Biopsychology Glossary - AQA Psychology A-level Topic 6

Adrenaline

• Definition: A hormone involved in a number of responses, namely the flight or fight response.
• Key point: Part of the body’s rapid response to stress, coordinating quick physiological changes to prepare for action.

Autonomic nervous system

• Definition: The nervous system responsible for automatic responses, such as sympathetic or parasympathetic responses.
• Key point: Regulates involuntary body functions without conscious control; subdivides into sympathetic and parasympathetic branches that typically have opposing effects.

Broca’s area

• Definition: An area in the left hemisphere dedicated to speech production i.e. the motor component.
• Significance: Central to language production; dysfunction linked to Broca’s aphasia.

Central nervous system

• Definition: The nervous system made up of the brain and spinal cord.

Circadian rhythms

• Definition: Biological processes which cycle in about 24 hours. (Origin: circadian = approximately; dian = a day)
• Example: Sleep–wake cycle.
• Key note: Approximately one day period; governs daily physiological and behavioral patterns.
• Mathematical note: The period is roughly $<br />\not\,\approx 24\ \text{hours}$, i.e. about 24 hours.

EEG

• Definition: Electroencephalogram (electro = electrical activity, encephalo = brain, gram = measuring).
• Function: An imaging technique to record electrical activity in the brain.

Endogenous pacemakers

• Definition: Internal “clocks” that regulate biological rhythms, e.g. the suprachiasmatic nucleus.
• Significance: Provide internal timing mechanisms that coordinate rhythms (e.g., circadian).

ERP

• Definition: Event-related potential – an imaging technique similar to an EEG, except baseline activity is filtered so electrical activity in response to a stimulus can be recorded.
• Use: Measures neural responses to specific events, helping isolate stimulus-locked activity.

Excitation

• Definition: A signal sent to the next nerve making it more likely to fire.
• Role in neural transmission: Increases probability of neurotransmitter release and action potential propagation.

Exogenous zeitgebers

• Definition: External cues that influence biological rhythms.
• Example: Daylight influences the sleep–wake cycle.
• Significance: Synchronize internal clocks with the external environment.

Fight-or-flight response

• Definition: The sympathetic responses that increase activity to areas designed to help you escape or prepare for a fight (e.g., increased blood flow to muscles, reduced blood flow to the gut).
• Mechanism: Rapid autonomic arousal to prepare for action.

fMRI

• Definition: Functional magnetic resonance imaging – an imaging technique that monitors blood flow in the brain.
• Significance: Allows insight into which areas of the brain are used for particular activities by detecting hemodynamic changes.

Glands

• Definition: An organ that synthesises and releases substances (e.g. hormones) for specific purposes.
• Note: Glands are a source of hormones in the body’s endocrine system.

Hormones

• Definition: Chemical messengers that travel through the bloodstream to regulate certain processes in the body.

Infradian rhythms

• Definition: Infra = below, dian = a day. Biological rhythms that occur less often than once a day, meaning they cycle in periods a lot longer than 24 hours.
• Example: The menstrual cycle.
• Etymology: Infra- (below) + dian (a day).

Inhibition

• Definition: A signal sent to the next nerve making it less likely to fire.
• Role: Opposite of excitation; reduces neural firing and neurotransmitter release.

Lateralisation (hemispheric) of function

• Definition: The concept that different hemispheres in the brain have differing functions.
• Example: Language functions are typically lateralised to the left hemisphere.
• Significance: Helps explain specialization of brain regions.

Localisation of function

• Definition: The concept of functions in the brain being specific to certain areas.
• Example: Broca’s area is specific to language production.

Motor neurons

• Definition: A type of neuron that activates an effector organ (muscles, glands, organs).

Peripheral nervous system

• Definition: The nervous system that exists outside the central nervous system, in the periphery; your arms, legs, etc.
• Subdivisions: Includes somatic and autonomic branches relative to voluntary vs. involuntary control.

Plasticity

• Definition: Specifically brain plasticity; the ability of the brain to adapt to situations, and change its structure - even to potentially regain previously lost function.
• Significance: Underpins learning, memory, and recovery from injury.

Relay neurons

• Definition: A neuron found in the CNS which allows communication between sensory and motor neurons.
• Role: Connects sensory input to motor output within neural circuits.

Sensory neurons

• Definition: A neuron that transmits sensory information from the environment to an interneuron after converting it to electrical activity.

Somatic nervous system

• Definition: The nervous system in control of conscious, voluntary movements of the periphery.

Suprachiasmatic nucleus

• Definition: Two small, paired nuclei in the brain that are responsible for controlling many circadian rhythms in the human body.
• Example: They regulate the sleep–wake cycle.
• Significance: Primary endogenous pacemaker influencing circadian timing.

Ultradian rhythms

• Definition: Ultra = above, dian = a day. Biological rhythms that occur more often than 24 hours, meaning they cycle in periods shorter than 24 hours.
• Example: The sleep cycle, occurring every $90\ \text{minutes}$.

Wernicke’s area

• Definition: An area in the left hemisphere dedicated to speech comprehension.
• Significance: Critical for language understanding; damage can impair comprehension.

Ethical, practical, and real-world considerations (overview)

• Ethical implications: Not explicitly discussed in the transcript. Practical relevance includes understanding basic brain function, diagnosis, and treatment of language and rhythm disorders, and informing education and ergonomics related to circadian biology.
• Real-world relevance highlights: How daylight and internal clocks influence sleep quality, performance, and wellbeing; how language centers support communication; how stress-related hormones affect bodily systems.

Quick references and equations

• Circadian rhythm period: $ext{Approximately } 24 ext{ hours}$
• Ultradian rhythm period: < 24 hours; sleep cycle example: $90 ext{ minutes}$
• Note on terminology: Endogenous = internal clocks; Exogenous = external cues.