chp 2. Flashcards
Neuroimaging Techniques
– Two techniques are used most often:
set of techniques in which pictures of the brain are taken in various ways to provide understanding of both normal and abnormal congnitity of aging
▪ Structural neuroimaging: provides highly detailed images of anatomical features of the brain
o Includes X-rays, CT, and MRI
▪ Functional neuroimaging: provides an indication of brain
activity
o Includes SPECT, PET, fMRI, and NIRSI
o In general, fMRI is the most commonly used technique.
Neuroscience Perspectives
– Neuropsychological approach
▪ Compares healthy older adults with those with pathological disorders of the brain (ex: damaged frontal lobe->dopamine, healthy adult-> dopamine)
– Neurocorrelational approach
▪ Links measures of cognitive performance to measures of brain structure or functioning(ex:cognitive tests and look at brain activity while doing test
– Activation imaging approach
▪ Links functional brain activity with cognitive behavioral data
▪ Compensatory changes(ex: children use on side of the brain with task, older adults use both sides of the brain.)
• How Is the Brain Organized Structurally?
Brain is made up of
Neurotransmitters travel across the
– Brain is made up of neurons.
• Neurons consist of
-dendrites(antennas to receive signals from other nearby neurons),
-axon- transmits information from the cell body to terminal branches.
-neuro-fibers
and terminal branches-releases chemical neurotransmitters so that Information passes on to other neurons
• Neurotransmitters travel across the synapse-are received by dentures of nest neuron.
Neuroanatomy:
The study of the structure of the brain
Neuronamoty involves the study of the structure of the brain including the
-cereberal cortex-outermost part of the brain consists of two hemispheres left and right
-corpus callous-thick bundle of neurons that connect left and right hemisphere
-prefrontal and frontal cortex-important for executive functions-carry out plans, switch between tasks and maintain attention and focus
-cerebellum-controlls equilibrium and coordination of fine motor movements
-hippocampous-located in the middle of the brain-memory
limbic system-emotion, motivation, long-term memory, balance
amygdala-emotion
• Age-Related Changes in Neurons Neurons Dentrites Axon fibers Proteins Synapses Diseases
– Number of neurons declines – Number and size of dendrites decreases – Tangles develop in axon fibers – Increases in deposits of proteins – Number of synapses decreases – These changes occur in greater numbers in diseases such as Alzheimer’s disease
Age-Related Changes in Neurotransmitters
– Dopamine is associated with higher-level cognitive functioning, so declines are related to poorer:
-working memory-memory for information tasks performed actively
• episodic memory(short-term memory)
• tasks that require higher-level cognitive functioning like inhibiting thoughts, attention, and planning.
– Other neurotransmitters
• Abnormal processing of serotonin has been shown to be related to cognitive decline.
• Damage to structures that use acetylcholine is associated with memory declines.
dopamine
serotonin
acetylcholine
- inhibit thoughts, attention, planning, emotion, movement, pleasure and pain
- memory, mood, appetite, sleep
- arousal, sensory perception, sustaining attention
dopaminergic system
neurons that use dopamine
white matter-
neurons that are converted by Myles that transmit info from one part of the cerebral cortex to another or other parts of the brain
Age-Related Changes in Brain Structures
Shrink
Wmh
Dti
– Considerable shrinkage occurs in the brain
• Especially in prefrontal cortex, hippocampus, and cerebellum
– White matter hyperintensities (WMH)-bright spotty appearance on images
• Indicates myelin loss or neural atrophy
– Diffusion tensor imaging (DTI)
-asses the rate and direction that water diffuses through the white matter
• Provides index of density or structural health of the white matter
What Structural Brain Changes Mean And ToM, executive functioning
– Theory of Mind (ToM) is the ability to understand that others have beliefs, desires, and viewpoints different from our own
• Research shows age-related decline in ToM
– Executive Functioning
• Difficulty focusing solely on relevant information
• Due to WMH and reduced volume of prefrontal cortex
memory and emotion changes
– Memory
• Specific structural changes (e.g., the hippocampus) result in memory decline
– Emotion
• Increased processing of positive emotional information with age but decreasing processing of negative emotional info
• Better emotion regulation with age-want meaningful relationships
-age-related increase in connections
social-emotional cognition and prefrontal cortex change
– Social-Emotional Cognition
• Older adults may rely more on automatic judgment processes than reflective processing.
– Prefrontal Cortex
• The Positivity Effect: Older adults are more motivated to derive emotional meaning from life and to maintain positive feelings than younger adults.-> explains why memory detritus and emotion does not
• The Parieto-Frontal Integration Theory
– Also known as P-FIT
– Proposes that intelligence comes from a distributed and integrated network of neurons in the parietal and frontal areas of the brain
Can Older Adults Compensate for Brain Changes?
– Studies show that, when presented with similar tasks, younger adults exhibit focal, unilateral activity in left prefrontal region, and older adults exhibit bilateral activity (both left and right prefrontal areas).
• Older adults are compensating.
– However, research separating cognitive processes found consistent patterns in the brain activity in younger and older adults challenging the conventional view.
• Bilateral activation in older adults plays a supportive role in older adults’ cognitive function.
Plasticity:
involves the interaction between the brain and the environment and is mostly used to describe the effects of experience on the structures and function of the neural system.
-result of people and their brains living in the world and accumulating and learning from experiences overtime
Neural stem cells
give rise to new neurons, persist in adult brains, and can generate new cells throughout adulthood.
-brain capable of making new brain cells at old age under right circumstances
compensation
based on the notion that there is plasticity in both brain changes and behavior across the adult life span.
Role of Exercise
– Brain plasticity is enhanced by aerobic exercise.
Role of Nutrition
– Researchers are beginning to understand the relations
between categories of nutrients and brain structures.
