Understanding Neural Plasticity and Human Development
Neural Plasticity
Neural plasticity is the brain’s ability to reorganize itself by changing the pattern of neural connections as we learn. This essentially means the brain can rewire itself. There are three main levels of connectivity:
- Pathways between brain areas
- Connections between individual neurons
- Individual synapses
Levels of Connectivity
Coarsest Level: Brain Areas and Pathways
This level involves brain areas and the pathways between them. It is primarily shaped during the prenatal and early postnatal period.
- Neurogenesis: The creation of new neurons through cell division from neural stem cells.
- Myelination: The gradual process of coating axons with myelin, an insulator that allows for rapid information transfer. Myelination begins in early development and continues into adulthood. Notably, the prefrontal cortex doesn’t become fully myelinated until adolescence.
Intermediate Level: Connections Between Individual Neurons
This level focuses on connections between individual neurons. Early development sees an explosion of synaptogenesis, followed by pruning.
- Long-range connections: These connections bring information from one brain area to another.
- Short-range neurons: These neurons operate within a specific area, enabling that area to carry out its function.
- Synaptogenesis: The formation of synapses. During childhood, the brain creates more synapses than it needs.
- Pruning: The elimination of unneeded synapses.
Finest Level: Individual Synapses
This level involves the individual synapses that interconnect individual neurons. It is the main mechanism of plasticity in adulthood.
- A strong synapse means the presynaptic neuron causes a large response in the postsynaptic neuron (and vice versa).
- Synapse: Allows signals to be transmitted effectively from the presynaptic neuron to the postsynaptic neuron.
- The number of receptors on the postsynaptic side of the synapse is a mechanism that controls synaptic strength. This is influenced by experience.
The Human Genome and Development
COMT: This gene plays a role in the operation of neurotransmitters. Without COMT, brains wouldn’t function properly, hindering language learning. The interaction between genes and the environment allows us to learn language.
Epigenetics: This field studies how gene expression can be turned on or off by experience. It focuses on the regulation of gene expression by the environment. Importantly, epigenetics does *not* alter the DNA itself; it simply influences how genes are expressed. For example, temperature can influence gene expression.
Long-Term Potentiation (LTP)
LTP is the process of forming long-term associations that lead to increased neuronal responses. It has two key components:
- Associative: The brain learns an association between two things.
- Long-term: The association lasts for days, weeks, months, or even years.
- Potentiation: Neural responsiveness increases.
Hebbian Learning
Hebbian learning states that if neuron B and C are active simultaneously, the strength of the connection from B to C will increase. This is often summarized as”neurons that fire together, wire together”
To illustrate this, imagine neuron A is already strongly connected to neuron C. If we stimulate area B, which has a weak connection to C, we initially see a weak response in C. However, if we repeatedly stimulate A and B together, the connection between B and C strengthens. Eventually, stimulating B alone will elicit a strong response in C.
APV and LTP
APV is a drug that blocks LTP. In Pavlov’s famous experiment, if APV were administered during the learning phase (when the meat powder was paired with the bell), the dog would not salivate in response to the bell during the test phase. This demonstrates the role of LTP in associative learning.
Environmental Influences on the Brain
Kim Noble’s Research: This research explored the effects of environment on the brain. However, it was correlational and did not prove that a low-income environment directly causes differences in brain size.
Kuzunmaki’s Research: This research focused on brain-derived neurotrophic factor (BDNF), a protein crucial for the growth of neurons. The study measured the amount of mRNA for BDNF in mice raised in enriched environments.
Developmental Psychology
Developmental psychologists study human development across the lifespan, including infancy, childhood, adolescence, and adulthood. They are interested in how change happens.
- Child psychologists: Focus on treating children with mental disorders.
- Lifespan development: Studies changes in adulthood, such as the transition to parenthood or the aging process.
Jean Piaget’s Stages of Cognitive Development
Jean Piaget was a renowned developmental psychologist who proposed four stages of cognitive development:
- Sensorimotor Stage (Infancy): Children think in terms of actions they can perform. They lack language and object permanence (understanding that objects continue to exist even when they can’t be seen).
- Preoperational Stage (Preschool, 2-7 years): Children think in symbols, like words and images, but struggle to manipulate or transform their thoughts. They have difficulty taking another’s perspective (egocentrism), as demonstrated by the”three mountains task”
- Concrete Operational Stage (7-12 years): Children can manipulate and transform their thoughts, but their thinking remains concrete. They can think about”what-i” scenarios, but only if they have experienced them.
- Formal Operational Stage (Adolescence): Children can think abstractly and reason about unfamiliar things. They can consider multiple solutions to a problem simultaneously (e.g., thinking about aliens). This stage is exemplified by the”pendulum problem”
Assimilation and Accommodation
Assimilation: Adding new information to your existing view of the world.
Accommodation: Changing your view of the world in light of new information.
Nature vs. Nurture
Nature (Internal, Genes): This perspective emphasizes that who we are and how we develop is largely determined by our genes. It suggests that certain traits are innate, inborn, and known without learning.
Nurture (External, Environment and Experience): This perspective emphasizes that people learn and develop based on their experiences.
The Case of Genie
Genie, a”feral chil” who grew up with minimal human contact, could not speak, suggesting that language development is heavily influenced by nurture. Even after being rescued and exposed to language, she struggled to learn to speak. This case highlights the concept of a”critical period” a time when children’s biology makes them especially adept at learning certain skills. Once this period passes, acquiring those skills becomes much harder.
Gene-Environment Interaction
The effects of environmental differences often depend on an individual’s genes. For example, individuals with phenylketonuria (PKU) who consume a diet high in phenylalanine will experience brain damage. However, a low-phenylalanine diet prevents this damage. This illustrates how genes and environment interact to shape development.
