The tatra pratyaya ekatanata dhyanam sutra speaks about the values of attention, reflection and contemplation. There lies a fine line of distinction between meditation through dharana and dhyana. In dhyana, the focus of attention is directed to one central point only, wherein one thinks about that and nothing else. Dharana tries to eradicate the wavering, uneven flow of energy. An undisturbed flow of consciousness (ekatanata) can be gained both by the means of asana and dhyana.

tatra there (in those places of concentration)
pratyaya base, content, belief, going towards, firm conviction, device
ekatanata continuous, uninterrupted flow of attentive awareness
dhyanam meditation, reflection, profound contemplation

A balanced, continuous flow of attention directed towards the same point or region is meditation (dhyana).

The distinguishable feature of meditation (dhyana) is the sustenance of a continual flow of attention on a fixed point or region, without interference or interruption. In dhyana, psychological and chronological time come to a standstill as the mind observes its own behaviour. The strength of attention in the field of consciousness neither alters nor vacillates, remaining as stable, smooth and constant as oil being poured from a jug. Upholding the same strength of awareness, the attentive awareness moves from one-pointed concentration to no-pointed attentiveness.

The dissimilarity between dharana and dhyana is that dharana is more concerned with the elimination of fluctuating thought-waves in order to achieve single-pointed concentration; in dhyana, the emphasis is on the maintenance of steady and profound contemplative observation.

Ekatanata connotes an unbroken flow of contact between the sadhaka`s consciousness and his sadhana. It can thus be seen that dhyana may be achieved in both asana and pranayama. In asana, there is a centrifugal movement of consciousness to the frontiers of the body, whether stretched vertically, horizontally or circumferentially, and a centripetal movement as the whole body is brought into single focus. If attention is steadily maintained in this manner, meditation takes place. Likewise, in pranayama, the flow of in- or out- breath is considerately measured and sustained, resulting in complete involvement with the self. During retention, when the breath, cells of the torso, consciousness and soul are brought into unison, meditation happens. In short, when attention, reflection and contemplation in action and observation are steadily sustained, dharana evolves into dhyana (1.2).