Unit 1

Introduction to physiological psychology

Definition

physiological psychology is the branch of psychology that studies the biological basis of behaviour, with a focus on how the brain, nervous system, hormones and other bodily processes influence thoughts, emotions and actions.

It examines the relationship between physiological process and psychological phenomena.

for eg → how brain activity affects memory, perception or decision making.

  • it is also referred to as biopsychology

  • it links mind and body parts

  • main focus on brain structure, nervous system, neurotransmitters, endocrine system and their effects on behaviour


Historical background

physiological psychology has deep roots in both philosophy and biology. Its development can be understood through several key milestones

  1. philosophical foundation (ancient - 17th century)


Ancient greek philosophers like Plato and Aristotle debated the role of brain and heart in behaviour and thought.



Methods

physiological psychology uses scientific methods to explore relationship between the brain, body and behaviour. These methods can be divided into invasive (often animal based) and non-invasive (human based) approaches.

  1. Lesson studies

    • description → damage or remove specific brain areas to study changes in behaviour

    • purpose → identify the role of specific brain regions

    • example → studying Broca’s area damage to understand speech production

  2. Electrical stimulation

    • description → apply mild electric currents to specific brain areas.

    • purpose → observe how stimulating a region effects movement, sensation or emotions.

    • example → Penfield’s cortical mapping in epilepsy patients

  3. Recording neural activity

    • single cell recording → measures electrical activity of individual neurons.

    • Electroencephalography (EEG) → records brain electrical patterns through scale electrodes.

    • purpose → study brain rhythms during sleep, attention or seizures

  4. Brain imaging techniques

    • CT scan (computed tomography) → x-ray images of brain structure

    • MRI ( magnetic resonance imaging) → high resolution images of brain anatomy

    • FMRI ( functional magnetic resonance imaging) → measures brain activity by tracking blood flow

    • PET scan ( positron emission tomography) → shows brain activity using radioactivity trackers

  5. Neurochemical methods

    • description → measure or manipulate neurotransmitter levels in the brain

    • purpose → understand chemical control of behaviour.

    • example → studying dopamine levels in Parkinson’s disease

  6. Genetic methods

    • description → use genetic engineering, twin studies or gene knockout techniques

    • purpose → determine genetic contribution to behaviour

  7. Psychophysiological recording

    • description → measure bodily response linked to psychological states

    • example → heart rate, skin conductance, muscle activity (EMG)


Approaches



Weight of human brain → approx. 1.3-1.5 kg

infant brain (1-2 month) → 1.5 gm approx.

nerve cells → 1011-1015 neurons





INTRODUCTION TO PHYSIOLOGICAL PSYCHOLOGY


The scientific study of anatomy, biochemical process and physiology of nervous system is known as neuroscience.

Biopsychology is closely related to neurosciences, also known as psychobiology, behavioural biology, behavioural neurosciences and biological bases of behaviour.

The biological approach to the study of human behaviour is known as bio-psychology. In which it is tried to investigate how biological process interact with cognition, emotions and other physiological processes.


It emerged in 20th century with research done by D.O. Hebb ( Canadian Psychologist) “organisation of behaviour” in 1949. So, biopsychology draws into from neuroscience and use this information to study human and animal behaviour.

there are some disciplines of neurosciences that are particular relevance with biopsychology are as follows

  1. Neuroanatomy → structure of nervous system

  2. Neurochemistry → chemical aspect of nervous activity

  3. Neuropathology → study of disorders of nervous system

  4. Neuroendocrinology → interaction between nervous system and endocrine system

  5. Neuropharmacology → study of impact of drugs on neural system or activity

  6. Neurophysiology → study of function and activity of nervous system.


Research methods in biopsychology

  1. Pure research

    • also known as basic/ fundamental research. It is exploratory in nature and driven by researcher interest.

  2. Applied research

    • It is conducted with pre-decided aim. It starts with the aim to solve an existing problem. So it is descriptive in nature and has practical implications.


