Neuro Exam 2 Content

Cranial nerve nuclei in medulla

(this is honestly so confusing idk what to write here) (•Spinal Nucleus of V: V, VII, IX, X, •Inferior Salivatory Nucleus: VII & IX, •Nucleus Ambiguus: IX, X, XI, •Dorsal Motor Nucleus: X, •Hypoglossal Motor Nucleus: XII, •Solitary Nucleus: VII, IX, X)

this structure of the brain facilitates smooth movement (through a direct or indirect pathway); selection and initiation of willed movements - associated with a variety of functions, including control of voluntary motor movements, procedural learning, habit learning, eye movements, cognition, and emotion - comprised of striatum (caudate and putamen), globus pallidus (internal and external), substantia nigra, and subthalamic nucleus

BG (basal ganglia)

_________ area is involved in the expressive aspects of spoken and written language (production of sentences constrained by the rules of grammar and syntax) - in the frontal lobe just rostral to the motor cortex damage to this area of the brain can result in the inability to speak, or difficulty forming words even though vocal cords, larynx, muscles, and innervation is normal (area 44/45 damage); can still comprehend/perceive language

Broca's (90% dominance on L hemisphere)

this tract conveys proprioceptive information from proprioceptors in the skeletal muscles and joints to the cerebellum - neurons from muscles and other structures project through the dorsal root ganglion (1st order neuron), into dorsal horn and synapses - specific nuclei (Clarke's nuclei): C8-L2, L3 (2nd order neuron) - tracts move lateral to the white matter up into the cerebellum which projects into the inferior cerebellar peduncles and into the cerebellum

DST (dorsal spinocerebellar tract)

what NT is inhibitory in the direct and indirect pathways of the basal ganglia

GABA

(Left/Right) side neglect is more commonly seen

Left

these mechanoreceptors of the skin sense touch and low frequency vibration

Meissner's corpuscles

these mechanoreceptors in the skin respond to light touch and are involved in tactile acuity (textures, shapes, etc)

Merkel's disks

the (Right/Left) hemisphere contains the following areas and abilities - - Geometrical spatial orientation - Music perception and skills (singing, playing instruments, etc) - Artistic talents - Formation of ideas (non-verbal ideation) - Perception and processing of emotions - Coordination of sensory info - More of what we feel vs what we think - Being conscious of our environment and emotions

Right

these mechanorecptors are found in the superficial dermis of both hairy and glaborous skin where they sense skin stretching and warmth

Ruffini's endings

this tract conveys proprioceptive information from the body to the cerebellum - info from dorsal root ganglion synapses onto neurons in the dorsal gray horn, axons cross to opposite ventral horn of spinal cord and project into the superior cerebellar peduncles and goes behind the spinal column, crossing to the ipsilateral cerebellum - crosses twice!! - nuclei below L2, L3

VST (ventral spinocerebellar tract)

_____________ area is the region of the brain that is important for language development. It is located in the temporal lobe on the left side of the brain and is responsible for the comprehension of speech, while Broca's area is related to the production of speech. damage to this area of the brain can result in not being able to comprehend language (written or spoken) but being able to speak (words put together make no sense); area 22 damage

Wernicke's (language cortex)

this condition is described as the inability to perceive sensations through otherwise normal functioning sensory pathways - inability to interpret sensations and hence to recognize things, typically as a result of brain damage - dysfunction in the association areas in the cerebral cortex leading to *dysfunction in conscious perception* - both special senses (vision, hearing, taste, etc) and general sensation (fine touch, crude touch, proprioception, etc) - general symptoms: disturbance of body image - not being able to recognize individual fingers, confuse L side of body with R

agnosia (loss of sensory perception)

this structure of the memory cortex is part of the telencephalon and is deep-seated within the nuclear complex - has more than one nucleus to be able to process different kinds of info in terms of learning - almond-shape set of neurons located deep in the brain's medial temporal lobe. Shown to play a key role in the processsing of emotions

amygdala

(Anterior/Posterior) commissure fibers interconnect portions of the temporal lobe; Olfactory pathway - crosses midline rostral to the fornix

