Psychobiology Test 1 Flashcards
(17 cards)
Define Psychobiology
the scientific study of the biology of cognition and behaviour.
Psychobiology Encompasses?
- Physiological Psychology: neural mechanisms of behaviour via direct manipulation & recording of brain in experiments
- Psychopharmacology: similar to PP but manipulates neural activity and behaviour via drugs
- Neuropsychology: psych. effects of brain damage
- Psychophysiology: relations between physiological behave & psych. Processes
- Cognitive Neuroscience: neural basis of cognition
- Comparative Psychology: behaviour of different species understand evolution, genetics and adaptiveness.
Gross Neural Structure
CNS:
Cluster of Cell Bodies= Nuclei
Bundles of Axons= Tracts
PNS:
Cluster of Cell Bodies= Ganglia
Bundles of Axons= Nerves
Glia Cells
CNS:
Oligodendrocytes: produces myelin for axons
Astrocytes: secures neurons to their blood supply brain-blood barrier
Microglia: protects neurons from pathogens via macrophages
Ependymal cells: produces cerebrospinal fluid
PNS
Schwann Cells: produce myelin
Satellite Cells: regulates external chemical environment, particularly calcium ions
Anatomy of Spinal Cord
- 31 vertebrae protect the spinal cord + maintains posture & enables muscle attachment
o Relays sensory (afferent) info to brain
o Sends motor (efferent) responses to body
o Also enables simple reflexive actions (e.g. withdrawal reflex
Divisions of the Brain (Forebrain)
Diencephalon
Thalamus
o relay station for S. and M. info
Hypothalamus o regulates eating, sleep, sexual behaviour and hormones from pituitary gland
Resting Membrane Potential
=difference between voltage inside & outside cell (rest= -70mV)
Extrasellar= Sodium (Na+) & Chloride (Cl-)
Intracellular= Potassium (K+) & organic anions
How is RMP maintained?
- Electrostatic Pressure
- Concentration gradient (ions move down the gradient, i.e. from high to low)
- Sodium/Potassium Pumps (removes Na+ and brings in K+)
Postsynaptic Potentials
When neurotransmitters bind to receptor sites on adjacent neurons, they may:
- Depolarise: excitatory post synaptic neuron (EPSP)
- Hyperpolarise: inhibitory post synaptic neuron (IPSP)
(threshold= -65mV)
AP Process:
- Voltage-Gated Na+ Channels open (Threshold met)
- Influx of Na+ depolarises intracellular region rapidly
- Na+ Channels close & Voltage-gated K+ channels open
- K+ Flows out Repolarisation (+ brief hyperpolarization)
- Ion balance is restored by Na+/K+ Pump Resting Membrane Potential
Exocytosis (Releasing Neurotransmitters)
- AP reaches terminals triggers release of NT
- Voltage-gated Ca2+ Channels Ca2+ influx causes vesicle fusion
- Small/Large NT release into synapse
After AP at synapse
- Receptor binding with NT at postsynaptic neurons dendrites excite or inhibit
- Deactivation Mechanisms: Reuptake of NT (NT return) and Enzymatic Degeneration (enzymes breakdown NT)
- Recycling: NT or broken-down ones are reused
=Chemical messengers b/w neurons (Small or Large)
Small vs Large NT
Small:
- Amino acids (glutamate, GABA)
-Monoamine (Dopamine, norepinephrine, epinephrine)
-Acetylcholine
Large
=slower, longer lasting and greater diffusing
Neuropeptides:
- Pituitary Peptides (e.g., oxytocin, vasopressin).
- Hypothalamic Peptides (various releasing hormones).
- Brain–Gut Peptides (e.g., substance P).
- Opioid Peptides (e.g., endorphins).
- Miscellaneous Peptides (others).
Agonists vs Antagonists
Agonists
Mimic/enhance NT
- Direct Receptor Activation: Ag. Binds to receptors same activation as NT
- Boost Release: stimulates more NT release
- Block Deactivation: blocks reuptake continued stimulation at receptors
Antagonists
Block/diminish NT
- Receptor Blockers: prevents NT stimulation
- Reduce Synthesis: less NT produced and so released reduced stimulation
- Prevent Release: less NT block vesicles reduced stimulation
Drug Tolerance
= decreased sensitivity to drugs with repetitive use.
2 Demonstrations
1. Same Dose Less Effect
2. Higher Dose Same Effect
Withdrawal & Physical Dependence
Withdrawal= occurs during cessation of prolonged use opposite symptoms of drugs effects
Physical-dependence Theories
Drug taking withdrawal cycle.
Emphasises negative reinforcement (avoidance of withdrawal).
Why It Falls Short
- Some highly addictive drugs (e.g., cocaine, amphetamines) produce mild withdrawal but are extremely addictive.
- Users can binge and detox repeatedly without breaking addiction.
- Detox alone often fails; relapse can occur long after withdrawal subsides.