Ethics in biopsychology →

The research conducted in biopsychology is varied in perspective, it is conducted on human and non-human participants including mice, rats, dogs etc.

There are some advantages on conducting research on human participants.

  • brain and behaviour of non-human participant is less complex compared to human participant, that is why the basic brain behaviour interaction may be possible to explain.

It is easy to conduct research on laboratory animals rather than human participants due to ethical reason, because it is governed by strict ethical guidelines frame by APA and ICMR ( Indian council of medical research )

Research in biopsychology may be pure and applied research and study is based on empirical investigation with its application.

The scope of research is to understand basis of behaviour. It aims to understand aspects like evolution of brain and its influence on behaviour. It also seeks to understand the role of genes and endocrine glands in the maintenance of behaviour


Divisions of Biopsychology

  1. Cognitive neuroscience

    • this division study about neural basis of cognition and higher order cognitive processes (thinking, attention, perception etc.). Hence human participants are required. The techniques used are non-invasive.

    • for eg → functional brain imaging methods

  2. psychopharmacology

    • This division study about medicines and drugs to observe their effect on behaviour. The purpose is to study interaction between brain and behaviour.

    • These experiments are applied in nature.

  3. Psychophysiology

    • This division is used to examine relationship between physiological activity and psychological process as learning and emotions in human participants.

  4. Comparative psychology

    • this division study the behaviour of different species to understand their behaviour from evolutionary, genetic and adaptation perspective.

    • The behaviour is studied in either laboratory conditions or it may be observed in its natural environment.


Methods to study biopsychology

  1. Ablation method

    • Ablation means removal of brain areas (damaged part tissue removal). It involves destruction of some tissues in the brain. This is followed by assessing the change that occurs in behaviour due to removal of tissue.

  2. Fixation method

    • in this method a fixative is used to fix a tissue. The tissue is cleaned and dipped in a fixative and used for further observation.


Psychological recording method

  • EMG (electromyography) → It helps to record muscular tension. The electrodes are attached to the skin over the muscle that is to be investigated. When the muscle contracts it produces muscular tension which is recorded. It helps to know about muscle tone.

  • EEG (electroencephalography) → the electrical is recorded using electroencephalograph and the technique is known as electroencephalography. Electrodes are placed on the scalp of the person and the recording is done through monitor. EEG signals help in diagnosis of various brain disorders, epilepsy, speed of processing information and memory functioning with an increasing in age.

  • EOG (electrooculography) → the eye movements are recorded using EOG. There is a slight difference in the electrical potential on back and front of eye ball, and it is recorded with the help of electrodes placed near the eyes.

  • Electrodermal activity → 2 main indices of electrodermal activity are skin conductance level (SCL) and skin conductance response (SCR). This activity of skin is recorded by attaching electrodes on the fingers and record the fluctuations in skin conductance.

    • SCL measures the background level of skin conductance associated with particular vibration and SCR associated with different type of experiences.

  • Neuroimaging → brain imaging is known as neuroimaging. Structural imaging methods are used to image the brain structures. These images help to diagnose any injury or disease in brain areas.

    • functioning images help to understand the function of brain and help to diagnose disease related to metabolism or brain disorders.

    • techniques → X-ray, CT scan, MRI, PET scan

  • Neuropsychological assessment

  • various tests are employed to make assessment of different cognitive functions such as learning, memory, discriminatory task, intelligence, reasoning, etc. These tests are administered to check mental status of patient or client.

  • it includes comprehensive examination of behavioural and neurological assessment of client and help to get clinical picture of client with respect to their cognitive strength as well as difficulties in cognitive areas. These evaluations help in treating client with appropriate medical or behavioural procedures. Apart from this it also provides valid information about the kinds of impairment etc.

  • Few common tests used are → Wechsler intelligence test, listening test, Rorschach ink blot test, thematic apperception test, etc.













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