Biopsychology

Biopsychology

Objectives: Section 1

  • Learn the basics of genetics and their impact on psychological outcomes

  • Understand the basic structures and function of nerve cells and neurotransmitters

  • Know how to identify the structure and function of the lobes of the brain

The Basics of Genetics

Genotype vs. Phenotype:

  • Genotype: The genetic constitution of an individual, representing their unique genetic makeup.

  • Phenotype: The observable physical and physiological traits of an individual, which result from the interaction of the genotype with the environment.

Genes and Alleles:

  • Genes: Segments of DNA that control traits.

  • Allele: A specific version of a gene.

Dominant vs. Recessive Alleles:

  • Dominant Alleles: Express their trait even if only one copy is present.

  • Recessive Alleles: Express their trait only if two copies are present.

Sickle-Cell Anemia and Natural Selection

What is Sickle-Cell Anemia?

  • A genetic condition that results in crescent-shaped red blood cells, leading to blockages and tissue damage.

  • Despite being deadly, the sickle-cell anemia gene is prevalent among people of African descent.

  • Survival of the Fittest?: The gene provides some protection against malaria, demonstrating a selective advantage in certain environments.

Gene-Environment Interactions

  • This concept asserts that genes set the boundaries of potential.

Range of Reaction:

  • Our genes influence our environment, and conversely, our environment influences gene expression.

  • Example: An athletically gifted child may flourish in a sports-rich environment facilitated by supportive parents, enhancing their genetic predisposition.

Genetic Environmental Correlation:

  • The study of how the same genotype can lead to different phenotypes depending on environmental contexts.

Epigenetics:

  • The field studying how environmental factors can modify gene expression without altering the DNA sequence itself.

The Schizophrenia Study

Study Design:

  • Researchers conducted a study on adoptees whose biological mothers had schizophrenia (high genetic risk) and compared them with adoptees with a low genetic risk, considering their rearing environments (disturbed vs. healthy).

Key Findings:

  • Adoptees with high genetic risk raised in disturbed family environments had a 36.8% likelihood of developing schizophrenia.

  • Adoptees with high genetic risk in healthy environments had a significantly lower rate of 5.8%.

  • Adoptees with low genetic risk showed low rates (5.3% in disturbed and 4.8% in healthy environments).

Neuron Structure

Overview

  • Neurons are the fundamental building blocks of the nervous system.

Components of Neurons:

  • Soma (Cell Body): Contains the nucleus and essentials for neuron survival.

  • Dendrites: Branching extensions that receive signals from other neurons.

  • Axon: A long extension transmitting the electrical signal from the soma to terminal buttons.

  • Myelin Sheath: A fatty substance insulating the axon, increasing the speed of electrical signals.

  • Terminal Buttons: Small knobs at the axon’s end containing synaptic vesicles.

  • Synaptic Vesicles: House neurotransmitters, the chemical messengers of the nervous system.

  • Synaptic Cleft: The small space between a terminal button of one neuron and a dendrite of another.

How Neurons Communicate

Electrochemical Process

  • Neuronal communication involves both electrical and chemical events.

The Action Potential (Electrical Signal):

  • Resting potential: With a negative charge inside relative to the outside of the neuron.

  • Threshold of excitation: The level of stimulation required to trigger an action potential.

  • All-or-none event: Action potentials occur fully or not at all.

Synaptic Transmission (Chemical Signal):

  • Neurotransmitters travel across the synaptic cleft and bind to specific receptors (a "lock-and-key" relationship).

  • Reuptake: Excess neurotransmitters are reabsorbed by the original neuron.

Drugs and Neurotransmitters

Types of Substances:

  • Agonists: Chemicals that mimic neurotransmitters by binding to their receptors and activating them.

  • Antagonists: Chemicals that block or impede neurotransmitter activity by binding to their receptors without activation.

  • Reuptake Inhibitors: Drugs preventing the reabsorption of neurotransmitters back into neurons.

  • Example: Selective Serotonin Reuptake Inhibitors (SSRIs) help increase serotonin levels in the brain.

Central vs. Peripheral Nervous Systems

Central Nervous System (CNS):

  • Comprises the brain and spinal cord.

