Biological Psychology: Structure and Function of the Nervous System

Biological Psychology

Introduction to Biological Psychology

Biological psychology, also known as behavioral neuroscience, explores the relationship between biological processes and behavior. This field examines how the brain, neurotransmitters, and other aspects of our physiology influence our thoughts, feelings, and actions.

Facilitated Communication (FC) and Critical Thinking

Facilitated Communication: Definition and Controversy

• Facilitated Communication (FC): A technique intended to help individuals with severe communication impairments (often autism) to communicate, typically by supporting their hand or arm as they type or point to letters.

• Controversy: Many researchers are skeptical of FC due to lack of scientific evidence and the possibility of facilitator influence.

• Testing FC: Investigators have tested FC by controlling what information is available to the facilitator and the individual, revealing that messages often originate from the facilitator, not the client.

• Not Me Fallacy: The belief that one is immune to errors in thinking that affect others. This fallacy is relevant in the context of FC, as people may believe they are not susceptible to being misled.

Examples of Harm: Several real-world cases have shown that reliance on FC can lead to false accusations, legal consequences, and even harm to individuals and families.

Neurons and Neural Communication

Structure and Function of Neurons

• Neurons: Specialized cells that transmit messages throughout the central nervous system (CNS).

• Cell Body (Soma): The neuron's life support center, containing the nucleus and organelles.

• Dendrites: Branch-like structures that receive information from other neurons and transmit it toward the cell body.

• Axon: A long, slender projection that carries electrical impulses away from the cell body to other neurons or muscles.

• Myelin Sheath: A fatty layer that insulates some axons, speeding up neural transmission. Degradation of myelin (as in multiple sclerosis) slows or disrupts signal transmission.

Neural Impulse and Action Potential

• Neurons generate electricity through chemical events involving the movement of ions.

• Resting Potential: The state of a neuron when not firing; the inside of the axon is negatively charged relative to the outside.

• Action Potential: A brief electrical charge that travels down the axon when the neuron fires.

Equation for Resting Potential:

$V_{rest} \approx -70\ \text{mV}$

Synaptic Transmission

Structure of the Synapse

• Axon Terminal (Button): The endpoint of an axon where neurotransmitters are stored.

• Synaptic Vesicles: Small sacs in the axon terminal that contain neurotransmitters.

• Neurotransmitters: Chemical messengers that transmit signals across the synaptic cleft.

• Synaptic Cleft: The gap between the sending neuron's axon terminal and the receiving neuron's dendrite or cell body.

• Neurotransmitters bind to receptor sites on the receiving neuron, similar to a key fitting a lock.

Neurotransmitters and Their Functions

• Acetylcholine (ACh): Involved in muscle movement, learning, and memory. Deficits are linked to Alzheimer's disease.

• Dopamine (DA): Involved in reward, learning, attention, and movement. Excess activity is linked to schizophrenia; deficits are associated with Parkinson's disease.

• Norepinephrine (NE): Affects arousal, wakefulness, and eating habits. Predominant in fear and stress responses.

• Serotonin (5-HT): Regulates mood, sleep, impulsivity, and aggression. Low levels are linked to depression.

• GABA (Gamma-aminobutyric acid): The main inhibitory neurotransmitter; increased by alcohol and anti-anxiety drugs, reducing anxiety.

• Endorphins: Natural painkillers that promote pleasure and well-being.

Agonists and Antagonists

• Agonists: Drugs or chemicals that mimic or enhance the action of a neurotransmitter.

• Antagonists: Drugs or chemicals that block or inhibit the action of a neurotransmitter.

• Example: Naloxone is an antagonist that blocks opiate effects.

Organization of the Brain

Cerebrum and Cerebral Cortex

• Cerebrum: The largest part of the brain, divided into left and right hemispheres.

• Corpus Callosum: A bundle of nerve fibers connecting the two hemispheres, allowing communication between them.

• Cerebral Cortex: The outer layer of the cerebrum, responsible for higher mental processes such as language, memory, and thinking.

• Glial Cells: Support, nourish, and protect neurons; produce myelin and may play a role in learning and thinking.

Lobes of the Cerebral Cortex

• Frontal Lobe: Involved in movement, problem-solving, decision-making, inhibition, language, and planning. The motor cortex is located here.