anterior

what are the three functional lobes of the cerebellum

anterior (spinocerebellum/paleocerebellum), posterior (middle lobe/pontocerebellum and neocerebellum), flocculonodular

this functional lobe of the cerebellum is associated with muscle tone maintenance, maintenance of posture, and gross voluntary movement

anterior lobe (spinocerebellum/paleocerebellum)

this is the loss of ability to understand or express speech/language caused by damage to specific brain regions general term for language disorders to include reading, writing, speaking, or comprehension of written or spoken words. Due to cerebral cortex or conduction dysfunction Common types: Broca's, Wernick'es, conduction, global

aphasia

this condition is a neurological disorder characterized by the inability to perform learned (familiar) movements *on command*, even though the command is *understood* and there is a willingness to perform the movement. Both the desire and the capacity to move are present but the person simply cannot execute the act. - PNS is funcitonal; no loss of cognitive function (understand request/command) - Loss of cortical function - Loss of function in the premotor and supplementary motor cortex (association areas) --> organize movement through primary motor cortex (precentral gyrus)

apraxia

___________ __________ = band of neurons that connect Wernicke's area to Broca's area

arcuate fasciculus

these are parts of the cerebral cortex that receive inputs from multiple areas; they integrate/blend incoming sensory information, and also form connections between sensory and motor areas. - surround the major cortical areas - damage here results in primary functions being affected (i.e. if the area close to the motor cortex is damaged then your ability to move will be affected; is the area close to the primary visionary cortex is damaged this will effect color vision and/or 3D depth perception)

association areas

these fibers in the brain, specifically in the semioval center, interconnect cortical regions of the *same* hemisphere - short (arch the floor of sulcus and connect adjacent gyri) and long (interconnect cortical regions of different lobes of the same hemisphere)

association fibers

this movement disorder is characterized by irregular, uncoordinated movements caused by a change to the *cerebellum*. - potential causes: brain tumors, stroke, cerebellar atrophy - this disorder (or its symptoms) clues to something being centrally wrong and that you should refer out

ataxia

besides the tectum and tegmentum, the mesencephalon (midbrain) has what two structures - one of these structures is at the front of the midbrain and arise from the front of the pons and contain the large afferent and efferent nerve tracts that run to and from the cerebrum from the pons - the second of these structures contains corticofugal fibers (the motor tracts traveling from the cerebral cortex to the pons and spine); most vental aspect

cerebral peduncles, crus cerebri (corticofugal fibers)

these fibers in the brain, specifically in the semioval center, interconnect corresponding cortical regions between hemispheres - includes and anterior group, posterior group, and the *corpus callosum*

commissural fibers

this is the most severe form of aphasia that includes damage to all three areas related to language expression and comprehension (Wernicke's, Broca's, and the Arcuate Fasciculus) - occurs *only* in the L hemisphere (dominant for language); largely due to stroke in this hemisphere - patients have the general disability to use language in any form

global aphasia

this component of the basal ganglia (BG) sends output out from the BG to the cerebral cortex mostly *by way of the thalamus*, as well as to nuclei of the brainstem - mainly *inhibitory on the thalamus* - produces the output in terms of what motor action needs to be performed - internal and external components

globus pallidus

what NT is excitatory in the direct and indirect pathways of the basal ganglia

glutamate

this condition is due to damage of the subthalamic region of the brain (likely due to stroke or bleeding) - characterized by violent, forceful involuntary movements of the extremities on the contralateral side of the lesion

hemiballism

this structure of the memory cortex is in the temporal lobe and is involved in *spatial* memory, as well as learning and memory - during Alzheimer's disease this structure accumulates plaques that prevent it from further processing stimuli (the person can recall things previously learned but cannot recall any new info learned) - runs dorsal (spatial learning) to ventral (other types of learning) in a curved fashion

hippocampus

____________ are released by the anterior lobe of the pituitary gland

hormones (thyrotrophic hormone, growth hormone, prolactin, follicle stimulating hormone, etc)

this type of movement disorder involves an increase in movement and uses an indirect pathway - Examples include: Huntington's disease

hyperkinetic (movement disorder) (decreased inhibition due to damage to subthalmic nucleus over time both direct and indirect pathway are excited leading to rigidity)

this type of movement disorder involved a decrease in movement and uses a direct pathway - Examples include Parkinson's disease

hypokinetic (movement disorder) (•Parkinson's due to the decrease of dopamine, which usually increases motor output, person will have rigid movement. •Increasing dopamine can improve symptoms and be diagnostic. •Anticholinergic drugs decrease inhibition to the thalamus.)

