Brain structure & function Flashcards
Hindbrain?
reptilian brain –> Hindbrain: Medulla, pons and cerebellum.
Medulla
reptilian brain, Hindbrain –> Medulla (myelencephalon): Controls heart rate, respiration, Most posterior division of brain, Consist of tracks (crossing-point) carrying signals between the rest of the brain and the body, reflexes
Pons
reptilian brain, Hindbrain –> Pons: bridge between cerebral cortex and cerebellum, sleep regulating neuron clusters, helps respiration, arousal.
Cerebellum
reptilian brain, Hindbrain –> cerebellum: Muscular movements, Learning, memory (especially predictions), Regulating fast changing complex behaviour. Higher brain regions intiate movement, C co-ordinates, also fine movement, ballet and cat.
Midbrain
reptilian brain –> Midbrain (Sensory motor neurons, Sends info on to forebrain, vital part of communication): Reticular formation, Tectum, Substantia nigra, (Thalamus).
Reticular formation
reptilian brain, Midbran/Hindbrain –> reticular form: collection of neurons, involved in arousal and stereotype patters, such as walking, area that runs through brain stem, (ascending) alerts higher brain, (descending) lets through or blocks (attention), if no reticular stimulation no conscious awareness, sleep, DAMAGE: coma.
Tectum
reptilian brain, Midbran –> tectum: formed by 2 colliculi, 1. Superior colliculus: visual-motor function/ eye movements: input from retina and visual cortex & 2. Inferior colliculus: auditory function, crossed and uncrossed fibres from the auditory relay
Substantia nigra
reptilian brain, Midbran (Basal ganglia) –> substantia nigra: part of the Tegmentum (ventral of the Tectum), Large pigmented sections of cluster of neurons, important component of sensorimotor system - In relation to Parkinson’s disease
Thalamus
Reptilian brain/Limbic brain, forebrain –> Thalamus: sensory relay station between higher and lower brain centres (part of the reptilian brain), located on top of the brain stem, relays information organises input from sensory receptors, damage here can cause hallucinations, schizophrenic symptoms
thalamus subcomponents // sensory relay nuclei:
Lateral geniculate nuclei: visual relay station, Medial geniculate nuclei: auditory relay station, Ventral posterior nuclei: somatosensory relay station
- All not just send information but also receive it, get feedback
Limbic system sturcture
(Forebrain) Thalamus, Hypothalamus, Hippocampus, Amygdala, Cingulate cortex
Hypothalamus
Limbic structure/forebrain –> Hypothalamus: many parts of behaviour, especially motivated behaviour E.g. eating, drinking, and sex, emotion and stress
- Intimate communication with endocrine system, controls many hormonal secretions by regulating the release of hormones from the pituitary gland.
Involved in reward and punishment
Hippocampus
Limbic structure/forebrain –> Hippocampus: In the medial temporal lobe, Learning and memory, Forming and retrieving memory, Especially special navigation (Taxi driver study & Rats and maze)
Amygdala
in each hemisphere, adjacent to the hippocampus in anterior temporal lobe. Involved in emotion processing and fear-learning, links areas of the cortex that process “higher” cognitive information with hypothalamic and brainstem systems that control “lower” metabolic responses (e.g. touch, pain sensitivity, and respiration) - allows amygdala to coordinate physiological responses based on cognitive information e.g. fight or fly
Cingulate cortex
regulation of emotion and pain, thought to directly drive the body’s conscious response to unpleasant experiences. Involved in fear and the prediction (and avoidance) of negative consequences. Memory: Learning to avoid negative consequences is an important feature of memory. Damage: Inappropriate emotions, lack of fear, learning impairments, impaired nociception (sensation of pain)
Basal Ganglia
Overlapping with the limbic system. Comprising structures regulate initiation of movements, balance, eye movements, and posture, skill learning. Strongly connected to other motor areas in the brain, link the thalamus with the motor cortex, involved in cognitive and emotional behaviors: an important role in reward and reinforcement, addictive behaviors and habit formation.
Damage in basal ganglia?
e.g. Parkinson’s and Huntington’s disease,
tremors, involuntary muscle movements, abnormal increase in muscle tone, difficulty initiating movement, abnormal posture
Substructures of basal ganglia:
caudate nucleus: long, tail-like structure, sweeping out of each amygdala
putamen: connected to caudate through series of fibre bridges
globus pallidus: located between Putamen and thalamus
nucleus accumbens: thought to be associated with rewarding effects of addictive drugs on other reinforcers
substantia nigra
subthalamic nucleus
Frontal cortex/lobe
Neo-cortex, Cerebral cortex. Prefrontal cortex, Frontal eye fields & Premotor cortex: Coordinating and initiating movements.
