Biological Psychology Practical Notes

Biological Psychology Practical: In-Depth Notes

1. Foundations of Physiological Measurement

• Definition: Biological psychology (physiological psychology) studies the relationship between psychological processes and physiological/biological processes.

  • Focuses on how biological traits (like genetics) influence psychological function.

  • Overlaps with psychophysiology, both concerned with measuring physiological changes.

  • Biological psychology often employs invasive techniques (e.g., brain center destruction) on animals, while psychophysiology typically experiments with humans using non-invasive methods.

1.1. Organization of the Nervous System

• Nerve Cells: Approximately 100 billion nerve cells in human nervous tissue, responsible for communication, information processing, and behavior.

  • Central Nervous System (CNS): Comprised of the brain and spinal cord.

  • Peripheral Nervous System (PNS): Comprises neurons outside the CNS, typically located in ganglia across the body.

• Neural Communication: Neurons transmit information unidirectionally from cell body to axon terminal.

  • Afferent Neurons: Carry impulses to the CNS (input).

  • Efferent Neurons: Carry impulses away from the CNS (output).

• Sensory Receptors: Provide information covering exteroception (environment), proprioception (motor system state), and visceroception (internal organs).

  • Output leads to behavior, integrating various inputs.

• Somatic and Autonomic Nervous System:

  • Somatic Motor System: Controls voluntary movements through striated muscles.

  • Autonomic Nervous System (ANS): Regulates involuntary functions (visceral), involving cardiac muscle, smooth muscles, and glands.

  • Divisions of ANS:

    • Sympathetic Nervous System (SNS): Prepares body for activity, increases heart rate, and involves catabolic processes (energy release).

    • Parasympathetic Nervous System (PNS): Conserves energy, decreases heart rate, and involves anabolic processes (energy storage).

    • Enteric Nervous System: Regulates gastrointestinal functions with about 400 million neurons.

1.2. Common Characteristics of Nerve Cells and Muscle Cells

• Characteristics:

  • Both cell types are elongated and excitable, crucial for nervous system function.

  • Nerve excitability and muscle contraction initiated by electrical impulses.

• Action Potential: Triggered by a local discharge reaching a certain threshold (>20-40 mV), leading to depolarization and subsequent repolarization.

  • Resting potential typically around -90 mV, maintained by Na+-K+ pumps.

• Synaptic Transmission: Neurons communicate through synapses; neurotransmitters released upon action potential influence postsynaptic potentials.

  • Postsynaptic potentials vary,

  • Excitatory: Increase likelihood of action potential.

  • Inhibitory: Decrease likelihood.

1.3. Bioelectric Potentials

• Neuronal and muscle activities generate bioelectric signals; recording them requires overcoming various challenges:

  • Only aggregated signals can be measured due to the complexity of synchronous processes.

  • Placement of electrodes significantly impacts the recorded signals.

  • High impedance of skin requires skin preparation (e.g., abrasion) to improve measurements.

1.4. Elementary Steps of Recording

• Recording Procedure:

  • Signal acquisition through electrodes—stable connections essential for accurate readings.

  • Usage of electrode paste reduces movement artifacts.

• Signal Adjustment:

  • Filters and amplifiers enhance signal quality and strength, with ECG (mV) and EEG (µV) varying in required amplification.

1.5. Basic Terms and Principles

• Tonic vs. Phasic Activity:

  • Tonic Activity: Baseline activity influencing interpretation of evoked responses.

  • Evoked Responses: Triggered by stimuli and varies widely among individuals.

• Individual Differences are important in biological psychology (e.g. individual response stereotypy).

• Directionality: Physiological changes can vary in direction; e.g., stress often increases heart rates while affecting skin conductance.

1.6. Safety and Ethics in the Lab

• Safety Protocols: Laboratories use potentially dangerous instruments, necessitating precaution for all participants.

  • Experimental setups must ensure protection from undue stress or physiological safety concerns.

• Ethical Considerations:

  • Participation in experiments must be voluntary and participants can withdraw at any time.

  • Data handling requires participant consent, respecting privacy and physical limits.

  • Awareness of fellow participants' conditions is crucial during demonstrations or practical classes.