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Questions and Answers
What is the primary area of the brain involved in behavior?
What is the primary area of the brain involved in behavior?
The left hemisphere of the brain is responsible for image processing.
The left hemisphere of the brain is responsible for image processing.
False
Name one main neurotransmitter involved in behavior regulation.
Name one main neurotransmitter involved in behavior regulation.
Dopamine
The _______ is the study of the biological mechanisms of normal and abnormal behavior.
The _______ is the study of the biological mechanisms of normal and abnormal behavior.
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According to the Rescola-Wagner Rule, the amount learned is proportional to:
According to the Rescola-Wagner Rule, the amount learned is proportional to:
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Match the following functions with the corresponding hemisphere of the brain:
Match the following functions with the corresponding hemisphere of the brain:
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Memory retention improves with more learning.
Memory retention improves with more learning.
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Describe the Law of Diminishing Returns in learning.
Describe the Law of Diminishing Returns in learning.
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What led to Tom being hospitalized?
What led to Tom being hospitalized?
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Tom is definitely not allergic to kale.
Tom is definitely not allergic to kale.
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What was the reward presented to the monkey in the experiment?
What was the reward presented to the monkey in the experiment?
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The monkeys in the experiment associated the visual cue with the __________.
The monkeys in the experiment associated the visual cue with the __________.
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Match the following terms with their meanings:
Match the following terms with their meanings:
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What happened to the monkey's brain activity when the reward was not presented after the visual cue?
What happened to the monkey's brain activity when the reward was not presented after the visual cue?
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The monkey showed more action potential once it learned that the reward followed the visual cue.
The monkey showed more action potential once it learned that the reward followed the visual cue.
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What occurs when an outcome is predicted in terms of learning?
What occurs when an outcome is predicted in terms of learning?
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What happens when a monkey predicts a reward?
What happens when a monkey predicts a reward?
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In humans, greater activity in the Nucleus Accumbens occurs during predictable trials.
In humans, greater activity in the Nucleus Accumbens occurs during predictable trials.
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What is the role of the VTA in learning?
What is the role of the VTA in learning?
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In the experiment with rats, over-expectation is when they anticipate _____ rewards instead of the actual amount presented.
In the experiment with rats, over-expectation is when they anticipate _____ rewards instead of the actual amount presented.
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Match the conditions with their outcomes in the experiments mentioned:
Match the conditions with their outcomes in the experiments mentioned:
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What was the outcome of the baby experiment when a car went through a block without making a sound?
What was the outcome of the baby experiment when a car went through a block without making a sound?
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Inactivating the orbitofrontal cortex inhibits the VTA prediction error.
Inactivating the orbitofrontal cortex inhibits the VTA prediction error.
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During the experiment with predictable outcomes, participants were given water and juice every ____ seconds.
During the experiment with predictable outcomes, participants were given water and juice every ____ seconds.
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Study Notes
Psychobiology Pre-lecture Work 1
- Psychobiology is the study of biological mechanisms of normal and abnormal behavior, focusing on the brain and body's functions.
- Behavior depends on body function.
- The brain plays a critical role.
Organization of the Brain
- The brain is divided into different lobes (frontal, parietal, occipital, temporal).
- Different structures like the sylvian fissure, pons, cerebellum, medulla, and spinal cord are also present.
- There are two hemispheres, each with specific functions:
- Left hemisphere: controls speech, abstract thinking, and the right side of the body.
- Right hemisphere: responsible for image processing, spatial thinking, and movement in the left side of the body.
- The two hemispheres connect via nerve fibers.
Neurons Structure
- Neurons consist of dendrites (receivers), a cell body, nucleus, axon (conducting fiber), myelin sheath (insulating layer), and axon terminals (transmitters).
- Schwann cells produce the myelin sheath.
- Nodes of Ranvier are gaps in the myelin sheath.
Main Neurotransmitters
- Glutamate
- Dopamine
- GABA
What is Learning?
- Learning is the acquisition of behavioral information.
- Memory is the retention of information.
- Learning is essential for adaptive behavior.
- Memory improves with learning.
Law of Diminishing Returns
- The same effort put into learning yields less improvement as learning progresses.
- The curve shows this relationship.
The Rescola-Wagner Rule
- Learning is influenced by surprise.
- More learning happens when the outcome is unexpected.
- Prediction error decreases as learning occurs.
Supporting Evidence - Pavlovian Blocking
- Blocking occurs when a new stimulus, with no predictive value, is presented along with a stimulus already associated with an outcome (stimulus with high predictive value).
