Electroencephalography (EEG)’s measure electrical impulses in the brain. For ASMR experiencers and non-experiencers, watching ASMR decreased theta power, and increased beta power.

ASMR and Electroencephalography 

Through alpha-theta training, people can increase sensory perception, abstract-thinking, and self-control.

EEG Alpha-Theta Training

This has a frequency of 3.5 to 7.5 hz and relates to slow activity. It connects to creativity, daydreaming, memory, emotion, sensation, reflection, meditation, and spiritual awareness. It’s the state that lies between being awake and asleep. Theta activity is abnormal in awake adults, but normal in children up to age 13. It reflects activity from the limbic system and hippocampus. If it works properly it can aid in learning.

New Mexico Highlands University

Uses fast Fourier transform on an amplitude vs. time graph to plot amplitude against frequency. Frequency bands, where lower bound is inclusive and upper bound is exclusive, and their indicators:

* Delta (0.5-4 Hz): sleep depth; homeostasis during NREM sleep.
* Theta (4-8 Hz): emotional memory consolidation.
* Alpha (8-12 Hz): visual perception; mental imagery; inhibition of neurons.
* Sigma (12-15 Hz): sleep spindles; learning and memory consolidation; sleep maintenance.
* Beta (15-30 Hz): arousal.
* Gamma (30-45 Hz): arousal.

EEG power spectral analysis

A self-regulation therapy that teaches patients how to control their brainwaves (as detected by EEG) by controlling their arousal levels. Some evidence suggests it may help with easing behavioral symptoms caused by head trauma, as well as ADHD and chronic stress.

Electroencephalogram (EEG) Neurofeedback

The hippocampus, a structure within the temporal lobes, is central to learning and memory. It is essential for consolidating new information into long-term memory, a process that involves transferring new learning for permanent storage. Research has shown its specific involvement in normal recognition memory and spatial memory, as demonstrated in studies where rats with hippocampal lesions showed impairment in tasks like object recognition and maze running. Furthermore, the hippocampus projects information to cortical regions, which helps to give memories meaning and connect them with other memories. It is also critical for contextualized emotional learning. The famous case of patient H.M., who could not form new memories after his hippocampus was removed, provided significant evidence for its role.

Hippocampus

The limbic system is made up of a number of different structures that are involved in processing both emotion and memory. Three of its most important components include the amygdala, the hippocampus, and the hypothalamus.

Limbic System

Definitions. (n.d.). Neurohealth. https://nhahealth.com/brainwaves-the-language/#:~:text=THETA%20(4%2D8%20Hz),-The%20next%20brainwave&text=Theta%20waves%20are%20strong%20during,is%20also%20normal%20during%20sleep.

Definitions

EEG Theta

Beta activity has 14 or greater Hz and is seen as fast activity. It tends to be the dominant brain wave in those who are alert, anxious, or have their eyes open. It relates to problem solving, decision-making, and processing information. Because it’s wide, it’s divided into three sections, including low, midrange, and high. 

EEG Beta

Components of measuring neurofeedback include:

- Hertz (Hz)
- Microvolts (μV)

Components of Neurofeedback Frequency

Delta waves have 0.1 to 3 Hz; and have the lowest frequency, highest amplitude, and slowest speed out of all the brainwaves. They are involved in deep sleep, specifically stages 3 and 4, and are the dominant brainwaves in infants. They reduce awareness of the tangible world, and allow people to access subconscious information. Peak performers reduce delta waves while focusing.

EEG Delta

Alpha is between 8 to 12 Hz and peaks at 10 Hz. It is associated with calmness, positive emotion, extroversion, creative problem-solving, mental work, and accurate perceptions of the world. It allows us to apply classroom learning to the real-world, and lets us to transition between tasks. It is the major rhythm in most relaxed adults, and starts being more prominent at age 13. Alpha brainwaves come from white matter in the brain, which is viewed as joining all parts of the brain together.

EEG Alpha 

Gamma is between 30 to 44 Hz, and is the only brainwave found in all parts of the brain. It deals with information processing involving multiple areas of the brain, as well as memory. Reduced Gamma is associated with learning disabilities. 

EEG Gamma

This method involves placing 21 electrodes, with 19 recording the cortical regions, and 2 serving as references. The 10-20 method refers to placing electrodes in 10-20% increments across regions of the skull.

EEG Electrode System 10-20

Types of neurofeedback include:
-	Frequency/power neurofeedback
-	Slow cortical potential neurofeedback (SSCP-NF)
-	Low-energy neurofeedback system (LENS)
-	Hemoencephalographic (HEG)
-	Live Z-score neurofeedback
-	Low resolution electromagnetic tomography (LORE-TA)
-	Functional magnetic resonance imaging (fMRI)

Types of Neurofeedback

Pros of neurofeedback therapy include it's safe, non-invasive, and it can improve several conditions.

Pros of Neurofeedback 

Cons of neurofeedback therapy include that there is inconclusive scientific evidence on its effectiveness, it's expensive, it is not covered by many insurance companies, it takes longer to see improvement, and the benefits are short-term.

