biopsychology test 2

Plasticity & Functional Recovery – Neuroplasticity

The brain’s ability to adapt structurally and functionally in response to learning, experience, or damage, includes structural and functional changes, shows the brain is flexible and not fixed

Plasticity & Functional Recovery – Structural Plasticity

Physical changes in brain regions, e.g., increased grey matter from synaptic strengthening, develops slowly in response to learning or trauma

Plasticity & Functional Recovery – Functional Plasticity

Healthy brain regions take over functions of damaged areas, example: E.B., a child who regained language after left hemispherectomy, recovery may be partial but functional

Plasticity & Functional Recovery – Axonal Sprouting

New nerve endings grow from surviving neurons, forming alternative circuits to compensate for lost functions

Plasticity & Functional Recovery – Reformation of Blood Vessels

Angiogenesis restores oxygen and nutrients to damaged areas, supporting recovery

Plasticity & Functional Recovery – Recruitment of Homologous Areas

Mirror-image regions in the opposite hemisphere adopt functions of injured zones, e.g., right Broca’s area compensates for left damage

Plasticity & Functional Recovery – Neural Pruning

Use-dependent synaptic refinement, frequently used synapses grow stronger, unused synapses are eliminated, increases network efficiency

Plasticity & Functional Recovery – Case Study E.B.

Left hemisphere removed at 2, right hemisphere adapted to recover language over 2 years, demonstrates functional recovery especially in young brains

Plasticity & Functional Recovery – Case Study H.M.

Hippocampus removed at 27, permanent anterograde amnesia, shows limits of adult neuroplasticity

Plasticity & Functional Recovery – Cognitive Reserve

Higher education associated with better recovery post-brain injury (Schneider et al., 2014), mental stimulation can enhance functional recovery

Plasticity & Functional Recovery – Evidence Maguire et al. (2000)

London taxi drivers had increased posterior hippocampal grey matter due to spatial navigation, repeated use strengthens neural connections

Plasticity & Functional Recovery – Evidence Draganski et al. (2004)

Jugglers’ mid-temporal cortex grey matter increased with practice, decreased after stopping, demonstrates neuroplasticity and synaptic pruning

Plasticity & Functional Recovery – Evidence Gotink et al. (2016)

Mindfulness practice increased prefrontal cortex grey matter, decreased amygdala grey matter, reduced stress and anxiety, shows structural plasticity in adults

Plasticity & Functional Recovery – Evaluation Strengths

Strong empirical support, multiple studies show consistent results, practical applications in neurorehabilitation

Plasticity & Functional Recovery – Evaluation Limitations

Plasticity not universal (e.g., H.M.), most studies correlational, small sample sizes, biological reductionism, age and experience affect recovery

Ways of Scanning the Brain – fMRI

Measures oxygenated blood flow (BOLD signal) to detect brain activity, high spatial resolution (~1mm), non-invasive, produces 3D images showing active regions

Ways of Scanning the Brain – fMRI Evaluation Strengths

Non-invasive, good spatial precision, ethical, practical applications in research and therapy

Ways of Scanning the Brain – fMRI Evaluation Limitations

Poor temporal resolution (~5s delay), expensive, small samples, only correlational data, cannot prove causation

Ways of Scanning the Brain – EEG

Records electrical activity of cortical neurons via scalp electrodes, shows amplitude (intensity) and frequency (speed) of brainwaves, used in sleep, memory, seizure studies

Ways of Scanning the Brain – EEG Evaluation Strengths

High temporal resolution, reliable, historically important in identifying sleep stages (Dement & Kleitman, 1957)

Ways of Scanning the Brain – EEG Evaluation Limitations

Only measures surface cortical activity, electrode placement and comfort issues, cannot detect deep brain activity

Ways of Scanning the Brain – ERP

Derived from EEG, measures electrical responses to specific stimuli, real-time measurement, allows investigation of cognitive processes

Ways of Scanning the Brain – ERP Evaluation Strengths

Cheaper than fMRI, millisecond precision, useful for cognitive and clinical research

Ways of Scanning the Brain – ERP Evaluation Limitations

Electrode cap may be uncomfortable, source localization is not precise, signals may overlap

Ways of Scanning the Brain – Post-Mortem Examination

Examines brain after death to correlate structure with past function, used in H.M. and Broca’s patient Tan

Ways of Scanning the Brain – PME Evaluation Strengths

Ethical with consent, confirms diagnoses, gives structural insights

Ways of Scanning the Brain – PME Evaluation Limitations

Cannot measure live activity, retrospective, low ecological validity, consent issues may arise

Biological Rhythms – Circadian Rhythms

24-hour cycles controlling sleep/wake, hormones, temperature, coordinated by SCN and pineal gland, influenced by light and social cues

Biological Rhythms – SCN & Pineal Gland

SCN receives light input from optic nerve, regulates pineal gland melatonin secretion, SCN is master clock synchronizing body rhythms

Biological Rhythms – Melatonin

Hormone secreted in darkness, promotes sleep, suppressed by light, regulates circadian rhythm

Biological Rhythms – Exogenous Zeitgebers

External cues like light, environmental, social cues that entrain biological rhythms

Biological Rhythms – Entrainment

Synchronization of internal rhythms to external zeitgebers, prevents drift from 24-hour day

Biological Rhythms – DeCoursey et al. (2000)

Chipmunks with SCN lesions lost sleep/wake cycles, many killed, SCN critical for adaptive behavior

Biological Rhythms – Infradian Rhythms

cycles over 24 hours, e.g., menstrual cycle (~28 days), hormone-driven, can be synchronized by pheromones

Biological Rhythms – McClintock & Stern (1998)

29 women’s menstrual cycles synchronized via pheromones, shows exogenous influence, evolutionary advantage in coordinated reproduction

Biological Rhythms – Reinberg (1967)

Woman in cave, lack of natural light shortened menstrual cycle, shows light as a key zeitgeber

Biological Rhythms – SAD

Seasonal affective disorder, winter onset, higher melatonin and disrupted serotonin, prevalence higher in northern latitudes, light therapy reduces symptoms

Biological Rhythms – Ultradian Rhythms

Biological Rhythms – Sleep Stages 1–2

Light sleep, alpha & theta waves, sleep spindles, easily woken

Biological Rhythms – Sleep Stages 3–4

Deep sleep, delta waves, restorative, difficult to wake

Biological Rhythms – Stage 5 REM

Rapid eye movement, dreaming, CNS paralysis, high brain activity, eye movements match dream content

Biological Rhythms – Dement & Kleitman (1957)

REM correlated with dreaming, eye movements matched dream content, controlled, reliable study

Biological Rhythms – Randy Gardner (1964)

11 days awake, sleep recovery prioritized Stage 4 & REM, suggests essential role of these stages

Biological Rhythms – Tucker et al. (2007)

Individual differences in sleep stage duration, biological variability, typical “average” cycles may lack generalisability

Biological Rhythms – Evaluation Strengths

Controlled, reliable, practical applications (e.g., light therapy for SAD), replications support REM-dream link

Biological Rhythms – Evaluation Limitations

Small samples, temporal validity issues, external factors (light exposure, technology) may alter rhythms, generalisability limited

endogenous pacemakers

internal cues from within the body - act as body clocks that regulate biological rhythms