Psychology test 1

Neurotransmission

Neurotransmission

The process of communication between neurons,

Types of messages sent: electrical and chemical messages.

Neurotransmitters

The chemical messengers.

When messages reach the end of the neuron, chemical messengers called neurotransmitters are released into the synapse.

Synapse

The space between neurons.

Excitatory Neurotransmitters

Chemicals that bind to receptors and increase the chances of the post-synaptic neuron firing. (accelerator)

Ex: glutamate and acetylcholine.

Inhibitory Neurotransmitters

Chemicals that bind to receptor sites and reduce the chances of the post-synaptic neuron firing. (break)

Ex: GABA and Glycine.

Agonists

Chemicals that amplify the effects of a neurotransmitter by binding to and activating its receptors.

Ex: GABA (neurotransmitter) — Alcohol (chemical) — increases GABA, so it’s an Agonist.

Antagonists

Chemicals that block the effects of neurotransmitters by binding to and blocking their receptor sites.

Ex: Glutamate (neurotransmitter) — Alcohol (chemical) — decreases Glutamate, so it’s an Antagonist.

Acetylcholine (ACh)

A neurotransmitter that plays an important part in learning and short-term memory, and is responsible for muscle contraction.

Acetylcholinesterase (Cholinesterase)

An enzyme that will degrade ACh into its A and Ch parts.

Martinez & Kesner (1991) Study

Research demonstrating ACh's role in spatial memory through a rat maze experiment with three groups each getting a different injection, scopolamine, physostigmine, and no injection.

Antonova et al. (2011) study

Research showing the impact of ACh on human spatial memory using fMRI scans and seeing the difference, injecting one group with scopolamine and the other with a placebo and then switching 3–4 weeks later.

Invasive Techniques

Procedures involving lesioning or ablation of brain tissue, often raise ethical concerns as these are mostly done on animals and cause brain damage which is irreversible.

Case Studies

In-depth examinations of individuals with brain damage, using medical studies, which was popular before the emergence of imaging technology.

Strengths of case studies

• They are naturally occurring brain damage (no unethical damage done to human brains to be used in a study.)

• Has ecological validity, and no ethical violations.

• All qualitative data has ecological validity

• Longitudinal (long term, short term) examination of short-term and long-term effects of brain damage. (range of effects)

• Examination of the range of effects of the damage rather than just focusing on a single behavior.

• Triangulation of research methods for richer data and a more detailed picture of the case.

  • Interview with the family

  • Psychometric testing (IQ)

  • Experiments

  • Observations

• Lots of different research methods to study one thing.

Limitations of case studies

• Cause and effect relationships cannot be determined, as there's no manipulation of an IV.

• Findings cannot be generalized as each case is unique, and a single individual is studied. Lacks population validity as it's an extremely small sample size.

• Replication is not possible because we cannot control the variables, and we can't harm other people to replicate a case study, as it would be unethical to cause harm to humans.

• Accurate information can be difficult to obtain about what the patient was like before the damage took place.

MRI

Imaging technique producing detailed 3D images of brain structure by using magnets and radio waves measuring the hydrogen nuclei in the body.

Strengths of MRI’s

• Can produce detailed 3D images that allow for diagnosis of tumors, bleeding in the brain, and damage caused by injury, infection, or stroke

• It's a non-invasive, so it's safer than other techniques

• It doesn't use radiation

• The quality of images is continually improving

Limitations of MRI’s

• It can be very noisy

• It's difficulty for people to stay still while they are being scanned, and movement affects the quality of the images

• It cannot be used on people with metal inserts in their body as it uses very powerful large magnets

• It's an expensive procedure

fMRI

Imaging technique measuring brain activity through blood flow through the brain, providing high-quality images of brain function.

Can be turned into a 3D, colored, moving image of the brain.

Strengths of fMRI’s

• The image is high quality, and it produces a film that demonstrates change in the brain over the period of the scan

• It's non-invasive, so it's safer than other techniques

• It doesn't use radiation

• It can be combined with other techniques like EEG’s to get more detailed data.

Limitations of fMRI’s

• Its expensive

• It records activity more slowly than an EEG

• It cannot be used on people with metal inserts in their body as it uses very powerful large magnets

• The fMRI is not a natural environment, which means research based on its use, may lack ecological validity

• It's an environment that may make people feel anxious and that could affect the scan that is taking place

• The use of colors may exaggerate the activity of the brain

• Much of the brain activity is spontaneous and is not a reaction to stimuli

• It's difficult to know exactly which areas of the brain are active in a behavior

Theory of Localization of Function

When a specific part of the brain is responsible for a specific function.

One specific part of the brain is responsible for a function:

• The brain stem (a specific part of the brain) is responsible for controlling our breathing and heart rate (specific functions).

Theory of Distribution of Function

When different parts of the brain are responsible for a function.

Two or more parts of the brain are responsible for a function:

• The frontal lobe and the cerebellum (parts of the brain) are both responsible for movement (function).

Connectome

A neural network across which a certain function or behavior is distributed.

• How is it related to both theories?

  • Areas of localization are joined by neutral pathways that together make a connectome which is a neutral network across which a certain function of behavior is distributed.

Case Study of HM

The study of HM, who lost his explicit LTM due to surgery in 1953 where they removed both of his hippocampi.

Explicit Long-Term Memory

Type of memory HM lost, evidenced by his inability to recall memories from the past decade after surgery (episodic) and the inability to retain information but still be able to work with it (semantic).

Implicit Long-Term Memory

Type of memory HM retained, allowing him to perform learned skills without conscious recollection (procedural) and be able to remember JFK’s assassination due to it being such a shocking event (emotional conditioning).