T1 L6: Global Brain Activity, 24/10/23, NS
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Questions and Answers

Which imaging technique reveals the static physical characteristics of the brain?

  • Lesion
  • Optical
  • Pharmacology
  • Structural imaging (correct)

    • What does the BOLD signal measure in fMRI?

  • Changes in brain physiology (correct)
  • Neural activity
  • Concentration of oxygen in the blood
  • Blood flow to a region

    • What triggers an increase in blood flow to a region in the brain?

  • Optogenetics
  • Neural activity (correct)
  • PET imaging
  • Pharmacological tracers

    • Which imaging technique measures relative changes in neural activity?

    <p>Functional imaging</p> Signup and view all the answers

    What is the HRF in fMRI?

    <p>Haemodynamic response function</p> Signup and view all the answers

    What does the BOLD signal in fMRI correlate with?

    <p>Cognitive function</p> Signup and view all the answers

    Which imaging technique measures changes in the amount of deoxyhaemoglobin in a region of the brain?

    <p>Functional imaging</p> Signup and view all the answers

    What is the main function of brain rhythms?

    <p>All of the above</p> Signup and view all the answers

    During which sleep state does the main neurotransmitter modulation come from histamine?

    <p>Non-REM</p> Signup and view all the answers

    Which imaging technique provides better discrimination between white and grey matter?

    <p>MRI scan</p> Signup and view all the answers

    What is the main difference between PET and fMRI?

    <p>PET measures blood flow, fMRI measures blood oxygen concentration</p> Signup and view all the answers

    What is the main purpose of the external magnetic field in MRI scans?

    <p>To align the protons in the brain</p> Signup and view all the answers

    What is the relationship between metabolic activity of neurons and blood supply to the region?

    <p>Metabolic activity of neurons increases blood supply to the region</p> Signup and view all the answers

    Which sleep state is characterized by reduced motor activity and decreased response to stimulation?

    <p>Non-REM</p> Signup and view all the answers

    Which neurotransmitter provides the main modulation during REM sleep?

    <p>Acetylcholine</p> Signup and view all the answers

    What is the main purpose of brain rhythms?

    <p>All of the above</p> Signup and view all the answers

    Which imaging technique provides dynamic maps of the brain's moment-to-moment characteristics?

    <p>fMRI scan</p> Signup and view all the answers

    Which imaging technique measures the physiological signals of the brain and is commonly used to study brain function?

    <p>fMRI</p> Signup and view all the answers

    What does EEG measure?

    <p>Brain rhythms</p> Signup and view all the answers

    Which structure in the brain is involved in the generation of synchronous brain rhythms?

    <p>Thalamus</p> Signup and view all the answers

    What is the main requirement for signal detection in EEG?

    <p>A whole population of neurons must be active in synchrony</p> Signup and view all the answers

    Which imaging technique provides detailed structural information about the brain?

    <p>MRI</p> Signup and view all the answers

    Which of the following is NOT a brain rhythm measured by EEG?

    <p>Gamma</p> Signup and view all the answers

    Which imaging technique measures changes in blood flow and oxygenation levels in the brain?

    <p>fMRI</p> Signup and view all the answers

    Which of the following is NOT a method of imaging the living brain?

    <p>EEG</p> Signup and view all the answers

    How do brain rhythms relate to the environment?

    <p>They are influenced by day and night cycles</p> Signup and view all the answers

    Which part of the brain acts as the pacemaker during sleep?

    <p>Brainstem</p> Signup and view all the answers

    What is the purpose of the hand clapping mechanism in brain activity coordination?

    <p>To maintain signals</p> Signup and view all the answers

    What type of brain waves are observed during slow wave sleep?

    <p>Delta waves</p> Signup and view all the answers

    What is the main function of brain rhythms?

    <p>Unknown</p> Signup and view all the answers

    Which technique can be used to study the activity of large populations of neurons?

    <p>Electroencephalography (EEG)</p> Signup and view all the answers

    What are the three topics discussed in the presentation?

    <p>Brain rhythms, sleep cycle, imaging techniques</p> Signup and view all the answers

    Which imaging technique provides dynamic maps of the brain's moment-to-moment characteristics?

    <p>Functional Magnetic Resonance Imaging (fMRI)</p> Signup and view all the answers

    What is the main purpose of brain rhythms?

    <p>To generate synchronous brain activity</p> Signup and view all the answers

    What is the main factor that determines the amplitude of an EEG signal?

    <p>The number of active cells</p> Signup and view all the answers

    What type of neurons are primarily recorded in an EEG signal?

    <p>Pyramidal neurons</p> Signup and view all the answers

    Which sleep stage is characterized by reduced motor activity and decreased response to stimulation?

