Biopsychology- Revision- Notes PDF

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Concise full notes of second year biological psychology module...

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BIOPSYCHOLOGY REVISION NOTES

WHAT IS BIOPSYC HOLOGY ? -

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Hebb’s The Organisation of Behaviour (1949) is thought to be the key factor in the development of Biopsychology. Brain & Behaviour are two critical subject of interest in scientific research. Biopsychology focuses on the relation between them. It is defined as a scientific study of the biology or behaviour (Dewsbury, 1991).

WHAT IS NEUROSCIENCE? - Neuroscience is the study of the nervous system; neuroscience includes many different approaches such as: - Neuroanatomy, neurophysiology, neurochemistry, neuroendocrinology, neuropharmacology, and neuropathology

Biology as a discipline of Neuroscience § § §

Biopsychology integrates these various approaches to the study of the nervous system. BP is an integrative discipline and Draws together knowledge from other neuroscientific disciplines and applies it to the study of behaviour such as language, memory, emotion and language.

Diversity of Biopsychological Research Human vs. non-human Advantages of human 1. Can follow instructions 2. Report subjective experiences 3. Have a human brain! 4 Of l i

Advantages of non-human 1. Possible to use comparative cross species approach. 2. Valuable cues into cortical function 3. Differences are more quantitative 4. Simpler nervous system & brain

The ethics of both human and animal research is regulated and carefully scrutinized by independent committees.

Responsible for non-human research §

American Psychological Association (APA): Guidelines for Ethical Conduct in the Care and Use of Animals

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§ www.apa.org/science/leadership/care/guidelines.aspx Understanding Animal Research § www.understandinganimalresearch.org.uk Animal Research for Life § www.animalresearchforlife.eu American Physiological Society (APS): Animal Research § www.the-aps.org/pa/policy/animals/intro.htm

Experiments vs. Non-Experiments

Non-Experiment (Quasi Experimental Design) §

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Compared alcoholics with non-drinkers § Worse performance on perceptual, motor & cognitive tasks § Brain scans revealed extensive brain damage… Poorly educated Prone to accidental head injury Likely to use other drugs Likely to have poor diets

Non-Experiment (Single -Case studies) § § §

Case studies focus on a single individual § such as Jimmie G. Usually more in in-depth than other approaches, but may not be generalizable Generalizability – the degree to which results can be applied to other cases

Another type of non-experimental design is called a case study case studies are scientific studies that foucs on a single subject the main problem with case studies is their poor generalizability, or the extent to which their results tells us something about the general population Non-Experiments – The major short-coming of a quasiexperimental study is that although researchers can examine relations between the variables of interest (e.g., alcohol consumption’s relation to brain damage), a quasi study cannot control for potential confounding variables Pure VS. Applied Research – Pure research is motivated primarily by the curiosity of the researcher; it is motivated by the desire to find out how things work; it focuses on establishing building blocks or basic concepts that may provide information salient to many problems. Applied research intended to bring about some direct benefit Some research projects may have elements of both

Diversity of Biopsychological Research 1. Physiological Psychology. Focuses on the direct manipulation of the nervous system in controlled laboratory settings (e.g., lesions, electrical stimulation, invasive recording) Subjects are usually laboratory animals strong focus on pure research 2. Psychopharmacology. Nervous system is manipulated pharmacologically Focuses on drug effects on behavior and how these changes are mediated by changes in neural activity Many favor pure research use drugs to reveal the nature of brain-behavior interactions Others study applied questions (e.g., drug abuse, therapeutic drugs) 3. Neuropsychology. focuses on the behavioral deficits produced in humans by brain damage, typically cortical damage can’t be studied in humans by experimentation; deals almost exclusively with case studies and quasi experimental studies most applied; neuropsychological tests of brain-damaged patients facilitate diagnosis, treatment, and lifestyle counseling 4. Psychophysiology. focuses on the relation between physiology and behavior by recording the physiological responses of human subjects

because humans are used, all brain recording is noninvasive (i.e., from the surface of the head) usual measure of brain activity is the scalp electroencephalogram (EEG) muscle tension, eye movement, heart rate, pupil dilation, and electrical conductance of the skin are other common measures 5. Cognitive Psychology. newest division of biopsychology focuses on the neural bases of cognitive processes like learning and memory, attention, and complex perceptual processes often employs human subjects; key methods are noninvasive, functional brain imaging techniques often involves collaborations between researchers with widely different backgrounds (e.g., psychology, linguistics, computer science) 6. Comparative Psychology. Study of evolutionary & genetic factors of behavior Features comparative & functional approaches Features laboratory research as well as studies of animals in their natural environments

