Psychobiology WK 11 - Implications and Ethical Research

Deep Brain Stimulation (DBS)

Electrodes are implanted in key subcortical areas which exert electrical impulses that are regulated by an external generator (similar to pacemaker)

Used since 1987

Used in a number of medication-resistant forms of neurological diseases or motor disorders (particularly Parkinson’s Disease; PD)

Needs precise mapping of stimulation targets using MRI imaging

Deep Brain Stimulation and Parkinson’s Disease

Parkinson’s Disease medication resistance and side effects can build up within 5 years of use

Targets dopamine depletion in Parkinson’s Disease (Subthalamic nucleus)

Risks of Deep Brain Stimulation

Invasive technique, where 46% of participants experience misplacements, leading to:

• Impedance

• Device malfunction

• Infenction

Imprecise targeting can lead to less efficacy, requiring larger amp, thus worse side-effects

Long-term psychological effects of DBS

Similar effects to Parkinson’s Disease:

• Motor disruption and slurred speech (related to STN)

• Cognitive processing decline

• Decreases memory and intelligence (as sensitive to frontal lobe dysfunction)

However, sometimes improvements are seen:

• Sometimes improvements in the same functions

• No extreme side effects (mortality/suicide)

• Decreased depression scores

Personality change and DBS

Electrode placement in emotional functional networks connect to fronto-subcortical network and basal ganglia (particularly neuroticism)

This affects regions related to emotional self-regulation and cognitive control

Can impact narrative identity: the sole fact that a machine is inside of you

Changes to habits, daily routine, socialisation (mostly positive)

Ethical implications (for any invasive technique, not just DBS)

• Placement issues can be overcome with higher advanced technology in neuroimaging (e.g. 3T or 7T MRI scans instead of original 1.5T)

  • Higher resolution, but more expensive

• Participant has control over device - can turn it off, battling identity issue

• Electrode revisions, facilitate by general advances in surgical practices

  • Possible but costly (monitoring is needed)

• More research for extended practice (depression, pain)

Non-invasive alternative: TMS

Excitability changes, particularly in dlPFC, leading to relief rates above placebo

Limited side-effects: sore neck, fatigue, tiredness

Rare risk of seizures <1 in 60,000

Limited to treatment of very specific symptoms

Endogenous method: neurofeedback

A self-regulation method - measures brain activity and provides a feedback signal based on desirable or undesirable brain activity

Operant conditioning - develops healthier brain patterns neuroplasticity

Success in treating depression and addiction, but problems with adequate control conditions and protocols

Dual systems model of risk-taking in adolescence

Socioemotional system:

• Rapid increase in dopaminergic activity, especially in amygdala and ventral striatum areas

Control system:

• Slower development of control related regions (prefrontal cortex) and its connection to socioemotional areas

Temporal gap = Higher risk-taking

Peer influence on risk-taking

Chein et al 2011 Stoplight task

Sample of children, adolescents, adults

Aim: to drive to the end of the street in minimum amount of time

Risk: Run amber stop lights vs wait

2 conditions: alone or with peers

When with peers, risk-taking increased (and ventral striatum activity) and adolescents did not recruit lPFC the way adults did

Emotional influence on self-control

Casey (2013)

Go/no go task: requires participant to suppress pressing button on no go

When emotional stimuli (smiling face) was presented with don’t go, less self-control was exhibited and higher ventral striatum activity

Adolescents make more false alarms on positive social cues

Criminal responsibility for adolescents

Steinberg (2009) argues that adolescents have diminished responsibility as they are more susceptible to things outside of their control

Brain regions that regulate impulse control and resistance to peer influence are still developing (prefrontal cortex)

Animal research in the UK + opinions

In 2020, there were 2.9 million animal research procedures in the UK

Mice, rats and fish account for 92% of this figure

1 in 4 people are completely against animal research

Two thirds of people allow animal research as long as it is not harmful, it is for medical purposes, and is necessary (there is no other method)

Reality of animal procedure regulations in UK

Animal procedures are strictly regulated, rated between non-severe, mild, moderate and severe

It is hard to get authorisation that goes beyond mild (i.e. anything that alters normal living: medication)

• Behavioural induction of stress would already be moderate

Animal (Scientific Procedures) Act in 1986 regulated by the Home Office

Attempts to reduce amount of animals used and prioritise welfare

Beneficial for science: the happier the animal, the more consistent the results

Extent of strictness of regulations

Violation of regulatory animal research is punishable by criminal prosecution

Animal research is highly regulated and documented:

• For example, mice that are slightly underfed to motivate them for treats cannot fall under 85% of their normal weight - they are routinely weighed and recorded

Any injury or harm is always reported and investigated: including post-mortems by vets and research projects scrutinised

Journals commonly require extensive reports on welfare

NC3Rs (also includes BPS Guidelines for working with animals)

Prioritises the minimum amount of harm done to animals by using:

• Replacement - using other methods of investigation like 3D printed bioprinted tissue, less sentient animals, secondary data analysis (e.g. ratlife.org)

• Reduction - reducing the amount of animals used to its bare minimum

  • Consider appropriate pilot studies, reliable measures of behaviour, good experimental design, appropriate use of statistical tests

• Refinement - ensuring to reduce harm both to environment and animal as much as possible. Use latest technologies to maintain welfare, providing adequate housing to animals, training animals to cooperate with procedures