L1: Genetics, Neurosnatomy & Biochemistry of Behavior Flashcards
Studies for Examining The Genetics of Behaviour
- Family Risk Studies
- Twin Studies
- Molecular Studies
Family Risk studies
Def of Twin Studies
Adoption studies using monozygotic twins or dizygotic twins and reared in the same or in different homes.
Importance of Twin Studies
used to differentiate the effects of genetic factors from environmental factors in the occurrence of psychiatric disorders.
Outcome of Twin Studies
If there is a genetic component to the etiology, a disorder may be expected to have a higher concordance rate in monozygotic twins than in dizygotic twins.
(i.e. if concordant, the disorder occurs in both twins).
Molecular Studies
Is Intelligence Genetic or Environmental?
Divisions of Brain
- Anatomically
- Functionally
- By arrangement of neuron layers or cytoarchitecture.
Functional Divisions of Brain
Anatomical Divisions of Brain
Connections between the two hemispheres
functions of the hemispheres are lateralized, how?
Sex differences in cerebral lateralization
What does a lesion in Frontal lobe cause?
Mood changes:
- dominant hemisphere lesions → depression
- non-dominant hemisphere lesions → mood elevation
What does a lesion in Dorsolateral area of Frontal lobe cause?
Difficulties with motivation, concentration, attention,
orientation and problem solving
What does a lesion in Orbitofrontal area of Frontal lobe cause?
- Difficulties with judgment, inhibitions, emotions.
- Personality changes
What does a lesion in Broca’s area of Frontal lobe cause?
- Inability to speak fluently
What does a lesion in Temporal lobe cause?
- Impaired memory
- Psychomotor seizures
- Changes in aggressive behavior
- dominant lesions —-> Inability to understand language (i.e. Wernicke’s aphasia)
What does a lesion in Parietal lobe cause?
What does a lesion in Occipital lobe cause?
- Visual hallucinations and illusions.
- Inability to identify camouflaged objects.
- Blindness.
What does a lesion in Limbic lobe cause?
What does a lesion in Hypothalamus cause?
- Ventromedial nucleus damage > incresed appetite leading to obesity
- Lateral nucleus damage → decreased appetite leading to weight Loss
- Effects on sexual activity and body temperature regulation.
What does a lesion in Reticular system cause?
- Changes in sleep-wake mechanisms (e.g., / REM sleep)
- Loss of consciousness
What does a lesion in Basal Ganglia cause?
What does a lesion in Substantia nigra cause?
Parkinson disease
What does a lesion in Caudte & Putamen cause?
Huntington disease
What does a lesion in Caudate cause?
Tourette syndrome
Devisions of ANS
sympathetic & parasympathetic
Functions of ANS (Related to Psychology)
- Innervates the internal organs to coordinate emotions with visceral responses such as heart rate, blood pressure, and peptic acid secretion.
- Visceral responses to a psychological stress are involved in the development and exacerbation of some physical illnesses
what are types of memory systems?
- Declarative (explicit or conscious) involves the knowledge of acts
- Non-declarative (implicit or unconscious) how to perform an act
Types of Declarative memory (explicit or conscious)
- Episodic
- Semantic
Anatomy associated to Episodic memory
- Temporal lobes (medial)
- anterior thalamic nuclei
- fornix
- hippocampus
- mammillary bodies
- prefrontal cortex
Length of recall of Episodic memory
Long term
Episodic Memory used to remember ….
Personally experienced events
e.g., what you ate yesterday
Anatomy associated with Semantic memory
Inferolateral temporal lobes
Length of Recall in Semantic memory
Long term
Semantic memory used to remember …..
General knowledge about the world
e.g.. the capital of New Jersey
Types of Non-declarative (implicit or unconscious) memory
- Procedural
- Working
Anatomy assoiated with Procedural Memory
- Cerebellum
- basal ganglia
- supplementary motor area
length of recall in Procedural Memory
Long term
Procedural Memory used to remember …….
Things you do automafically
e.g., how to tie your shoes
Anatomy associated with Working memory
- Prefrontal cortex
- Language and visual-association areas
Length of recall in Working memory
Short term
Working memory used to remember …….