Converging Operation & Clinical Implications Converging Operations. For example • Korsakoff’s syndrome – a condition characterized by severe memory loss and most commonly seen in alcoholics • Is Korsakoff’s the result of the toxic effects of alcohol on the brain? Clinical Implication. Alcoholics counselled to stop drinking Treated with massive doses of thiamine Thiamine limits the development of further brain damage Slight improvement in the patient’s condition Unfortunately, the brain damage that has already occurred is largely permanent Critical Thinking. - Moniz - Nobel Prize for development of prefrontal lobotomy as treatment for psychiatric disorders - Moniz’s psychosurgery based on observation of a single chimpanzee! - Failed to evaluate the consequences of surgery in patients o Prefrontal lobotomies of little therapeutic benefit o Produced wide range of undesirable side effects o 40,000 patients lobotomized in the United States alone o Prefrontal lobotomies continue to be performed in some countries

NEURONS, NEUROTRANSMISSION AND COMMUNICATION. Organization of nervous system

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The Central Nervous system (CNS): brain and the spinal cord The Peripheral Nervous system (PNS): connects central nervous system to rest of body.

Structures of the Human Brain BRAIN. § Brain areas: the hindbrain, the midbrain, the forebrain § Spinal cord enters brain - enlarges & forms the brainstem § The oldest part - medulla

> 90 % of body's neurons Brain areas: the hindbrain, the midbrain, the forebrain Spinal cord enters brain - enlarges & forms the brainstem The oldest part - medulla Controls: breathing, heart rate, salivation, vomiting Point at which nerves from left part of body cross to right side of the brain & vice versa

THE CEREBRAL VENTRICLES.

Protecting the brain Chemical protection

The blood-brain barrier – tightly-packed cells of blood vessel walls prevent entry of many molecules Physical protection Skull Meninges Cerebrospinal fluid (CSF) § § § §

Hindbrain found in even the most primitive vertebrates The pons, located just above the medulla, connects the top of the brain to the cerebellum Chemicals produced in the pons help maintain our sleep-wake cycle The cerebellum is divided into two hemispheres & handles reflexes

Major Fissures of the cerebral hemisphere

The human diencephalon.

Limbic System or the Papez circuit

Basal Ganglia

Cells of the Nervous System Billions of neurons underlie activity of the nervous system § Electrically excitable cells Process and transmit information around the nervous system. §

Nodes of Ranvier

Cells of the nervous system: Neurons – the messengers Hodgkin-Huxley Model. § § § § § §

This theory was proposed in 1950s (see Catterall et al., 2012) Was a major advance in understanding neural conduction Provided a simple, effective introduction to how neurons conduct signals. Problem is that this does not represent the variety, complexity and plasticity of the neurons in the mammalian brain. Based on study of the squid motor neurons. Hundreds of different neurons are found in the mammalian brain and may of these actions not found in motor neurons (see Nusser, 2009).

Cells of the nervous system §

Communication between neurons through dendrites, via synapses § Dendrites, pick up and carry messages to the cell body. § Axon carries outgoing messages from the cell § A group of axons make up a nerve § Some axons are covered with myelin sheath § Myelin sheath made up of glial cells § increases efficiency

Neural Impulse: Resting vs. Action potential § § § § § §

At RP higher concentration of negative ions exists inside the membrane surrounding the cell body than outside A negative electrical charge inside relative to outside. Incoming message is strong = change in the electrical charge. AP neuron is depolarised. Incoming messages cause graded potentials, when combined, may exceed the minimum threshold of excitation – make the neuron fire. Refractory period is the characteristic recovery period. During this time the cell is incapable of repeating the action potential.

Action Potential.

