Question

Why is memory thought to involve changes in particular synapses? a. At some synapses, more neurotransmitters are released after learning takes place. b. At some synapses, a different type of neurotransmitter is released after learning takes place. c. When researchers stimulated certain neurons electrically, individuals replayed memories. d. When researchers changed synapses in the brains of patients during surgery, the patients' memories changed.

Short answer

Memory is thought to involve changes in particular synapses because of two main reasons: 1) At some synapses, more neurotransmitters are released after learning takes place, which strengthens the connections between neurons and facilitates memory formation through synaptic plasticity, and 2) Changing synapses during surgery has been observed to alter patients' memories, indicating a direct relationship between synapse structure and function in memory formation and storage.

Step-by-step solution

Option A: More neurotransmitters released after learning

At some synapses, it is observed that more neurotransmitters are released after learning has taken place. This increase in neurotransmitter release can strengthen the connections between these neurons, allowing for a more efficient and stronger communication between them. This is called synaptic plasticity, and it's a key mechanism involved in the formation of memories. Therefore, option A is a valid reason for why memory is thought to involve changes in particular synapses.

Option B: Different neurotransmitter types released after learning

At some synapses, different types of neurotransmitters may be released after learning has taken place. While changing neurotransmitter types could theoretically alter the communication between neurons, there is no strong evidence to suggest that this mechanism is involved in memory formation. Therefore, option B is not a valid reason for why memory is thought to involve changes in particular synapses.

Option C: Electrical stimulation and memory replay

When researchers stimulated certain neurons electrically, individuals sometimes replayed memories. This suggests that activating specific neurons can have an effect on retrieving stored memories, but it doesn't directly imply that memory formation or storage involves changes in particular synapses. Therefore, option C is not a valid reason for why memory is thought to involve changes in particular synapses.

Option D: Changing synapses during surgery and altered memories

When researchers changed synapses in the brains of patients during surgery, the patients' memories changed. This suggests that the structure and function of synapses are directly related to the formation and storage of memories. Changing or altering synapses could therefore impact a person's memories. Hence, option D is a valid reason for why memory is thought to involve changes in particular synapses. In conclusion, two valid reasons for why memory is thought to involve changes in particular synapses are provided by options A (more neurotransmitters are released after learning) and D (changing synapses during surgery alters patients' memories).

Key concepts

Neurotransmitter Release

Neurotransmitter release is a fundamental process in the nervous system enabling neurons to communicate with each other. This communication occurs at the synapse – a specialized junction between neurons.

The release of neurotransmitters is triggered by an action potential reaching the end of a neuron, leading to the release of these chemical messengers into the synaptic cleft. They then bind to receptors on the neighboring neuron, causing changes in the receiving cell that can result in an action potential.

Role in Synaptic Plasticity

During the learning process, the efficiency of neurotransmitter release can be altered in a phenomenon known as synaptic plasticity. Importantly, as a result of learning, some synapses may release more neurotransmitters, enhancing the synaptic connection and making the transmission of signals more efficient. This heightened release is crucial for stronger signaling and is believed to be a physical basis for memory formation.

Reinforcement of Neural Pathways

With repetition and practice, these reinforced pathways become more dominant, forming a basis for the memory retention and recall processes. Notably, after learning, the changes that occur are not about releasing different types of neurotransmitters but rather the quantity released, which is in line with the steps provided by option A of the original exercise.

Memory Formation

Memory formation involves complex processes that are still not fully understood. However, it is acknowledged that memories are formed through changes that occur in the brain – structural, chemical, and functional. One of the key aspects of memory is its plastic nature; the brain can reorganize itself in response to learning.

Changes at the Synaptic Level

Synaptic plasticity plays a crucial role in this process. When learning occurs, synapses may strengthen or weaken, facilitating or hindering the passing of information across the neural network. This strengthening, known as long-term potentiation (LTP), is considered one of the cornerstones of memory formation and is heavily influenced by the amount of neurotransmitter released. LTP enhances signal transmission between neurons and is associated with the growth of new dendritic spines, providing a structural basis for memory.

Research, as outlined in option D of the exercise, has shown that altering the synaptic structure during surgery can lead to changes in a patient’s memory, indicating a direct relationship between synaptic adjustments and memory storage.

Neural Connections

Neural connections are the links between neurons that allow for the relay of information throughout the nervous system. These connections form a vast and intricate network that enables everything from simple reflexes to complex thoughts.

Building a Network for Learning and Memory

As learning unfolds, certain neural pathways become more frequently used, leading to a reinforcement of those connections. This process is not static; it continues to evolve as new information is learned and as experiences necessitate adaptation.

Impact of Experience and Repetition

With experience and repetition, neural connections can undergo both functional and structural changes, making them more efficient in transmitting signals. This idea relates back to the concept of synaptic plasticity, where the strength of synaptic contacts can be modified, resulting in a network that is tailor-made for the individual's experiences and learning. These ever-changing neural connections are the essence of how the brain grows and adapts, ultimately shaping an individual's ability to remember and learn new things.