- The presence of the pre-existing predictive value blocks the learning of the new stimulus.
Biological Evidence - Hollerman & Schultz: Monkey
- Monkeys associate visual cues with rewards (banana milkshake).
- Dopamine neurons, within the ventral tegmental area, in the mid brain, fire when rewards are expected.
- No output when the prediction is correct.
Plot 3: Dopamine Neurons and Prediction Error
- Monkeys see images, but no reward is given.
- This leads to no response.
- The reward firing increases once the reward is released.
Plot 1: New Stimulus
- First time reward is given—no prediction (no association) between image and reward yet.
- This leads to unpredicted behavior.
- Before reward there is brain activity.
- More action potential when reward is presented.
Plot 2: Rewarded Stimulus
- Monkey learns reward after seeing image
- No activation when reward is predicted.
- Increased action potential after image indicating prediction of reward.
Conclusion
- VTA activation occurs when reward is not predicted and no response when not expected.
- No activation if reward is expected.
Humans:
- Participants given water & juice every 20 seconds.
- Activity was greater for unpredictable trials.
- Activities depend on higher firing in the VTA.
Prediction Error Signals
- Overexpectations increase predictions to learn the proper outcome.
- There is a need to weaken the memory to learn the correct outcome.
IN RATS: The Experiment
- Aimed at testing what happens to the prediction error signals in rats.
A1 Sound, A2 Sound, A3 Sound
- Over expectation happens when the stimulus is presented with the original expectation of a reward but only 1 is released.
- People take less time waiting.
In Babies: The Experiment
- Show solid block / object
- Show the solid object/block
- Show a car through
- The first experiment, the sound and the block. Second experiment- the car drives through the block.
Memory Consolidation
- When memories are formed, new proteins are produced. ○ DNA → Template → mRNA → tRNA → Amino acids → Protein
- Scientists used Anisomycin in the amygdala of rats to inhibit protein synthesis.
Arc (activity-related cytoskeletal-associated memory) Protein
- Scientists used fluorescent antibodies to identify the Arc protein in brain slices.
- They showed increase in Arc with paired stimulus, suggesting a role in consolidation.
- Scientists inhibited the forming of Arc to prevent its formation.
NMDA Receptors
- Bind to glutamate (excitatory neurotransmitter)
- Removing them abolishes memory acquisition.
- They are correlated with the Arc protein
Why is this important?
- Epilepsy is linked to memory deficits and modified BDNF expression.
- People with epilepsy may have impaired consolidation mechanisms.
- Potential treatments include Met supplementation to fix memory issues.
Why Consolidate?
- Consolidating memory is energy-intensive.
- The brain prioritizes important information.
- Memory can be altered by attention.
- Memories can be integrated with existing ones.
Synaptic Plasticity
- Change in synaptic strength based on activity.
- Key terms: intrinsic, homosynaptic, extrinsic, heterosynaptic
Long-Term Potentiation (LTP)
- Increase in synaptic strength from high-frequency stimulation.
- Discovered by Bliss and Lomo in rabbit hippocampi.
2 Types of LTP
- Non-associative: dependent solely on presynaptic neuronal activity
- Associative: occurs in coincident pre- and post-synaptic activity. This happens in the cerebellum
LTP and Fear Conditioning
- LTP occurs in the amygdala.
- Requires protein synthesis (more Arc when inducing LTP).
- Requires NMDA receptors.
- Synaptic potentiation happens during fear conditioning.
Making an Artificial Fear Memory
- Scientists presented mice with a tone without prior foot shock.
- Optogenetics was used to control neuron activity using light.
- Without foot shock, the mice still displayed fear of the tone.
Long-Term Depression (LTD)
- Decrease in synaptic strength due to low-frequency stimulation.
- Observed commonly in the cerebellum.
- May underlie motor learning.
LTD and LTP Coexist
- These processes can coexist—and both lead to increased responding.
Neural Communication (Resting Membrane Potential)
- Difference in electrical charge across a neuron's cell membrane when at rest.
- Typically around -70mV.
- Maintained by the sodium-potassium pump.
Action Potential
- Rapid change in electrical potential across a neuron's membrane in response to a stimulus.
- Depolarization—sodium ions rush in.
- Repolarization—potassium ions rush out.
- Refractory period—time delay between action potentials.
Synapses and Synaptic Transmission
- Junction between neurons where neurotransmitters are released to pass signals between neurons.
