Higher Cortical Functions Flashcards
1
Q
Thalamic Syndrome
A
- usually involve damage to lateral group of thalamic nuclei (VPL)
- initially a contralateral hemianalgesia
- Soon painful sensation appears with noxious stimuli
- later pain is provoked by pressure, touch, vibration
- threshold for pain seems higher, but once threshold is reached, pain has strong emotional overtone to it
2
Q
Hypothalamus: Lateral Hypothalamic Area
A
- induces eating when stimulated
- Ablation causes anorexia and starvation
3
Q
Hypothalamus: Tuberomammillary Nucleus
A
- important in attention and arousal (actively inhibited during sleep)
4
Q
Hypothalamus: Medial Pre-optic Nucleus
A
Regulate gonadotropin secretion from adenohypophysis
- sexually dimorphic and is regulated by testosterone
5
Q
Hypothalamus: Supraoptic Area
Suprachiasmatic Nucleus
A
- dorsal to the optic chiasm
- receives direct input from retina
- critical role in control of circadian rhythmicity
6
Q
Hypothalamus: Supraoptic Area
Anterior Hypothalamic Area
A
- Sense heat and response by dissipating excess heat
- Lesion causes Hyperthermia
- Stimulatory drive of PS of ANS
7
Q
Hypothalamus: Supraoptic Area
Paraventricular Nucleus
A
- Release neuropeptides
- neurons that synthesize and release ADH, oxytocin, and CRH
8
Q
Hypothalamus: Supraoptic Area
Supraoptic nucleus
A
- Contains neurons that synthesize AVP and oxytocin
9
Q
Hypothalamus: Tuberal Region
Dorsomedial Nucleus
A
- BP regulation
- When stimulated–> aggression and savage behavior
10
Q
Hypothalamic: Tuberal region
Ventromedial Nucleus
A
- inhibits the urge to eat when stimulated
11
Q
Hypothalamic: Tuberal region
Arcuate Nucleus
A
- produce hypothalamic-releasing factors
- play a prominent role in feeding
12
Q
Hypothalamus: Mammillary region
Posterior Nucleus
A
- involved in thermoregulation
- poikilothermia
13
Q
Hypothalamus: Mammillary region
Mammillary Nucleus
A
- receive input from hippocampus via fornix
- project to ANTERIOR Nucleus of Thalamus
(mammillothalamic tract)
-Damage is associated with memory disturbances
14
Q
Hypothalamus: Major fiber tracts
A
Fornix: projections from hippocampus
Mammilliothalamic tract: projections from mammillary bodies to thalamus
Stria Terminalis: connects amygdala to hypothalamus
Medial Forebrain bundle:extends through entire hypothalamic zone
Supraopticohypophyseal: conducts fibers from supraoptic–> neurophypophysis (ADH or oxytocin)
Tuberoinfundibular: arcuate nucleus–> hypophyseal portal system (carry neuropeptide releasing or inhibiting factors on anterior pituitary cell)
Hypothalamospinal tract: regulate spinal cord preganglionic neurons of sympathetic or PS ANS
15
Q
Hypothalamus Functions
A
Homeostasis Endocrine/Electrolyte Autonomic NS (Stress response) Limbic/ emotion Body temperature, eating/feeding, satiety, metabolism, reproduction
16
Q
Lesion to Anterior Hypothalamic Nucleus
A
Hyperthermia
17
Q
Lesion to posterior hypothalamic nucleus
A
Poikolothermia
- lose cold-sensitive neurons and warm sensitive tracts
18
Q
Stress response
A
Flight or flight response
-integrate signaling from pre-frontal cortex, limbic forebrain and brainstem
19
Q
Feeding and Energy Metabolism
A
- Lateral hypothalamic area (feeding)
- Ventromedial nucleus (satiety)
- Arcuate nucleus
20
Q
Role of Leptin
A
- produced by fat cells
- acts at arcuate nucleus
- inhibits food intake and activates POMC
21
Q
Role of POMC / CART in feeding
A
Increase in satiety/ Decrease food intake
- stimulated by Leptin
22
Q
Role of AgRP/ NPY in feeding
A
Decrease satiety/ Increase food intake
- stimulated by ghrelin
23
Q
Craniopharyngioma
A
Congenital tumor originating from remnants of Rathke’s pouch
- pressure on optic chiasm results in bi-temporal hemianopsia