this structure of the diencephalon serves visceral, ANS, and endocrine functions; controls body temperature, hunger, emotional states (rage, hate, aggression), thirst, sex drive, fatigue, sleep, and circadian rhythms. - communicates with the pituitary gland (connected through the infundibulum) - lies beneath the thalamus - mammillary bodies on the caudal portion (damage to these --> spatial memory deficit) - afferent and efferent connections with retina, hippocampus, amygdala, olfactory regions, & fornix

hypothalamus

Purpose of the (Direct/Indirect) pathway of the basal ganglia: *limit unnecessary movement* or fine tunes movement

indirect

this tract is associated with proprioception, touch and pressure. - info goes into the dorsal root ganglion, crosses over (anterior commissure), synapses onto the inferior olivary nucleus (ION), crosses over the midline and then projects through the inferior cerebellar peduncles and into the cerebellum - the ION is known to coordinate signals from the spinal cord to the cerebellum to regulate motor coordination and learning.

inferior olivary tract (spinocerebellar tract)

the hollow stalk which connects the hypothalamus and the posterior pituitary gland

infundibulum

these mechanoreceptors respond to touch and pressure

krause end bulbs

this is a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina

lateral geniculate nucleus

the (Right/Left) hemisphere contains the following areas and abilities - - Broca's and Wernicke's areas (speech and language) - Logical and analytical ability - General math ability - Processing large volumes of info - Ability to be rational and pragmatic - More about what we think vs what we feel - doing-consciousness

left

Most somatosensory receptors are ____________ - these receptors have *unmyelinated* axon terminals

mechanoreceptors

this component of the myelencephalon is a long stem-like structure which makes up part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions - helps regulate breathing, heart and blood vessel function, digestion, sneezing, and vomiting

medulla oblongata

this division of the rhombencephalon (hindbrain) gives rise to the cerebellum and pons

metencephalon

the rhombencephalon (hindbrain) is further divided into what two divisions

metencephalon, myelencephalon

*Afferent* cerebellar input primarily travels via which peduncles

middle, inferior

what are the three layers of the cerebellar cortex (grey matter)

molecular (basket, stellate, and golgi cells), purkinje (purkinje cells), granular (granular cells)

(Anterior/Posterior) commissure fibers are involved with visual reflexes and interconnect the superior colliculi and the pretectum (midbrain to midbrain) - located in the *diencephalon* - smallest of the commissural fibers - anterior to the pineal gland

posterior

this functional lobe of the cerebellum is associated with the coordination of fine voluntary movement

posterior lobe (middle lobe/pontocerebellum and neocerebellum)

these fibers in the brain, specifically in the semioval center, connect one specific part of the cortex to other parts of the CNS. - contain both afferent and efferent fibers - arranged in a radiating mass to the brainstem called the *corona radiata* - condenses into internal capsule

projection fibers

this type of agnosia is characterized by the inability to recognize (familiar) faces; can associate other features to recognize the individual as a know entity (i.e. voice) - usually results from a stroke or TBI - damage to cortex of temporal lobe

prosopagnosia

functions of skin:

protection, prevent evaporation of body fluids (I don't agree with this Sree you should just say temperature regulation) (provides direct contact with world, obviously)

Electromagnetic receptors use what type of photoreceptors to detect visible light

rods, cones

this structure in the brain is a mass of white matter (cellular processes - axons/dendrites) that lies between the cerebral cortex, basal ganglia and the ventricular system. - made up of 3 types of fibers (commissural, association, and projection fibers)

semioval center (centrum semiovale)

A __________ _________ is an aspect of a stimulus or what is perceived after a stimulus. This term is often used interchangeably with sense. The basic senses include: light, sound, taste, temperature, pressure (crude/light touch and fine touch), and smell.

