Introduction to Biological Bases of Behavior

Biological bases of behavior explore how our biology influences actions, thoughts, and emotions
This area combines psychology, neuroscience, and biology to understand the relationship between the brain, nervous system, and behavior.

The Nervous System

The nervous system is responsible for regulating and coordinating body activities
It is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).

Central Nervous System (CNS)

Brain: The control center for the entire nervous system, processes sensory information, regulates bodily functions, and controls behavior
- Cerebrum: Involved in higher brain functions (thought, action, emotion)
- Cerebellum: Coordinates voluntary movements (posture, balance, coordination, speech)
- Brainstem: Controls essential body functions (breathing, swallowing, heart rate, blood pressure), connects the brain to the rest of the body
Spinal Cord: Transmits information between the brain and the rest of the body, involved in reflexes

Peripheral Nervous System (PNS)

Somatic Nervous System: Controls voluntary movements of skeletal muscles
Autonomic Nervous System (ANS): Regulates involuntary body functions
- Sympathetic Nervous System: Prepares the body for stressful or emergency situations ("fight or flight")
- Parasympathetic Nervous System: Conserves energy and restores the body to a resting state ("rest and digest")

Neurons: Building Blocks of the Nervous System

Neurons transmit information throughout the nervous system.
Dendrites: Receive messages from other neurons.
Cell body (soma): Contains the nucleus and other organelles.
Axon: Transmits messages away from the cell body to other neurons, muscles, or glands.
Synapse: The junction between neurons where communication occurs via neurotransmitters.

Neurotransmitters and Their Functions

Neurotransmitters are chemicals transmitting signals across a synapse between neurons.
Acetylcholine (ACh): Involved in muscle action, learning, and memory.
Dopamine: Regulates mood, reward, and motor control.
Serotonin: Affects mood, appetite, and sleep.
Norepinephrine: Influences arousal and alertness.
Gamma-Aminobutyric Acid (GABA): Inhibitory neurotransmitter that reduces neuronal excitability.
Glutamate: Primary excitatory neurotransmitter involved in learning and memory.

Brain Structures and Their Functions

Forebrain:
- Thalamus: Relays sensory and motor signals to the cerebral cortex.
- Hypothalamus: Regulates basic functions (hunger, thirst, temperature, endocrine).
- Limbic System: Involved in emotion, memory, and motivation (amygdala and hippocampus)
Midbrain: Tectum and Tegmentum—involved in auditory and visual reflexes and motor control.
Hindbrain:
- Medulla Oblongata: Controls basic life functions (breathing, heart rate).
- Pons: Relays information between the cerebrum and cerebellum.
- Cerebellum: Coordinates voluntary movements and balance.

The Endocrine System

The endocrine system regulates body functions through hormones released by glands
Pituitary gland: Controls other endocrine glands ("master gland")
Pineal gland: Regulates sleep-wake cycles through melatonin
Thyroid gland: Regulates metabolism
Adrenal glands: Produce hormones for metabolism, immune response, and stress
Pancreas: Regulates blood sugar
Gonads (ovaries/testes): Produce sex hormones

Genetics and Behavior

Genes and Chromosomes: Genes are units of heredity made of DNA, chromosomes are structures in cells containing genes.
Genotype and Phenotype: Genotype is genetic makeup, phenotype is observable traits and behaviors.
Behavioral Genetics: Studies genetic and environmental influences on behavior.
Twin and adoption studies help understand the genetic basis of behavior.

Brain Imaging Techniques

EEG: Measures electrical activity in the brain.
MRI: Creates detailed images of brain structures using magnetic fields.
fMRI: Measures brain activity by detecting changes in blood flow.
PET: Uses radioactive tracers to visualize brain activity.

Neuroplasticity and Neurogenesis

Neuroplasticity: The brain's ability to reorganize itself by forming new neural connections throughout life.
Neurogenesis: The process of forming new neurons, occurring in specific areas like the hippocampus.

Sensation and Perception

Sensation: The process through which sensory receptors and the nervous system receive and represent stimulus energies from the environment.
Perception: The process of organizing and interpreting sensory information to recognize objects and events.
Sensory Receptors: Specialized cells that detect stimuli (e.g., photoreceptors for light, mechanoreceptors for pressure, thermoreceptors for temperature, nociceptors for pain).
Sensory Processes:
- Reception: Detecting physical stimuli.
- Transduction: Converting physical stimuli into neural signals, processed by the brain.
- Transmission: Relaying neural signals from receptors to the brain.
Thresholds: Minimum stimulus intensity to be detected 50% of the time (absolute threshold), minimum difference between two stimuli to be detected 50% of the time (difference threshold).
Sensory Adaptation: The diminished sensitivity to a constant stimulus over time.

