Exam 3 Flashcards
What is Diffusion Tensor Imaging (DTI)?
o Type of structural MRI
o Measures patterns of movement/diffusion of H2O and O2
o Reveals integrity/density of axon fibers
o Measure of connectivity
What are the four ventricles called?
o Lateral (1st & 2nd)
o 3rd
o Cerebral aqueduct
o 4th
What are the ventricles filled with?
Ventricles are filled with Cerebrospinal fluid (CSF)
What sensory/ motor areas are in the frontal lobe?
- Primary motor cortex
- Prefrontal cortex- planning, problem solving, working memory
- anterior cingulate cortex
*.olfactory cortex - gustatory cortex
What sensory/ motor areas are in the temporal lobe?
- Primary auditory complex
- olfactory cortex
- Object, face recognition
What sensory/ motor areas are in the parietal lobe?
- Perception of spatial relations, action planning
- Primary somatosensory cortex
What sensory/ motor areas are in the occipital cortex?
visual cortex
What are the steps of neurotransmitter release?
1.Action potential propagates from soma
2.Action potential arrival at synapse triggersneurotransmitter (NT) release
3.NTs diffuse across synaptic cleft & bind to next neuron
What measure(s) of brain structure or function decline in childhood and adolescence?
Total grey-matter increases minimally
Myelination slows down
Cubic, quadratic, or linear declines in cortical thickness
Where do cells that can make new neurons & glia in adult mammals reside?
Most are found near the ventricles, neural progenitor cells/ stem cells
How do mammalian brains compare?
o Vertebrates have similar brain plans
o Species differ in relative size of parts
o Brain sizes scale with body size
Some animals have big brains for their bodies
o Humans
o Crows
o Porpoises
How does the human cerebellum size compare to non-human animals?
Cerebellum is comparable to other animals, including other primates
What does the monoamine hypothesis of depression include?
o More: euphoria
o Less: depression
o Reserpine (antagonist for NE & 5-HT) can cause depression
o Low serotonin (5-HT) metabolite levels in CSF of suicidal depressives Samuelsson et al. (2006)
What is the Evidence for link between serotonin dysfunction and depression- Measuring serotonin (5-HT)?
o CSF, platelets, plasma, urine, saliva
o CSF & platelets correlate highly Audhya, Adams, and Johansen (2012)
o But, salivary 5-HT does not correlate with mood symptoms Leung et al. (2018)
What is an SSRI?
Selective Serotonin Reuptake Inhibitors (SSRIs)
o Fluoxetine (Prozac, Paxil, Zoloft)
o Prolong duration of 5-HT in synaptic cleft
o Also increase brain steroid production
What is an SNRI?
SNRI- Selective Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
What is ECT and how is it used?
Electroconvulsive Therapy
* Last line of treatment for drug-resistant depression
* Electric current delivered to the brain causes 30-60s seizure.
* ECT usually done in a hospital’s operating or recovery room under general anesthesia
* Once every 2 - 5 days for a total of 6 - 12 sessions.
* Remission rates of up to 50.9% Dierckx et al. (2012)
* Seems to work via
o Anticonvulsant (block Na+ channel or enhance GABA function) effects
o Neurotrophic (stimulates neurogenesis) effects
What are the treatments for bipolar disorder?
- Anti-depressants not especially effective Sidor and MacQueen (2012)
- Mood stabilizers
o Lithium (Li)
o Valproate (Depakote) - Anticonvulsants
o Typically used to treat epilepsy
o GABA agonists
o e.g. lamotrigine (Lamictal) - Atypical antipsychotics
- Psychotherapy
- Electroconvulsive Therapy (ECT)
- Sleep medications
What are the risk factors for depression and schizophrenia?
Higher risk in people with hereditary history +environmental factors, especially monozygotic twins
What brain abnormalities are linked with schizophrenia?
Larger ventricles, especially in males
Smaller hippocampus, amygdala, thalamus, nucleus accumbens
May have rapid grey matter loss in adolescents
Widespread disruption in white matter connectivity
Increased white matter loss over age
What is the dopamine hypothesis for schizophrenia?
- DA (D2 receptor) antagonists (e.g. chlorpromazine)
o improve positive symptoms - Typical antipsychotics are DA D2 receptor antagonists
- DA agonists
o amphetamine, cocaine, L-DOPA
o mimic or exacerbate symptoms - Tardive Dyskinesia a side effect of DA antagonists
What are the flaws for the dopamine hypothesis of schizophrenia?