    <p>Stage 3 sleep</p> Signup and view all the answers

    What is the main purpose of brain rhythms?

    <p>To synchronize activity across different brain regions</p> Signup and view all the answers

    Which neurotransmitter is the main modulator of REM sleep?

    <p>Acetylcholine</p> Signup and view all the answers

    Which neurotransmitter is responsible for keeping us alert and attentive?

    <p>Noradrenaline</p> Signup and view all the answers

    Which sleep state is characterized by reduced motor activity and decreased response to stimulation?

    <p>Stage 2 non-REM sleep</p> Signup and view all the answers

    Which brain adaptation allows dolphins and seals to sleep while keeping half of their brain awake?

    <p>Asynchronous brain activity</p> Signup and view all the answers

    What is the main purpose of the gel used in EEG?

    <p>To improve the conductance of the electrodes</p> Signup and view all the answers

    What is the main requirement for signal detection in EEG?

    <p>Large populations of synchronously firing neurons</p> Signup and view all the answers

    What type of brain activity can EEG only record?

    <p>Massive synchronous firing of pyramidal neurons directly below the EEG electrode</p> Signup and view all the answers

    What is the purpose of the wires connected to the EEG electrodes?

    <p>To safely transport the signal to devices for filtering and amplification</p> Signup and view all the answers

    During non-REM sleep, what happens to the synchronization and amplitude of neuronal activity as we progress from stage 1 to stage 4?

    <p>Synchronization increases and amplitude increases</p> Signup and view all the answers

    Which brain rhythm is typically observed during REM sleep?

    <p>Beta rhythm</p> Signup and view all the answers

    What is the main difference between the generation of synchronous brain rhythms and asynchronous brain rhythms?

    <p>Synchronous brain rhythms are generated by a pacemaker, while asynchronous brain rhythms are generated through feedback and improvisation</p> Signup and view all the answers

    What is the purpose of the spindle feature in the thalamus?

    <p>To activate calcium channels and send a signal to the cortex</p> Signup and view all the answers

    During REM sleep, the main neurotransmitter modulation is provided by which neurotransmitter?

    <p>Histamine</p> Signup and view all the answers

    Which sleep state is somewhere in between awake and REM sleep in terms of levels of neurotransmitter modulation?

    <p>Non-REM sleep</p> Signup and view all the answers

    Which sleep states have high levels of activation?

    <p>Awake and REM sleep</p> Signup and view all the answers

    Which sleep states have entirely different neurotransmitter modulation compared to each other?

    <p>Awake and REM sleep</p> Signup and view all the answers

    Which sleep states have entirely different information sources compared to each other?

    <p>Awake and REM sleep</p> Signup and view all the answers

    Which sleep states are the most opposite ones in terms of neurotransmitter modulation and information source?

    <p>Awake and REM sleep</p> Signup and view all the answers

    During REM sleep the main neurotransmitter modulation is provided by:

    <p>Acetylcholine</p> Signup and view all the answers

    Four basic EEG phenomena: The alpha rhythm, 8-13Hz, awake subjects with eyes closed The beta rhythm, 14-60 Hz, indicates mental activity and attention, eyes open Theta waves, 4-7 Hz, indicates drowsiness and sleep or a pathological condition. Delta waves, <4 Hz, as in 3.

    What is the order of the waves from shortest to longest?

    <p>Delta waves, theta waves, alpha rhythm, the beta rhythm</p> Signup and view all the answers

    What is a true statement regarding generation of small fields in pyramidal cells?

    <p>It takes many thousands of underlying neurons, activated together, to generate an EEG signal big enough to see at all.</p> Signup and view all the answers

    What is NOT true regarding basic requirements for signal detection?

    <p>This population of neurons must be aligned in a parallel orientation so that they summate rather than cancel out.</p> Signup and view all the answers

    The amplitude of the EEG signal partly depends on how synchronous the activity of the underlying neurons is. Number of active cells, total amount of excitation, timing of activity.

    What is NOT true regarding Synchronous activity?

    <p>If the inputs are regular, their algebraic sum will have a small amplitude, as occurs in the waking state.</p> Signup and view all the answers

    What is NOT true regarding generation of synchronous rhythms?

    <p>Brainstem nuclei modulate the rhythm of interactions between the medulla oblongata and the cortex.</p> Signup and view all the answers

    A one neuron oscillator Thalamic cells have a set of voltage-gated ion channels that allow each cell to generate rhythmic, self-sustaining discharge patterns, even in the absence of external inputs. The rhythmic activity of each thalamic pacemaker neuron then becomes synchronised with many other thalamic cells via a hand-clapping kind of collective interaction.