Perception

Perceptual Processes:
- Selection: Focusing on certain stimuli.
- Organization: Structuring sensory input into patterns (Gestalt principles – proximity, similarity, continuity, closure).
- Interpretation: Assigning meaning to sensory information.
Depth Perception: Binocular cues (retinal disparity and convergence) and monocular cues (interposition, linear perspective, relative size, texture gradient, relative height, motion parallax)
Perceptual Constancy: Perceiving objects as unchanging despite changes in sensory input (size, shape, color).

Sensory Systems

Vision: Cornea, pupil, iris, lens, retina, photoreceptors (rods and cones), optic nerve.
Hearing: Outer, middle, inner ear, ossicles, cochlea, hair cells, auditory nerve.
Taste (gustation): Taste buds, taste receptors, gustatory cortex.
Smell (olfaction): Olfactory receptors, olfactory epithelium, olfactory bulb, olfactory cortex.
Touch (somatosensation): Receptors (pressure, temperature, pain), somatosensory cortex.

The State of Consciousness

Consciousness: The state of being aware of one’s existence, thoughts, feelings, and environment.
Levels of Consciousness:
- High-level: involves attention, focus, deliberate thought.
- Low-level: involves automatic, routine processes.
- Altered states: differ significantly from normal consciousness.
Importance of Studying Consciousness: Understanding human cognition, emotion, behavior and medical diagnosis and treatment

Biological Rhythms and Sleep

Circadian Rhythms: 24-hour cycles influencing sleep-wake patterns, body temperature, and hormonal activity (regulated by the suprachiasmatic nucleus (SCN) in hypothalamus)
Ultradian Rhythms: Biological cycles shorter than 24 hours (e.g., stages of sleep)
Infradian Rhythms: Biological cycles longer than 24 hours (e.g., menstrual cycle)
Sleep-Wake Cycle: Includes Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) stages with unique characteristics.

Meditation

Meditation: A practice of focused attention, often involving deep breathing, to achieve a state of mental clarity.

Near-Death Experiences

Near-Death Experiences (NDEs): Reported experiences of people close to death; they often involve visions of light, detachment from the body, or deceased loved ones.
Theories (NDEs): May be due to lack of oxygen, unusual brain activity, and/or spiritual beliefs

Memory Processes

Encoding: Transforming sensory input into a form stored in memory.
Types: Visual, acoustic, and semantic encoding.
Storage: Retention of encoded information.
Types: Sensory memory, short-term memory, and long-term memory.
- Sensory memory: Brief storage of sensory information (e.g., iconic memory for vision)
Retrieval: Accessing and bringing stored information into consciousness.
Types: Recall (e.g., essay question), recognition (e.g., multiple-choice question), and relearning.

Types of Memory

Explicit (declarative) memory: Consciously known facts and experiences (e.g., episodic memories of personal events, semantic memories of general knowledge)
Implicit (non-declarative) memory: Unconscious skills and procedures (e.g., procedural memories, classical conditioning.)
Brain Structures Involved in Memory: Hippocampus, amygdala, prefrontal cortex, cerebellum, and basal ganglia.

Neurotransmitters and Memory

Acetylcholine, Glutamate, Dopamine play crucial roles in memory and learning.

Forgetting and Memory Distortion

Forgetting: The inability to recall stored information.
Theories of Forgetting: Decay, interference, and retrieval failure. Motivated forgetting include suppression or repression.
Memory Distortion: Misinformation effect, source amnesia, and confabulation.

Enhancing Memory

Rehearsal: Repeated practice.
Mnemonics: Memory aids (e.g., acronyms, imagery, rhymes).
Chunking: Grouping information into meaningful units.
Elaborative Rehearsal: Connecting new information to existing knowledge.

Role of Healthy Habits (Memory)

Nutrition: Proper nutrients are essential (e.g., Omega-3 fatty acids, antioxidants)
Exercise: Physical activity improves cognitive function.
Sleep: Adequate sleep is imperative for memory consolidation.
Stress Reduction: Mindfulness and relaxation techniques are crucial for cognitive well-being

Applications of Memory Research (Memory)

Education: Tailored teaching strategies; age-appropriateness.
Legal and Forensic Settings: Reliability and accuracy of eyewitness testimony.
Clinical Applications: Memory rehabilitation programs for various conditions.