- Key terms: input neurons, terminals, neurotransmitter, output neuron, dendrites, receptors, ligand
Postsynaptic Potentials
- Hypo-polarization: Depolarization, Excitatory, Opening of cation channels
- Hyperpolarization: Inhibitory, Opening of anion channels
Spatial/Temporal Summation
- Spatial: multiple neurons triggering threshold.
- Temporal: one neuron's frequency triggering threshold.
Receptors
- Ionotropic: directly coupled to an ion channel (ligand binds → ion channels open).
- Metabotropic:
- Ligand binds to receptor.
- Changes receptor shape.
- Activates intracellular signaling cascade.
- Can alter ionotropic receptors.
Neurotransmitters
- Excitatory: Glutamate (binds to at least 8 different receptors)
- Inhibitory: GABA (Gamma-aminobutyric acid, most abundant inhibitory neurotransmitter)
- Unusual: Glycine (an amino acid, binds to inhibitory receptors)
- Monoamines:
- Dopamine
- Serotonin
- Noradrenaline
- Neuropeptides
Psychopharmacology
- Study of psychoactive drugs affecting brain function.
- Key Terms: pharmacology, drugs, psychopharmacology
Pharmacokinetics
- What the body does to a drug.
- Absorption: How a drug enters the body.
- Distribution: How a drug moves through the body.
- Metabolism: How a drug is transformed.
- Excretion: How a drug is eliminated.
Routes of Administration
- Oral (ingestion)
- Rectal
- Other mucous membranes
- Transdermal
- Inhalation
- Injection
First Pass Effect
- Liver breaks down active drug to metabolites.
Absorption
- Drugs cross cell membranes to enter bloodstream.
- Lipid solubility affects absorption rate.
Distribution
- Drugs in plasma reach various body parts, including the brain.
Metabolism
- Drug transformation in the body.
- Primarily occurs in the liver.
Elimination
- Different routes of drug elimination, including urine, breath, sweat, and hair.
Pharmacodynamics
- How drugs alter chemical neurotransmitters
- Agonists:
- Direct agonists: mimic neurotransmitters, producing similar responses.
- Indirect agonists: enhance the action of neurotransmitters.
- Antagonists: reduce
- Direct antagonists: prevent neurotransmitters from binding to receptors.
- Indirect antagonists: inhibit neurotransmitter release/production.
- Agonists:
Allosteric Modulation
- Chemical alters receptor's response to neurotransmitter binding.
Quantifying Drug Effects
- Dose-response curves are used to quantify drug potency and efficacy.
- ED50 is the dose producing 50% of the maximal effect.
The Therapeutic Index
- Ratio of toxic dose to therapeutic dose.
Action of Psychoactive drugs: Alcohol
- Can be a depressant or stimulant depending on dose.
- Affects GABA and NMDA receptors.
Effects of Alcohol on the Brain
- Enhances GABA transmission by increasing Cl- ions through GABAA receptors
- Inhibits NMDA (glutamatergic) receptors
- Indirectly affects neurotransmission in serotonin, opioid, and dopamine systems.
Biotransformation of Alcohol
- Metabolized by alcohol dehydrogenase to acetaldehyde.
- Further metabolized to carbon dioxide and water.
Factors Affecting Alcohol Metabolism
- Food in the stomach.
- Sex differences.
- Genetics and ethnicity/race
Cocaine
- A stimulant drug extracted from the coca plant.
- Routes of administration: nasal, inhaled (e.g., crack)
- Effects: reduces tiredness, dilated pupils, hyperactivity
- Effects on the brain: blocks dopamine transporter, prolongs dopamine effect.
Chronic Physical/Psychological Effects of Cocaine
- Cardiovascular damage
- Lung congestion (snorting)
- Damaged nasal membranes
- Psychosis
- Formication
Amphetamines
- Synthetic stimulants.
- Acts similar to methamphetamine.
- Routes: swallowed, snorted, injected, smoked.
- Affects the brain: blocks dopamine reuptake, increases dopamine release, increases neurotransmission.
Effects on the Brain: Amphetamines & Nicotine
- Blocks dopamine and noradrenaline reuptake.
- Stimulates the release of dopamine and noradrenaline.
- Nicotine patch administration can be used for replacement and slows in the brain's absorption rate comparatively speaking.
Caffeine
- Acute effects: increased alertness and decreased fatigue.
- Indirect agonist for adenosine receptors, which decreases inhibition of dopamine transmission.
Opiates
- Natural or synthetic drugs (Morphine, Codeine, Heroin, Fentanyl, Oxycodone)
- Crosses the blood-brain barrier easily.
- Brain metabolizes heroin into morphine.
- Various opioid receptors, especially mu receptors (analgesia and dependence).