Peripheral Nervous System (PNS):

  • Encompasses all the nerves extending from the CNS to the rest of the body.

Somatic vs. Autonomic Nervous Systems

Overview

  • The PNS is divided into two subdivisions:

Somatic Nervous System:

  • Controls voluntary actions and relays sensory and motor information.

Autonomic Nervous System:

  • Regulates involuntary functions such as heart rate, digestion, and breathing; operates to maintain homeostasis (balance).

Sympathetic vs. Parasympathetic Nervous Systems

Overview

  • The Autonomic Nervous System is subdivided into two complementary divisions:

Sympathetic Nervous System:

  • Prepares the body for high-arousal, stressful situations (commonly referred to as the "fight or flight" response).

Parasympathetic Nervous System:

  • Returns the body to routine day-to-day operations (known as the "rest and digest" state).

The Two Hemispheres of the Brain

Cerebral Cortex

  • The brain’s surface, characterized by bumps (gyri) and grooves (sulci).

  • Longitudinal Fissure: Separates the brain into left and right hemispheres.

Lateralization

  • Refers to the specialization of functions in each hemisphere.

  • The left hemisphere generally controls the right side of the body, linked to language production and comprehension.

  • The right hemisphere governs the left side of the body, often associated with spatial and perceptual skills.

  • Both hemispheres communicate via the corpus callosum.

The Lobes of the Brain

Overview and Functions

  • Frontal Lobe: Involved in reasoning, motor control, emotion, and language. Contains:

    • Motor Cortex: Controls movement.

    • Prefrontal Cortex: Responsible for judgment and impulse control.

    • Broca's Area: Associated with language production.

  • Parietal Lobe: Processes sensory information like touch, temperature, and pain via the Somatosensory Cortex.

  • Temporal Lobe: Linked to hearing, memory, and emotion, housing the Auditory Cortex and Wernicke's Area (speech comprehension).

  • Occipital Lobe: Primarily responsible for vision through the Primary Visual Cortex.

Subcortical Structures of the Forebrain

Important Structures

  • Thalamus: Acts as a sensory relay station.

  • Limbic System: A collective of structures involved in emotion and memory.

    • Hippocampus: Essential for learning and memory.

    • Amygdala: Related to emotional experiences and associating emotions with memories.

    • Hypothalamus: Regulates homeostasis, affecting body temperature, appetite, and blood pressure.

Midbrain and Hindbrain Structures

Midbrain:

  • Located between the forebrain and hindbrain.

  • Reticular Formation: Regulates sleep/wake cycles, arousal, and alertness.

  • Substantia Nigra and Ventral Tegmental Area (VTA): Produce dopamine and play critical roles in movement and mood.

Hindbrain:

  • Located at the head's back.

  • Medulla: Responsible for autonomic processes such as breathing and heart rate.

  • Pons: Bridges connections between the hindbrain and the rest of the brain, also involved in sleep.

  • Cerebellum: Known as the "little brain," it governs balance, coordination, movement, and procedural memory.

Brain Imaging Techniques

CT (Computerized Tomography) Scan:

  • Utilizes X-rays to create detailed images of brain structures. Good for identifying tumors or atrophy.

PET (Positron Emission Tomography) Scan:

  • Displays brain activity by tracking a radioactive tracer in the bloodstream, illustrating active areas during tasks.

MRI (Magnetic Resonance Imaging):

  • Uses magnetic fields for detailed brain structure imaging.

fMRI (Functional Magnetic Resonance Imaging):

  • Tracks blood flow and oxygen levels, showing changes in brain activity over time with high temporal accuracy compared to PET scans.

EEG (Electroencephalography):

  • Measures overall electrical activity of the brain using scalp electrodes. Valuable for studying sleep patterns and seizure activity.

Objectives: Section 2

  • Learn and identify the use and function of the endocrine system

  • Discuss consciousness and the functions of sleep along with various sleep theories

  • Understand the mechanics behind drug use and abuse

  • Learn about various drug classes and their interactions with the nervous systems

What is the Endocrine System?

Overview

  • Endocrine System: A network of glands producing and secreting hormones into the bloodstream to control various bodily functions.

