Neuroplasticity

Question 1

How do neurons link?

Answer 1

Neurons communicate with each other via electrical events called ‘action potentials’ and chemical neurotransmitters. Dendrites contain voltage-gated ion channels giving them the ability to generate action potentials. A dendritic spike is initiated in the same manner as that of an axonal action potential. Depolarisation of the dendritic membrane causes sodium and potassium voltage-gated ion channels to open. The influx of sodium ions causes an increase in voltage. If the voltage increases past a certain threshold, the sodium current activates other voltage-gated sodium channels transmitting a current along the dendrite. This complex processes allows for a junction to occur between two neurons (synapse), thereby resulting in the transmission of chemical neurotransmitters.

Question 2

How does your brain grow? – Learning, struggle, adversity, getting things wrong

Answer 2

• The human brain is considered to be a highly dynamic system that consistently alters throughout an entire lifespan.
• Throughout the course of cognitive neuroscience, research has posited that neuroplasticity refers to the lifelong capacity of the brain to change and rewire itself in response to the stimulation of learning and experience.

Question 3

What is neuroplasticity?

Answer 3

According to empirical research, neuroplasticity constitutes in the ability of the brain to form and reorganise synaptic connections, especially in response to learning or experience or following injury.

Question 4

Describe the Maguire et al. study:

Answer 4

Maguire et al. (2000) found that spatial memory in London taxi drivers is localised in the hippocampus. Taxi drivers in London must go through extensive training in order to become licensed taxi drivers. This training is called “The Knowledge” and takes approximately 2 years to complete.

• Structural MRIs of the brains of humans with extensive navigation experience, licensed London taxi drivers, were analysed and com-pared with those of control subjects who did not drive taxis.
• The posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects.
• A more anterior hippocampal region was larger in control subjects than in taxi drivers. Hippocampal volume correlated with the amount of time spent as a taxi driver (positively in the posterior and negatively in the anterior hippocampus).
• It seems that there is a capacity for local plastic change in the structure of the healthy adult human brain in response to environmental demands

Question 5

Evaluate the findings of Maguire et al. study:

Answer 5

• Limited sample size.
• All participants were male.
• MRI provided understanding of structural differences in hippocampus rather than specific neuronal activities.
• This was a correlational study, and correlation does not imply causation.

Question 6

Explain the following study:

Fisher et al (2005)– Dopamine fMRI scans in VTA when shown image of loved ones

Answer 6

Fisher (2004 & 2005) “addiction to love” -Dopamine fMRI scans in VTA when shown image of loved ones

Fisher suggests that “being in love” has similarities to
“being addicted”.

There was activation in the areas of the brain associated with feelings of reward and pleasure –the dopamine-rich areas including the ventral tegmental area (in the centre of the midbrain) and thecaudate nucleus (again close to the midbrain).

Dopamine increase desire and reward by triggering the
same emotional rush of pleasure as if you took a drug
like cocaine.

Dopamine can explain the highs of romantic passion
(high levels) and the lows of rejection (low levels of
dopamine).

Question 7

Crockett (2010)– Serotonin and pro-social behaviour (trolley dilemma)

Answer 7

Throughout the study conducted by Crockett (2010), the role of serotonin in moral judgement and behaviour was assessed.

• Serotonin and dopamine had distinct effects on decisions to harm self versus others
• Computational models revealed a hyper altruistic preference to harm self over others.
• Pharmacological enhancement of serotonin increased harm aversion for self and others
• Pharmacological enhancement of dopamine reduced hyper altruism.

Question 8

Inhibitory Neurotransmitters vs Excitatory Neurotransmitters

Answer 8

Excitatory neurotransmitters increase the likelihood of a neuron firing by depolarizing the neuron. Excitatory neurotransmitters include acetylcholine.

Inhibitory neurotransmitters decrease the likelihood of a neuron firing by hyperpolarising the neuron. Inhibitory neurotransmitters include GABA.

Metabotropic neurotransmitters only indirectly affect the neuron and are considered neither excitatory or inhibitory. Metabotropic neurotransmitters include serotonin, dopamine, and norepinephrine.