PS1090: BEHAVIOURAL NEUROSCIENCE
TOPIC A01 (KNOWLEDGE) A02/3 (EVIDENCE+EVAL)
- BN: is the field that relates behaviour to bodily processes, especially the workings of the brain.
- AIM: to understand the biology underlying behaviour and experience.
INTRODUCTION TO
BEHAVIOURAL FUNDAMENTAL ASSUMPTIONS
- Biological mechanisms & processes underpin all behaviour
NEUROSCIENCE & ITS - We need an understanding of biological functions to understand human behaviour
TECHNIQUES - Animal research provides essential contributions to understand hb.
- The study of electrical phenomena associated with nervous & other bodily activity.
SPATIAL: precision in the localization of brain activity
ELECTROPHYSIOLOGY SINGLE UNIT RECORDING
/function
TEMPROAL: precision in the timing of brain activity/f
(a technique used to record brain - Is the use of an electrode to record the electrophysiological activity (AP) generated by a single
activity) neuron. This is used in animal studies. The firing rate of the AP is recorded. PROs CONs
- There are 3 (main) recording - An AP is the mode through which a neuron transports electrical signals and communicates. It’s SUR Precise (1 neuron) invasive
an explosion of electrical activity in the membrane of a neuron. Excellent spatial &
activities temproal
- Mirror neuron system: neurons that are activated both while observing & performing Non-invasive, useful in Poor spatial
EEG
actions/emotions/pain. These mirror neurons are found in F5 in the ventral premotor cortex. a range of clinical resolution (many
applications. excellent neurons)
temporal resolution
- Multi-unit recording: studies the composite electrical activity of groups of neurons. Used in AS. (approx. 1msec)
- EEG: measures electrical activity of large populations of neurons. Used in HS.
- EEGs are used to detect changes in brain patterns (detect epilepsy, sleep disorders & tumors)
- ERP: Measured brain response that is the direct result of a specific motor/cognitive (etc) event.
, - Involves FMRI in human studies.
- Neural activity consumes oxygen, in order to compensate increased oxygen consumption, PROs CONs
NEUROIMAGING more blood is pumped to the active region. fMRI Good spatial (SUR is POOR temporal,
(a technique used to record brain - fMRI measures the blood oxygenation in the brain. As neural activity increases, there is a 25% better tho) (several seconds)
activity) local change of blood oxygenation.
BOLD = - fMRI measures the concentration of deoxyhaemoglobin in the blood. This is called the BOLD
BloodOxygenLevelDependant response. The change in the BOLD response over time is called the haemodynamic response - HR peaks in 6-8 seconds which is why the
contrast function. Has a number of distinct phases. temporal resolution is so poor.
- By looking at the haemodynamic response, we can see if an area is activated or not.
- Can be used to measure sensory processing, motor control, decision making, emotions, etc.
- fMRI experiment measures brain activation by detecting an increase in oxygen levels in active
neural structures. =
- To infer a function, we compare relative differences in brain activity between two or more
functions. A region is active if we see a greater change in the BOLD signal between two
conditions. The BOLD signal is based
of the measure of the
(In particular area)
deoxy/oxy balance.
Combining fMRI + EEG can help increase the spatial-temporal resolution.
- Suspended in cerebrospinal fluid, 100,000,000,000 neurons in the brain. 700,000,000,000,000
synapses in the brain. - Neuron Doctrine: Santiago Ramon
NEUROANATOMY NEURAL CIRCUITS “Neurons are the basic unit of the NS. Are
- Neuron: receives and processes signals, connects to other neurons (stimulate or inhibit) to distinct & separate from each other.”
make circuits.
- Nerve: an enclosed bundle of axons
- Divergence allows one neuron to communicate with many other neurons in a network.
- Convergence allows a neuron to receive input from many neurons in a network.
- Principles of neural circuits: brain consists of a myriad of interconnected neural circuits
performing different functions. The function of a neural circuits depends on how the neurons are
connected. How strong the synapses are, whether the synapses are excitatory or inhibitory.
- Glial cells: support neurons. Protect neurons and also have a metabolic functions. small, low
(or no) contrast under microscope.
- Four types of glia: Astrocytes, Oligodendrocytes, Schwann cells, Microglia.
- Astrocytes: Attach to blood vessels & neurons, help control blood flow. Separate synapses.
- Oligodendrocytes: Support axons, provide electrical insulation. In the PNS: they’re schwann c.
- Microglia: Precursors of blood cells, part of brain’s immune system.
, THE NERVOUS SYSTEM DIRECTIONS:
- PNS: two structural subdivisions: cranial nerves (from brain), spinal nerves (from spine) - Lateral: to the side
- 12 pairs of cranial nerves. Eg. optic, olfactory, Facial, vagus, etc. 31 pairs of spinal nerves. - Medial: to the middle
- Each nerve has a ventral root & a dorsal root. - Ipsi: same
- Contra: opposite
- Ipsilateral: On the same side
- Contralateral: On the opposite side
CNS (brain & spinal cord) PNS (cranial nerves/spinal nerves) - Bilateral: On both sides
Origin of all complex commands & decisions PNS transmits info from the CNS to the muscle & - Superior: to the top
glands. - Inferior: to the bottom
- Largest part of TNS. - 12 pairs of cranial nerves (from the brain)
- Anterior: to the front
- 31 pairs of spinal nerves. - Posterior: to the back
- Dorsal: towards the backbone
- Has a cushioned fluid: cerebrospinal fluid. Subdivided into the autonomic ns & somatic ns. - Ventral: towards the stomach
- Protected by bone. Brain: has the skull & the - Somatic: controls muscle movement - Rostral: towards the snout
spinal cord: vertebrate. - Autonomic: governs vital, involuntary functions in - Caudal: towards the tail
- Covered by membranes “meninges” the body. Controls homeostasis.
- Brain & spinal cord parts can be distinguished - Parasymp: controls relaxed state.
due to grey & white matter. This is because.. - Sympathetic: activates body for vigorous activities
- GM: cell bodies of neurons (fight or flight)
- WM: axons of neurons (white because
surrounded by mylelin sheath).
CNS ORGANIZATION
- The brainstem: controls homeostatic functions (eg. breathing, heartbeat..)
- Cerebellum: receives sensory & motor info. Coordinates movement.
- The Diencephalon: (between-brain). Consists of thalamus & hypothalamus
Thalamus: complex cluster of nuclei- motor/sensory. Connected to almost any area of cortex.
Hypothalamus: regulates homeostasis, metabolic processes & autonomic activities.
- Forebrain: Basal ganglia, Limbic system, Isocortex - Gyrus fold = a ridge
Basal Ganglia: important for movement control - Sulcus = a groove
Limbic system: involved in emotion, motivation & emotional memory.
Limbic system has the hippocampus: essential for memory formation.
Isocortex: involved in sensory perception, cognition, etc. (has six layers of cells)
- Cerebrum: largest part of the brain. Consists of two cerebral hemispheres (L&R) which are
connected by the corpus callosum (bundle of white matter fiber)
- Cerebral cortex: outermost layer of the brain. Has diff folds (which increases surface area).
- The CC ^ is organized into cortical areas (apprx 100-150). Each area is defined by having a
unique combo of 3/4 specific criteria: physiology, architecture, connectivity & topography.
