Function of various regions in the brain Flashcards
Amygdala esp. lateral/basolateral nucleus of the amygdala
Fear conditioning from senses. Sends to central nucleus to respond.
Amygdala lesion causes
Urbach-Wiethe disease (impairment of fear)
Korsakoff
Lesion of mamillary body and dorsomedial thalamic nucleus
Hypothalamus and mamillary body
Emotional responses
Anterior cingulate gyrus (subgenual sector)
The ability to feel happy, sad.
Depression etiology
Impaired anterior cingulate gyrus (subgenual sector)
Posterior cingulate gyrus
Increases activity during happiness vs sadness
Hypothalamus (emotion)
Increases activity during anger vs fear
Episodic memory
medial temporal lobe
Semantic memory
Medial temporal lobe
Procedural memory
Striatum, cerebellum
Operant conditioning A-B-C
Antecedent - Behavior - Consequence
Operant conditioning reinforcement
Extinction
Punishment
Positive & negative reinforcement
What type of reinforcement is this: You hit a dog to stop them from biting you.
Punishment
What type of reinforcement is this: you give a dog a treat to continue licking you.
Positive reinfocement
What type of reinforcement is this: You stop giving a dog belly rubs when he bites you.
Extinction
What type of reinforcement is this: You stop pulling on your dog’s leash when he stops pulling on it.
Negative reinforcement
Papez circuit is…
Emotional modulation + long-term memory formation
Papez circuit components
- Hippocampus X H.Molaison, Khluver-Bucy syndrome
TRACT: FORNIX - Mamillary body X N.A. (fencing accident), Korsakoff’s
TRACT: MAMILLOTHALAMIC T. - Thalamus : anterior nucleus
TRACT: ANTERIOR LIMB OF INTERNAL CAPSULE (THALAMOCINGULAR FIBERS) - Cingulate gyrus
TRACT: CINGULUM - Hippocampus
Hippocampus fxn
new longterm memories
Schizophrenia has increased __ and decreased __ .
Striatal dopaminergic fxn, prefrontal cholinergic
FEF
Commander of horizontal conjugate eye movements (saccade). Only component of the tract that is contralateral.
MLF lesion: Internuclear ophthalmoplegia due to stroke, MS
Ipsilateral eye cannot move to desired position. Other eye develops nystagmus due to diplopia and FEF commands.
Adduction impairment of ipsilateral eye.
Abducting nystagmus of contralateral eye.
Preserved convergence.
Uncontrolled saccade
Omnipause neuron lesion
@ Dorsal raphe nuclei, responsible for both horizontal and vertical saccades
Excitatory burst neuron
Signals to contract lateral rectus. @ PPRF, riMLF
Neural integrator
Maintains muscle tone @ interstitial nucleus of Cajal (vertical)
Gaze-evoked nystagmus (cannot maintain at full right gaze)
Neural integrator lesion. Lower brainstem lesion, cerebellar lesion, vestibular lesion.
PATTERN GENERATOR
Vertical gaze center =
horizontal gaze center =
Rostral interstitial nucleus of MLF = riMLF
PPRF
Posterior commisure
Bilateral projection from riMLF to CN III and CN IV nuclei
Vertical gaze palsy e.g. parinaud, dorsal midbrain
Pinealoma compressed posterior commissure fibers that control upward gaze but preserved light reflex in convergence (Light-near disassociation, Pseudo Argyll-Robertson pupils) due to preserved supraoculomotor nuclei
Superior colliculus
Integration of motor and visual information required for saccade. Can take over after FEF lesion recovery.
Smooth prusuit higher centers
FEF, IPS, TEF (temporal eye field)
Pattern generator smooth pursuit
Dorsolateral pontine nuclei ipsilateral side –> cerebellum –> vestibular nuclei –> MLF to CN III, IV, VI
Supraocolumotor nuclei
Sends accomodation reflex commands to CN III nuclei and EW n.
VOR causes the head to move to the __ when the left CNVIII is stimulated
RIGHT
Away from excitation
The fast phase of nystagmus wants to
Correct to neutral position
OKR VS VOR
Optokinetic reflex overrules VOR if the scene is moving.
The eyes’ slow phase moves following scene, fast phase attempts to correct to neutral position