- pressure on hypothalamus leads to hypothalamic syndrome ( adiposity, diabetes insipidus, temp reg. distubances, somnolence)
24
Q
Hypothalamic memory disturbances
A
Posterior hypothalamic lesions involving mammillary bodies
- inability to form new memories ( episodic) for context and time specific events
25
Klein-Levin Syndrome
Hypothalamic disorder in adolescent males
- hypersomnolence
- episodic compulsive eating
- hypersexuality
associated with decrease in dopaminergic tone
26
Horner's Syndrome
Ptosis
Miosis
Anhidrosis
27
Autonomic Dysreflexia
disordered autonomic response d/t injury of the spinal cord at T6 or above
Bowel or bladder distention --> pain fibers cannot ascend--> leads to activation of local reflexive sympathetic outflow--> widespread vascoconstriction and elevated BP
Sx: Headache, hypertension, bradcardia, piloerection, pallor
28
Hirschprung's Disease
- congenital absence of myenteric plexus
- No peristalsis in denervated colon compared to proximal part of colon which becomes distended
Sx: constipation
Tx: attach normal colon to rectum
29
Hypothalamus: Anterior
```
PS area
Hyperthermia
insomnia
DI
Emaciation
```
30
Hypothalamus: Lateral
Drinking center
adipsia
Emaciation
apathy
31
Hypothalamus: Medial
```
Hyperdipsia
DI
SIADH
Obesity
Rage
Amnesia
Dwarfism
Ipsilateral Horner
```
32
Hypothalamus: Posterior
```
Sympathehtic area
hypothermia, poikilothermia
hypersomnia
coma, narcolepsy
ipsi Horner's syndrome
```
33
Hypothalamic Nuclei
Anterior: Preoptic, supraoptic, suprachiasmatic, anterior
Posterior: Posterior
Medial: ventromedial, dorsomedial, paraventricular, arcuate
Lateral: lateral tuberal nucleus, lateral hypothalamic area
34
Hypothalamic nuclei
ANTERIOR
- Anterior nuclei
- Supraptic nuclei
- Preoptic
- Suprachiasmatic nuclei
- Anterior nuclei: PS/ Cooling
- Supraptic nuclei: regulates water intake, ADH
- Preoptic: sexual & repro function (sexually dimorphic)
- Suprachiasmatic nuclei: Circadian Rhythm
35
Hypothalamic nuclei
MEDIAL:
- Ventromedial
- Dorsomedial
- Paraventricular
- Arcuate
- Ventromedial: Satiety
- Dorsomedial: Hunger/ Savage behavior
- Paraventricular: Oxytocin/ ADH
- Arcuate: Feeding & controls release of hormones
36
Hypothalamic nuclei
LATERAL
- Lateral hypothalamic area
- Lateral pre-optic
- Tuberomammillary nucleus
- Lateral hypothalamic area: Induces eating
| - Tuberomammillary nucleus: Wakefulness (activated before sleep)
37
Hypothalamic Nuclei
POSTERIOR
- Posterior nucleus
- Mammillary nucleus
- Posterior nucleus: cold sensing (lesion= poikiothermia)
| - Mammillary nucleus: project to mammillothalamic tract ( memory disturbance)
38
Diabetes Insipidus
loss of water in urine, serum sodium concentration rises (hypernatremia) d/t lack of ADH
39
Syndrome of inappropriate ADH
ADH causes water retention--> decreases sodium concentration due to water retention
40
Lesion in superchiasmatic nucleus
Fx: regulates circadian rhythm (stimulated by light hitting retina)
Sx: insomnia
(can occur in Alzheimers, people who work at night have inadequate stimulation of this nucleus)
41
Lesion in anterior nucleus
Fx: dissipate heat
Sx: hyperthermia
(Often stimulated by endogenous pyrogens) including IL1 and PGE2--> induces fever)
Tx: PGE2 inhibition by aspirin
42
Lesion in Medial Hypothalamus
Fx: regulates feeding
| Sx: obesity due to over eating
frequently due to craniopharyngioma, pituitary adenoma, also found in Prader-Willi
43
Craniopharyngioma
Tumor within hypothalamus
Primarily in children
Tumor expansion--> headaches, bitemporal hemianopia and endocrine disturbance
44
Prader-willi
Chromosomal deletion of 15q 11-13 inherited from father
| Sx: hyperphagia with eventual obesity, narcolepsy, short stature
45
Sympathetic pathway
Neurons originate in the PARAVENTRICULAR nucleus of the hypothalamus.