Cons of Neurofeedback

The following areas of brain lobes can be considered when implementing neurofeedback:

- Parietal lobes
- Frontal lobes
- Temporal lobes
- Occipital lobes
- Sensorimotor cortex
- Cingulate gyrus
- Broca's area
- Left hemisphere
- Right hemisphere

Brain Lobe Considerations When Using Neurofeedback

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548359/#:~:text=Hippocampus%20is%20a%20complex%20brain,of%20neurological%20and%20psychiatric%20disorders.

NCBI: Hippocampus in Health and Disease 

Meditation training may enhance stress resilience via hippocampal structure alterations. This notion comes from the idea that hippocampal atrophy is associated with clinical disorders that involve stress, anxiety, and depression. These clinical disorders may also be associated with problems of concentration and memory. Thus, structural increase in the hippocampus relate to meditation's potential betterment of these clinical conditions.  There may also be structural differences in the hippocampus because of memory reconsolidation.  Many meditative practices place a strong emphasis on re-evaluating past behavioral patterns and default emotional reactions to events. 
The differences in the hippocampus may be due to the region playing a role in seeing past experiences in a new light and allowing for greater flexibility in present behavior.  Structural differences in the hippocampus may be related to the effort involved in re-contextualizing spontaneous thought processes, memories, and simulations during meditation practice.

Hippocampus in meditation

Long-term potentiation has been most commonly studied in the hippocampus, more specifically in the Schaffer collateral axons of the ca3 neurons and the ca1 pyramidal cells.

Long-term Potentiation in Hippocampus

Clive Wearing was a highly skilled musician who suffered severe damage to his hippocampus due to an illness. As a direct consequence of this brain injury, he completely lost the capacity to encode and retain any new memories, illustrating the critical role of the hippocampus in memory formation.

Case Study of Clive Wearing

In an experiment to understand the hippocampus's function, researchers created lesions in the hippocampi of rats. These rats subsequently showed impaired memory in various tasks, including object recognition and navigating mazes. The results indicated that the hippocampus is vital for normal recognition memory and spatial memory.

Example of Hippocampus's Role in Memory: Rat Lesion Experiment

The hippocampus plays a crucial role in organizing memories by projecting information to various cortical regions. This process is essential for giving memories their meaning and for establishing connections between different, related memories.

Hippocampus's Role in Connecting and Contextualizing Memories

Injury to the hippocampus, a structure located within the temporal lobes, prevents the processing of new declarative memories. This means that an individual with such damage loses the ability to form new long-term memories for facts and events, a condition exemplified by the famous case of patient H.M.

Effect of Hippocampal Injury on Declarative Memory

Anterograde amnesia is the inability to form new long-term memories following an event like brain trauma, while memories from before the injury remain intact. This condition, often linked to hippocampal damage, disrupts the consolidation of information from short-term to long-term memory. A key characteristic of this amnesia is the differential impact on memory systems: individuals are typically unable to form new episodic (events) or semantic (facts) memories, but they often retain the ability to form new procedural memories (skills).

Anterograde Amnesia

Based on the specific pattern of preserved and impaired abilities described in the case study, which brain structure is most likely damaged? Justify your answer by explaining the distinction between the types of memory demonstrated by the patient.

Analysis of Memory Deficits

Henry Molaison (H.M.) is one of psychology's most famous case studies. In 1953, surgeons removed large sections of his hippocampus to treat severe epilepsy. While the surgery successfully stopped his seizures without affecting his IQ or personality, it left him with anterograde amnesia. His short-term memory remained intact, but he permanently lost the ability to transfer new information into long-term memory—a process known as consolidation. This case was crucial for memory research because it demonstrated a clear dissociation between short-term and long-term memory and highlighted the temporal lobes' essential role in memory consolidation.

Case of Henry Molaison (H.M.)

Key brain structures involved in memory have specific anatomical locations: the prefrontal cortex is situated in the frontal lobe, the cerebellum is at the rear, and the amygdala and hippocampus are located deeper within the brain.

Locations of Memory-Related Brain Structures

Three Main Structures in the Limbic System

The sense of smell is unique in that its sensory information projects directly to the limbic system. This direct connection explains why odors can often trigger strong emotional responses more readily than other senses.

Olfaction's Direct Link to the Limbic System

The hypothalamus contributes to emotional reactions by activating the sympathetic nervous system, which is responsible for the body's physiological responses during an emotional event.

Role of the Hypothalamus in Emotion

Functioning as a sensory relay center, the thalamus directs incoming sensory information to both the amygdala for immediate emotional processing and to higher cortical regions for more detailed cognitive analysis.

Role of the Thalamus in Emotion

The hippocampus is involved in integrating emotional experiences with cognitive functions, helping to form the context-rich memories associated with emotions.

Role of the Hippocampus in Emotion

Interactive 3D brain simulators, like the one from Open Colleges, provide a virtual environment to review the brain's components and their roles. These tools allow users to navigate to specific regions, such as the limbic system, for detailed exploration.

Exploring Brain Structures with an Interactive 3D Simulator

Structures within the limbic system, specifically the amygdala and hippocampus, are not only central to normal emotional processing but are also implicated in the development and manifestation of psychological conditions such as mood and anxiety disorders.

Role of Limbic Structures in Psychological Disorders

Given the following clinical case, identify the interconnected brain circuit most likely affected by the injury and explain your reasoning.

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