  • Hormones: Chemical messengers traveling through the bloodstream to target cells throughout the body.

  • Hormones typically influence functions with widespread and long-lasting effects compared to neurotransmitters.

  • Controlled primarily by the hypothalamus and the pituitary gland.

Major Endocrine Glands

  • Pituitary Gland: Secretes growth hormone and endorphins for pain relief.

  • Thyroid Gland: Regulates metabolism, appetite, and growth.

  • Adrenal Glands: Release hormones such as epinephrine (adrenaline) and norepinephrine (noradrenaline) in response to stress.

  • Pancreas: Manages blood sugar levels by secreting insulin (reducing blood sugar) and glucagon (increasing blood sugar).

  • Gonads:

    • Ovaries (in females) secrete estrogen and progesterone.

    • Testes (in males) secrete androgens like testosterone.

Endocrine System Overview

Hormones vs. Neurotransmitters:

  • Both serve as chemical messengers.

  • Neurotransmitters: Localized, fast-acting.

  • Hormones: Spread over larger areas, slower-acting.

  • The endocrine system collaborates with the nervous system for overall function and balance.

What is Consciousness?

  • Consciousness refers to our awareness of ourselves and our environment, encompassing both internal stimuli (thoughts, feelings) and external stimuli (sights, sounds).

  • Levels of consciousness fluctuate throughout the day.

  • Circadian Rhythm: The body's internal 24-hour cycle regulating sleep and wakefulness.

  • Suprachiasmatic Nucleus (SCN): The brain's "master clock," synchronizing with light cues from the external environment.

The Importance of Sleep

  • Homeostasis: The body's tendency to maintain a stable balance, which sleep helps restore.

  • Sleep Regulation: Controlled by the brain, with varying biological rhythms termed chronotypes ("night owls" vs. "early birds").

Consequences of Sleep Deprivation:

  • Impaired cognitive function and memory.

  • Reduced emotional regulation.

  • Increased risk of accidents.

  • Weakened immune system, leading to long-term health risks.

Why We Sleep:

  • Sleep is crucial for memory consolidation and strengthening new neural connections.

Stages of Sleep

Brain Wave Patterns:

  • Alpha Waves: Low-frequency, high-amplitude brain waves during relaxed wakefulness.

Sleep Stages:

  • Stage 1: Transitioning from wakefulness to sleep.

  • Stage 2: Deeper relaxation.

  • Stage 3: Deep sleep (slow-wave sleep) characterized by delta waves (low-frequency, high-amplitude).

  • REM Sleep: Rapid eye movements occur, marked by brain activity similar to consciousness, where voluntary muscles are paralyzed.

  • REM Rebound: The tendency to spend increased time in REM sleep following deprivation.

Dreaming and Sleep Hormones

Dream Theories:

  • Freud: Dreams reveal hidden desires and provide access to the unconscious mind.

  • Jung: Dreams connect to a collective unconscious, housing universal archetypes.

  • Cartwright: Dreams facilitate emotional and personal situation processing, supported by scientific research.

Hormones during Sleep:

  • Melatonin: A hormone from the pineal gland regulating biological rhythms and immune system functions.

  • Pituitary Gland Hormones: Secretes growth hormone and reproductive system-regulating hormones.

Substance Use and Abuse

Overview

  • Substance Use Disorder: A compulsive drug use pattern despite negative consequences.

Dependence Types:

  • Physical Dependence: The body's adaptation to a drug's presence.

  • Psychological Dependence: An emotional need for the drug.

  • Tolerance vs. Withdrawal:

    • Tolerance: The necessity for increased drug dosage for the same effect.

    • Withdrawal: Negative symptoms following drug cessation.

Drug Classes:

  • Depressants: Decrease central nervous system activity.

  • Opioids: Possess analgesic properties and are highly addictive due to interaction with the brain's natural opioid system.

  • Hallucinogens: Induce perceptual changes and affect various neurotransmitter systems.

Objectives: Section 3

  • Understand the differences between sensation and perception

  • Learn the structures and processes involved in sensation

  • Discuss perceptions and their interaction in the brain/mind

  • Learn general principles of Gestalt theory observable through sensations

Sensation vs. Perception

Definitions

  • Sensation: The process through which sensory receptors recognize sensory input, serving as raw input from the senses.

