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Main structures of limbic system

- hippocampus and parahippocampal gyrus
- amygdala
- entorhinal cortex
- cingulate cortex
- prefrontal cortex
- septal nuclei

1

Mirror neurons

premotor and parietal cells (in ventral premotor and rostral inferior parietal lobe areas)
- fire similarly when self performs action OR watch action performed
--> neurophysiological mech for imitation and empathy

2

Autism and empathy

reduced activity shown in frontal lobe in response to facial expressions,
--> reduced empathy matched w/ reduced mirror neuron activity

3

Antipsychotic drugs

high binding affinity to dopamine D2 receptors = high effectivity,
1st gen: Chlorprozamine, haloprol
-- side effects: sedation, hypotension
2nd gen: "Atypical" ie: clozapine (fewer side effects)

4

Antidepressant drugs

increase monoamine transmission by...
a) inhibit neuronal reuptake
b) inhibit degradation (enzymatic --> MAO-A/B)

5

Korsakoff's Syndrome

Thiamine (B12) deficiency, = severe neurological disorder
* esp. in chronic alcoholism.
= damage to medial thalamus and mammillary bodies
--> amnesia, confabulation, apathy and decreased insight

6

Poikilothermic

= manner of body temperature regulation,
where change behavior to reach set pt temp.
(in reptiles and amphibians)

7

Cingulate Gyrus

responsible for motivation,
- Output to Hippocampus
- feedback Input from Anterior Thalamic nucleus

8

Prefrontal cortex

==> goal-directed behavior, moral reasoning and logical processing.
inhibits Amygdala.

9

Hippocampus

responsible for learning and memory (esp. declarative and spatial);
Input = from Cingulate gyrus
Output = to Septal nuclei and Mammillary bodies

10

Mesolimbic System

=> pleasure, addiction, euphoria, etc.
*uses Dopamine as NT, stimulated by cocaine and amphetamines
parts:
PFC, Amygdala, Hippocampus

11

amygdala

part of limbic system, for emotional memories;
* inhibited by Prefrontal cortex
Output: to Septal nuclei and Hypothalamus

12

Septal Nuclei

for reward and associative learning,
* lesion --> decreased fear conditioning
- associated w/ nucleus basalis of Meynert (& Alzheimer's)

13

Hypothalamus

in limbic system: regulates stress,
* uses NE as NT*
input = from amygdala and septal nuclei
Output = to brainstem/spinal cord (+ Raphe nuclei)

14

Raphe Nuclei

= in brainstem and spinal cord,
* use serotonin (5-HT) as NT

15

anterior thalamic nuclei

in limbic system, --> alertness.
* feedback to cingulate gyrus
input = from mammillary bodies

16

Urbach-Weithe Disease

bilateral calcifications of Anterior Medial Temporal lobe and Amygdala;
--> decreased emotional processing, loss of emotional memory,
*** decreased fear conditioning!

17

Post-Traumatic Stress Disorder

increased activity in amygdala and hypothalamus bc decreased PFC activity.
--> hyperarousal, avoidance of similar situations, anxiety, flashbacks

18

Schizophrenia

--> enlarged lateral ventricles and cortical thinning,
= fragmented thought process, decreased emotional response.
+: delusion, hallucination
-: apathy, social withdrawal, decreased working memory and executive f(x)
Treatment: serotonin/dopamine R agonists

19

Major Depressive Disorder

decreased monoamine f(x) --> decreased activity of Ant. Cingulate gyrus and Septal Nuclei/Nuc. Accumbens
*MA gene modulation by CREB
treatment: MAO inhibitors, SSRIs (block reuptake), DBS

20

Alzheimer's Disease

Hippocampal and PFC deficits, neurodegenerative
* amyloid plaques & neurofibrillary tangles (entire neocortical surface!)
- genetic (100%) if APP, PSEN1/2 mutations
- sporadic: increase risk if have ApoE2,3,4 polymorphism
--> dementia, poor planning/spatial/judgement, change mood

21

Chronic Traumatic Encephalopathy ("CTE")

from concussions/head trauma (to PFC and Cingulate cortex),
cortex shrinks and ventricles enlarge, increased tau deep in brain.
--> depression/suicide/mood disorders

22

posterior pituitary function

releases:
1. vasopressin --> vasoconstrict & increase H2O resorption
2. Oxytocin --> milk ejection, uterine contraction, sexual arousal/ejaculation

23

Anterior Pituitary Function

releases:
1. GH (I-- somatostatin)
2. Prolactin (I-- Dopamine)
3. TSH/FSH/LH
4. ACTH/B-endorphin

24

Diabetes Insipidus:

due to decreased vasopressin secretion,
Treatment: vasopressin analog that = anti-diuretic but Not vasoconstrictor;

25

Galactorrhea-Amenorrhea

disease: hyperProlactinemia + stop menstruating.
#1 cause: micro-adenoma in pituitary
--> increase prolactin, decrease LH and FSH
Treatment: 1. Dopamine R agonist
2. Surgery to remove tumor