Untitled Quiz

Synaptic Plasticity

• Two stages of prenatal and postnatal development
• Prenatal development involves pattern formation
• Axon guidance mechanisms arrange axons in the correct location
• A coarse retinotopic map develops, but it is not as refined as the adult map
• Postnatal development refines prenatal patterns through activity-dependent mechanisms
• Environmental interactions influence brain development across age
• Ocular dominance columns develop
• Inputs from left and right eyes are segregated in layer 4C of V1
• Ocular dominance columns are anatomically and physiologically demonstrable
• Injected radioactive AA shows no dominance columns at birth, appearing later

Ocular Dominance Columns Development

• Neuronal activity creates precise retinotopic maps
• Competition between eye inputs happens, shaping the map
• Hebb's rule: neurons that fire together wire together
• Retinal fibers are spontaneously active in utero
• Neighboring retinal cells tend to be active together
• Activity patterns in two eyes are not always correlated with each other
• Cooperation and competition between eye inputs sharpen the segregation in the cortex

Critical Period

• Critical time period in development when brain circuitry is highly refined
• Monocular deprivation (MD) from birth to ~6 weeks in monkeys, and 12-13 weeks in cats, yields no binocular interactions after this critical period. Deprived eye loses out in competition in target space, and the eye with most activity "wins"
• Alternating deprivation has no effect implying cooperation and competition is important
• Strabismus (eye misalignment) leads to amblyopia (loss of binocular vision) if not corrected
• Early correction is important for visual development and binocular vision

Hubel and Wiesel 1963 OD Column Experiment

• The experiment highlighted how ocular dominance columns are formed.

Severe Strabismus

• Surgical intervention to realign eyes
• Important for developing normal binocular interactions in the brain

Memory and Learning

• Learning is the acquisition of new information or knowledge
• Memory is the retention of learned information
• Declarative memory: memory for facts and events
• Nondeclarative (implicit) memory: procedural and associative learning
• Short-term memory: lasts seconds to hours
• Long-term memory: can be recalled days, months, or years after storage
• Memory consolidation: converting memories into permanent forms
• Working memory: temporary storage, digit span test (measuring how many numbers a person can repeat back sequentially).
• Amnesia: diseases or injuries causing memory loss or learning impairment.
• Retrograde amnesia: losing memory of events before the trauma
• Anterograde amnesia: inability to form new memories after the trauma
• Hippocampus: crucial for learning and memory, including spatial tasks. Plays a key role in memory formation and consolidation, related to encoding of emotional episodic memories, but not long-term storage.

Place Cells

• Found in the hippocampus, particularly active in a given location
• Fire when an animal is in a specific location in the environment
• Form a cognitive map that shows how the animal relates to its surroundings
• Internal and external cues shape place field locations

Grid Cells

• Location-based system
• Excited when in multiple locations across a large environment
• The overlap is where the animal is

Long-Term Potentiation (LTP)

• Synaptic modification is thought to be the cellular basis for memory storage
• Increased synaptic strength
• Needs synchronous pre-and-post synaptic activity
• Influenced by Ca2+ levels

Emotions

• Emotional states involve three components:
• Emotional experience (feelings): subjective conscious sensing
• Emotional expression (body language): somatic motor responses
• Emotion expression: visceral motor responses.

Early Theories of Emotions

• James-Lange theory: emotional experience is a consequence of the physiological changes
• Cannon-Bard theory: emotional experience and physiological changes occur simultaneously.

Brain Rhythms and Sleep

• Electroencephalogram (EEG): measures electrical activity in the brain
• Alpha, beta, theta, and delta rhythms characterize different brain states
• EEG rhythms correlate with alertness and sleep stages
• Neural oscillators, including thalamic pacemakers, in part generate rhythmic brain activity
• Sleep stages: Non-REM (stages 1-4) and REM
• Sleep cycles occur ~90 minutes and repeat throughout the night
• Sleep disruptions affect cognitive functions

Seizures and Epilepsy

• Seizures: synchronous, excessive neuronal activity
• Generalized seizures: involve entire cerebral cortex
• Partial seizures: in an isolated area of the cortex
• Epilepsy: recurring seizures
• Causes: tumors, trauma, metabolic issues, infection

Language

• Language is a communication system unique to humans
• Parts of the brain for speech and understanding
• Broca's area (speech production), Wernicke's area (language comprehension)
• Wada Test is used to diagnose speech location
• Brain areas for language are used for different languages (e.g. deaf languages using sign language)

Mental Illness

• Diagnosable disorders of thought, mood, or behavior causing distress
• Interactions of genes and environment are crucial

Bipolar Disorder

• Cycling mood changes from extreme highs (mania) to extreme lows (depression)

Anxiety Disorders

• Characterized by excessive or maladaptive fear, symptoms of worry, panic attacks
• Stressors and learned experiences are key part

Specific Phobias

• Persistent fear of a specific object, activity, or situation that leads to avoidance

Social Phobia

• Fear of being scrutinized in social situations, leading to avoidance behavior