Primary Motor cortex & Broca’s area: speech production
Dorsolateral prefrontal Cortex &Medial prefrontal cortex:
involved in complex executive behaviours
Parietal lobe/cortex
Neo-cortex, Cerebral cortex. Integrating sensory information.
Somatosensory cortex: Gets info from thalamus, Integrates it to create picture of the outside world, without it we could not plan behaviour for motor movements, Continually updated.
temporal lobe/cortex
Neo-cortex, Cerebral cortex. Long-term memory, auditory perception, emotion.
A large number of substructures associated with face perception, object recognition, understanding language.
includes Superior temporal Gyrus.
Superior temporal Gyrus
Neo-cortex, Cerebral cortex, temporal lobe –> Superior temporal gyrus. Wernicke’s area: Speech comprehension & Primary auditory cortex: Familiarity within different frequencies .
occipital lobe/cortex
Neo-cortex, Cerebral cortex
rich connections to other parts of brain, starts off process of interpreting visual info, visual perception
Corpus collosum (aivokurkiainen)
Neo-cortex, Cerebral cortex
connective tissue between the hemispheres
o Allows info to move between hemispheres
Frontal lobe functions
Help us identify, work towards and achieve personal goals, Resolve conflicts, Give us control over other higher functioning, Executive functioning and cognitive control
Working memory, interaction of frontal and posterior cortical areas
Working memory: storing information at the same time you have to process information
Interaction of frontal & posterior cortical areas: Talking about the golden gate bridge - Referencing location - Bringing to mind images while telling story - Have to use verbal information to communicate that - Controlling all this using some part of the frontal cortex - huge interplay of areas in the brain - Have to identify regions in order to better understand interplay
Cognitive neuroimaging, what and why it’s good
to study brain structure and function relevant to human cognition - establish where and when processes occur
- order of activations, and differences across areas
- range of techniques which vary in their spatial and temporal resolution (precision) - very high spatial and temporal resolution only required if very detailed account needed
Single-unit recordings?
Uses very tiny needles to do recording, Studies single neurons using micro-electrode, Very sensitive (detects 1 millionth of a volt), Very localised - don’t understand overall picture if we just look at single part
Event related potentials (ERPs)
looking at patterns of activity in response to psychological phenomena.
Sensory evoked potential: when we manipulate phenomena and measure response
Hard to get exactly where it is, just a general area. (EEG)
Electroencephalogram (EEG)
(ERP) Records brain (electrical) activity at surface of scalp, Present same stimulus numerous times, then average the effect on EEG output
High temporal resolution (ms) but low spatial resolution
Positron emission tomography (PET)
Inject tiny amounts of radioactive solution, gets taken up by brain’s blood vessels and processed
Allows us to see active vs non-active part of the brain by different colours, not real time info like EEG but see more specific regions
Need to adjust our experiment this way, cannot be a respond task
Magnetic Resonance Imaging (MRI)
For structional purposes
Radio waves excite atoms in brain producing magnetic charges detected by magnets
Changes detected by computer, which gives 3D image of brain
functional MRI
for functional purposes
Blood oxygenation in brain can be detected to indicate functional changes (BOLD response)
when brain region active it needs glucose, can map where the glucose is going to - see which brain region is active
Transcranial Magnetic stimulation (TMS)
Magnetic Coil delivers pulse which inhibits processing in given area - creates temporal ‘lesion’
Intervention technique, we determine what region we manipulate (disable)
All others are observation correlational approaches, this is causation approach
Cognitive neuropsychology
study of patterns of cognitive performance (intact and impaired) exhibited by brain-damage individuals - to provide knowledge about normal human cognition
complexities revealed when system malfunctioning e.g. patient HM: after lobotomy to control his epilepsy was unable to form new memories
Cognitive neuropsychology assumptions
- Functional & anatomical modularity: cognitive systems domain-specific, in specific identifiable areas
- Uniformity of functional architecture across individuals
- Substractivity: impairments cannot add to systems
Cognitive neuropsychology evidence
Performance dissociations (crucial): x impaired, y unimpaired, Double dissociation (ideal): above pattern in one individual, opposite true of another E.g. find someone who is able to perform one task but not the other. Individual (case studies) and group studies
cognitive neuropsychology limitations
o Compensation for impairment?
o Typically, damage is extensive
o Diverse patients with broadly similar brain damage