sensory modality

The size of the receptive field governs the spatial frequency of the information: (small/large) receptive fields are stimulated by high spatial frequencies, *fine detail*; (small/large) receptive fields are stimulated by low spatial frequencies, coarse detail. - use *Two-Point Discriminatory test* to decipher size and density of field - Increased computing power --> the *higher* the receptive field density the *more* brain tissue dedicated to the area

small, large (The fingertips have the highest spatial resolution, and the smallest receptive fields, while the thigh and calf region have the lowest spatial resolution, and largest receptive fields)

__________ sensation enables the body to detect touch, pain pressure, temperature, and tension on the skin - feel aches, sense temperature, and pressure - responsible for touch and pain - receptors broadly distributed and respond to many kinds of stimuli

somatic

_________ ________ is caused by an imbalance of signals from the CNS (brain and spinal cord) to the muscles. - damage to precentral gyrus and associated areas --> lose functionality in the mm it's innervating - UMN = neurons from precentral gyrus and association areas - LMN = ventral horn of spinal cord

spastic paralysis

this movement disorder is the inability to produce and control bodily movements, that presents as increased tone or stiffness of the muscles. - lesions of the cortical spinal tracts, upper motor neuron (UMN) lesions resulting in hyperreflexia, stroke, SCI, MS, CP - positive clonus test

spasticity

afferent neurons that convey proprioceptive data from the spinal cord to the cerebellum. - play a critical role in cerebellar-cortical-spinal feedback loops necessary for balance and coordination. - *All respond to proprioception* (unconscious sensation of limbs in space). Constant info from body with reference to space - Dorsal tract (DST): C8-L2, L3 - Ventral tract (VST): below L2-L3 - Cuneocerebellar tract (CT): C1-C7 - Spino-olivary tract (climbing fibers) - DST, VST, and CT fibers in cerebellum are called "Mossy Fibers"

spinocerebellar tract

this is an ascending pathway of the spinal cord. It is one of the most important sensory pathways of the nervous system. - responsible for the transmission of pain, temperature, and crude touch to the somatosensory region of the thalamus.

spinothalamic tract

this condition is characterized by a cluster of neurological abnormalities arising from the partial or complete severing or *lesioning of the corpus callosum*, the bundle of nerves that connects the right and left hemispheres of the brain. - if touching something with your R hand it would go to the L hemisphere but your R hemisphere would have no idea about this info - integration between the L and R is problematic - very important with vision because we use both hemi's with that special sense

split brain syndrome

this component of the epithalamus is rostral to the Habenula; makes both afferent and efferent connections to communicate with the Habenula, hypothalamus and thalamus

stria medullaris

this component of the basal ganglia receives input from the motor cortex that is passed on to the globus pallidus (internal and external depending on the pathway); also receives input from the substantia nigra - made up of the caudate nucleus (body) and putament (tail) - all input to the basal ganglia arrives via this structure from the motor cortex

striatum

this component of the basal ganglia receives (excitatory) input from the subthalamic nucleus, send (inhibitory) output to the subthalamic nucleus, and sends dopamine neurons into the striatum

substantia nigra

this component of the basal ganglia is especially important for the indirect pathway; sends (excitatory) output to the substantia nigra and receives (inhibitory) input from the substantia nigra - also receives inhibitory input from the globus pallidus external - sits below the thalamus

subthalamic nucleus

this is the most ventral part of the diencephalon that is involved in controlling involuntary muscle function and motor integration activities - contains subthalamic nucleus

subthalamus

*Efferent* cerebellar output primarily travels via which peduncles/projections

superior (cerebellar peduncle), fastigial (efferent projections)

this type of agnosia is characterized by the lack of ability to recognize (familiar) objects through touch (and proprioception). The weight and texture of an object may be perceived, but the person can neither describe it by name nor comprehend its significance or meaning - due to lesions of the posterior parietal cortex of the dominant hemisphere (if R hemi affected L hand wouldn't be able to recognize what it's touching)

tactile agnosia

this part of the mesencephalon (midbrain) contains the superior and inferior colliculus which receive sensory info from the eye and ear, respectively - dorsal part of midbrain

