Core Concepts in Biological and Cognitive Psychology: Exam Study Guide

Biological Bases of Behavior

Neurons and Neural Communication

The nervous system relies on specialized cells called neurons to transmit information throughout the body. Understanding the structure and function of neurons is fundamental to biological psychology.

• Neuron Structure: Key parts include the dendrites (receive signals), cell body (processes signals), axon (transmits signals), and terminal buttons (release neurotransmitters).

• Synaptic Transmission: Synaptic vesicles filled with neurotransmitters are located in the terminal buttons. When an action potential reaches the axon terminal, these vesicles release neurotransmitters into the synaptic cleft.

• Nodes of Ranvier: Gaps in the myelin sheath that allow for saltatory conduction, speeding up neural transmission.

• Myelin Sheath: Insulates axons and increases the speed of neural conduction.

• Action Potentials: When a neuron depolarizes, sodium ions rush into the cell through open channels, initiating the electrical signal.

• Refractory Period: During the absolute refractory period, a neuron cannot fire another action potential regardless of stimulus strength.

Neurotransmitters and Drugs

Neurotransmitters are chemical messengers that transmit signals across synapses. Many drugs and medications act by altering neurotransmitter activity.

• Endorphins: Natural pain control in the nervous system relies on endorphins.

• Selective Serotonin Reuptake Inhibitors (SSRIs): These antidepressants work primarily by blocking serotonin reabsorption (reuptake), increasing serotonin levels in the synaptic cleft.

• Dopamine: Dopamine projections most closely tied to movement originate in the substantia nigra.

Major Brain Structures and Functions

The brain is organized into specialized regions that control different aspects of behavior and cognition.

• Medulla: Vital for breathing and heart rate.

• Cerebellum: Contributes most to smooth coordinated movement and helps coordinate smooth motor movement.

• Corpus Callosum: The structure that forms the communication bridge between the brain's left and right hemispheres.

• Somatosensory Cortex: Located at the front of the parietal lobes, it registers and processes body touch and movement sensations.

• Thalamus: Relays sensory and motor signals to the cerebral cortex and helps keep body temperature, hunger, and sexual drive in check.

• Hippocampus: Critical for forming new episodic memories.

• Pituitary Gland: Often called the master gland because it regulates other endocrine glands.

Autonomic Nervous System

The autonomic nervous system regulates involuntary bodily functions and is divided into two main branches:

• Sympathetic Division: Activates the 'fight or flight' response (e.g., rapid heartbeat, sweaty palms before a speech).

• Parasympathetic Division: Calms the body after a stressor and supports digestion.

Sleep and Consciousness

Sleep is a complex biological process with distinct stages, each characterized by unique brain activity patterns.

• Insomnia: Difficulty falling asleep and repeated night awakenings for weeks.

• Narcolepsy: Sudden sleep attacks during daytime activities.

• REM Sleep: EEG activity in REM resembles quiet wakefulness. Called 'paradoxical' because the brain is active while the body is largely inactive.

• EEG: Best for measuring real-time electrical activity at the scalp.

• fMRI: Most directly measures oxygenated blood flow changes related to neural activity.

Sensation and Perception

Sensory Receptors and Pathways

Sensory systems convert environmental stimuli into neural signals through specialized receptors.

• Hair Cells: Receptors that convert sound waves into neural signals in the cochlea.

• Photoreceptors: Rods operate best in low light; cones are responsible for color vision and fine detail in bright conditions.

• Olfactory Receptors: Located high in the nasal cavity, responsible for smell.

• Touch Receptors: Areas with the fewest touch receptors include the back of the neck.

Visual and Auditory Processing

Vision and hearing involve complex processing of sensory information.

• Color Vision: Relies most on cones. The trichromatic theory proposes three types of cones tuned to red, green, and blue.

• Optic Chiasm: Information from each visual field crosses to the opposite hemisphere.

• Cochlea: A fluid-filled spiral structure in the inner ear that transduces sound.

Perceptual Organization

The brain organizes sensory input into meaningful patterns and objects.

• Perception: Making sense of incoming sensory data.

• Monocular Depth Cues: Relative size, interposition, and linear perspective help perceive depth with one eye.

• Shape Constancy: Recognizing a door's shape as rectangular whether open or closed.

• Change Blindness: Failing to notice a change in a scene after a brief interruption.

• Inattentional Blindness: Missing a background event while focusing on a counting task.

• Cocktail Party Effect: Selective attention to salient stimuli, such as hearing your name in a noisy room.

Learning, Memory, and Cognition

Types of Memory and Processing

Memory and cognition involve encoding, storing, and retrieving information.

• Explicit Memory: Conscious recall of facts and events.

• Implicit Processing: Unconscious, automatic memory or skills (e.g., a novice driver paying close attention is using controlled processing).

• Priming: Exposure to one stimulus influences response to another.

Language and Aphasia

Language processing involves several brain regions, and damage can result in specific language deficits.

• Broca's Aphasia: Difficulty producing speech.

• Wernicke's Aphasia: Fluent speech that lacks meaning and poor comprehension.

Tables

The following table summarizes key sensory receptors and their functions:

Receptor Type	Stimulus Detected	Location
Hair cells	Sound waves	Cochlea (inner ear)
Rods	Low light	Retina (eye)
Cones	Color, fine detail	Retina (eye)
Olfactory receptors	Odor molecules	Nasal cavity
Merkel cells	Touch	Skin

Additional Key Concepts

• Weber's Law: The just noticeable difference is a constant proportion of the standard stimulus: $\Delta I / I = k$

• Signal Detection Theory: A 'hit' occurs when a signal is present and you report it.

• Kinesthesia: Sensing body movement and limb position.

• Chronic Traumatic Encephalopathy (CTE): Linked most strongly with repeated head injuries.

Example: Missing a man in a chicken suit while counting passes illustrates inattentional blindness.

Example: Sounding out a completely new word illustrates bottom-up processing.

Example: Working hard at pottery because you love the process reflects intrinsic motivation.