (chronic) OR quick decline w/ poorer prognosis (acute)

Subdural

___________ hematoma/hemorrhage shows up as a white (acute) or darker (chronic) crescent on imaging

Subdural

___________ hematoma/hemorrhage is associated w/ a sudden catastrophic headache ("thunderclap")

Subarachnoid

___________ hematoma/hemorrhage shows up as white blotches seeping into sulci on imaging

Subarachnoid

___________ hematoma/hemorrhage shows up as a whitened area of the brain w/ symptoms that depend on the area of the brain affected

Intracranial/intraparenchymal

_________ herniation involves the cingulate gyrus --> falx cerebri w/ no clinical presentation (typically)

Subfalcine (note: MAY impact the ACA --> motor and/or sensory loss to the contralateral leg)

_________ herniation involves uncus --> tentorium cerebelli

Transtentorial (uncal)

_________ herniation involves ipsilateral blown pupils (compression of CN III), contralateral hemiplegia (compression of cerebral peduncles), and coma (compression of reticular formation)

Transtentorial (uncal)

_________ herniation involves brainstem --> foramen magnum

Central

_________ herniation involves traction to CN VI, bilateral uncal herniations, tonsilar herniation

Central

_________ herniation involves downward displacement of cerebellar tonsils through foremen magnum --> compresses medulla --> respiratory arrest, BP, instability

Tonsillar

Name the artery most likely involved: L hemineglect, L face and arm motor/sensory loss

R MCA - superior

Name the artery most likely involved: L hemineglect, motor neglect w/ normal strength, some L weakness w/ R gaze preference

R MCA - inferior

Name the artery most likely involved: L hemiplegia + L hemianesthesia + L homonymous hemianopia + L hemineglect + R gaze preference

R MCA - stem

Name the artery most likely involved: R face and arm motor/sensory loss, Broca's aphasia, agraphia

L MCA - superior

Name the artery most likely involved: R face and arm sensory loss (motor findings usually absent), Wernicke's aphasia, R visual field deficit

L MCA - inferior

Name the artery most likely involved: R hemiplegia + R hemianesthesia + R homonymous hemianopia + GLOBAL APHASIA + L gaze preference

L MCA - stem

Name the artery most likely involved: L leg weakness/sensory loss, grasp reflex, frontal lobe behavioral abnormalities, transcortical aphasia

R ACA

Name the artery most likely involved: R leg weakness/sensory loss, grasp reflex, frontal lobe behavioral abnormalities, transcortical aphasia

L ACA

Name the artery most likely involved: L homonymous hemianopia, L hemisensory loss and hemiparesis

R PCA

Name the artery most likely involved: R homonymous hemianopia, alexia w/o agraphia (larger --> aphasia, R hemisensory loss, R hemiparesis)

L PCA

Name the artery most likely involved: contralateral sensory loss and hemiparesis of face and arm > leg

MCA

Name the artery most likely involved: aphasia (L hemisphere) or hemineglect (R hemisphere)

MCA

Name the artery most likely involved: hemianopia/ gaze preference to side of lesion

MCA (stem)

Name the artery most likely involved: contralateral motor and/or sensory loss of leg > face and arm

ACA

Name the artery most likely involved: frontal lobe dysfunction -- apraxia (L hemisphere > R), impaired judgment (R hemisphere > L), grasp reflex, abulia (indecisiveness), incontinence, flat affect

ACA

Name the artery most likely involved: contralateral homonymous hemianopia

PCA

Name the artery most likely involved: proximal/deep infarcts @ thalamus & posterior limb of internal capsule --> contralateral sensory loss and hemiparesis, thalamic aphasia, alexia

PCA

Function: lateral corticospinal tract

Voluntary movement of contralateral limbs

Crossing: lateral corticospinal tract

Pyramidal decussation of caudal medulla

Function: rubrospinal tract

Unconscious movement of limbs; posturing (especially during injury--i.e., non-purposeful flexion)

Crossing: rubrospinal tract

Ventral tegmental decussation of midbrain

Function: anterior corticospinal tract

Voluntary trunk control and proximal girdle muscles

Crossing: anterior corticospinal tract

WARNING!! The anterior corticospinal tract does NOT cross. It remains ipsilateral throughout the spinal cord until it birfurcates @ its level of termination.

Function: medial vestibulospinal tract

Positioning of head and neck via vestibular input

Crossing: medial vestibulospinal tract

Bifurcates in medial intermediate zone of spinal cord (technically, this means it doesn't cross per say)

Function: lateral vestibulospinal tract

Balance via promotion of antigravity postural control and protective extension

Crossing: lateral vestibulospinal tract

WARNING!! The lateral vestibulospinal tract does NOT cross.

Function: tectospinal tract

Coordination of head and eye movement via visual and auditory info

Crossing: tectospinal tract

Dorsal tegmental decussation of midbrain

Function: reticulospinal tract

Automatic posture and gait-related movements

Crossing: reticulospinal tract

WARNING!! The reticulospinal tract does NOT cross.

Function: DCML pathway

Afferent transmission of fine & discriminative touch, CONSCIOUS proprioception, vibration

Function: anterolateral pathway

Afferent transmission of noxious $, temperature, & crude touch

Crossing: DCML pathway

Arcuate fibers of medulla

S/S: DCML pathway

Patient may report tingling, numbness

S/S: anterolateral pathway

Patient may report sharp, burning, and/or severe pain

Crossing: anterolateral pathway

Anterior white commissure of spinal cord -- IMMEDIATE CROSSING

Name the anterolateral pathway: discrimination of location & intensity of $ -- "sharp pain in my heel, hot water on my hand"

Spinothalamic

Name the anterolateral pathway: emotional & arousal aspects to medulla-pontine reticular formations -- "ouch, that hurts"

Spinoreticular

Name the anterolateral pathway: central modulation of $ to periaqueductal gray -- "aah, that feels better"

Spinomesencephalic

PNS vs. SNS: pupil constriction

PNS (via CN III)

PNS vs. SNS: heart rate increases

SNS

PNS vs. SNS: bronchodilation

SNS (hint: bronchodilation vs. bronchoconstriction always follows pupillary repsonse)