tectum

what are the two components of the mesencephalon (midbrain)

tectum, tegmentum

this part of the midbrain has a red nucleus and substantia nigra (black substance) that control voluntary movement ventral part of midbrain contains Dopaminergic neurons (related to the reward center) forms floor of cerebral aqueduct

tegmentum

this component of the prosencephalon (forebrain) gives rise to the cerebral hemispheres, cerebral cortex, basal ganglia, and lateral ventricles

telencephalon

the prosencephalon (forebrain) is further broken down into what two components

telencephalon, diencephalon

this structure is the largest portion of the diencephalon that serves as a relay center through which sensory nerves transmit signals from the spinal cord and brainstem on the way to the cerebral cortex - receives afferent and efferent input - *gateway for info going into the brain*

thalamus

this movement disorder associated with the basal ganglia has rhythmic or semi-rhythmic oscillations; 3 types - - Resting (occurs when limb relaxed; Parkinson's) - Postural (occurs when limb is held in a position and disappears at rest; e.g. Essential) - Intention/Ataxic (occurs when Pt attempts to move limb)

tremor

the sensation of limb and joint position and range and direction of limb movement. It is involved in the acquisition and maintenance of complex, skilled movements such as walking, talking and writing. - sensory info goes directly to cerebellum - *spinocerebellar tract* that terminates in the ipsilateral cerebellum - defects in this pathway manifests in postural deficits and *ataxia* (abnormal voluntary coordination of muscle)

unconscious proprioception

the ______________ system is part of the motor system network causing involuntary actions

extrapyramidal

this functional lobe of the cerebellum is associated with the maintenance of equilibrium

flocculonodular lobe

this is a specialized brain structure that consists of both commissural and projection fibers that connects the telencephalon with the diencephalon - two-way reciprocal connection

fornix

Pain, thermo (temperature), and chemoreceptors all use unspecialized, afferent nerve fibers to send their signal to a sensory neuron - what are these nerve fibers called?

free nerve endings

this is a relatively rare form of aphasia that involves damage to the arcuate fasciculus (band of neurons that connects Wernicke's and Broca's areas) - patient's with this damage are *less fluent* in language than with only Wernicke's aphasia (comprehension is good but ability to repeat is poor) - largely due to a stroke in that brain hemisphere - numerous symptoms - *Paraphasic errors* = substitute incorrect words - naming things is impaired, reading aloud is abnormal (motor response = impaired) but can read silently with good comprehension, writing (another motor response) is abnormal with misspelled words and omissions of words

conduction aphasia

The ability to sense the position of your body in space and to feel where your natural range of movement should take you. Think about activating your main muscles of movement and becoming aware of the sensory information they provide. - static, dynamic/kinesthetic sense, normal gait and posture - sensory info goes to brainstem and fiber *decussate* to the contralateral side through the spinothalamic tract to the post-central gyrus - defects in this pathway manifest as stumbling, knuckling (? ok Sree)

conscious proprioception

Upper motor neuron (UMN) paralysis (spastic paralysis) typically effects the (ipsilateral/contralateral) side of the body

contralateral

A thick band of axons that connects the two cerebral hemispheres and acts as a communication link between them. - made up of *commissural* fibers - major means of communication b/w the two hemispheres

corpus callosum

this tract is similar to the dorsal spinocerebellar tract. Specifically, it conveys information related to the *upper limbs, head, and neck* - C1-C7 - sensory info from the dorsal root ganglion moves upwards *ipsilaterally* through the spinal cord - synapses onto a special nucleus in the medulla (accessory cuneate nucleus) - external arcuate fibers project through the inferior cerebellar peduncles and projects into the cerebellum

cuneocerebellar tract (CT)

this type of agnosia is the inability to appreciate thickness or depth of objects - involves association areas of the occipital lobe

depth agnosia

this component of the prosencephalon (forebrain) gives rise to the thalamus and hypothalamus (as well as epithalamus and subthalamus)

diencephalon

Purpose of the (Direct/Indirect) pathway of the basal ganglia: *produce movement*

direct

abnormal involuntary muscle movements caused by change in function of the basal ganglia - i.e. those seen in Parkinson's disease