Potential goes up to reach the d equilibrium for sodium potential, which is around 58 miliVolts. AT the point of Action potential the voltage gated potassium channels to open. So now we have inside the cell a bunch of pota. Ions and such a positive charge that the potassium wants to leave (as +ve repels +ve). This now leads to repolarization where the membrane potential is going down. Now the potassium wants to reach it’s equilibrium potential which is -93 miliVolts. That is where it is most comfortable. Considering that the resting membrane potentia is -70, the membrane potential goes significantly lower than that -70 and ths phase is called hyperpolization (or the refractory period). All along this process the sodium potassium pumps pump out of the cell…3 sodium ions out and 2 potassium ions in, causing the membrane to reach the resting state (-70mV). An EPSE, IPSP and EPSP followed by a typical AP

Neurotransmitters Small-molecule neurotransmitters.

Large-molecule Neurotransmitters.

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Neurotransmitters: Acetylcholine

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Abbreviated as AcH is a small-molecule neurotransmitters. Created by adding acetyle group to a choline molecule. It is broken down by in the synapse by the enzyme acetylcholinesterase. Neurons that release acetylcholine are said to be cholinergic. Link between acetylcholine and Alzheimer's disease.

Neurotransmitters: Dopamine § §

Drugs to block dopamine used to reduce excess in the frontal lobes linked to schizophrenia Too little in the motor areas link to Parkinson's disease - uncontrollable muscle tremors

Neurotransmitters: Serotonin & Non-epinephrine Serotonin § Too little serotonin lead to depression, anger control, obsessive-compulsive disorder (OCD), suicide § Prozac, prevents neurons from "vacuuming" up excess seratonin, more left in synapses Norepinephrine § Stress depletes adrenalin § Exercise increase it Neurotransmitters Endorphin § Are endogenous opioid neuropeptides in humans and animals. § Structurally very similar to opioids; opium, morphine, heroin, § Allows hibernation § Heroin slows heart-rate, respiration, and metabolism in general - sometimes heroin slows it down to permanent hibernation! Glutamate § Most common neurotransmitter in the central nervous system § E.g. Motor Neurone Disease (MND) results from excessive glutamate production GABA (gamma - aminobutyric acid) § Too little suffer anxiety disorders. § Drugs like Valium, alcohol & barbiturates enhance effects of GABA § Deficiency can result in epilepsy Endorphins are produced as a response to certain stimuli, especially stress, fear or pain. They originate in various parts of your body -- the pituitary gland, your spinal cord and throughout other parts of your brain and nervous system -- and interact mainly with receptors in cells found in regions of the brain responsible for blocking pain and controlling emotion

PERCEPTION (I) SEEING.

Basically. What happens is, there is physical energy in the world, made of light. The photoreceptors detect the light. This gets transmitted to the brain. This may seem simple. However, we have seen that the information that is sent to the brain is not complete. Instead there is gap. This means the brain fills it in. Thus, do we actually “see” why the eyes? An interesting piece of evidence is an experiment by XXX in which participants stood in a darkened room with a pin point of light. Participants were asked how much the light moved. The participants reported seeing the pinpoint light move. Another instance was direct stimulation of the visual cortex of the brain caused people to report seeing flashes. That is, blindfolded so they couldn’t see – participants reported seeing flashes of light – stars. This was caused by either striking the back of the head, or direct electrical stimulation. Thus, it seems we do not see with the eyes – we see with the brain.

THE EYE.

Having considered what light is, we must consider how light leads to seeing. The sense organ that detects light is the eye. The eye is gelatanous spheroid with several components each doing separate things. Muscles: There are six muscles around the eye that control the movements of the eyes. Two muscles control horizontal movements (the lateral and medial rectus muscles) – medial refers to closer to the nose, lateral further away. Two muscles control the vertical motions (the superior rectus muscle and the inferior rectus muscle) – superior at the top, inferior at the bottom). Two oblique muscles are located further back and control rolling movements of the eyes – one at the top (Superior) and one at the bottom (inferior). Cornea – the cornea is a transluscent layer that protects the delicate eye. A mis-shaped cornea causes astigmatism – this will cause objects in the periphery to appear blurred. Iris – contains two layers: a pigmented layer that gives the colour and a layer containing blood vessels. Pupil – the little black circle in the centre of the eye is actually a gap or a hole. It is where light is let into the eye. If it is dark, it opens wider to allow more light in. If it is light, the pupil is narrower to allow less light in to prevent damage. This is because, too much light entering the eye causes damage as we shall soon see. The pupil shrinks as people get older. This means that less light gets into the eye. This means that it becomes more difficult to discriminate high contrast stimuli. As we have seen, the receptors detect light – they then send a signal out of the eye. However, there is only part of the eye that connects to the brain. All the retinal ganglion cells leave the eye at this point. Due to this, there is a part of the retina that does not have any photoreceptors. This means that at part of the retina, no light is detected – yet, there is no