Discontinuity and Stability in Development
Discontinuity: The emergence of new characteristics or abilities that were not evident previously (e.g., learning to write in paragraphs).
Stability: Although some things change, the organism retains the same genes and underlying biology.
Qualitative changes in development may reflect nurture or experience.
Dynamic Systems Theory
The dynamic systems perspective views development as:
- Multiterminal: Multiple systems interact to produce change.
- Self-organizing: Development occurs without a predetermined plan. Interactions between components produce change without central control.
- Continuous: Reflects gradual changes in underlying factors, even if the outward manifestation (e.g., walking) appears to have a sudden onset.
Erikson’s Psychosocial Development Theory
Erikson’s theory emphasizes the social nature of development, in contrast to Freud’s focus on sexual development. While Freud believed personality is shaped solely in childhood, Erikson proposed that personality development continues throughout the lifespan.
Kohlberg’s Stages of Moral Reasoning
Kohlberg presented individuals with moral dilemmas and categorized their responses into stages of moral reasoning:
Level 1: Pre-conventional Morality
- Stage 1: Obedience and Punishment: Behavior is driven by avoiding punishment.
- Stage 2: Individual Interest: Behavior is driven by self-interest and rewards.
Level 2: Conventional Morality
- Stage 3: Interpersonal: Behavior is driven by social approval.
- Stage 4: Authority: Behavior is driven by obeying authority and conforming to social order.
Level 3: Post-conventional Morality
- Stage 5: Social Contract: Behavior is driven by a balance of social order and individual rights.
- Stage 6: Universal Ethics: Behavior is driven by internal moral principles.
Attachment Theory
Attachment: A long-standing connection or bond with others.
Secure Base: A parental presence that gives the child a sense of safety as they explore their surroundings. Secure attachment is the most common and healthiest type of attachment.
Attachment Styles
- Avoidant Attachment: The child is unresponsive to the parent, does not use them as a secure base, and does not seem to care if the parent leaves. The parent is treated like a stranger.
- Resistant Attachment: The child exhibits clingy behavior but then rejects the attachment figure’s attempts to interact with them. They may show distress when the parent leaves but resist comfort upon their return.
- Disorganized Attachment: The child behaves oddly in the Strange Situation, a standardized procedure for assessing attachment. They may freeze, run around erratically, or try to run away when the caregiver returns.
Parenting Styles
- Authoritative: The parent sets reasonable demands and consistent limits, expresses warmth and affection, and listens to the child’s point of view. They explain the reasons behind rules and are flexible when appropriate.
- Authoritarian: The parent values conformity and obedience above all else. They are often strict, closely monitor their children, and show little warmth.
- Permissive: The child has a lot of freedom and few rules. Permissive parents make few demands, rarely use punishment, and are very nurturing and loving. They may act more like a friend than a parent.
- Uninvolved: The parents are indifferent, uninvolved, and sometimes considered neglectful. They provide little guidance, nurturing, or support.
Gender and Sex
Gender: A social category.
Sex: Biological or medical (anatomical) aspects of sex, including gonads, hormones, and internal and external reproductive organs.
Developmental Cascade: One aspect of sex development leads to changes that set up the next aspect of sex development.
Intersex: Individuals who do not fit the typical binary definition of male or female.
Gender Identity: An individual’s subjective sense of being a man or woman (their internal concept of themselves).
- Cisgender: Gender identity matches biological sex.
- Transgender: Gender identity is different from biological sex.
Gender Role: Socially and culturally defined expectations for what is appropriate, acceptable, and typical for men and women.
Gender Schema: An individual’s experience and understanding of what it means to be a man or woman, shaped by gender norms and expectations.
Gender Nonconformity: Often punished by ostracism, bullying, and violence.
Felt Stigma: The feeling of needing to conform to cultural gender norms.
Cognitive Science
: ( perception: acquiring info from env, memory= how knowledge is stored, language- how knowledge is communicated, thinking- how we use knowledge to solve problems and make decisions)
-schema: part of ur overall conceptual network tht applies to specific domain ( car schema- info related to cars)+ script: mental rep for common sequence of action and events
The rotation occurs in the mental representation of the letter somewhere in your brain ( intermediate representation) – only created temporarily in the course of series of mental operation
Algorithm: sequence of operation tht is guaranteed to reach correct solution. Heuristic: sequence of op tht usually reachers correct solution but sometimes fails ( faster than algorithM) schema is ex of heuristic
G→ measure and compare among individual Crystallized intellignce: acquired knowledge and ability to retrieve it ( ability to recall), fluid intellig: ability to see complex relationships and solve problem
1. IQ= intellig ( NOT TRUE)IQ: measure of someone’s ability to do well on set of test, intelligence undertsnaind thing and figuring out what to do 2. Mozart Effect:no evidence tht mozart makes babies smarters, but learning music ins increases scores on cognitive abilities 3. 10% brain – inactive region are ventricle , one person brain may be more efficient 4. left/ right brain: corpus callosum: connect right and left to keep both together ( right = creative) 5. Iq determine success: self discipline better 6. Intell cannot be changed: increases modestly 7. Intelligence decreasing: we get higher IQ tests 8. Intell is genetic: gene and env work together to determine intelligence, MONOZygotic: twin sep from birth and raised in diff env found tht correlation is a little lower than for twins raised together
-dynamic system perspective : development is multiterminal ( multiple systems interact to produce change) , developement is self organizing rather than pre-determined ( interaction produces change without plan) develops without any plan or central control ( self organizing) reflects graudla change in the underlying factors ( continuous) even tho the actual walking appears to onset