• Parietal Lobe: Processes touch, spatial ability, and attention. The somatosensory cortex is located here.

• Occipital Lobe: Responsible for vision, including edge detection, shape, and form.

• Temporal Lobe: Involved in memory, hearing, language, and complex visual processing (e.g., face recognition).

Specialized Brain Areas

• Broca's Area: Located in the frontal lobe; critical for speech production.

• Phineas Gage Case: Demonstrated the role of the frontal lobe in personality and decision-making.

Methods of Studying the Brain

• Electroencephalogram (EEG): Measures electrical activity in the brain; useful for detecting rapid changes.

• Transcranial Magnetic Stimulation (TMS): Uses magnetic fields to enhance or disrupt brain activity in specific regions.

• Magnetic Resonance Imaging (MRI): Uses magnetic fields and radio waves to produce detailed images of brain structures.

• Functional MRI (fMRI): Measures changes in blood oxygenation to assess brain activity.

• Positron Emission Tomography (PET): Measures changes in brain activity by tracking glucose consumption.

• Computed Axial Tomography (CAT): Uses X-rays to create 3D images of the brain.

Major Brain Structures and Their Functions

Structure	Main Function(s)
Medulla	Controls automatic functions: heartbeat, breathing, blood pressure, vomiting, swallowing
Pons	Facial movement, touch sensations, sleep, and dreaming
Reticular Formation	Regulates attention, arousal, and alertness; filters incoming stimuli
Amygdala	Involved in fear, aggression, and emotional memory
Hippocampus	Processes memory; damage impairs formation of new memories
Thalamus	Relay station for sensory information
Hypothalamus	Regulates hunger, thirst, body temperature, and sexual behavior
Cerebellum	Coordinates movement, balance, and motor learning; involved in implicit memory

Application: Brain Functions in Driving a Car

• Cerebellum: Coordinates hand movements on the steering wheel; enables automatic actions while daydreaming.

• Medulla: Regulates breathing and heart rate.

• Pons: Coordinates eye movement and alertness.

• Reticular Formation: Maintains alertness or drowsiness.

• Thalamus: Relays sensory cues to the cerebrum.

• Hypothalamus: Monitors body needs (temperature, hunger, thirst).

• Amygdala: May be active during emotional responses like road rage.

• Hippocampus: Forms memories of road hazards.

• Corpus Callosum: Shares sensory and motor information between hemispheres.

• Frontal Lobe: Initiates movement (e.g., braking).

• Parietal Lobe: Assists in spatial tasks (e.g., parallel parking).

• Occipital Lobe: Processes visual information (e.g., road signs).

• Temporal Lobe: Processes auditory information (e.g., sirens, horns).

Split Brain and Hemispheric Specialization

Split Brain Research

• Myth: People are either 'right-brained' (creative) or 'left-brained' (logical). In reality, both hemispheres work together for most tasks.

• Left Hemisphere: Generally dominant for language, reading, writing, speaking, and math.

• Right Hemisphere: More involved in spatial, artistic, and emotional processing.

• Corpus Callosum: Allows communication between hemispheres; damage can disrupt this communication.

Sample Exam Questions and Applications

• Sequence of neural conduction: dendrites → soma (cell body) → axon → axon terminal.

• Synaptic vesicles are analogous to gel capsules filled with medication (they store and release neurotransmitters).

• Myelin sheath and nodes of Ranvier speed up neural transmission.

• Reuptake is the process by which neurotransmitters are reabsorbed into the presynaptic neuron (like sucking mustard back into a squeeze bottle).

• GABA activity is increased by alcohol and anti-anxiety drugs, leading to inhibitory effects.

• Damage to the hippocampus impairs the formation of new memories but leaves old memories intact.

• Acetylcholine is the neurotransmitter most involved in memory problems.

• Damage to the corpus callosum disrupts communication between brain hemispheres.

• Prosopagnosia (face blindness) is linked to damage in the fusiform gyrus.

• The amygdala is activated during fear responses (e.g., feeling afraid when hearing footsteps at night).

• Parkinson's disease is treated by increasing dopamine levels.

• There is no scientific evidence for strict hemispheric asymmetry in complex tasks; both hemispheres function together.

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard academic knowledge in biological psychology.