  • Humans possess more than five senses.

  • Perception: The process of organizing, interpreting, and consciously experiencing sensations, allowing the brain to make sense of sensory data.

The Difference:

  • Not all sensations lead to perception.

Processing Types:

  • Bottom-Up Processing: Perception lies in sensory input; the image is constructed from basic sensory attributes.

  • Top-Down Processing: Perceptions are influenced by existing knowledge and expectations.

Waves and Wavelengths

Light Waves:

  • Visible Spectrum: Refers to the small portion of the electromagnetic spectrum visible to humans.

Sound Waves:

  • Frequency: Linked to pitch perception. High-frequency waves correspond to high-pitched sounds, while low-frequency waves indicate low-pitched sounds.

  • Amplitude: Associated with loudness. Higher amplitude waves result in louder sounds.

The Sense of Vision

Anatomy of the Eye:

  • Light enters via the cornea and pupil; the lens focuses it on the retina, which includes specialized photoreceptors.

Photoreceptor Types:

  • Rods: Highly sensitive to light, excel in low-light conditions, responsible for peripheral vision and motion detection.

  • Cones: Function in bright light scenarios, enabling color and fine detail perception. Concentrated in the retina's fovea.

Important Features:

  • Blind Spot: A part of the visual field lacking photoreceptors where the optic nerve exits; the brain compensates for this blind area, leading to unnoticed gaps.

  • Optic Chiasm: A structure enabling optic nerve crossing. It ensures visual information from the right visual field of both eyes integrates into the left hemisphere and vice-versa.

Color and Depth Perception

Color Vision Theories:

  • Trichromatic Theory: Proposes three cones sensitive to different wavelengths (red, green, blue).

  • Opponent-Process Theory: Describes color coding in opponent pairs (black-white, yellow-blue, red-green). This explains color signal processing post-retina.

  • Both theories are correct and operate at different nervous system levels.

Depth Perception:

  • The ability to perceive spatial relationships in three dimensions.

Depth Cues:

  • Binocular Cues: Utilize information from both eyes.

  • Monocular Cues: Rely on one eye's information.

The Sense of Hearing

Sound Processing

  • Sound waves enter the ear and vibrate the eardrum.

  • Vibrations shift through the ossicles; the final ossicle, the stapes, pushes against the cochlea's oval window, generating fluid movement inside.

  • This fluid motion activates hair cells within the basilar membrane.

Sound Transduction Theories:

  • Temporal Theory: Asserts pitch is dictated by action potentials' frequency from hair cells.

  • Place Theory: Indicates differing pitches correspond to various basilar membrane regions.

  • Both theories elucidate pitch perception varying by frequency.

Sound Localization:

  • Binaural Cues: Utilize information from both ears for sound localization.

  • Monaural Cues: Based on unilateral information.

The Other Senses

Overview

  • Chemical Senses:

    • Gustation (Taste) and Olfaction (Smell)—termed chemical senses due to receptors reacting to molecules.

    • Food flavor arises from a combination of taste and smell.

  • Somatosensation (Touch): Encompasses the senses of touch, temperature, and pain.

  • Nociception (Pain): A sensory indication of potential harm.

Gestalt Psychology

  • A field studying the organization of sensory information into meaningful wholes.

Key Concepts

  • Figure-Ground Relationship: Our tendency to perceive a visual field as a central figure against a distinct background. Camouflage exhibits a real-world application of this principle.

  • Other Gestalt Principles:

    • Proximity: Grouping nearby objects.

    • Similarity: Grouping similar-looking elements.

    • Continuity: Perceiving continuous patterns rather than fragmented ones.

    • Closure: Filling gaps to perceive complete objects.

Implicit Perception

  • Perceptions can be influenced by implicit biases. Research, such as showing non-Black participants identifying weapons faster with images of Black individuals, indicates this bias.

  • Implicit biases are often involuntary but can be altered with deliberate effort.

Module Concluding Remarks

  • End of Module

  • Reminder: Don't forget to take your Quiz!