- Increases dopamine release in the nucleus accumbens by inhibiting GABA receptors.
Cannabis
- Active ingredient: Cannabinoid Delta-9-THC
- THC is lipid-soluble, requiring metabolism for elimination
Cannabinoid Receptors
- CB1 and CB2 receptors.
- THC is a direct agonist.
- Also affects dopamine release.
Factors Contributing to Differences in Drug Effects
- Individual differences.
- Body size
- Age (Metabolic, Excretion)
- Sex
- Socio cultural factors (ethnicity, race)
- Environmental factors.
Tolerance and Sensitisation
- Metabolic: drug is metabolized faster
- Cellular: target cells adjust function (e.g., change in transmitter synthesis/release/receptor number).
- Experiential
- Context-dependent
Placebo Effects
- A placebo is a pharmacologically inert substance but can still produce effects.
- The effect is often due to expectations and context.
Emotional Responses & Theories
- Physiological changes.
- Behavioural consequences
- Subjective feelings
- Evolutionary theory
- Cannon-Bard, Schachter-Singer, and Cognitive-Labeling Theory
Amygdala
- Input and output of sensory information.
- Involved in emotional memory and responses.
Emotional Facial Expressions
- Six core expressions: anger, sadness, happiness, fear, disgust, surprise.
- Amygdala involvement in facial expression recognition
- Facial expressions are partly innate, partly learned.
Biological Basis of Emotional Facial Expression
- Neural basis → emotional facial expressions are automatic/involuntary.
- Genuine smiles & different smiles have different processes.
Volitional/Emotional Facial Paresis
- Volitional → damage to motor cortex
- Emotional → damage to prefrontal cortex/thalamus.
Facial expressions in non-humans
- Similar facial expression found in various animals.
Facial Expressions- Innate Responses?
- Some evidence suggests facial expressions are innate due to cross-cultural similarities.
- But more evidence to be gathered for complex interactions between innate, learned, and social/environmental mechanisms.
Bodily Maps of Emotions
- Different emotions produce distinct activation/deactivation patterns in the body.
Upstream and Downstream Structures in the Amygdala
- This shows the biological makeup of the fear response
Prefrontal Cortex and Emotion
- PFC regulates aggression through functional studies.
Maladaptive Fear Memories in PTSD
- PTSD patients have reduced cortisol and enhanced noradrenaline which might potentiate traumatic memories when recalled.
- Impaired vmPFC activity in PTSD is associated with symptom severity.
- Reduced vmPFC activity and excessive amygdala activation.
Neurodegeneration & Recovery
-
Varios kinds of degeneration (Neurotraumatic, Neurodegenerative, Neuropsychiatric disorders)
-
Fast (stroke/hypoxia)
-
Slow (neurodegenerative diseases, normal ageing)
-
Brains get smaller during neurodegeneration due to neuron death which affects the synapse connections.
-
Various causes of neuronal dysfunction/synapse loss including: hypoxia, excessive activity (excitatory toxic lesions), Idiopathic/sporadic, etc.
Huntington's Disease
- Monogenic disorder (mutation in the huntingtin gene).
- Characterized by motor symptoms (e.g., chorea), cognitive impairment and anxiety.
- The initial degeneration happens in the basal ganglia.
Repair and Recovery in the CNS
- Repair possible in the Peripheral Nervous system - not really in the CNS.
- Reconnecting neurons and adult neurogenesis are not as useful in the recovery process.
Neurogenesis in the Brain
- New neurons formed in some brain regions (e.g., hippocampus).
- Myelination of neurons allows faster signal transmission through neural circuits.
Parkinson's Disease
- Second most common neurodegenerative disease.
- 2-3% of the global population is affected..
- Characterised by motor symptoms (e.g., tremor, rigidity, bradykinesia) and non-motor symptoms.
- Three main types: idiopathic, drug-induced, genetic.
- Degeneration of dopamine neurons in the substantia nigra pars compacta is a defining feature of Parkinson's disease.
Early Degeneration
- Degeneration extensive before symptoms appear.
- Potentially early detection can help in better management of the condition.
Detection of Dopamine Transmission
- Methods for detecting dopamine transmission levels, like dopamine transporter activity and uptake using radioactive tracers (e.g., PET scan).
- Helps to identify abnormalities in the levels of dopamine in patients.
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Test your knowledge on the fundamental concepts of behavioral neuroscience with this quiz. Explore the roles of brain structures, neurotransmitters, and learning principles in behavior regulation. Perfect for students studying psychology or neuroscience!
