Prof. Muni Mahendra Kumar
Amygdala:
An almond shaped basal part of brain situated at the front of the limbic system, affecting rage and aggressiveness and other emotional behavior.
Axon:
Part of a neuron (the nerve-cell); a long fibre that carries nerve-signals away from a nerve-cell-body, often for a long distance to neighboring neurons, (see, neuron)
Brain:
A highly organized constituent of nervous system, composed of millions of nerve-cells, providing the programs of action by detecting events and comparing them to a set of standards and to its memory record.
Brainstem:
The range of bulges that forms the central core of the brain, running from the top of the spinal cord into the middle of the brain.
Cerebellum:
The twin-lobed, oval structure at the back of the brain, responsible for coordinating movements, having close inter-relation with the cerebral cortex.
Cerebral cortex:
Thin, convoluted, outer layer of the brain composed of gray matter in the cerebrum; birthplace of man's higher mental functions. It receives signals via the thalamus from all sense-organs and sends signals to the lower parts. Each neuron of its receptive areas represents some external feature and those of its motor areas represent movements of muscles.
Cerebrum:
Main part of the brain; about seven - eighths of the total weight of the brain, it fills the upper part of the skull. It is a mixture of grey and white matter. It is divided into two identical hemispheres and each one of them is further divided into four regions called lobes.
Cingulate cortex:
The middle part of the cortex (where the two sides lie against each other). It is concerned largely with emotional programs, but is little understood.
Corpus callosum:
The bridge of nerve-fibres connecting the left and right cerebral hemispheres; it permits the exchange of information between them.
Core brain:
The central part running the whole length including the reticular system; regularising sleeping and waking and emotional responses.
Dendrites:
Short receptive branches of a neuron, extending from the nerve-cell-body receiving impulses from nearby neurons.
EEG:
Electroencephalogram; the waves of change of electrical potential recorded by electrodes attached to the scalp recording the amplitude and frequency of bra in-waves.
EEG
Machine: A machine used to get the EEG record.
ESB:
Electrical stimulation of the brain through electrodes, implanted in the brain, used to map brain-functions and study behavior.
Frontal cortex/Frontal lobe:
One of the four regions of the cerebral cortex. The anterior part, important for its general inhibitory actions, especially repressing inappropriate programs. Lies directly behind the forehead. It's hindmost part contains the motor cortex.
Hippocampus:
A part of the brain (shaped like a sea-horse) lying close to the cerebral cortex. It is a part of the limbic system; thought to play an important part in learning and short term memory.
Hypothalamus:
A very important part of the brain; region at the base of the forebrain essential in coordinating central nervous system functions, including the regulation of body-temperature, sex-drive, thirst and hunger. It contains reference systems or standards of the programs for ensuring homeostasis. Through pituitary gland, it regulates endocrine activity and plays important role in emotions of pain and pleasure.
Limbic System:
An integrated network which includes thalamus, hypothalamus, hippocampus, amygdala and parts of the reticular formation as well as limbic region of cerebral cortex; is involved in emotions and behavior.
Medulla oblongata:
The hindmost part of the brain that provide the programs regulating essential activities such as breathing and blood-circulation.
Memory:
Act of summoning up the past or that of fixing of present data for future reference; the set of brain programs that allows addition of information to the programs already available for self-maintenance.
Microneurons:
Small nerve-cells that have no long axon carrying signals away to a distance, e.g. cells of retina in the eye.
Mid-brain:
The region behind the thalamus. It is concerned with programs for visual and auditory search.
Neocortex:
The most recently evolved part of the brain, essential for much of the special human programs such as those for seeing, thinking, speaking and planning.
Nerve-cell-body:
The main portion of a neuron, containing the nucleus.
Nerve-impulse:
The signal that passes without decrement along a nerve fibre, also called an 'action potential.'
Neuroendocrine system:
The integrated actions of nervous and endocrine systems, usually controlling slow processes such as growth.
Neuron:
A nerve-cell; the basic conducting unit of nervous system. It includes a cell-body with nucleus, receptive dendrites and an axon carrying nerve-impulses away.
Occipital lobe:
The lower portion of the cerebral cortex, containing the visual area.
Parietal lobe:
The side of the cerebral cortex. It is concerned with touch and with programs involving several senses, such as language and information about spatial orientation.
Pleasure centers/reward centers:
Nerve-circuits within the hypothalamus and other limbic system sites where pleasurable feelings are believed to originate.
Pons:
The band of tissue bridging the left and right halves of the cerebellum, containing many important groups of nerve-cells.
Prefrontal cortex:
The most anterior part of the cortex; may be related to the ability to plan and to make choices.
Purpose:
The aim or objective of a living system (or artefact).
Raphe:
The region where the two halves of the medulla oblongata are joined. The name literally means 'a seam'.
Reflex (action):
An inherited program for performing a single action in response to an external stimulus.
Reticular formation and RAS:
A dense network of neurons in the brainstem that regulates consciousness and channels the brain's attention. It and its pathways running from the spinal cord to the cortex are known as the 'reticular activating system' (RAS).
Reticular System:
A network of short neurons running up and down near the center of the brain and responsible for the programs of arousal to action and sleep.
Somatosensory cortex:
The part of brain that deals with signals sent from the skin; e.g. for touch.
Spinal Cord:
It constitutes the central nervous system together with brain. It is body's main nerve circuit, carrying out reflex actions and sending nerve impulses to and from the brain through its nerve tracts; it extends from the base of the brain-stem to the second lumbar vertebra and is enclosed by the spinal column.
Standard:
Goal, set-point, reference-point. Hereditary standards are basically defined by the genetic program.
Synapse:
The microscopic gap between two adjacent nerve-cells. The terminal knob (button) by which the end of a presynaptic axon comes into contact with the dendrite of a post-synaptic nerve-cell; the joint effect of many of these knobs activates the post-synaptic cell, usually by releasing a chemical transmitter.
Temporal lobe:
A part of the side of the brain containing the temporal cortex on the outside (largely concerned with hearing) and certain basal lobes within that are concerned with emotion, located near the temples of the skull.
Thalamus:
A twin-lobed part of the brain consisting of cells at the center of the brain, which sends signals from various sensory systems to the cortex. Also has other functions. The name literally means 'a chamber'.
Transmitter (Neurotransmitter):
A chemical substance - one of approximately thirty - at synaptic nerve-endings released either to excite or inhibit the post-synaptic cell. Stored in axon terminals, this chemical substance is released into the synaptic gap when a neuron fires, and locks on to a receiving cells dendrites, e.g. acetylcholine or noradrenaline.
