Topic 3.1: Biological Psychology

What is the nervous system?

1. Control Center: Acts as the control centre and communication network. Allows you to interact with the world around you and keeps your body functions working smoothly

2. Transmits Signals

Neurons carry electrical signals to and from your brain and spinal cord. These signals tell your muscles to move, let your brain know when you feel something, and keeps your organs running properly.

3. Coordinates Actions

The nervous system helps different parts of your body work together by sending messages through neurons. These messages travel quickly, like signals moving through wires.

How does the NS work?

• The nervous system functions by using neurons that carry messages throughout the body.  

How do neurons communicate

• Neurons communicate using electrical and chemical signals. These signals travel along the neuron until they reach a synapse, which is a small gap between neurons.  

• When the signal reaches the synapse, neurotransmitters are released to carry the signal across the gap to the next neuron/muscle, allowing communication to continue.

Key functions of the NS

1. Sensory input: The nervous system collects information from the external environment  through sensory receptors. 

2. Integration

The brain processes and interprets the sensory information to make decisions about how to respond. 

3. Motor output

The nervous system sends signals to muscles or glands to make the body respond.

Brain mapping methods: Phrenology

The detailed study of the shape and size of the cranium as a supposed indication of character and mental abilities. 

• Pros: None. 

• Cons: based on anecdotal evidence. 

• Injuries did not result in hypothesized deficits.  

• Outer surface of the skull does not represent the inside.  

2. Brain injury

Pros:  No batteries required. Neuropsychological tests allows scientific assessment. 

Cons: Accidental injuries are rarely identical. Brain plasticity: The brain's lifelong ability to change, adapt, and reorganize its structure and functions by forming new neural pathways. Ethics. 

3. EEG

3. Measures electrical activity generated by the brain. Patterns and sequences in the EEG allow scientists to infer whether a person is awake or asleep, dreaming or not, and to tell which regions of the brain are active during specific tasks. 

• Pros: Fast detection. Cheap. Good for mapping initial routes for mind functioning. Measures sleep and/or reaction time (as examples)

4. Computed Tomography (CT):

4. The development of neuroimaging changed things. Uses X-rays and computers to produce detailed, cross- sectional "slices" of the body's internal structures, revealing bones, soft tissues, and organs that are not visible with conventional X-rays.  

• Pros: 3D imaging. 

• Cons: Doesn’t detect soft tissue.  

5. Magnetic Resonance Imaging (MRI):

5. Technique that uses magnetic fields to indirectly visualize brain structures. 

• Pros: Detects soft tissue better than CT scans.  

• Cons: Does not show brain function.  

6. Positron Emission Tomography (PET):

A nuclear imaging test that uses a radioactive tracer to show how cells and organs are functioning at a molecular level. can create images of the body's metabolic processes, often combined with CT scans to provide more detailed anatomical and functional images.  

• Pros: Shows what areas of the brain are active. Good spatial resolution.  

• Cons: Invasive. Expensive (Not widely used anymore).

7. Functional MRI:

A non-invasive medical imaging technique that shows which parts of the brain are active by detecting changes in blood flow. When a brain region is active, it needs more oxygen, increasing blood flow to that area. 

• Pros: Good spatial resolution. Cheaper and less invasive than PET.  

• Cons: Poor temporal resolution

8. Magnetoencephalography:

8. Technique that measures brain activity by detecting tiny magnetic fields generated by the brain.  

• Pros: High temporal resolution. Good spatial resolution. 

• Cons: Expensive

Brain scan considerations

1. Control tasks. 

2. Inhibitory neurons. 

3. Chance findings. 

Brain manipulation methods

Transcranial  Magnetic stimulation (TMS): Technique that applies strong and quickly changing magnetic fields to the surface of the skull that can either enhance or interrupt brain function.  

• Pros: Non-invasive. Can infer causation. 

• Cons: Doesn’t penetrate deep in the brain.  

2. Deep Brain Stimulation (DBS):

2. Technique in which electrodes and a battery source are implanted in the brain to deliver electricity and specific areas.  

• Pros: Promising treatment methods for Parkinsons, Dementia, Epilepsy.  

• Cons: Invasive. Uses battery.