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A triune model for sleep and dreams
Published in Frederick L. Coolidge, Ernest Hartmann, Dream Interpretation as a Psychotherapeutic Technique, 2018
Frederick L. Coolidge, Ernest Hartmann
Winson (1990) has established that a theta rhythm of 6 Hz arises from the hippocampus of awake animals in specific and important functions, such as exploratory behavior in rats, a fear response resulting in rigidity in rabbits, and predation in cats. Furthermore, these behaviors are not rigidly genetically encoded like feeding and procreation, but occur in response to changing environmental circumstances. Because the role of the hippocampus has been well documented in establishing the permanence of memory in both people and animals, he reasoned that the theta rhythm might be the cause of permanent memory transformations. He also found the same theta rhythm in REM sleep in rats, and the same neurons of the hippocampus fired during REM sleep that had fired while the rats were awake and learning a maze. Because exploratory behavior in rats appears critical to their survival, Winson argued that the purpose of REM sleep might be to process and strengthen this critical information.
Therapeutic Applications of BCI Technologies
Published in Chang S. Nam, Anton Nijholt, Fabien Lotte, Brain–Computer Interfaces Handbook, 2018
Optimal task preparation can also be produced by delaying trial onset until spontaneous fluctuations in the EEG indicate that a desired brain state is present. Griffin et al. (2004) showed that state-dependent trial presentations could affect learning of classical eyelid conditioning in rabbits. Trial presentation was contingent on the presence of hippocampal theta rhythm, as measured with implanted electrodes. A theta-contingent group learned the task much quicker than a non–theta-contingent group. State-dependent trial presentations were also used by Salari and Rose (2016) to evaluate the effects of scalp-recorded activity on memory in human subjects. EEG was recorded at frontal and temporal locations and spectral power was separately summed in theta or beta bands. Presentation of visual images in a recognition memory experiment was dependent on either high or low summed power in these bands. Subsequent recognition memory was better for high beta presentations than low beta presentations while theta-dependent presentations did not differ significantly.
The Stress System
Published in Len Wisneski, The Scientific Basis of Integrative Health, 2017
In Chapter 1, we discussed the fact that the theta rhythm occurs during that period of deep relaxation between sleep and wake, sometimes referred to as hypnagogia. However, there are events during which theta is not associated with relaxation, but rather with learning, memory, and receiving information. Individual neurons in the hippocampal formation exhibit oscillatory activity within the theta-frequency band, firing rhythmically at high rates (Jinno et al., 2007). When subicular pyramidal neurons are at a theta-frequency resonance, they contribute to the network's oscillatory function of communicating cortical association information that occur during theta-related behaviors, such as sensory encoding, exploration, rapid eye movement (REM) sleep, and various cognitive functions. Blocking synaptic transmission with glutamate or γ-aminobutyric acid (GABA) does not arrest the oscillations; however, changing the frequency by hyperpolarizing the oscillating cells or by suppressing the sodium current will eliminate them (Glasgow and Chapman, 2007). Therefore, network oscillations are voltage-dependent and function separately from synaptic activity. Theta rhythms have been called the fingerprint of the hippocampus, and curiously, neuronal firing that occurs while words are being encoded differs depending on whether the words are later retained or forgotten.
Action observation training and brain-computer interface controlled functional electrical stimulation enhance upper extremity performance and cortical activation in patients with stroke: a randomized controlled trial
Published in Physiotherapy Theory and Practice, 2022
Su-Hyun Lee, Seong Sik Kim, Byoung-Hee Lee
The attention threshold to initiate BCI-FES for each patient was determined before each training session. To obtain the threshold value, the patients were asked to watch wrist extension DVD and to imagine performing the task. While concentrating for imagination, the EEG was measured and the value was calculated using the (SMR+mid beta)/theta formula. If patients correctly imagined the movement, their attention threshold level went up. The attention threshold used the average of the value obtained by repeating 10 times the task. In a state of concentration, the theta rhythm decreases, while the sensory motor rhythm (SMR) and mid-beta rhythms increase (de Zambotti et al., 2012). Increased SMR implies unfocused attention, whereas mid-beta rhythms connote focused attention and cautiousness. SMR was in the range of 12–15 Hz (unfocused attention) and mid-beta rhythm was in the range of 15–18 Hz (focused attention) (Mohammadi, Malmir, Khaleghi, and Aminiorani, 2015). SMR was observed when a subject focused on solving problems without being nervous or stressed.
Time estimation exposure modifies cognitive aspects and cortical activity of attention deficit hyperactivity disorder adults
Published in International Journal of Neuroscience, 2020
Rhailana Medeiros Fontes, Victor Marinho, Valécia Carvalho, Kaline Rocha, Francisco Magalhães, Iris Moura, Pedro Ribeiro, Bruna Velasques, Mauricio Cagy, Daya S. Gupta, Victor Hugo Bastos, Ariel Soares Teles, Silmar Teixeira
This study has some limitations, which include sample size, and non-homogeneity. However, the moderate effects and statistical power in the analyzes decrease the possibility of a type II error. In addtion, the follow-up period could provide greater consistency to our results. Another limitation involves non-EEG uptake during all experiments days. The current analysis can reinforce changes in theta rhythm with the time estimation task, and demonstrates further improvement of the cognition in ADHD patients. Another limitation is non-association with sub-second level tasks, since it could provide a broader view of neurophysiology in timing. Instruments may be used in future studies to assess attention and memory in order to relate both time interval interpretation and the activity of the cortical areas. Future studies would also include phenotypes analysis related to dopaminergic activity, which are important for time perception. This study would address to neurochemical effects on time judgment, in addition to controlling interindividual changes at dopaminergic levels in the current study.
An assistive technology program for enabling five adolescents emerging from a minimally conscious state to engage in communication, occupation, and leisure opportunities
Published in Developmental Neurorehabilitation, 2022
Fabrizio Stasolla, Alessandro O. Caffò, Sara Bottiroli, Donatella Ciarmoli
Because they met the eligibility criteria, namely (a) a history of coma, (b) TBI, (c) a diagnosis of emergence from a minimally conscious state, (d) an age between 13 and 18 years, and (e) their improvements in their adaptive behaviors, the participants (Alexis, Christine, Eloise, Frank, and George) were enrolled. Their ages were 15, 14, 16, 17, and 18 years, and had been involved in a traffic accident 2, 3, 2, 4, and 3 years prior to the beginning of the study, respectively. They were hospitalized at the beginning of the study although they had a different background (i.e., history) of coma with at least 6 months of hospitalization. They received comprehensive neurorehabilitation services in the medical centers in which they were hospitalized. Each participant reported extensive TBI. The coma duration for Alexis was 10 days. Her coma condition turned into a vegetative state and evolved into a minimally conscious state. Her computerized tomography (CT) revealed right parieto-occipital damage with an extended hematoma, which was evacuated after decompressive craniotomy. Her electro-encephalogram activity (EEG) showed low diffuse voltage of the theta rhythm. Alexis evidenced visual atrophy, left hemiplegia, limited body control (i.e., minimal head and trunk movements), and lack of speech, although she was capable of “YES” and “NO” responses through smiling or abstaining from it appropriately. Alexis was fitted with a gastronomy tube for nutrition. Her total score on the Coma Recovery Scale-Revised (JFK-CRS-R)30 was 16 with partial scores of 3, 3, 4, 2, 2, and 2 on auditory, visual, motor, oromotor/verbal, communication, and arousal subscales, respectively.