Week 6 revision content Flashcards
d’ (d-prime)
DISCRIMINATION - A measure of perceptual sensitivity, indicating how well an individual can distinguish between signal and noise. Higher values = better discrimination.
c (criterion)
Reflects decision bias or strategy—whether someone tends to say “yes” or “no” when uncertain. Influenced by factors like expectations or consequences of errors.
Hit
Correct identification of a present signal (True Positive).
Miss
Failure to detect a present signal (False Negative).
False Alarm
Incorrect identification of a signal when none is present (False Positive).
Correct Rejection
Correct identification that no signal is present (True Negative).
ROC Curve (Receiver Operating Characteristic
Graphs hit rate vs. false alarm rate to illustrate sensitivity.
Corpus Callosum
A large bundle of nerve fibers connecting the two hemispheres, enabling interhemispheric communication.
Left Hemisphere:
Controls motor and sensory functions of the right side
Dominant for language production (Broca’s area) and comprehension (Wernicke’s area)
Involved in logical, analytical, and verbal tasks
Right Hemisphere:
Controls left side of body
Specializes in spatial awareness, facial recognition, musical ability, and emotional processing
Split-brain patients:
Result from surgical severing of the corpus callosum (often for epilepsy treatment)
Exhibit unique behaviour (e.g., inability to name objects in left visual field)
Single Dissociation:
Damage impairs function A but not B; may suggest—but not confirm—functional independence.
Double Dissociation:
Stronger evidence—proves that two functions rely on different neural systems.
Primary Visual Cortex (V1):
Lesions cause cortical blindness; may retain blindsight, i.e., ability to detect motion or emotion without awareness.
V4
Responsible for color perception. Damage causes achromatopsia (color vision loss).
V5/MT:
Involved in motion perception. Damage results in akinetopsia—difficulty seeing objects in motion.
Ventral Stream (“What Pathway”):
Passes from occipital to temporal lobes
Associated disorders:
- Apperceptive Agnosia: Impaired object perception
- Associative Agnosia: Impaired object recognition
- Prosopagnosia: Face blindness (often linked to fusiform gyrus)
Dorsal Stream (“Where/How Pathway”):
Projects to parietal lobe
Related impairments:
- Optic Ataxia: Poor hand-eye coordination
- Simultanagnosia: Inability to perceive more than one object at a time
Biased Competition Model of Attention
Basic Idea: Attention selects stimuli through competition—resources are finite.
Bottom-Up (Exogenous) Factors:
Driven by stimulus features: brightness, contrast, movement, novelty
Top-Down (Endogenous) Factors:
Influenced by task goals, expectations, and memory
Neural Basis of Biased Competition Model of Attention
Attention enhances neural activity for selected stimuli and suppresses others (e.g., in visual cortex)
Central Executive
Directs attention, integrates info, and manages the other subsystems
Working Memory:
Temporary, limited-capacity storage for active processing
Phonological Loop:
Verbal/auditory info (Broca’s area, left parietal)
Visuospatial Sketchpad:
Visual/spatial imagery (right hemisphere)
Episodic Buffer:
Multimodal integration; links to episodic LTM
Episodic memory
Personal events; hippocampus-dependent
Semantic
Facts/concepts; stored in anterior temporal lobe
Procedural
Motor skills; relies on basal ganglia/striatum
Classical Conditioning:
Emotional/physiological associations; cerebellum and amygdala
Phoneme
Smallest sound unit that changes word meaning (e.g., /b vs. /p/)
Morpheme
Smallest meaningful unit in language (e.g., “un-,” “cat”)
Syntax
Rules governing sentence structure
Rule-based Learning:
Conscious use of grammatical rules; depends on hippocampus and prefrontal cortex
Statistical Learning:
Unconscious tracking of input patterns; striatum and other basal ganglia structures
Sensitive/Critical Periods
Biological windows for optimal learning (e.g., early childhood for phoneme discrimination)
ionotropic receptors
(fast, direct ion flow)
metabotropic receptors
(slow, involves second messengers like cAMP)
FATE:
Formation: Neurotransmitter synthesis
Action: Triggered by AP and Ca²⁺ influx
Transmission: NT crosses synapse
Elimination: Via reuptake (e.g., serotonin) or enzymatic breakdown (e.g., acetylcholine)
Hebb’s Rule:
Cells that fire together wire together”