Descend as the descending hypothalamic fibers in brainstem (lateral in brainstem)
DHF synapase onto cell bodies in Intermediolateral cell column in thoracic cord
Pre-ganglionic neuron exits cord and enters sympathetic chain
Synapse onto ganglia
Post-synaptic neuron sends axon to target
46
Sympathetics to the eye
pre-ganglionic fiber exits IML cell column--> Sym chain--> ascends Superior Cervical Ganglion--> Post-ganglionic neuron--> ascends on ICA--> dilator muscle of pupil
47
Miosis d/t Horners
Injury to lower trunk of brachial plexus (klumpke): T1 (as DHF descend)
Pancoast Syndome: infiltration of SCG or lower brachial plexus d/t tumor
Dissection of ICA: separation of various layers of artery--> explands artery--> stretches parasympathetics traveling on artery
Cavernous sinus thrombosis: inflammation d/t embolism compress nerves traveling through the sinus
48
Pupillary light reflex
Light--> pre-tectal nucleus--> Bi-lateral innervation to Edinger-Westphal nucleus--> ciliary ganglion--> Ciliary constrictor muscle
49
Micturition inhibitory Center
Maintain continence: voluntarily inhibitor flow of urine
MIC--> Pontine micturiction center--> IML cell column activated and PS inhibited
Storage ( Internal urinary sphincter activated and detrusor relaxed)
Alpha motor neurons in S2-S4 (pudendal nerve) mediates contraction of external sphincter
50
Hyperactive Spastic Bladder
Sx: urinary incontinence
-Underactive sphincter
(too much PS innervation d/t lesion of Sym)
Tx: Anti-cholinergic
51
Hypoactive Flaccid bladder
Sx: urinary incontinence
-Overactive sphincter
(too much S d/t lesion of PS)
Tx: Anti-adrenergic or self-catheterization
52
Papez's circuit
Cingulate--> Hippocampus--> fornix--> mammilary bodies--> anterior thalamus--> cingulate
53
Expansion of Papez's circuit
includes hypothalamus, septal area, orbitofrontal cortex, nucleus acumbens and AMYGDALA
54
Fornix
Tract between hippocampus and mammillary/ septal nuclei
Major efferent
55
Mammillothalamic tract
Tract between Mammillary bodies and Ant. Thalamus
56
Perforant path
Tract between Entorhinal cortex and Dentate gyrus (hippocampus)
Major Afferent
57
Outer Core Structures and Fx:
Cingulate Cortex
Orbital Frontal Lobe
Temporal Lobe
Cingulate Cortex:
- Rostral: emotions and motor
- Caudal: visual spatial and memory
Orbital Frontal Lobe
- personality, behavioral control and self-awareness
```
Temporal Lobe (hippocampus, parahippocampus, entorhinal cortex)
- memory
```
58
Inner core Structure and Fx:
Hypothalamus
Amygdala
Septum
Hypothalamus: pleasure center, autonomic, endocrine integration
Amygdala: Preservation of self, emotion, social behavior, aggression and defense response, sexual behavior, affect of faces, affective regulation
Septum: preservation of species, sexual behavior and emotionality
59
Stria Terminalis
Tract between amygdala with septum, hypothalamus, nucleus accuumbans
60
Ventral amygdalofugal
Connects amygdala with hypothalamus, brainstem and septum
61
Medial Forebrain bundle
tract between the hypothalamic nuclei and amygdala and brainstem nuclei
62
Kluver Busy Syndrome
Cause: bilateral lesion in temporal lobe including amydala, hippocampus and uncus
(Loss of connection)
Sx:
- increased oral activity
- Hypersexuality
- Hypermetamorphosis
- Placidity: flattened affect, lack of aggressive behavior/ fear
- Visual agnosia: loss of recognition of people
- Bulimia
63
Geshwind Syndrome
Sensory limbic hyperconnection
Strengthening of synaptic connections
- increased concern with philosophical, cosmic or religious issues
- Hyposexuality
- Hypergraphia
- Viscosity
64
Addictive drugs
Produce potent effects by enhancing mesolimbic DA activity
65
Lesion to Ventromedial nucleus