- Evidence against DA hypothesis…
o New, atypical antipsychotics
(e.g. Clozapine) INCREASE DA in frontal cortex, affect 5-HT
o Mixed evidence for high DA metabolite levels in CSF
What is the alternative to the dopamine hypothesis for schizophrenia?
glutamate hypothesis
* Psychomimetic drugs…
o Phencyclidine (PCP), ketamine
o NMDA receptor antagonists (NMDA glu + voltage-gated)
* …can induce schizophrenia-like states
* Schizophrenia -> underactivation of NMDA receptors?
o Related to NMDA receptor role in learning, plasticity
What is the locations account for emotion?
brain hypothesized to be associated with emotion categories:
Disgust- insula
Anger-OFC
Sadness- ACC
Fear-Amygdala
What is the constructionist account for emotion?
- assumes that emotions are psychological events that emerge out of more basic psychological operations that are not specific to emotions. In this view, mental categories such as anger, sadness, fear, etc, are not respected by the brain. Emotions emerge when people make meaning out of sensory input from the body and from the world using knowledge of prior experiences.
What are the focal points of Plutchik’s perspective?
Emotions…
* Vary in valence
o Positive/negative
* Vary in intensity (arousal)
* Vary in action tendency
o Approach/avoid
* Emotions (can) serve biological goals
o Ingestion
o Defense
o Reproduction
o Affiliation
Compare humans and non-human behaviors/ physiology
Fear and stress response similar to humans
What are the neurotransmitters involved in affective states, and what emotions are they linked to?
Happiness- Dopamine, Serotonin, Norepinephrine, Acetylcholine
Acute stress: cortisol (hormone), norepinephrine, epinephrine
What are the nodes in the rewarding circuit
-ventral tegmental area in midbrain
-nucleus accumbent, ventral striatum
-Hypothalamus
-Amygdala
-Hippocampus
-Dorsal Nucleus/ locus Coeruleus
-Prefrontal cortex
Prefrontal cortex
* Endorphins: Endogenous morphine-like compounds
o e.g., morphine, heroin, oxycontin (oxycodone) are opioids
* Endogenous cannabinoids
o Cannabinoids == psychoactive compounds found in cannibis
o Cannabinoid receptors: CB1 in CNS; CB2 in body, immune system
What brain sites release dopamine
Ventral tegmental area and the substantia niagra
what are the typical cortisol release patterns?
- ACTH (hypothalamus) -> CRH (anterior pituitary) ->
- Adrenal cortex releases cortisol
o Increases blood glucose levels
o Suppresses immune system
o Reduces inflammation
o Aids in metabolism - Receptors in brain and body
- Cortisol receptors in hippocampus, amygdala, hypothalamus
o Hippocampus regulates HPA axis via hypothalamus - Prolonged cortisol exposure reduces hippocampus response
o Reduces volume, connectivity in hippocampus - Hippocampus critical for long-term memory formation
o Chronic stress impairs long-term memory - But, cortisol -> stress link not straightforward
What is the difference between acute stress and chronic stress?
- Acute stress
o Short duration
o Fast action required
o HPA (Cortisol), SAM (NE/Epi) axes
o Brain detects threat
o Mobilizes physiological, behavioral responses - vs. Chronic stress
o Long duration, persistent
What is the interoceptive sensory system?
How am I? deals with inside state and body position in relation to space
What is the exteroceptive sensory system?
What is in the world, and where it is
What are the properties of the cutaneous (skin) receptors?
o Cutaneous (receptors in the skin) senses
o Hot, cold
o Pressure
o Vibration
Plus Kinesthesia
* Receptors specialize in different info types, properties
Why do spicy tasting foods also seem hot?
o Taste dimension -> chemo receptor ≠ temperature dimension
o Why are minty foods cool?
o Why are spicy foods hot?
o Receptors that sense chemicals AND temperature
o Menthol/mint receptor (CMR1)
o Also signals “cool” temperatures
o Vanilloid Receptors (TrpV1/VR1, VRL1)
o Respond to capsaicin (in peppers), allyl isothiocyanate (in mustard, wasabi)
o Also signal “hot” temperatures
What sensory signals propagate quickly and which one’s p[propagate slowly?
Fastest- proprioception (muscles/movement in space)
Then touch, then pain/ temp., then pain/itch
Thickness and myelination plays a role in speed
Free Nerve Endings
pain, temperature
Merkel’s disc
touch
Pacinian corpuscle
vibration
Ruffini’s ending
stretch
Meissner’s corpuscle
touch
