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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.