Brain

Dissociation & fMRI

Q: What are the main sources of knowledge from patient studies?

A: Trauma, stroke, tumours, degenerative/infectious diseases, epilepsy, neuropsychiatric disorders, neurosurgery.

Q: What is agnosia?

A: Loss of ability to recognise objects, people, sounds, shapes, or smells despite intact sensory systems.

Q: What is aphasia?

A: Loss or impairment of language ability.

Q: What is apraxia?

A: Disorder of action—difficulty performing learned movements.

Q: What is amnesia?

A: Loss of memory abilities.

Q: What is ataxia?

A: Poor coordination and unsteadiness due to impaired control of posture and movement.

Q: What is the purpose of behavioural testing in neuropsychology?

A: To identify impaired vs spared functions and understand the structure of cognitive processes.

Q: What is a single dissociation?

A: When a patient performs poorly on one task but normally on another.

Q: Why is single dissociation limited?

A: Differences may be due to task difficulty or other factors (e.g. attention), not distinct cognitive systems.

Q: What is a double dissociation?

A: Two groups show opposite deficits on two tasks → strong evidence for separate cognitive processes.

Q: What are limitations of patient studies?

A:

• Brain plasticity (reorganisation)

• Large/variable lesions

• Inaccurate anatomy

• Individual differences

• Poor temporal resolution

Q: What is modularity of function?

A: The assumption that mental processes operate independently in specific brain regions.

Q: What is MRI based on?

A: Alignment of hydrogen nuclei in a magnetic field and detection of emitted radiofrequency signals.

Q: What is the BOLD response in fMRI?

A: Changes in blood oxygenation following neural activity, used to infer active brain regions.

Q: What has fMRI contributed to neuroscience?

A:

• Identifying functional areas

• Confirming previous findings

• Mapping function in healthy brains

Neurons, Learning & Reward

Q: What did Cajal contribute to neuroscience?

A: Proposed neurons are discrete units and discovered synaptic transmission direction.

Q: What is Hebb’s rule?

A: “Cells that fire together wire together” → repeated co-activation strengthens synapses.

Q: What is the resting membrane potential?

A: حوالي −70mV, maintained by ion gradients and the Na⁺/K⁺ pump.

Q: What happens during an action potential?

A:

• Na⁺ enters → depolarisation

• K⁺ exits → repolarisation

• Signal propagates along axon

Q: What is an EPSP?

A: Excitatory postsynaptic potential—moves neuron closer to firing.

Q: What is an IPSP?

A: Inhibitory postsynaptic potential—moves neuron away from firing.

Q: What is temporal vs spatial summation?

A:

• Temporal: inputs over time add

• Spatial: inputs from different locations add

Q: Main excitatory neurotransmitter?

A: Glutamate

Q: Main inhibitory neurotransmitter?

A: GABA

Q: What is the role of dopamine?

A: Modulates reward, learning, and motivation.

Q: What is the mesolimbic reward system?

A: Dopamine pathway from VTA to nucleus accumbens involved in reward and reinforcement.

Q: How does cocaine affect the brain?

A: Blocks dopamine reuptake → increases dopamine → strong reward signal.

Q: How does alcohol affect the brain?

A:

• GABA agonist (sedative)

• NMDA antagonist (impairs learning/memory)

• Increases dopamine

Q: Difference between learning and memory?

A:

• Learning = acquisition

• Memory = storage & retrieval

Q: What is classical conditioning?

A: Association between two stimuli → conditioned response.

Q: What is operant conditioning?

A: Behaviour shaped by reinforcement.

Q: What is LTP (Long-Term Potentiation)?

A: Strengthening of synapses following repeated activation.

Q: Role of NMDA receptors in LTP?

A: Allow Ca²⁺ entry → triggers synaptic strengthening.

Q: What is the role of the hippocampus?

A: Consolidation of new declarative memories.

Q: What did patient H.M. demonstrate?

A: Hippocampus is essential for forming new long-term memories but not short-term memory.

Attention & Executive Function

Q: What is attention?

A: Selective processing of information.

Q: What is early vs late selection?

A:

• Early: filtering at perceptual level

• Late: filtering at semantic level

Q: What did Posner’s cueing paradigm show?

A: Faster responses to validly cued locations → attention enhances processing.

Q: Difference between top-down and bottom-up attention?

A:

• Top-down: voluntary, goal-driven

• Bottom-up: automatic, stimulus-driven

Q: What is visual search?

A: Finding a target among distractors.

Q: Feature vs conjunction search?

A:

• Feature: “pop-out”

• Conjunction: requires attention

Q: What is hemispatial neglect?

A: Failure to attend to one side of space (usually left) after right parietal damage.

Q: Three attentional networks?

A:

• Alerting

• Orienting

• Executive

Q: What are executive functions?

A: Planning, inhibition, working memory, flexible thinking.

Q: Role of dorsolateral PFC?

A: Working memory and cognitive control.

Q: Role of ventromedial PFC?

A: Emotion, decision-making, impulse control.

Q: What is the anterior cingulate cortex (ACC)?

A: Monitors conflict, errors, and guides behaviour.

Q: What is the somatic marker hypothesis?

A: Emotions guide decision-making via bodily signals.

Asymmetry & Consciousness

Q: What is cerebral asymmetry?

A: Functional and anatomical differences between hemispheres.

Q: What connects the hemispheres?

A: Corpus callosum.

Q: What is split-brain syndrome?

A: Disconnection of hemispheres → independent processing.

Q: Which hemisphere is dominant for language?

A: Usually left hemisphere.

Q: Right hemisphere specialization?

A: Visuospatial processing, global perception.

Q: What is blindsight?

A: Ability to respond to visual stimuli without conscious awareness.

Q: What is the Global Neuronal Workspace theory?

A: Consciousness arises when information is widely broadcast across the brain.

Q: What evidence challenges Cartesian dualism?

A: Brain damage alters consciousness → mind depends on brain.