Recent information
E.g: the phone number just obtained from a new acquaintance
Def of Neuronal plasticity
The changeability of number or affinity of receptors or specific neurotransmitters
Steps of Transmission of neuronal information
Importance of Neuronal plasticity
can regulate the responsiveness of neurons
Def of Presynaptic and postsynaptic receptors
proteins present in the membrane of the neuron
Function of Presynaptic and postsynaptic receptors
can recognize specific neurotransmitters
Effect of Neuritransmitter on Presynaptic and postsynaptic receptors
classification of neurotransmitters
Regulation of neurotransmitter activity
Psychiatric Conditions and Associated Neurotransmitter Activity
Synthesis of Dopamine
Receptor of Dopamine
At lease five dopamine receptor subtypes (D1 -D5) have been identified
Site of action for antipsychotic agents
- traditional antipsychotic agents → D2 (major site of action).
- newer “atypical” antipsychotic agents → D1 and D4 as well as D2.
what are Dopaminergic tracts?
- nigrostriatal tract
- mesolimbic-mesocortical tract
- tuberoinfundibular tract
nigrostriatal tract
mesolimbic-mesocortical tract
tuberoinfundibular tract
Synthesis of Serotonin
Levels of serotonin and assossiated behavioral changes
site of serotonergic cell bodies
Antidepressants and serotonin
Significance of Norepinephrine
- As a catecholamine, it plays a role in mood anxiety, arousal learning, and memory.
Synthesis of Norepinephrine
Site of Noradrenergic Neurons
Most of them (Approximately 10000 per hemisphere) are located in the locus cerelus in brainstem.
Serotonin & associated Psychopathology
NE & associated Psychopathology
Dopamine & associated Psychopathology
Characters of Histamine
- It’s an ethylamine
- affected by psychoactive drugs.
Significance of Histamine
Histamine receptor blockade with drugs such as antipsychotics and tricyclic antidepressants is associated with common side effects of these drugs such as:
- sedation
- Increases appetite leading to weight gain.
Characters of acetylcholine
- quaternary amine
- it’s the transmitter used by nerve-skeleton-muscle junctions
Synthesis & Degradation of acetylcholine
Degeneration of cholinergic neurons is associated with ……….
Alzheimer disease, Down’s syndrome, and movement and sleep disorders (e.g., decreased REM sleep)
Blocking the action of AchE with drugs such as …….. may ………..
- donepezil (Aricept), rivastigmine (Exelon), and galantamine (Reminyl)
- delay the progression of Alzheimer disease but cannot reverse the function already lost.
Blockade of muscarinic Ach receptors with drugs such as antipsychotics and Tricyclic antidepressants results in:
- the classic “anticholinergic” adverse effects seen with the use of these drugs, including dry mouth, blurred vision, urinary hesitancy, and constipation.
- central anticholinergic effects such as confusion and memory problems.
Anticholinergic agents are commonly used to treat the ……… caused by antipsychotic agents.
Parkinson-like symptoms caused by
Significance of Glutamate
- It’s an excitatory neurotransmitter
- It contributes to the pathophysiology of neurodegenerative illnesses such as Alzheimer’s disease and schizophrenia.
Role of Glutamate in AD
The mechanism of this association involves:
- activation of the glutamate receptor N-methyl-d-aspartate (NMDA) by sustained elevation o glutamate.
- Such activation results in calcium ions entering neurons leading to nerve cell degeneration and death through excitotoxicity.
How to treat AD using Memantine?
Memantine (Namenda), an NMDA receptor antagonist:
- ultimately blocks this influx of calcium.
- indicated for patients with moderate to severe Alzheimer’s disease.
Synthesis of GABA
- It is synthesized from glutamate by the enzyme glutamic acid decarboxylase, which needs vitamin B6 (pyridoxine) as a cofactor.
…….. is the principal inhibitory neurotransmitter in the CNS.
GABA
GABA is closely involved in the action of ……….. agents such as benzodiazepines (e.g., diazepam [Valium]) and barbiturates (e.g., secobarbital [Seconal])
antianxiety
GABA is closely involved in the action of antianxiety agents such as benzodiazepines (e.g., diazepam [Valium]) and barbiturates (e.g., secobarbital [Seconal]) how?
Endogenous opiods
- Endogenous opioids such as enkephalins, endorphins, dynorphins, and endomorphins are produced by the brain itself.
- They act to pain and anxiety and have a role in addiction and mood.
Placebo effects & Neuropeptides
- Placebo effects may be mediated by the endogenous opioid system. For example, prior treatment with an opioid receptor blocker such as naloxone can block placebo effects.
Done
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