Sx: produces pain, rage or strong aversive reactions, long lasting hyperemotionality
(stimulation of Dorsolateral also produces rage)
66
Lesion to Amygdala
Fx: Modulation of experience of emotional reactions
- normal social interactions
- role in integration of emotions, fear and memory
Lesion: tameness or reduced emotionality
67
Lesion to Septal Area
Sx: increased sexual activity d/t damage from VP shunts
Tumor: results in rage like attacks and increased irribility
68
Lesion to hippocampus
Sx: amnestic state
- Declarative (explicit) memory: Acquisition of facts and events
- episodic: personal events
- Semantic: facts
69
Wernicke Korsakoff Syndrome
Due to chronic alcoholism and nutritional deficiency (thiamine)
Acute encephalopathy: confusion, disorientation, oculomotor dysfunction, ataxia
Chronic: retrograde amnesia
70
Cingulate gryus
Anterior: emotion and motor
Posterior: visuospatial and memory
Lesion: Contralateral neglect (attention)
Sx: apathy, disinhibition, placidity, depression, anxiety, OCD, heightened sexuality, bulimia
Akinetic Mutism
71
Tourette
Abnormality in anterior cingulate gyrus--> Affective vocalization
Associated with OCD
Excessive emotional signals (anxiety), motor (tics),
Excessive filtering of emotions and motor behavior ( apathy, akinesis, mutism)
72
Orbital frontal lobe syndrome
Disinhibited, tactless, bawdy, boastful, impulsive, inattentive, dress carelessly
73
Frontal/Convexity or dorsolateral
Apathetic, slow, little initiative or spontaneity, vacant expression
74
Medial Frontal
Akinetic mutism, inert, speechless, loss of drive to speak,
| "motionless, mindless, wakefulness"
75
Primary Motor cortex
Control Contralateral movement
- reduced function causes contralateral hemi-paresis
- Activation ( seizure) causes contralateral clonic movements
76
Jacksonian march
seizure in primary motor cortex that travels along gyrus and activates muscle seen on motor homuculus
77
Frontal Eye Fields
Voluntary eye movements to the contralateral field
| Lesion causes ispilateral gaze preference
78
Broca's Area
Fluency of language
Lesion: Broca's aphasia= non-fluent aphasia, halting, effortful, few words
(MCA)
79
Pre-frontal cortex
Provides order
| mediates personality, executive function, ability to sequence and organize tasks, abstract, problem solving
80
Orbital frontal cortex
Provides Restraint
| - inhibits socially inappropriate behavior
81
Pick's Disease
Frontotemporal dementia: progressive dementia
- affects prefront cortex first ( personality change, irritability, mood changes)
(atrophy of fronto-temporal)
82
Mesiofrontal cortex
Provides Initiative
-Mediates motion, goal-directed behavior, MIC
lesion: Akinetic mutism, abulia, incontinence
Cause: NPH (stretch fibers)
83
Gerstmann syndrome
Agraphia
Acalculia
Finger agnosia
R/L confusion
Lesion of dominant parietal cortex (angular gyrus)
84
Wernicke's area
- comprehension of language
- Fluent aphasia
- non-sensical gibberish
MCA
85
Conduction aphasia
- inability to repeat, mediated by arcuate fasciulus
86
Global aphasia
loss of comprehension, repetition and fluency
87
Hemianopia with macular sparing
- dual blood supply to occipital oole
| - primary blood supply is PCA (secondary is MCA)
88
Balint syndrome
Lesion of Occipital- Parietal pathway (where)
- spatial relations
- Simultanagnosia: inability to perceive visual field as whole
- Optic ataxia: inability to reach for objects
- Ocular apraxia: inability to look at objects in visual field using saccades
Cause: MCA/PCA watershed infarcts
89
ACA-MCA watershed infarcts
```
Cerebral hypoperfusion (stenosis of ICA)
- Man in a barrel syndrome: torso and shoulder paralysis with sparing of the hands and feet
```