dyskinesia (bradykinesia/hypokinesia = slowed movement; akinesia = no / lack of movement)

dysfunction of basal ganglia symptoms fall into what two categories

dyskinesia, variations in muscle tone (hypertonicity/rigidity)

the outer layer of skin is the ________ and the inner layer is the __________

epidermis, dermis

The _____________ is a dorsal posterior segment of the diencephalon that includes the habenula (involved w/ limbic system), stria medullaris, pineal gland, and posterior commissure. Its function is the connection between the limbic system to other parts of the brain. - most posterior by the posterior commissure - borders the epithelial roof of the 3rd ventricle comprising of the Choroid Plexus that produces CSF

epithalamus

Indirect Pathway of Basal Ganglia steps: - puts "brakes" *on* the thalamus

motor cortex excites striatum --> excitatory neurons (in striatum) synapse with inhibitory neurons going to the GP external (globus pallidus external) --> inhibition from the GP external onto the subthalamic nucleus is reduced --> subthalamic nucleus allowed be more active (excited) --> subthalamic nucelus excites GP internal --> increased inhibition affect of the GP internal on the thalamus --> decreased excitation from the thalamus on the motor cortex --> decreased (muscle) movement (in the background: substantia nigra allows thalamus to excite the motor cortex a little to allow our muscles to move a little more. Subthalamic nucleus excites substantia nigra --> dopamine neurons from the substantia nigra go to the striatum --> dopamine binds with D2 receptors in striatum --> turns down activity in the excitatory neurons in the striatum --> can't excite the inhibitory neurons acting on the GP external as much --> increased inhibition of GP external on the subthalamic nucleus --> reduced excitation from subthalamic nucleus on the GP internal --> decreased inhibition from GP internal on thalamus --> increased excitation from thalamus on motor cortex --> movement)

Direct Pathway of Basal Ganglia steps: - takes the "brakes" *off* the thalamus

motor cortex excites striatum --> excitatory neurons (in striatum) synapse with inhibitory neurons going to the GP internal (globus pallidus internal) --> inhibition from GP internal onto thalamus is reduced --> thalamus allowed be more active (excited) --> thalamus sends excitatory messages to motor cortex --> motor cortex increases muscle output --> movement (in the background: if subthalamic nucleus is exciting the substantia nigra --> substantia nigra sends dopamine to D1 receptors in striatum --> enhances striatum inhibitory effect on GP internal --> reduces further the inhibitory effect of GP internal on the thalamus --> enhanced excitement from thalamus onto motor cortex --> more muscle movement) (if substantia nigra doesn't want to be excited anymore it can send inhibitory signal to subthalamic nucleus --> substantia nigra no longer receives excitatory messages from subthalamic nucleus --> substantia nigra stops sending dopamine to striatum --> decreased inhibitory effect of the striatum on the GP internal --> enhanced inhibitory effect of GP internal on thalamus --> reduced excitation from thalamus to motor cortex --> decreased muscle movement)

In this type of agnosia a person cannot discriminate between stationary and moving objects - involves association areas of occipital lobe; cannot perceive movement of objects (def shouldn't be driving if you got this problem lol)

movement agnosia

this division of the rhombencephalon (hindbrain) gives rise to the medulla oblongata

myelencephalon

this condition, usually the result from a stroke or TBI, occurs when a patient fails to perceive an entire side of their body (L or R) due to damage in the posterior part of the parietal lobe. Whichever side of the brain is damaged the *contralateral* side of the body will be affected

neglect

these are one of the four major types of mechanoreceptor cell in glabrous (hairless) mammalian skin. They are nerve endings in the skin responsible for sensitivity to vibration and *pressure*/mechanical deformation

pacinian corpuscles (#2 in photo)

this component of the epithalamus is a small endocrine gland that produces melatonin which is involved with the onset of puberty (loss of melatonin levels), clinical depression, sleep and circadian rhythms

pineal gland

Damage to the __________ gyrus may produce a loss of proprioception, astereognosis (the loss of the ability to identify objects through touch), loss of vibratory sense, and loss of two-point discrimination in the trunk or extremities - primary somatosensory cortex in parietal lobe

postcentral