    What is NOT true regarding generation of synchronous rhythms?

    <p>Hyperpolarisation of the cell (by injecting current or stimulating the cholinergic reticular activation system) transforms the oscillatory activity into a tonically active mode.</p> Signup and view all the answers

    What are EEG rhythms?

    <p>Window of the functional states of the brain</p> Signup and view all the answers

    What is NOT a behavioural criteria for sleep?

    <p>Relatively hard reversibility</p> Signup and view all the answers

    What is NOT a functional states of sleep

    <p>Sleep</p> Signup and view all the answers

    Predatory animals, like humans, can indulge in long, uninterrupted periods of sleep. The animals that are prayed upon need to have constant vigilance, and usually sleep only a few minutes at a time (e.g. rabbits, giraffes). Dolphins and seals have come up with a particularly ingenious solution:

    <p>one hemisphere sleeps, while the other is awake.</p> Signup and view all the answers

    What is NOT true regarding summary scheme of sleep-wake states?

    <p>In NON- REM sleep, activation is also high, the modulation is cholinergic, and the information source is internal.</p> Signup and view all the answers

    What is NOT a function of Sleep and Dreaming

    <p>Release of metabolic energy</p> Signup and view all the answers

    What is NOT true regarding Structural imaging?

    <p>Functional magnetic resonance imaging, fMRI</p> Signup and view all the answers

    What is NOT true regarding functional imaging?

    <p>An example: Magnetic resonance imaging, MRI</p> Signup and view all the answers

    What is NOT true regarding Imaging techniques?

    <p>Structural imaging always measures relative changes in activity (e.g. activity while performing a task vs. baseline or a control task).</p> Signup and view all the answers

    What is NOT true regarding the BOLD signal?

    <p>Haemodynamic response function, describes the BOLD signal</p> Signup and view all the answers

    What stages in the Non REM stage of sleep?

    <p>Stage 1: Theta Rhythms, Stage 2: Spindle and K complexes, Stage 3: Delta Rhythms, Stage 4: Delta Rhythms</p> Signup and view all the answers

    In the awake stage of sleep, what rhythms are present?

    <p>Alpha and beta rhythms</p> Signup and view all the answers

    In the REM sleep stage, what rhythms are present?

    <p>Beta rhythms</p> Signup and view all the answers

    The neurons that control sleeping and waking are part of the diffuse modulatory neurotransmitter systems (brain stem). Those systems control the rhythmic behaviours of the thalamus, which in turn controls many of the EEG rhythms of the cortex. What is true regarding the diffuse modulatory neurotransmitter systems (brain stem)?

    <p>modulation is aminergic (NE (Locus coeruleus), 5-HT (raphe nuclei)), and the information source is external.Histamine-containing neurons in the tuberomammilary nucleus (TMN) of the hypothalamus are also involved (~ drowsiness as a side effect of an antihistamines which supress the TMN network).</p> Signup and view all the answers

    Study Notes

    Brain Activity and Imaging Techniques

    • Presentation is for personal use only and not to be copied or used outside of BSMS Global Brain Activity
    • Presentation covers activity of large populations of neurons, electroencephalography (EEG), brain rhythms, sleep cycle, and methods of imaging the brain
    • Learning outcomes include understanding EEG, frequency bands, role of thalamus in brain rhythms, stages of sleep, and differences between structural and functional imaging techniques
    • Brain rhythms are influenced by environmental factors and include sleeping and waking patterns, breathing cycles, and stages of night sleep
    • EEG measures the synchronous activity of a population of neurons aligned in a parallel orientation, with amplitude depending on the synchrony of the neurons
    • EEG and brain rhythms correlate with pathology and behavioral states
    • Thalamic cells generate rhythmic, self-sustaining discharge patterns that synchronize with other thalamic cells to generate brain rhythms
    • Sleep is characterized by reduced motor activity, decreased response to stimulation, stereotypic postures, and relatively easy reversibility
    • Sleep has functions such as conservation of metabolic energy, cognition, thermoregulation, neural maturation, and mental health
    • Structural imaging techniques include computerized tomography (CT) and magnetic resonance imaging (MRI), which provide static maps of brain tissue
    • Functional imaging techniques include positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), which provide dynamic maps of brain activity associated with cognitive processing
    • PET measures changes in blood flow, while fMRI is sensitive to the concentration of oxygen in the blood, both indirectly measuring neuronal activity

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    Global Brain Activity Presentation PDF

    Description

    Test your knowledge on the activity of large populations of neurons, brain waves, sleep cycles, and imaging techniques such as EEG, CT, MRI, fMRI, and PET. This quiz is designed to enhance your understanding of neuroscience and behavior.

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