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.
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.
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.
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.
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.
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.
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.