The biology of behaviour
Introduced| English | Meaning |
|---|---|
| neuron/ˈnjuːrɒn/ | A nerve cell that carries electrical signals. |
| synapse/ˈsɪnæps/ | A junction through which a neuron communicates with another cell, usually using a chemical transmitter. |
| neurotransmitters/ˈnjuːrətrænsmɪtəz/ | Chemical messengers released by neurons to transmit signals across synapses. |
| central nervous system/ˈsentrəl ˈnɜːvəs ˈsɪstəm/ | The brain and spinal cord, which process information and coordinate responses. |
| peripheral nervous system/pəˈrɪfərəl ˈnɜːvəs ˈsɪstəm/ | The nerves and associated structures outside the brain and spinal cord. |
| cerebral cortex/ˈserɪbrəl ˈkɔːteks/ | The outer layer of the cerebrum, involved in perception, voluntary action and higher cognitive functions. |
| sleep/sliːp/ | sleep |
| REM sleep/rem sliːp/ | A phase of sleep characterised by rapid eye movements, active brain patterns and greatly reduced muscle tone. |
A signal needs more than one structure
- A hand withdraws from a hot surface before a deliberate decision. A spinal pathway can coordinate that response while signals also reach the brain.
- A neuron 神经元 receives and transmits signals. At a chemical synapse 突触, released neurotransmitters 神经递质 act on receptors across the gap.
In the chemical-synapse model, how is communication across the gap mediated?
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Released neurotransmitters act at receptors of the receiving cell. Electrical synapses also exist.
Bound the communication model
- Electrical activity can lead to chemical release and a change in the receiving cell. The response depends on receptors and the relevant circuit.
- This is a chemical-synapse model. Electrical synapses also exist, so “no signal ever crosses electrically” is too broad.
Match each system to what it includes.
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Brain and spinal cord form the CNS; peripheral nerves carry sensory input and motor output in a spinal reflex pathway.
Locate the systems
- The central nervous system 中枢神经系统 includes brain and spinal cord. The peripheral nervous system 周围神经系统 connects them to the rest of the body.
- A reflex pathway still involves sensory input and motor output; a spinal response does not mean the entire event happens without peripheral nerves.
Using the lesson’s rough introductory estimate, about how many minutes is a sleep cycle?
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About ninety minutes is an approximation. Actual cycle lengths and stage proportions vary; this is not a personal measurement.
Avoid one-region explanations
- The cerebral cortex 大脑皮层 has lobes associated with different functions, but complex behaviour uses interacting systems. Association alone does not establish sole control.
- Sleep 睡眠 alternates through stages. REM sleep 快速眼动睡眠 often includes vivid dreams, but dreams also occur outside REM and cycle lengths vary.
Which statement does the evidence support?
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The qualified statement recognises interacting regions and avoids claiming sole responsibility for a complex process.
Which claim fits the chemical-synapse diagram?
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The diagram models communication at a chemical synapse. It does not establish every synapse or a complete behavioural explanation.
Check what a summary can claim
- A sleep-cycle estimate of about ninety minutes is an introductory approximation, not a fixed personal timetable or a measurement of this student.
- Use the appropriate level of explanation and state the evidence. A brain description and a psychological account may address related processes without either automatically proving the other.
Use the appropriate level of explanation and state the evidence. A brain description and a psychological account may address related processes without either automatically proving the other.
Read more: Electrical synapses: a different communication mechanism.
A brain-level explanation is more scientific than a psychological one.
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The scientific quality depends on the question, method and evidence, rather than whether an account names a brain structure.