gap in our vision. Firstly, you could argue that we have two eyes, thus two retinas. The blindspot of one retina does not correspond with the blindspot in the other eye. Thus, the brain combines the image to remove the blindspot. However, there is still no blindspot even if you look with one eye. Why might this be? We will be exploring this further in subsequent lectures and is something to consider. Let us demonstrate the blindspot. DEMONSTRATION. Visual Perception Basics

Retinal Ganglion Cells

HERMANN GRID.

THE BRAIN: VISUAL CORTEX.

PATHWAYS.

SIMPLE CELLS.

TILT AFTEREFFECT.

COMPLEX AND HYPERCOMPLEX CELLS.

GRANDMOTHER CELLS.

- Unitary hierarchical object processing system (Bright, Moss, & Tyler, 2004) - Multimodal cells linking unimodal representations (Bowers, 2009)

- Convergence Zones (Damasio, 1992) DARK AND LIGHT ADAPTATION.

CONTRAST SENSITIVITY FUNCTION. -

Spatial Frequency – the rate at which a pattern repeats itself (cycles per degree) Contrast/amplitude – how black or white a pattern is (differences in lightest and darkest part divided by the average) Phase – starting point of a pattern Temporal Frequency – the rate at which a pattern repeats itself Orientation – angle of presentation

CONTRAST SENSITIVITY FUNCTION.

SPATIAL FREQUENCY ADAPTATION

PERCEPTIO N 2 – HOW DO WE Trichromacy & Opponent Processing. Three major types of colour cones: PERCEIVE? - S cones absorb 420 nm -

M cones absorb 534 nm L cones absorb 564 nm

There are far fewer S cones than M or L cones. This means that perception and acuity of blue objects is more difficult than other colours. There are 1 million S Cones, 5 million M Cones and 2 million L Cones. There are no S Cones in the fovea suggesting that for a small region in the fovea you cannot identify the colour blue. There are three channels in colour vision. There is the achromatic channel that processes black and white. There is a chromatic channel that response to blue-yellow and finally one that responds to red-green. These are designed to maximally code the environment without involving too many channels. Adaptation -

Neuronal fatigue Adaptation is adaptive (Clifford & Rhodes, 2005) Dynamic adaptation reduces the need for constant firing Adaptation acts as comparison to previously seen images

Colour Constancy No simple relationship between wavelength and colour perceived. Objects colour is reflected light from source. This source differs, yet colours remain perceived the same (Land, 1977). Sunlight gives out light of all wavelengths, whereas tungston lights give out wavelengths at the longer wavelengths. The colour that enters the eye is reflected light from a source. If the source gives off different light then the wavelength entering your eye is different from the same object. Nevertheless, a rose will appear red in both conditions. This is the idea that the colour appears the same even if the wavelength entering the eye is different. Why is this? This is due to a perceptual constancy, whereby objects are perceived the same even if the retinal image is different. Clearly then the brain uses knowledge joined with the retinal image to perceive. Methods of assessing (Foster, 2003): - Colour-patch naming e.g. Land 1977, but too many labels to choose from - Colour-patch rating e.g. Speigle, 1997 – difficult to analyse - Colour-patch matching e.g. Land, 1977 – must be careful about instructions - Achromatic adjustments – judging differences to white

EXPLANATIONS -

Anchoring/Retinex – Land, 1977 and Valberg, 2005 Adaptation – von Kries, 1905; Shevell, 2000 Computations – Hurlbert & Wolf, 2004 Experience, Sugita, 2004

Categorical perception l Colour naming task (Harnad, 1987). l Cross-category discriminations easy l Within-category discriminations difficult l Hues reliably named one colour not another l Certain hues never confused The interplay of language Linguistic Relativity l Whorf (1956) – if we do not have a word for something, we cannot perceive it l Warping of internal colour space (Davidoff, 1991) Universals of (colour) perception l We are genetically pre-programmed to perceive certain colours (Heider, 1970) l Based on trichromacy Univer...