Chapter 5 Flashcards
(26 cards)
importance of play
- play is one of the defining behaviors of mammals
- mammals have instinctive tendencies to engage in this complex behavior
- is categorized in the more specific discipline of neuroethology (the study of the neural basis of animals’ natural behaviors
- helps animals learn about their physical and social environments
What three behaviors are assessed when researchers observe play?
- chasing
- dorsal contacts (in which one animal climbs on another’s back
- pins (in which one animal flips another onto its back and pounces on top of its belly
Subcortical areas of the brain
mesolimbic dopamine system is important for reward aspects of play
Thalamus
- parafascicular area
- ->Regulate somatosensory input necessary for choreographing specific play responses along with the striatum influence on intentional movement patterns
- Periaqueductal gray area
- ->Regulate play response
what reduces play duration?
amphetamine and methylphenidate significantly reduce play duration, perhaps b/c of an increase in norepinephrine
DNA methylation
a mechanism in which genes can be modified by the addition of a methyl chemical compound to the cytosine nucleotide base in DNA, usually preventing expression of the gene
Pluripotent
new cells during the earliest stages of development are able to become many different types of cells
Stem cells
the category of cells that are able to become many different types of cells
progenitor cells
another category of rapidly dividing cells
- Although they retain their ability to eventually produce a specific type of cell, they do not have the ability of stem cells to produce pluripotent (unspecialized) cells
- More specialized than stem cells
radical cells
- a type of glial cell that play an extremely important role in the developing cortex by providing a pathway for developing neurons to follow to their destinations
- serve as guidance paths for immature neurons, marking the way to their final destination
- may turn into astrocytes or just continue to exist
Nerve growth factor (NGF)
facilitates the growth of axons and dendrites and enhances the probability of neuronal survival
discovery of NGF marked the beginning of the identification of what additional neurochemicals
Brain-derived neurotrophic factor (BDNF)
Cell-adhesion molecules (CAMs)
3 layers of developing embryo
- A zygote is a fertilized egg.
- A human embryo will develop three cell layers:
1. Ectoderm
2. Mesoderm
3. Endoderm - Ectoderm, the outer layer, becomes the nervous system.
- -> The neural groove forms between ridges of the ectoderm.
Merzenich finger study
In as key study Merzenich and his colleagues amputated the third finger on an adult owl monkey’s hand and waited up to 8 months to see whether the monkey’s brain had reorganized itself to accommodate the loss of the finger
Just two months after losing a digit, the owl monkey cortical area representing each digit reorganizing to compensate for the lost incoming sensory information from ht lost digit maximizing responsiveness of the remaining digits
alzheimer’s disease
Characterized by severe memory loss an eventual loss of essential function such as swallowing, increases dramatically with age
(a) Alzheimer’s disease is characterized by amyloid plaques interrupting neuronal functioning, especially in the hippocampal area.
(b) Normally, tau works to stabilize microtubules, but in Alzheimer’s disease τ destabilizes microtubules, leading to neurofibrillary tangles and diminished neuronal processing and communication
(c) Patients with Alzheimer’s also show enlarged ventricles tubules, and significant shrinkage of the cortical and hippocampal areas.
Epigenetics
The environment can directly impact genetics
Key Experiment:
Offspring born to high-licking maternal rats exhibit less anxiety in the elevated plus maze compared with offspring from low-licking maternal rats
(a) Variation in the amount of maternal contact with the pups can have long-lasting neuronal and behavioral effects.
(b) One study of the influence of maternal care on the anxiety of the offspring used an elevated-plus maze. Rats that spent more time in the open arm were considered less anxious, and those that spent more time in the closed arm were considered more anxious.
(c) Rats who had been more frequently licked by their mother spent more time in the central area and open arm.
What happens when the brain is injured?
- when a person suffers an automobile accident causing the brain to slam against the inside of the skill
→ damage occurs as axons twist and tear, a process known as axon shearing
→ Often leads to a subdural hematoma (a localized blood clot)
If glucose and oxygen isn’t delivered to the cell (through the process of cerebral blood flow), the cell enters a phase of ionic flux, characterized by altered concentrations of ions such as decreased levels of magnesium and potassium and increased levels of calcium
Fail to locate resources → cell will die
Ischemia
disruption of blood flow
how does the brain recover from injury
- Training is critical to recovery
- Constraint-induced therapy
- younger brains cope better than older brains
constraint-induced therapy
- Require patients to use the affected limb(s) rather than providing a work around
- Restricts the use of the functional limb to encourage the use of the impaired limb
chronic traumatic encephalopathy (CTE)
- a condition due to head injuries from boxing, originally referred to as dementia puglistica or punch-drunk syndrome, that appears to result in progressive neurological deterioration
- atrophy to several brain regions
- behavioral/personality changes
- movement difficulties
cortical variations
the functional areas of the cortex change in accordance with the sensory and motor needs for the specific species’ arrival
Brain-derived neurotrophic factor (BDNF)
promotes the maturation of neurons and synapse formation throughout the brain
- Implicated in complex behaviors such as learning and in disorders such as depression
- Absence of forebrain BDNF early in development is associated with disruption of learning processes
Cell-adhesion molecules (CAMs)
- membrane proteins located on the cell’s surface that react differently to other cell surfaces and, by being attracted to certain proteins located on specific types of cells, provide one manner of neuron migration
key stages in the process of transitioning a burgeoning undifferentiated cell into a specific type of neuron that will eventually be incorporated into neural network
a) following neurogenesis, the cells must migrate to a specific geographical area of the developing brain where similar types of neurons will aggregate
b) Following this aggregation phase of development, the cells continue to differentiate, forming neural communities consisting of similar types of neurons
c) Functional circuits are formed as synaptogenesis (the formation of new synapses among neurons) occurs
d) Some neurons will be deemed unnecessary during circuit formation and will defnerate via a form of programmed cell death known as apoptosis
e) Often synapse rearrangement will take place as neurons are pruned throughout the brain
- Pruning process removes unnecessary cells so that neuronal processes once attached to now-degenerated cells must find new cells with which to form synapses
