Biological Approach to Behavior Notes
Techniques to Study the Brain:
Functional magnetic resonance imaging (fMRI):
Measures blood flow related to neural activity, not neural activity directly.
Maps cognitive functions and processes at a neural level.
Localisation of Function
Strict Localization: Specific brain regions perform specific functions.
Relative Localization: Functions managed by larger brain areas, such as hemispheres.
Paul Broca's Discovery (1861):
Studied patient "Tan" with speech impairment stemming from a lesion in the left frontal lobe (Broca's area).
Maguire et al (2000) Study:
Aim: Neuroplasticity impacts spatial memory in taxi drivers.
Participants: 16 licensed male taxi drivers with an average of 14 years' experience.
Method: MRI scans compared with control subjects (healthy right-handed individuals).
Results: Increased gray matter in the posterior hippocampus of taxi drivers, indicating neural adaptation.
Conclusion: Correlation between experience as a taxi driver and changes in gray matter.
Lashley (1929):
Investigated whether cortex lesions affect memory in rats.
Found memory related to the percentage of cortex destroyed, not lesion location.
Proposed the principles of mass action and equipotentiality in memory.
Neuroplasticity
Definition: Brain's ability to form and break synaptic connections and adapt.
Draganski et al (2004) Study:
Aim: Investigate whether environmental demands change brain structure.
Participants: Random sample of jugglers and non-jugglers.
Method: MRI scans before juggling training, after training, and after a no-practice period.
Results: Brain structure in jugglers changed, especially in areas linked to coordination.
Neurotransmission and Behavior
Definition of neurotransmitters and their role in brain communication.
Importance of Serotonin:
Involved in mood regulation and neural connectivity affecting aggression.
Passamonti et al (2012) Study:
Investigated the link between serotonin levels and violent behavior.
Method: Manipulated serotonin levels through diet in participants.
Results: Reduced serotonin led to decreased prefrontal cortex activation, linked to impulsivity and aggression.
Formation of Neural Networks
Definition: Connected neurons facilitating information transmission.
Dendritic Branching: Extensions of neurons connecting at synapses.
Draganski Study Revisited:
Juggling increased gray matter in coordination areas, confirming neural network formation through experience.
Role of Agonists and Antagonists in Neurotransmission
Agonists: Enhance neurotransmitter actions (e.g., SSRIs for serotonin).
Passamonti et al (2012) Study: Used to research serotonin's role in violent behavior.
Antagonists: Block neurotransmitter action (e.g., Ketamine's effect on glutamate).
Feder et al (2014) Study:
Evaluated Ketamine's effectiveness on PTSD symptoms, showing decreased symptoms with treatment.
Neuroplasticity and Neural Pruning
Definition: Elimination of unused neurons to strengthen frequent connections.
Luby et al (2013) Study:
Investigated cognitive/emotional development linked to environment and social circumstances.
Excitatory and Inhibitory Synapses
Excitatory Synapses: Promote action potentials, linked to increased neural communication and behaviors.
Inhibitory Synapses: Reduce action potentials, contributing to calming effects on brain function.
Explored in Passamonti et al (2012) study linking serotonin levels to aggression.
Role of Hormones and Pheromones
Oxytocin: Involved in bonding, empathy, and trust.
Kosfeld et al (2005):
Examined oxytocin's role in trust during monetary games.
Pheromones: Chemical signals that influence behaviors and emotions, examined by Lundstrom and Olsson (2005).
Genes and Behavior
Genetic inheritance plays a critical role in behavior and psychological development.
Twin Studies: Investigate genetic heritability and environmental influences on behavior.
DLX1 gene linked to stress response and brain development in Kaminsky et al (2008).